free hit
BrianK - The Lotus Forums #ForTheOwners Jump to content


Basic Account
  • Posts

  • Joined

  • Last visited

  • Days Won


BrianK last won the day on February 21 2020

BrianK had the most liked content!

About BrianK

  • Birthday September 26

More Info

  • Name
  • Car
    2005 Elise, 1974 Elite
  • Location
    Los Angeles, CA

Recent Profile Visitors

900 profile views

BrianK's Achievements

  1. I took a break from wrenching last week. Sure is lovely to drive. I pushed a little harder through the canyons this time - zero complaints from the car. Handles beautifully. This weekend, I'm towing the Elite up to Northern California to drop it off for a transmission rebuild. Even though the engine rebuild is only 3 years and <1000 miles old, I'm also having the timing belt and water pump done while the engine is out. Any other recommended "while you're in there" maintenance/upgrade work with engine and trans out of the car? The builder suggested new cams, but I don't know if my wallet will support that idea.
  2. I'd be curious to hear what you find. Unfortunately, I didn't measure the distance between holes in the brace, but according to the workshop manual, it should be 400mm (15.75 in).
  3. I got the rear suspension support brace over the weekend. Installation is straight forward - two jam nuts and you're done. Hardly worth an entry here other than to say that, now that I've seen it installed, this seems like an incredibly important part. Observations: The brace didn't fit, initially - it was too short by about 1/4". (Coincidently, 1/4" is about the same distance that the diff was out of alignment the first time I installed the rear suspension). I entertained the idea of enlarging the holes in the brace until it fit, however, with the rear nuts and hardened washers removed, I could see that the conical bushings in the chassis (those that support the bolt through the diff & lower links) were heavily loaded on the outside edge and not touching the inside edge. In other words, the bushings were being pushed towards the sides of the car - away from center - by the through bolts. I guessed that those bolts (or threaded rods, as the case may be) were pointed outward at the back and inward at the front? In any event, I went with the assumption that the brace was right and my non-braced setup was wrong, so I put a ratchet strap between the two bolts/rods and pulled them together the extra 1/4" until the brace could fit. With the brace partially on, I could see that the conical bushings in the chassis were now centered - no longer obviously loaded on one side or the other. It seems, then, that this is a critical part, and that the dimensions of the part are also important - which is to say that fabbing one up to fit the existing setup is probably not as good as getting one properly dimensioned. Thanks to @Neil D. and @Tony D for pointing out the fact that it was missing - I doubt I would have addressed it otherwise. 👍
  4. From the video, when you start the car in the marsh area (at around 7:40), I hear what I *think* is a faulty brake booster check valve. A bad check valve makes a ticking sound that appears to come from behind the binnacle. Personally, I found that sound to be incredibly annoying, so it was a high priority, for me, to find and fix. It's a very inexpensive and quick fix - the old one pulls out and the new one pushes in. A little silicone grease helps matters. check valve: grommet for the check valve (incorrect picture on this page, but the part is correct): Side note: Excellent drone work. I'm always surprised by how many drone videos have jerky turns & poor framing. Yours look great.
