502M

[Trunnion 74 158]

16 hours ago, silverfrost said:

Shame about not painting chassis but the factory finish looks nice also. 

Hi Dan, thought this might be a little controversial.  My thinking is this. 

When I got the car the chassis was covered in a wax coating.  Because of this I was able to locate/see several numbers written/scratched onto it.  Considering the amount of history I have so far been able to gather and that the car is, at the moment, the earliest survivor,  I want to preserve what I can.  Any other car and I would have probably painted it.  Once the chassis is fully rebuilt it will be sprayed with Bilt Hamber Dynax UC underbody wax,  which will protect the chassis and more importantly, in my view,  what's on it.  I suppose there is always the option, once the body is back on the chassis,  of applying a coat of stone chip to the underside to smarten things up if needed as this will not affect the location of the numbers.  But that decision is a while off yet.

 

[soldave 272]

Those spring compressor looks amazing! Is there enough space for that to work with the body on as well? If so I might have to rent that from you at some point this year

[Trunnion 74 158]

21 hours ago, soldave said:

Those spring compressor looks amazing! Is there enough space for that to work with the body on as well? If so I might have to rent that from you at some point this year

They sure can my friend!  These things are ambidextrous.  Reduce the rod height at the top and lock off, then wind up from the bottom.

Simples! 

 

[Trunnion 74 158]

More Engine news

Crank has been returned all nicely polished; no sign of those wear marks.  That stuff you can see on the bearings is an anticorrosive treatment that will get washed off in the parts washer.

Cylinder head all done.  Not much to see and it will have to be taken apart when it is fitted to the crank case.  It was returned with some interesting extras though…

This lot apparently came out of the head when it was cleaned!  The dreaded silicon again!

Took some close ups of the ports.

And even then found evidence of more sealant.  Only showed up when used the flash.

Crank case in parts washer being cleaned, again!

All cleaned ready for some new parts.  Well, almost clean still got some recesses to sort out.

Engine assembly lubricant “Jam” applied to the new bearing shells in the crankcase and the sandwich plate.

Crank in position.  Note the nice red line of the assembly lubricant, shows it is sitting correctly.

Another number on the underneath of the crankcase BD 255, not sure what it means yet.

Sandwich plate fitted along with the newly cleaned/refurbished oil pickup, all torqued up.  Took this picture then realised we hadn’t fitted the oil spray shield, doh!  Had to take it apart again, which did give an opportunity to demonstrate the use of sealant?  If you look at where the join is and along  towards the rear you can just see a small amount of squeeze out, it’s minimal.

This is achieved by using a thin smear of sealant applied and the piece placed on the crankcase

This is the pattern you get after you torque everything down.  Minimal squeeze out and no chance of sealant blocking any of the oil or water galleries or the pickup pipe

 

Water Pump.

I sent the water pump off to Lotusbits to be refurbished.  When I contacted them to check on progress I got a bit of a surprise.  Turns out my pump (on the right) is the wrong one.  Not only that but it has been modified!

The correct pump for my 502 is the one on the left.

This is how the pump should look

This is how mine looks.  Apparently it’s off a 501. And, as you can see it has had a piece of aluminium added to the back.  Having spoken to Mark he thinks the most likely explanation could be that someone has ordered, been sent the wrong pump and instead of getting the correct one has decided to modify it so it works with a car that has air con.

[Trunnion 74 158]

Even the measurements are slightly out. Not to worry though as Lotusbits are going to supply the correct housing and refurbish it all for me.  At their request I sent a photo of my pump with all its bits attached and they confirmed all the other bits were correct for the car I have.

Well that's it for the moment.  Engine work has hit the buffers    as the piston rings I ordered mysteriously don't fit the pistons.  The issue is to do with the oil ring.  More on that later.

Roland

[mikeeech 349]

Now it's amazing what you can find floating around in your head! It's satisfying to know when you are making things better particularly previous owners bodges.

[Trunnion 74 158]

Sometimes it’s the little things that give the most satisfaction.

  The Pressure Differential Warning Actuator (PDWA) is secured to the inboard side of the front O/S strut tower by a nut and bolt.   Whilst I was fitting the spring I realised that, on my car at least, there was no way I would be able to unbolt with the spring in place, no access.  So it had to come off to be refurbished sooner than I expected.  This is what it looks like inside.

