Engine failure update

[JJDraper]

To take the whole thing forward, get a new set of head gaskets - I have used Ajusa 85mm ones with my +60 bores with no bore-to-water way failure for many miles. I did have a strange H/G failure documented previously, but this may have been overpressure in the cooling system, or just age. Check out the fire ring/bore clearance in the pics on the thread below. Both the old & new gaskets were 85mm ones; you can see the old one has squished to the right size but the new one looks too big.

lotus-twincam-f39/rats-losing-coolant-t24742.html#p159787

May be worth getting a straight edge on the cylinder head, to put your mind at rest. If OK, clean up & put it all back together and see what happens - a 60 quid gamble I suppose, but I am an optimist (or lazy). No gasket cement on the main gasket but a smear of wellseal on the cork one. What harm could it do? The alternative is a lot of maybes, expensive testing, and not actually using the car.

If it does it again, time to do the other stuff.

Jeremy

[jono]

Well, I got the engine running again on Saturday and it's bad news - still the same

Possibly worse in fact - it actually spits small water droplets out of the tail pipe as well as steam. It is okay on start up but (steam) gets worse as the engine gets hot.

So back to square one but a worthwhile gamble I guess to do the gasket and see if it worked. My expectations were quite low.

So what next? I'm tempted to do a coolant pressure test with the engine warm and see what that tells me, but I'm beginning to suspect a cracked bore.

Are there any clues which might indicate a cracked/porous bore over a cracked head on a running engine or do either give the same symptom?

I guess it's engine out and strip down time. What a bummer on a newly built engine

Jon

[rgh0]

Hi Jon
Have you run it long enough to get the exhaust fully hot and dry? Are you still getting oil in the water or water in the oil still or loosing water?. There may have been some water in the exhaust system that is coming out as the engine heats up.

cheers
Rohan

[jono]

That's a very comforting thought Rohan - I really should remain optimistic.

Perhaps I should run it up and take it for a drive before I concede to my natural pessimism (it's these dark northern latitudes!).

There is also a lot of steam and drips coming out of the head beater tube which is currently diverted from the air box via a Cliveyboy conversion.

I noted bubbles, large ones, entering the re cuperator bottle but had just assumed this was air trapped in the system after re filling.

Incidentally I re torqued the head after one heat cycle - a couple of bolts moved about 1/2 a turn but the others clicked at 65 lbs.

Jon

[rgh0]

If your still convinced you have a leak between the engine oil and water systems then before you dismantle the engine drop the sump and pull off the cam cover and pull out the plugs, pressurise the water system and try to see if you can see where the leak is coming from and going to

cheers
Rohan

[jono]

Okay, further update time.

Mike Duff of this forum very kindly drove over 100 miles on Saturday to help me with this - sincere thanks once again Mike

With Mike's careful diagnostic approach and equipment an interesting discovery was made. It seems there have been 2 issues.

Firstly there is little doubt the head gasket was not sealing and a further examination of the old gasket has revealed significant corrosion between the 2 laminations of the gasket on the metal leaf. There was no evidence of repeated failure of the new gasket when we eventually removed the head on Saturday.

Using Mike's pressure device, the cooling system was pressurised with the engine hot and we removed the cam cover. A small 'fountain' of water was noted coming from between the front and rear covers around the water pump.

On splitting the front covers and carefully inspecting it was discovered that the mating faces are indented due to a previous person parting the cases with a hard instrument such as a screwdriver - this is right next to the waterway which then feeds the cylinder head through a 90 degree port in the block.

So, the water pump was not leaking, but the mating face was not sealing thus causing water to escape from the water port and into the crank case.

The covers are going to be welded and the faces re machined. The 'new' pump looked very rusty as well so that will be replaced at the same time.

So, there were 2 causes here - head gasket and a leak between the front and rear covers.

Jon

[RotoFlexible]

It's always a relief to find a smoking (or, in this case, squirting) gun. Talk about a dreaded previous owner...!

[Galwaylotus]

If the "new pump looked very rusty" that might indicate the wrong mix of coolant. Make sure not to run straight water. The antifreeze contains anticorrosion properties too.

[jono]

the engine was filled with Comma brand blue coolant, the rust was probably from when the engine stood for a period of time after being rebuilt.

[billwill]

The impellor can go rusty and that will not matter much.

Far more important is whether the seal has torn.