  5. After taking care of a few last minute odds and ends last night, I put the car down on the ground for the first time since January, then took it for a quick spin. It's better than ever, thanks to something simple I forgot to mention in my previous few entries: a new brake booster check valve. More on that later. First, because the Elite runs rubber bushings, when tightening suspension hardware, the workshop manual says that you need to preload the suspension so that the bushings aren't stressed while the car is sitting with driver and passenger. I mentioned this in previous post, but to mention it again: the manual states that preloading consists of two 150 lb people in the front seats, 80 lbs in the boot, and 7.5 imp gallons of fuel in the tank (in the previous entry, I quoted different figures - those were wrong) Last time, to achieve some sort of preload, I jacked up one wheel at a time while tightening - an inexact science at best. This time I tried something different - very slightly better, but still winging it. I had a spare transmission (60-70 lbs?) to go in the boot and about 6 US gallons of fuel in the tank, but no 150 lb people readily available. My garage has an inspection pit, however, which came to the rescue. I made a quick "seat" by hooking a tie-down strap to the chassis, then sat in the "seat" - which hung down in the inspection pit - while tightening: Is my 160 lbs on the rear axle + 70lbs in the boot + 6US gallons in the tank the same as 300 lbs in the front seats + 80 lbs in the boot + 7.5 imp gallons in the tank? Probably not, but hopefully not far off. I think we calculated that the CG of the race car was near the middle of the seat, which would mean 300 lbs in the seat would be pretty evenly split between the front and the back suspension... so maybe 150 lbs right on the back suspension is not so far off ideal. I've gotta say, I wish I'd done this sooner - having a seat with your head at wrench height sure did make things easier are more comfortable than squatting in the pit or lying on the ground/pit cover. This might become a "thing" for future under-car projects. 😁 After tightening the suspension, I took the car out for a quick spin. One thing immediately noticeable (and not related to suspension or diff): no more incessant ticking coming from behind the binnacle. That ticking had been a pet peeve, so its absence was heard loudly. Re: ticking: After Lotus Prepared by Claudius had rebuilt my carbs, Jason (Claudius's son and also a mechanic at the shop) went with me on a test drive and mentioned that the ticking sound was from a bad booster check valve. He also said those check valves were NLA and I was SOL unless I wanted to fab up a different solution. As luck would have it, Steve at SJ has already done that, so I ordered a new check valve from him: (new on left, old on right)'s ever so slightly different from the OE part, but it fits perfectly (a little silicone grease helps), and no more ticking noise. Ahhhh. Aside from the lack of ticking, there's a definite improvement in braking. I don't know if this is from the check valve, from the lack of leaking diff oil on the shoes, or the now properly bled rear brakes (which flushed out a lot of dirt/rust from one side); but they felt great. So good, in fact, that I now question the master cylinder and front caliper rebuild I had planned (and, for which, I already have parts). In other news, I found a Lotus specialist in Northern California who's offered to rebuild AND install my Lotus 5 speed for a *very* reasonable price, so I'm working out logistics to get the car up there in the next month or so. I don't think I want to drive the Elite 385 miles - each way - just yet, so I'm hoping to lean on a friend or two to borrow a tow vehicle. Now, it's time for some driving - I've only driven the car a handful of times since getting the carbs rebuilt, so I'm itching to do some miles. I may leave work a bit early today.
  6. Thanks Tony. You're the second person to mention this, but I guess I didn't look hard enough for a solution the first time. After a bit of googling, I think you're speaking about this part? Placing an order as we speak... Thanks for the heads up. Thanks, Pete. This is exactly the info I was after. Even the Conversion Components person (I've now forgotten his name) didn't know how the Toyota box fit in the Elite. While I do believe the Toyota box is the superior transmission, I'm now leaning towards having the Lotus 5-speed rebuilt.
  7. After the fuel line, getting back to working order just meant reassembly. Considering so much had been removed, I had access to areas I wouldn't normally have access to, so I did some rust abatement while everything was torn apart. That meant cleaning and painting the chassis above and around the diff and a few places in the tunnel, painting the actual diff, and painting various bits of the hubs and axles. I was a little careless when I ordered new paint, so some of the paint under the car is glossy, some is matte, and the rest is satin. At least it's consistent per component. 