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Techspy

Blown head gasket? Video

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"Professor Tim" just posted about head gaskets over on LotusTalk. There was a change that occurred in engines produced in January 1993. There were also (production) differences in some of the gaskets sold by JAE Parts.

 

Here's the link

http://www.lotustalk.com/forums/f164/head-gasket-445826/#post5753362

 


Atwell Haines

'88 Esprit

Succasunna, NJ USA

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Upgrade today to remove Google ads and support TLF.

Good info in that link. Shows just how one little thing can cause unintended consequences.

I got the crank pulley and timing belt off today. Ended up having to use a pry bar in the starter teeth on the flywheel to hold it while I loosened the bolt. It was pretty easy actually. Otherwise I got the cam towers, turbo and head cleaned up. Glad to see the turbo interior and intake was nice and dry so no turbo seal issues etc. The timing belt (5 years old, approx 10k miles, Gates) looks perfect but it will be replaced with a new one. I have all the shims labeled so hopefully the builder has notes on which one goes where. I will wait to clean the block and pistons until the day the parts are arriving so I can put the gasket on right after cleaning. I am not sure about cleaning the piston heads actually. Not sure I want to move them as I don't have liner clamps. I have read were it takes a lot of work to break the liners free from the sealant/locktight during a rebuild but my luck would be they move from a breath.

Couple questions;

- Recommended sealant for the cam towers? Just a good quality high temp RTV? What was on there was a semi-clear red color and was still kinda sticky. Both my Esprits always has small oil leaks around the cam towers. Any hints welcome.

- What should be lock-tighted? Just the crank pulley bolt? What about the cam tower bolts?

 


John
94 S4

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Permabond A136 sealant (or similar) for the Cam Towers.

A silicone based sealant will form a film between the Cam Tower and the Cylinderhead which makes setting the valve clearances a guess at best.

No threadlocking on the Cam Tower bolts or the Crank Pulley Bolt.

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Esprit Freak

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NO RTV!!!!

 

You can use Loctite 5188 (formerly 518) for the cam towers to head surface. It is an anaerobic sealant. You don't need much thickness, literally just 'paint' it on with a brush. Some folks have used the Loctite primer, as well, but that reduces working time. How nimble are you? :P

 

image.png.473691d36bb36057f8061efc969d44f8.png

 

My 5188 is holding up well after 4 years.

 

Regards the valve shims, don't forget that you need to fit the cam housings DRY then measure the gaps. You MAY need different shims.

 

I'd say don't mess with the carbon on piston tops.  That carbon provides extra compression! :devil: Plus, it looks about the same as mine look on the Borescope.


Atwell Haines

'88 Esprit

Succasunna, NJ USA

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Thanks Guys. Looks like I will have to start from scratch on the shims. Going to start reading the various posts on how to do it. Anyone know of a good video that shows the process? Anyone know of a good diy option for a head stand? Man, I was really hoping not to have to do this.


John
94 S4

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Clean any previous thread sealant off all the bolts, otherwise they can strip the aluminum threads out of the head.

 

Use an Excel spreadsheet to measure and sort the shims.  but yeah it really sucks if they fall out like that and you have to do it several times (DRY no sealant!).  Add about .0005" for the final numbers to account for the sealant.

 

Doing it on a head on a bench is much easier than on an engine!

Don't clean the pistons, it'll drive grit down into the rings, where it is impossible to clean.

Don't skim the head unless absolutely positively necessary!  A machinist messed mine up and tapered it into a trapezoid, which made the cam belt try to walk off!

 

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Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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Thanks Travis. Yeah, at least it will be on the bench for the shims. Not cleaning the pistons is the plan. Any preference on the cam tower sealant? Seems the Locktight 5188 is a bit more available around here. Oh, and did you use the angle method along with the ARP studs?

Edited by Techspy

John
94 S4

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5188 or the older 518 if you can find it. 

I did not use the torque angle method. I struggled with finding the correct torque.

The Lotus spec change to the torque angle when they went to the taller composite gasket (Goetze) IIRC. I used one back in 2002 and that held up fine, but I think I used the old Lotus spec for torquing. 

Later I used the JAE black gasket and added the ARP studs with fine pitch. That lasted ~6k miles and blew at #4 on the track after losing over a gallon of coolant due to a bad pressure cap on the overflow. I think I torqued that to the old Lotus spec as well.

Then I replaced that with another black gasket, and that lasted exactly 1/2 of a day. I torqued that to the newer spec for the ARB fine pitch studs, which was 100ft-lbf ARP Ultra Torque lube (from Jeff at JAE). But I think that one died due to an overheat due to poor coolant flow out of the back of the head, which was due to a sensor that I had added to measure coolant temp out of the head...


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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Good info. Just spoke to Joe at JAE and he said no angle method needed and that the studs are basically hand tight into the head and incremented to 110 for the nuts. I will get some 5188 ordered.

Edit: Wow, 518 available on amazon next day delivery. Ordered.