  It’s a simple device, when you lose pressure on one circuit the higher pressure on the other moves the piston and activates the switch and a light on the dashboard tells you of a problem.  Why so satisfying to refurbish it?  Well to buy a new complete unit the cheapest I could find was an eye watering £190!!! For a piece of metal with holes in it!  New switch cost £40.  To make life easier to remove in the future I will be fitting a Rivenut for it to bolt into.

 

    

 

[Trunnion 74 158]

Hi Guys n Gals, been a little while since my last update but I haven't been idle....

Rear brakes done and final drive all sorted

 

Rear springs going on                                                                                                                   Trailing arms and rear hubs

 

Rear wheels.

 

Finally, it's back on all four again!!  NB. None of the wheels have been refurbished yet

 

Some more engine work.  Had to take off the cams in order to fit the head to the block

.

Clutch, oil pump and water pump on                                                                                 Engine statically timed and new stainless inlet and exhaust manifold studs in

[Trunnion 74 158]

Remember these grotty cam covers?                                                           

 

I sent them to CTC powder coating, done in the correct colour. Cost £135 but money well spent as it makes a big difference.

                                                                                                                              

                                                                                                                                                                             

Decided to refurb the starter moter myself.                          Stripped down to its various parts ready for refurbishment.  Learning as I go, never done one before.

 

 

All internals refurbished and exterior cleaned                                                                 Allmost there! And it turned out it’s not as difficult as I was expecting.                                                

 

Well that's it for this update.  I am currently in the process of refurbishing the carburettors and putting together a "how to" as I go so will post that as soon as complete. Not sure if it will be here or in the engine section.

Roland

 

[Trunnion 74 158]

Chassis back off to the workshop

[Trunnion 74 158]

This is a strip down of the Dellorto DHLA 45 carburettors off my 1974 Elite.  I have never  tackled any carbs like this before so for reference I purchased the excellent book “How To Build & Power Tune Weber & Dellorto DCOE DCO/SP & DHLA Carburettors 3^rd edition”  Full of useful info including “read the book through several times before you start a rebuild.”

Rebuild parts are readily available and can be ordered from Eurocarbs.                                                                        

https://www.dellorto.co.uk/product-category/dellorto-car-carburettors-parts/parts/

And if you want a description of how this carb actually operates then have a read of this, sixth post down  

http://www.lotuselan.net/forums/viewtopic.php?f=40&t=39727&start=

The photos were taken during the actual strip down so I had no idea what I was going to find.  All the screws were tight so I used some plus gas to help them along.  I also started with the cleanest looking carb.

In the picture below, the turret top centre, houses the choke piston assembly.  The spring is supposed to return the cam when that choke is released, on this one it only went half way.  The whole top assembly can be purchased new and when I checked a photo on Eurocarb’s website I noticed that where the spring anchors is too high.  Once re-anchored to the underneath the lower arm full function was restored.

The first part off was the very top jet cover which exposes the emulsion tubes and the idle jet covers

 

Next off was the main cover. Be careful when removing this as the floats are attached to it.  First signs that it may not be as clean as I thought.

 

Top cover with the floats and needle valve removed.  When removing the pin that holds the floats you need to be very careful.  Looking at both the legs you will see one has a split in it, this is the side that applies the clamping force to the pin.  Use a suitably sized drift and tap out the pin from the none split side. If you try to tap it out from the split side you are likely to break the leg.

 

Now you can see all the various tubes and holders that will need to be removed in a controlled and methodical manner.  Make sure you have plenty of clean zip lock bags handy, you don’t want to lose anything.  And don’t go poking anything metal down the holes to clear them, carb cleaner is your friend.  If you do have to put something down them to clear then use some suitably sized fishing line.

 

First two out are the idle jet holders with long idle jets.  Long ones were used in early carbs, later ones had much shorter ones both types are still available.  We will have a closer look at all the jets and tubes when it’s put back together.

Next out are the emulsion tubes.

Followed by the cold start jet. The small tower in the centre is the choke diffuser

Next out are the two that sit either side of the cold start jet. These are the pump jet spacer rod and check ball.  These are just two caps, once unscrewed they reveal brass rods underneath which are two small ball bearings.  To get these out you will need to turn the carb upside down, they should just fall out.  Make sure you don’t lose any bits.  You can get replacements if you do.