🤷‍♂️ For some reason, I neglected to replace the trailing arm bushings when I replaced all other suspension bushings, so I went ahead and took care of those as well. New and old trailing arm bushings: painted driveshaft: painted diff: Cleaned up hub / half shaft assemblies: All of the major threads in the rear suspension are 1/2-20 (fine thread), so I got myself a rethreading die. Not only were some of the threads caked in grime (pictured), the quite large lower-link-to-hub-carrier-to-trailing-arm partially threaded rod gets hammered pretty good going through each of those components when they aren't perfectly inline. I was happy to have it: After a few hours of slogging, it was all back together: So what do we have here? New (to me) hub carriers New castle nuts New wheel bearings New half-shaft UJs Rebuilt diff (well... "refreshed" maybe. New bearings and seals, but original gears) New propshaft UJs New fuel line New trailing arm bushings New hardware where possible (nuts and bolts) I learned a few things removing and reassembling the diff for the first time and the rear suspension a second time: The hardest part of disassembly is removing the 3 long bolts/rods on either side (two at the hub carrier and one at the diff/lower link). One of the 3 is going to be an absolute pain, then the other two will be slightly easier because they can now be moved around to be under less stress. I'm not sure which is best to do first, but I've been removing the lower link on the hub side first. Hefty use of a pry bar and dead-blow hammer is required. The diff isn't that difficult to remove when you know what you're doing: remove half shafts and drums. This is easiest with a 9/16" socket on a long wobble extension. disconnect propshaft. (two 1/2" wrenches) support diff with jack remove rear fasteners (shared with lower link) and slightly loosen front fasteners. Be sure the lower links have already been removed from the hub side if possible. lower diff slightly for access disconnect parking brake by removing the pin on the drum side of the parking brake rod(s). Slide rods off brake lever remove front diff fasteners lower diff a few inches - mind the brake hard-lines that go to the bleed valves (visible in the picture of the diff above). You'll probably need to shimmy the hard line on one side past the frame rail, then tilt the whole thing to lower that side an inch, then lower the whole thing, then shimmy the other side past the frame rail & level back out. Now, with more access to brake lines, undo brake lines on both sides. IIRC, you'll need both 14 and 15mm wrenches for this. cap brake hard lines Once the diff is out, the driveshaft just slides out. Don't forget to grease the end before re-inserting. Order of operations for rear suspension reassembly is important! The first time I reassembled the rear suspension (last year), I installed one side of the suspension before the other. Because one side was attached and under stress, I had to use a bottle jack to spread the frame rails apart far enough to line up the diff with their rear attachment point for the other side. This time, I installed the two lower links on the diff before any other suspension components. This is the way to go. No bottle jack required - everything can be aligned by hand. To be clear, that means insert the long rod from the back, through chassis/bushings, then through lower link, then through the diff. Don't forget the hardened washers on either side of the lower link, lest you'll have to start over (I had to start over ). That's step 1. The trailing arms have very tight tolerances at their front mounting points, so you'll want to install those with zero tension, so they go on second. Next, I did the trailing arm to hub carrier, but not the lower link yet. Instead, I sent the rod through just beyond the trailing arm. You won't be able to fit the lower link if the rod is all the way through. Next, the bolt that holds the shock. Take care to use the correct number of washers/spacers here, especially if using aftermarket shocks. I needed an extra hardened washer that didn't' come with the shocks. Finally, attach the lower link to the hub side. I found it a little easier to jack up the suspension at this point - doing so put the components slightly more in line with each other. Even at that, getting the rod through is a challenge. Again, a thread-chaser was nice to have for this. After everything was back together, I bled the brakes with the help of a friend. A good bit of muck came out of one of the bleeders. Between that and the fact that one of the drums is no longer soaking in oil, I'm hopeful that brake performance will be improved. So it's all back together now, after 6 months off the road. I still need to add fluids and go through the proper suspension torqueing procedure, but that's just an afternoon's work. Of course now that the car's back on the road, we enter the hot months of the year here in LA. Tomorrow, it's supposed to be 97 degrees (that's 36 degrees in "science units" ). Perfect timing. 😛 Next project: transmission. Interestingly, I sent an email to Conversion Components back in 2019 asking about their conversion kit for the Toyota Supra (W58) gearbox to the Lotus 907. Rather than respond to my email in 2019, they decided to call me... yesterday. "Hi, I'm calling you about your email" ... from 2019. bizarre. I also have a friend about 5 hours drive away who builds roll cages for race cars and is a big British car fan. He's offered to take a swing at rebuilding one of my 2 spare Lotus transmissions. Decisions, Decisions. One thing I'm sure of: I only want to do the transmission once. hmmmmmm...... Any thoughts on which route to go - Toyota W58 conversion or Lotus 5-speed rebuild? Before you recommend Getrag, the one for the job just isn't available in the 'States. IIRC, the specific model was only on the e30 M3 here; and between their value and the use of those transmissions in E-type jag conversions, e30 M3 transmissions just don't exist.