Edited by Techspy

John
94 S4

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Do make sure your head studs are fully seated in the bottom of the bore, (hand tight, do not torque). See below.

http://arp-bolts.com/p/FAQ.php

Quote

Do the head studs only go in hand, or finger tight?

Yes, cylinder head studs are installed only hand tight. Other than the use of an allen wrench on the hex broached into the end of the stud (to ease installation, not to apply torque), use no tools to seat them in the block. However, it is extremely important to ensure that the studs are fully bottomed out in the hole in the block and not hung up on damaged or corroded threads in the block preventing the stud from being fully seated. This is often indicated when the stud threads extend past the deck surface.

 

The reason is that you want the stud to be bottomed out and unable to turn more when torque is applied to the nut. If they weren't then it is possible to strip the block.

 


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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Intake shims are done and all are between .005 and .007 except one that is .009. As I understand it the measurement gets tighter as it wears. Should I be concerned about the .009? Exhaust is next which will be a lot more trial and error. Got the intake done in 2 attempts.

Thanks.

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John
94 S4

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I would investigate or adjust the one that is .009.  (Is there a worn spot in one of the shims on that valve position?  It could have been OK if initially measured on the worn area.)

 

In my experience, the intakes can be adjusted to the specified clearance range.  The exhausts (which are MORE prone to tightening) should be purposely set to the loose side of spec.  (That's what I do on my Hondas and my Esprit, anyway.).


Atwell Haines

'88 Esprit

Succasunna, NJ USA

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i really enjoy your Youtube movies about removing the Cylinderhead,

i have done it a lot before, but i always take the engine out, (only because then i have space all around the engine)

and it works faster then with the engine in....

 

please also make a movie when you build it up again, its nice to see a "newby" working on a 910 engine!

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Boy I screwed that up (don't ask). I will be ordering shims tomorrow. I have 9 total (intake and exhaust) that are just out of spec. I was able to swap 4 (2 on the intake and 2 on the exhaust).

Yep, I plan on a video per day of working on this until it is back on the road. Fingers crossed I will be done by the weekend. Would have been sooner if I didn't have to order shims.

 

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John
94 S4

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7 hours ago, Techspy said:

Boy I screwed that up (don't ask). I will be ordering shims tomorrow. I have 9 total (intake and exhaust) that are just out of spec. I was able to swap 4 (2 on the intake and 2 on the exhaust).

Yep, I plan on a video per day of working on this until it is back on the road. Fingers crossed I will be done by the weekend. Would have been sooner if I didn't have to order shims.

 

Saab / Rover shims are the same, that ones i always order very cheap and easy to get

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Anyone have an online source for rover/saab or compatible shims?

All needed in stock and ordered from JAE.

Edited by Techspy

John
94 S4

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keep in mind a little carbon grit can hold a valve open (increasing clearances). A little pop with a plastic mallet can pop open the valve enough to get it to seal better against the seat.


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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53 minutes ago, Vulcan Grey said:

keep in mind a little carbon grit can hold a valve open (increasing clearances). A little pop with a plastic mallet can pop open the valve enough to get it to seal better against the seat.

Good info. Thanks


John
94 S4

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While waiting on the shims I am gathering the coolant, oil etc for changing once back together. But, I am trying to decide on the best coolant. There are so many different opinions in various threads but most are kinda old. What do you guys run in your engine nowadays? Also, as far as flushing it really well, should I just fill with water and run for a few miles and then drain and add the proper coolant mix? As for oil, as long as it has been sitting, especially with the head off, I am planning on draining the oil before it goes back together and filling up once the head is back on (filter too).

Thoughts?


John
94 S4

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Blue coolant is the recommended, not the later red OAT.

As for oil, personally I use Mobil 1 10W/60, however you have a much wider selection of oils to use in the US than we do here. No doubt they’ll be other suggestions from other owners forthcoming, too. I do think it’s a wise move to change the oil and filter, and like they say, “oil is cheaper than engines”. Thanks for the posts and videos, really enjoy them, although it’s sad to see you’ve had the head gasket problem.


Margate Exotics.

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Well I picked up some Zerex G40 that is described as pink in color. Is that what I should avoid?

https://hd.valvoline.com/our-products/zerex-g-40r

If so, can you provide more info on what you mean by "Blue coolant"? Do you mean this formula which comes in red or blue?

https://www.valvoline.com/our-products/antifreeze-products/zerex-asian-vehicle-antifreeze-coolant

More vids posted, just not spamming the thread here with them.

Thanks

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John
94 S4

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Nevermind, I swapped it for some G05 that seems to be recommended by Valvoline and other Esprit owners.


John
94 S4

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John, i am now doing a lotus excel, cylinderhead rebuild.

i took the engine out this morning, and get the cylinderhead off

when i did that i was thinking back on your movie, hahaha wish you good luck with building up and set the valve´s right!

 

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Price and availability of the Valvoline VR-1 20W/50 oil are good, and it has the zinc compounds that are supposed to be good for our tappets.

 

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