This is how they go together when they are in place.

Now move onto the barrels.  Next two out are the pump jet screw, covers. (Apologies for the focus)

Next out are the progression hole covers.  Once you take the covers off you should see some very small holes, I have five each side. The number of holes varies from carb to carb so don’t be surprised if you have more or less.

The progression holes deal with the transition between idle (butterfly’s closed) and throttle open (butterfly’s open).  They must be clear and dirt free to operate correctly.

The way they work is quite simple. The holes are drilled directly into the barrels just downstream from the butterfly’s.  Fuel from the emulsion tube is sucked by the venturi effect to the progression holes by an internally drilled tract (you can see the line it takes). With the engine at idle the butterfly’s sit just in front of the holes.  As the throttle is opened the butterfly’s progressively sweep past the holes increasing the venturi effect and sucking more fuel into the barrels.  This only happens until the main fuel circuit kicks in.  So their job is to smooth the transition between the idle circuit and the main circuit.  So if your carbs are struggling going from idle to throttle then check the holes, they may be in need of cleaning.  Carb cleaner and air is all you need

These next two show the progression holes viewed from inside the barrel. They show you how the butterfly’s sweep past the holes.

     

 

 

 

 

[Trunnion 74 158]

The next two out sit just inboard of the progression hole caps and are the pressure tap screws

Next out are the bypass screws

And finally the last two are the idle mixture adjustment screws.  That’s it, all the tubes and holders removed from the top of the carb.

 

Now for the accelerator pump housing underneath.

First to come off is the diaphragm housing.  Interesting, should be a spring in here.  Maybe it’s on top of the diaphragm?

Not there either???

Next off it’s the pump body casting. Top middle is the pump no return valve which just unscrew

More of this stuff again.  Don’t know what it is, but it’s all through the carb.  It looks like damp sawdust but is slightly gritty.  Can only assume it’s crud that built up over the years.

I am not taking out the throttle spindle or the butterfly’s as there are no sign of any bearing wear so will leave them alone.

That’s it all stripped. Conclusions?  There are some O rings missing as well as a spring.  The idle adjustment screws are missing O rings and a washer and it needs a very good clean.  So much for picking the cleanest looking one.  There is no way that the carb, in this state would have run.

Time to get busy with the carb cleaner!  

[Drawfiler 13]

Well done so far, I then cleaned the body up with carb cleaner and then put body into an ultrasonic tank followed by the jets and screws. I bough the the kit from Eurocarb but made the mistake by not getting the float needles with polymer rings on them as an extra, these are so much better and stop the dreaded flooding, remarkably they are not in the standard kit.

[mikeeech 349]

Great how to. I'm following the carb rebuild with interest since I have not done mine yet

[Trunnion 74 158]

22 hours ago, Drawfiler said:

Well done so far, I then cleaned the body up with carb cleaner and then put body into an ultrasonic tank followed by the jets and screws. I bough the the kit from Eurocarb but made the mistake by not getting the float needles with polymer rings on them as an extra, these are so much better and stop the dreaded flooding, remarkably they are not in the standard kit.

I have my ultrasonic bath on standby.  By polymer rings I presume you are talking about Viton tipped needle valves?  Must be down to the type of kit as mine shows they come as part of it.

 

 

1 hour ago, mikeeech said:

Great how to. I'm following the carb rebuild with interest since I have not done mine yet

Better make sure I do it right then

[Drawfiler 13]

That's interesting, my kit had plain brass needles.

[Trunnion 74 158]

First closer look at some of the jets/holders/covers and screws.

These are the pump jet rod/ball caps, in good nick, just need a clean                               These are the pressure tap screws, only need a clean up

 

 

These are the Pump jet cap and jet.  As you can see they come apart so different jets can be used. They're okay, just need a clean and new seals.                                                                                             Note the flat side on the jet it will only srew down in its hole if it is put in the correct way.

Also, there is supposed to be a fine particle filter, sits inside the slit area, both missing.  It's a starnge thing, It looks like a spring but is in fact a filter.