  8. This year, the Elite has suffered greatly from while-you're-in-there-itus. What started as a single rear wheel bearing and hub carrier replacement has turned into bearings on both sides, hub carriers on both sides, rebuilt half-shafts, replaced trailing arm bushings and various suspension hardware, rebuilt diff, rebuilt propshaft, and replaced fuel line with more modern (read: thicker) hose. While it's still a work in progress, I just finished the fuel line; and, holy cow, that was a job. It would have been dead simple had the transmission and exhaust been removed, but with both in place, access to important bits was incredibly limited. Add to that the fact that I can't get the car very high off the ground and you've got a recipe for frustratingly difficult jobs that would otherwise be simple. The job took close to 3 days, so today's entry will be exclusively about that 17-18' of rubber hose routed through the chassis. Quick backstory: My previous entry mentioned how a home renovation was getting in the way of car work, and that I had a car show coming up at the end of last month. That car show was delayed until August (due to COVID), and I had a bit of a medical issue that sidelined me for 3 weeks, so neither the house nor the car is done, but at least I didn't miss the show. Back to fuel line... The original (OE) line was clear (well, brown now) polyurethane (I think?). 46+ year old plastic that is now soaking in some non-zero amount of ethanol. Considering I had the diff out of the car, and the propshaft simply slides out, I was never going to be closer to the fuel line through the backbone, so I thought now was the time. I ordered 20' of new Earl's Performance 5/16" ID fuel line (I believe the OE line is metric, but 5/16" was very much close enough), a new filter, and fuel-line hose clamps. The lot was surprisingly expensive - well over $100. I probably paid more for the name than those hose, but, oh well, such is life. The previous owner replaced the fuel pump, which is only a few years old, so no need to replace it. Original fuel line and filter (both of which may have been fitted at the factory): The OE fuel line has an OD of around 3/8", but the new line has an OD of 9/16". This poses a problem as the line is routed through the backbone - going through two bulkheads (for lack of a better term), two reinforcement plates, the rear suspension upper crossmember, and the body under the fuel lank. All of those holes needed to be widened and grommeted. The line also passes through three loop-clamps and two spring clamps - all of which were too small for the new hose. Finally, the OE line is connected to the tank via compression fitting (like what you'd find in a water line that goes to your fridge), the sleeve for which was too small for the new line. OE compression fitting under the tank: Having cataloged what I was up against, I started by removing and draining the tank. As has been the case through most of this resto, I am very lucky with the condition of the equipment. No rust to speak of, and everything came out easily. The tank is held in by two 17mm bolts in the trunk area, the nuts for which live just above the suspension towers - accessible through the wheel well. If you've got long arms, it's a one-person job to get a wrench on one side and a socket on the other. After disconnecting the tank from its mount, getting the filler pipes off posed a bit of a challenge. Man-handling them got the job done. I don't think there's a subtle way of doing it... just lots of pulling a swearing. With the filler caps off, I siphoned most of the fuel out of the tank through one of the filler openings. Lucky for the me, the tank had about 6 gallons of fuel, because I only had a 5 gallon container. With a gallon or so of fuel left in the tank, I was able to turn it on its back to access the underside without spilling anything. Top tip: cover the filler openings, lest you suffocate on fumes. With access to the underside of the tank, I came to the first obstacle - the compression fitting. As with many things, I made this more complicated than it needed to be. What I didn't realize is that the compression sleeve is a male-end thread that threads into the banjo assembly. To change it to a barbed fitting (that would accept the new fuel line) simply involved screwing a barbed fitting into the banjo assembly. Easy-peasy. To make matters better, we had a spare barb sitting idle in one of the parts cars for the race car, so I brought it home, and after a little cleanup, had a suitable fuel pickup: After a smattering of Permatex Aviation Form-a-Gasket, it was ready to go. Next up was enlarging and adding new grommets to the chassis pass-throughs. I initially ordered a grommet kit from Amazon - 125 grommets of various sizes for about $10. Of course, when I got them, none of them were the correct size, and, after seeing them, I wondered about their ability to survive in a hot, oily environment. I then went to our trusty McMaster Carr where I found every type and size of grommet known to man. I ordered grommets in three thicknesses - one set for the front/rear tunnel bulkheads which are around 1/8" thick, one set for the upper rear crossmember which is about 1/16" thick, and one set