Head gasket failure....

[leifanten]

Well, this is less of a call for help than it is a sigh of "oh bugger!"

I was out enjoying my +2 that has 200 miles on since I replaced the water pump (head off and all of that good stuff) when all of a sudden this big plume of steam shows up in my rear view mirror. First thought was: there is no way that is from me. However upon looking around and seeing no Icelandic volcanoes around, my second thought was Cylinder head gasket must have crapped out! I guess I was wrong when I thought that "that looks good to go" when re-assembling after rebuilding the water pump. Back then (200 miles ago) I figured that since I had not blown the previous gasket, there was no need to skim the head prior to mounting.

I was about 5 miles from home, and when driven at speed there was no steam coming out, only when letting up on the throttle so that the vacuum could build did the steam appear in spades. (we are talking serious fog with zero backward visibility) I made it home without over heating. Turned engine off and coasted the final 300 yards when the temp gauge began creeping towards 95.

No water in the oil, no oil in the radiator, so it must have blown in a way that only included coolant and cylinder internals.

I am pulling the head off again tonight to assess the failure. Third time lucky (first to replace a snapped head bolt, then to rebuild water pump, then finally to fix a blown gasket)

Well, saving 50 bucks then certainly seems to have been a big bummer!

I have ordered a Cometic gasket and found an engine builder that can pressure test and skim the head for $100.

.....note to self: when you have the head off for whatever reason: have it professionally checked for straightness and skim it to straighten out any pitting or out of straightness feeling pretty dumb right now.

[robertverhey]

...and maybe crack tested as well? Symptoms are similar to when mine cracked...Fortunately it's repairable.

A cooling system pressure tester can be useful to isolate the leak prior to the head coming off (you take the plugs out, pressurise the system and see which plug hole the water comes out of!)...but hopefully the cause will be obvious when you whip the head off

Robert

[leifanten]

I took it off last night. In a couple of hours time. It was the gasket that had failed. Quite radically I would say. If I had any idea of how to post pictures I could show you. (whenever I try they are always too big)

I will have the head pressure tested, and if it is broken, I have a spare head that I can build on in case the repair work is too extensive. Would prefer to use the original though.

This might be a good chance to have new valve guides and seats put in if the pressure test comes back below ideal numbers.

However, I am beginning to wonder if the temporary storage of the bonnet/hood is actually on the car and not in our bedroom....

[paddy]

Was the head re-torqued after running at all?

I find it surprising always how much more you can turn the head bolts after a bit of time and a few miles' running. If the failure is shortly after replacement like in this case I would be suspicious that it just wasn't tight enough.

Paddy

[leifanten]

Paddy,
my suspicion is that you are bang on in your theory. I (wrongly) figured I should run it for 300 miles or so before re-torquing. When I unscrewed the head the bolts that were located around where the failure in the gasket turned out to be felt a lot less tight than the other bolts. This time I will a) install a cometic gasket, b)have the head pressure tested and skimmed and c) re-torque after less than 100 miles and then again after 300 miles just to be on the safe side.

After all, I should not complain. It was my own mistake that lead to this incident, and I did buy the Lotus because my Mercedes 450SLC 5.0 rally homologation car was too reliable and did not provide me with enough hobby.

[paddy]

I would not rush to skim the head - if it ws re-skimmed every time it was removed and refitted there would be nothing left after 40 years. I think I would check it but expect to find it's fine.

Paddy

[Old English White]

... Had similar head gasket failure ...
All happen on my way to my engine man for a service .
He discover the situation looking at oil that turn from "gold" to "light grey" in 80 km ...
Nothing bad on engine . Only a bad quality gasket .
When re-torque , the copper that was far too soft , made some kind of wave ; later the water get thru cylinder 3 & 4 ...
"OEW" run now with a resin gasket . No need to re-torque .
Christian.

[prezoom]

Leif,

If you can find someone with a lapping plate, a couple of figure 8 passes will identify any out of flat spots on either the head or the block. I use mine anytime I remove an aluminum head.

Rob Walker
26-4889

[RobL7/Elan]

Leif,

Another thing to consider doing is to replace the head bolts with ARP bolts. Available from Bean and the regular sources, these bolts are vastly superior to stock and really allow smoother torquing and maintain even pressure. Definitely worth the price. Also have had good luck with Payen head gaskets.

Rob
65 S2

[Mr.Gale]

"OEW" run now with a resin gasket

What is a "resin gasket"?
Gale

[RobL7/Elan]

Gayle,

A resin gasket is one of the newer generation gaskets that, unlike the older version like copper, have a resin coating on the gasket to ensure proper sealing. The Payen gasket i used in my head gasket repair was of this type and worked well. Also those ARP studs and remember to re-torque the head.

Rob
65 S2

[leifanten]

Rob,
I have new bolts from RD enterprises. Not sure if they are ARP or another brand. They are black with a 12 sided 1/2 head. (I bought them when as a result of re-torquing the old bolts one snapped - leading to the first removal of the head)

What is a lapping plate?

cheers

[leifanten]

Christian,
I do actually think the gasket looks like it was sub-prime. But then again the failure mode could be consistent with the need for a re-torque. I guess I will never find out , and it is what it is. Going to the engine builder tomorrow to measure the flatness/straightness and pressure test it. Then humpty dumpty will get bolted together again once any faults have been fixed.

cheers.

[RobL7/Elan]

Leif,

The bolts from RD sound like the ARP ones I used. I'm sure they will be great. Remember to use the special lube for the threads of these bolts to allow smooth torquing of the head. Best of luck!

Rob

[dusty]

I've worked on a few Triumph Stag engines over the last year (known for warped heads and gasket failures) the recommendation with those engines is that you do the following:

Fit cyl head with new gasket and torque to spec.

Run engine up to working temp and leave running for 5-10 minutes at temp.

Allow engine to cool over night and then loosen (just a fraction) and re-torque bolts, tightening an extra 5ftlbs

Then run for 3-500 miles and check and re torque as necessary (without loosening)

This advice has served well and since the twincam is also an engine with an alloy head on an iron block I wonder if this would also apply.

Cheers
Jon