 

Below left are the air bypass screws.  New ones need ordering as one is bent.  On the right are the idle adjustment screws.  I'll be ordering new ones as these have seen better days

I will be doubling up on any replacement parts needed so I have enough for both carbs.  I expect I will have similar issues the the other one.

[Trunnion 74 158]

The emulsion tubes.  Three parts, the holder/air corrector jet the emulsion tube and the main jet.  The holder also acts as an air corrector jet (110) is number 5 on the list of 32.     The emulsion tube (7772.5)  is number 5 on the list of 17 and the jet (142) is number 24 on the list of 54

 

Idle jet holder/emulsion tube and idle jet.  The number for the holder (7850.1) is number 1 on the list of 10.  The Idle jet number (55) is number 7 on the list of 8.

one of these jets is very blocked, even after an overnight in the sonic cleaner.  Will need more work

 

Cold start emulsion tube and Jet.  The number (7482.1) is number 1 on a lsit of 4.  The jet (70) is number number 17 on a list of 34.

[Trunnion 74 158]

This is the needle valve (bottom) and seat (top).  The valves are responsible for helping, along with the floats to regulate the fuel in the bowls, you get new ones of these in the re-furb kit.  They do have a number on them as well and it is important to get the correct ones for your carbs.  It's also important to get the Viton tipped needle valves they give a better sealing when closing.  Viton is just a rubber compound that is fuel resistant.

 

This is the injection pump non return valve, it sits inside the main assembly underneath the carb.  There is a tiny ball bearing inside, you can just see it inside the hole, this must be freely moving or it won't do its job properly.

 

And these are the jet covers, they sit right on the top of the carb.  Mine are metal and have a brass mesh air intake screen although you can get plastic covers as well.  Left one all nice and clean right one gives you an idea of how they can get.

 

[Trunnion 74 158]

All this lot now needs to go back in the carb

In good Haynes fashion, fitting is the reversal of removal. We start with the accellerator pump housing.  First part is the gasket then the pump non return valve with the freely moving ball bearing, which can just be seen in the pic

Followed by the diaphragm and spring

Then screw cap down.  Bottom done.

 

Turn the carb the right way round and first part in the top is the mixture screw

Then the progression hole caps

Then the vacuum blanking screws

The air bleed screws

 

Then the pump jet assembly, holder, filter and jet.  This is the micro filter I mentioned previously

All this goes in here.  Make sure when fitting to get the flat edge seated correctly.  You'll know if it's wrong as the cap will not screw down.

 

 

[Trunnion 74 158]

Next in are the pump jet check ball, weight and the cap, in that order.

followed by the starter emulsion tube

The main emulsion tubes

and the idle emulsion tubes

Then a new throttle return spring.  This comes as part of the genuine carb rebuild kit.

Now for the top cover.  On top of the choke piston go a spring and a cap

.

Turn over and fit the float needle valve seat.  Then put the gasket on before you fit the floats.  When fitting the float pivot pin make sure you insert it from the side without the slit.  If try to fit it from the slit side you have a greater risk of breaking one of the legs.

Before you put the cap on check the floats distance measured from the gasket.  On mine at full droop it is 25mm and when the valve is just closed the distance is 15mm.  They can vary.

Screw the top down and then fit the jet cover not forgetting the gasket

This is the fuel inlet banjo assembly.  New filters and gaskets are supplied in the kit.

That's it, done!  All that is needed now is to fit the trumpets.

 

 

New cork gasket and trumpets fitted.

One down, one to go...

[soldave 272]

Awesome pictorial guide there

[EXCEL V8 152]

I shall be referring to this as I rebuild mine!  Thanks Roland 

Pete

[oilmagnet477 747]

@Trunnion 74 I reckon the sellers of that Carb book (which I have) will be after you for loss in sales - no copyright issues as you did it all yourself - but IMO better and easier to understand!

You are a legend!

[Trunnion 74 158]

Thanks guys.

Here are some pics of number 2 carb. This was the dirtiest of the two.

Not looking good.

Oh dear..

That's in a worse state than the last one

Yuck!  The emulsion tubes were hard to get out

As were the weights and check balls, needed sharp taps to dislodge them. All the other caps and srews proved difficult as well, and all the progression holes were completly blocked.

Underneath wasn't much better either

At least there was a spring this time

This one is in a worse state than the other one was.  Looks like I've got lots to do!