for the body which is about 1/4" thick. I got 5 of each, and each set of 5 was around $10. Go figure. Enlarging the holes caused much pain. I figured a stepped drill bit was the right tool, but how do you get it between the chassis and transmission? Well... there exists "quick-change" drill bits that have a hexagonal shank... nuts are also hexagonal. That means that you can put a quick-change drill bit in a socket at the end of a socket extension; so with a socket adaptor for a drill, you've got a bit that can sit any distance away from the drill. It's sloppy, but it works. In the end, going long wasn't as good as making a 90 degree turn, but there's a solution for that as well. It looks like this: Those front and rear tunnel bulkheads are fiarly thick, so it took quite a while to get through them with this setup, but after some patience, we had a newer, larger pass-through for the new line (the new hole is below center-right): Same setup was used for the rear bulkhead (above center-left): ... and again for the remaining two holes. With that, I was ready to send fuel line through. I decided to start at the front and work my way back, as going through the tunnel would be the most difficult part, so I wanted to start with that. The line starts at a loop through the block right next to the bell housing, then along the chassis rail, through a loop clamp, and then the front bulkhead. I lubed the hose with silicone lubricant (didn't want to use oil on rubber, though I suppose fuel line should be able to handle it) and sent it through. When everything's slippery, there's not much too it. Ignoring the spring clips for now, I went to pass through the two reinforcement plates near the back of the tunnel. The OE line was clipped between the two plates and simply passed through the half-circles cut in those plates at the top of the tunnel. The new line, however, was large enough that it was in constant contact with those plates, which are about 1/16" thick - thin enough to cause concern for cutting. The recesses cut in the plates were not the right shape or size to accommodate a grommet, and there was no way of getting a drill to the front of the two plates to enlarge the hole for a grommet. I thought that the biggest issue with running the line through those recesses was the possibility of the plates cutting their way through the rubber, so eliminating that possibility was top priority. After a bit of head-scratching I came up with what I hope is a reasonable solution: I made two 1/16" plates look like one 3" tunnel with no sharp edges by cutting a piece of metal to shape, then flaring the ends to hold it in place: Only one end is flared in the above pic, but the other would be flared in-situ. Because there's a large surface area between the chassis and hose, I believe that vibration wear will be minimal, and there's no longer a cutting edge against the line so.... job done. (installed picture below). If this trips anyone's safety alarm, feel free to speak up. Running the rest of the line was a non-issue. Through the crossmember, through the body, and the line is now run.... but wait, there's more! The OE line was also held in place by 2 spring clips and 3 loop clamps. One of the spring clips was made unnecessary by the half-tunnel above, and the loop clamps were simply replaced by larger rubberized versions I also found at McMaster. The spring clamp in the center of the tunnel, however... that one was a challenge. Firstly, that clamp is darn near inaccessible. I am not a small person - 6' 5" - with long arms. I could *just* reach it with my finger tips by reaching down the tunnel from the rear - though not well enough to do much while in there. There is, however, a 3"x6" access hole at the front of the tunnel on the underside - just above the exhaust pipe. With an exhaust hanger removed, while pulling the exhaust to one side, I can *just* get my arm up there (with a scraped and scabbed-over arm to prove it), but again, not so much that I could do much with the clamp. I tried various ways of getting the new line in the clamp, but was unsuccessful. On my last "all or nothing" try, I broke the clamp. If there were small children around, I should apologize, as the streak of foul language that came audibly pouring from my mouth was ... well... impressive. I sat under the car staring through that little access hole for some time before coming up with a solution: the left-over clip-on nuts that I got for the front bumper project would clip onto the parking brake relief in the chassis, assuming I could drill a hole in the chassis for a bolt to pass through. Enter drill bit extension #2! ... and after a bit of fiddling, a new clamp was in place, albeit 4-5" further forward than the old one: (this will eventually get some paint to cover the bare metal scratches) With that, the new hose is run. What an absolute pain that could be incredibly easy under better conditions. It should be noted that I haven't tested this yet. It's possible it may all have to come out again. Time will tell. ... and now it's time for some housework. We also have our first endurance race at the end of the month (also in an Elite), so I suspect it will be mid to late June before this Elite is back on the road.
  9. All sorted. It was silly simple - I just didn't understand how it came together until I took it apart. What I didn't realize is that the compression fit collar is an NPT fitting that can be replaced by anything else that has an NPT thread - so it was just a matter of getting an NPT barb. One of the parts cars at our "race shop" already had the barb in its very-corroded tank. A couple new copper washers, a bit of a clean-up, & job done. (To be honest, I'm not sure if it's actually NPT - I got the barb out of the same spot on the parts car, so I knew it was the correct thread) old compression fitting on old hose: Banjo assembly with new barb Assembled & sealed, ready for new hose:
  10. I'm starting down the road of replacing the original fuel line with more modern lines. The modern lines have thicker walls (which require enlarging the pass-through holes in the chassis, I'm aware), but I'm wondering how to attach the new line to the fuel tank pickup? It appears that the original line has a compression fitting - where the line passes through a threaded collar, that, when tightened, compresses the line around a "barb". My new fuel hose has an OD that is too large to fit through that collar. How have others solved this? Ignore the collar and replace it with a clamp over the original barb? Use a small bit of old line, then a coupler with clamps on either side to connect the new line? Different banjo assembly for the tank? Some sort of adapter that replaces the threaded collar? While I'm asking questions - I notice a bit of fuel weeping around the bajo bolt - not enough to cause a drip, but it's damp & I'm sure causing some fuel smell. Any words of wisdom on sealing that? I'm thinking Teflon tape on a fuel line isn't the smartest idea. For the record, for all of the above I'm speaking about #32 in this image (under the tank):
  11. Freshly refreshed, non-leaking diff. Considering I was only a few bolts away from having the diff out after removing the half shafts and hub carriers, it was a no-brainer to fix the leaky diff now rather than wait until later. As is probably clear from my previous posts, I'm not a mechanic... I'm a software developer with a need to use my hands on occasion. As such, I'm well aware that there are some items on my to-do list that are beyond my ability. Believing the diff to be one of those things, I elected to farm the work out to a local specialist. Again, I went to Lotus PBC, who were more than happy to accept the parts already removed from the car, and price their work accordingly. After some discussion, we went with a partial rebuild - that meant replacing all seals (input and output) and the output bearings (which need to come out to replace the inner retaining collar's o-ring), but not touch the gears or input shaft bearings. Speaking of bearings, the rear wheel bearings are what started this whole mess, so they, of course, needed addressing. Being that I don't have a large enough press to remove the bearings, I brought both hub assemblies and a new set of wheel bearings with me when I dropped off the diff & asked if Lotus PBC would do them. They agreed and did the service for free while they were refreshing the diff. Another, "while you're in there" item was the half-shaft UJs... which we decided to replace, though the UJs were far from free. Removing everything from the car, sourcing replacements, and rebuilding has taken a good chunk of time. I just picked everything up yesterday. Unfortunately for the Elite, I've started another home renovation, so the Elite is on the back-burner again. I've been really pushing through the reno so I can get back to the car -- I'm hoping to be done with the house after a couple more weeks of nights and weekends. I've registered the Elite to be in an all-British car show at the end of April, so... the clock's ticking.
  12. Steve found the spares. New bearings are on the way. All is well in the world. During this process, I removed the brake drums to find that one side of the diff is leaking so bad that it’s made that brake useless. It might be a little hard to see in the pic, but those shoes are soaked in oil. I think I’ll pull the diff and have it rebuilt - or at least re-sealed - while I’m back here (rebuilding the diff on my own is above my pay grade)
  13. Hub carriers for different bearings would be amazing! I’ve fallen in love with the cartridge type - where the bearing comes in a housing, so the whole housing gets replaced instead of just the bearing... 4 bolts and you’re done. I figure, while I’m tossing coins into the wishing well that I’d make that suggestion. I believe the hub is an early type simply because it’s a ‘74 elite. I read, on SJ, that the earlier models have a different “dirt flinger” but I don’t know what that is to determine which mine is.
  14. Welp... When I pulled the hub off, I found that the circlip that retains the bearing was just floating between the carrier and hub. I’m not sure if the bearing failed and caused the circlip to weaken and pop out; or if the circlip wasn’t seated properly, which then caused the bearing to fail. Regardless, the bearing pushed through the hub carrier until the half shaft was grinding on the hub carrier - seems that was the only thing that prevented it from pushing all the way through. I suppose because of the difference in materials, I heard no noise and noticed no grinding as the half shaft removed material from the carrier. In fact, I thought I just had a sticky brake until I got out of the car to notice smoke (from burnt bearing grease) coming from the rear wheel. My hope, now, is that we kept the rear hub carriers from the race car when we swapped in its jag XJS unit (for those not following along, I race an Elite with a V8 that now runs a complete Jag XJS IRS). My teammate is rummaging through our spares today looking for it (Thanks Steve!). If not, those eBay links above will come in handy. Also worthy of note: those bearings are pricey!
  15. Prepare for another entry in which I drone on at length about a subject with which I recently became familiar - carburetors, specifically Dellorto DHLA carburetors. The TL;DR (too long; didn't read) version is: After researching Dellorto carburetor calibrations until my eyes dried up, in trying to properly tune my completely-out-of-tune DHLA45's, I second guessed my findings and abilities to the point that I took the car to a specialist who, without my intervening, charged well over $1000 to do *exactly* what I had planned to do, had I done the work myself (though, let's be honest... they probably did a better job). Such is life. Here's the story: Prior to the big drive in my last post, I'd only driven around the block (several times). It never really ran right, but I hadn't yet touched the carbs, so I figured they needed some attention and just accepted the sputters and pops until it was time to address them. Poor running was never really an issue then, but when I started to navigate traffic, the lack of low-end stability was becoming a problem. Some background: "Federal" cars (those destined for the US, Canada, and Japan, if I'm not mistaken) ran Stromberg carburetors. My understanding is that engines running Strombergs had lower emissions than those running Dellortos (lower emissions being required to pass then-new pollution laws in the US). It is also my understanding that the Stromberg equipped cars ran 10-20hp less than the Dellorto equipped cars. At some point in my car's history, the previous owner opted to install Dellorto carburetors (and a Lumenition ignition - which will play into this post later). Back to my car: Prior to re-jetting, my car had a real problem getting off the line - especially under higher loads (like pulling away from a stop on a hill) where it would sputter and nearly die until I dipped the clutch and got the revs back up. It sounded like there was an occasional misfire at low rpm (idle and just off idle) and the exhaust didn't smell right - it didn't smell like unburnt fuel or burnt oil, so much as it just smelled a little "hot," for lack of a better term (I assumed it was overly lean). However, above about 3000 rpm, it ran great, pulled hard, sounded great, and never missed a beat. With that, it was time to start digging into the carbs. I have limited experience with carburetors... not zero, but my experience is very narrow. By "narrow", I mean that I've done a good bit of work with Holley carburetors on small block Chevy V8s, but that's the extent of it. With a couple ounces of Holley confidence, I started getting into the Dellortos - initially by picking up a copy of Des Hammill's "How to Build and Power Tune Weber & Dellorto ... Carburetors" and a 4-pot manometer. The book is interesting, but not exactly what I was after. It's a book you really need to take as a whole - reading one chapter by itself won't solve any problems or make anything run better, but having the whole thing sat in your brain serves as good reference when you're trying to decide on a path to take. By itself, the book wasn't enough, so I did a *ton* of research online. Lots of good info from this and the Jensen Healey forums; and I kept coming across Tim Engel's fantastic posts. One thing I learned from Tim's writings was to pay attention to the Lotus carb "spec" (specification), or, more importantly, the Dellorto "calibration." Ahhh, carb specs... what a deep hole that turned out to be. For the uninitiated, Dellorto worked with many OEMs as a carburetor supplier. Every Dellorto carb has an ID tag, and that ID tag can be used to determine for which car the carburetor was made. Not only does the ID tag tell you the car, but it tells you the exact calibration: chokes, jets, holders, emulsion tubes, etc that are in use. The exact calibration is necessary for our cars, as Lotus changed the spec several times during the course of a model run, and sometimes changed the calibration within a specification (for example, there are 2 different calibrations for "spec 9" and 3 different calibrations for "spec 10", depending on the model of car - Esprit, Elite, Excel, etc). Now, I'm no expert on this topic, so take it with a grain of salt, but from what I gathered, for the 907, Lotus used 3 different specifications called spec 1, 3, and 5. For the 2.2, they used "spec 9", then for the 2.2 HC, they used "spec 10". I'm sure there are more specs beyond that, but that's as far as my research went. According to Tim (and others), Spec 5 is the sweet spot for the 907 - spec 1 was too rich and spec 3 too lean. With that, I had a reasonable target, but what I didn't know was the starting point - What calibration did I have? The Elite/Eclat workshop manual has a carb spec table (page 13 in the technical data section at the front), but it only goes to spec 9, and it doesn't associate a spec with a tag number, so no way to see which spec I had. Lots and lots of searching for my ID tags was coming up empty - I even found a pdf of all Dellorto calibrations, but my tag numbers were nowhere to be found. I was pretty convinced I had an off-the-shelf carb, or one calibrated for a different OEM. Several days into my search, I decided to look at an Esprit S3/Turbo workshop manual (one I stumbled across online). In that manual, the carb table not only had all the tag numbers, but it had Spec 10 carbs as well. Looking closely at that table ::insert angels singing:: I finally found my id tags! For the uber curious, I made a Google Sheets version of the various Lotus calibrations from that Esprit workshop manual. Maybe someone will find it useful: The big discovery: my carbs originally came on an Excel with the 2.2, high compression engine - Spec 10. My Lumenition ignition is also from an Excel. If I'm not mistaken (again, I'm no expert here - just someone with moderately capable Google Fu), we never got the 2.2 HC engine in the US, and we certainly never got the Excel. It appears, then, that the previous owner, in attempt to get more power, imported parts from the UK some time prior to 2003 (when the car was last registered). Kudos to them - that couldn't have been cheap or easy. Now that I know the start and end, it should just be a matter of sourcing parts and swapping everything out to convert my spec 10s to spec 5. At least, that was the plan, but there was one major difference between the Spec 10 and everything prior: Spec 10 is a DHLA 45D - which comes with a power jet (as opposed to the DHLA 45E which, at least according to the table, does not have a tunable power jet) As with many problems I've tried to solve with this car, the power jet turned out to be a nothing-burger when it came to my tune. I could have, and should have, just ignored it. After all, the power jet (if I understand correctly) only comes into play at wide open throttle above 3K rpm when there's very little vacuum... an area where I never had a problem. However, because I am one to overthink things, I convinced myself, falsely, that the power jet was making up for the leaner main jets of the spec 10 vs spec 5, and that by going with spec 5 mains, I'd be entirely too rich in the top end. I made myself crazy trying to work out how to determine the correct size of the power jets in relation to the main jets. I figured the only route to solution was experimentation - which would have been easy enough if I had a library of chokes, jets, holders, tubes, etc. to play with, but I didn't. This meant that every iteration would require a new set of parts. Not only is that expensive, but I found it difficult to source Lotus-specific jet sizes in the US... which meant shipping from the UK for each iteration of tune. With 6 or 7 tunable parts per throttle bore and a few others per carburetor, that becomes an expensive and time consuming process. So after all that research and planning, on the day I intended to go buy an ultrasonic cleaner to help with a full rebuild, I decided, instead, to call a local classic Lotus specialist to see if they had a tuning "library" and time to have a look at my car. The answer to both questions was yes, so I bit the bullet and handed the keys over to a pro to do the work. (For the curious, the shop was "Lotus Prepared by Claudius" - which seems to have a "love it or hate it" relationship with the Lotus community, but, in the end, they did great work and were very open to sharing their methods and capabilities of their shop) It cost me dearly to do so, but the outcome was absolutely perfect. It has the same or better power in the top end, but, most importantly, is silky smooth at lower rpms. I can drive the Elite like any other street car - which makes driving so much more enjoyable, especially relative to the sputtery limping off the line prior to the tune. So what was the magic recipe? Spec 5. Ignore the power jet & just go with spec 5 - just as I had planned. Of course, along with spec 5 parts, the carbs got a full rebuild - which, I'm sure, played a roll in improving overall performance, too. So now having the ability to drive reasonable distances, I've taken the car on a few shakedown runs in the canyons. The most recent was one of the better drives I've had - about 50 miles of mostly beautiful, twisty roads, only encountering one other car on the road (I even managed to get a quick video I'll share in the future). That trip, however, was not without its troubles - only a mile or so from home (on the way back), something I mentioned in a previous post as "I might kick myself for that later" has failed and caused big problems. The Elite is now sidelined for, I'm guessing, another month while I determine what's wrong and source new parts (I suspect a catastrophic rear wheel bearing and hub carrier failure). This was just last weekend, so I'll save the entry until after I can do a proper post-mortem (still waiting on tools for that). That may be a bitter-sweet ending to this entry, but it's all part of the process. No one said it was going to be easy. The bright part is this: it now runs, runs very well, and is an absolute joy to drive!
  • Create New...