HEALEY 100 Head Gasket Gone ?

[OWD724]

Hello all from UK. For sometime I have noticed a very little amount of water leaking out near the two middle plugs. Also some emulsion on the rocker box, but no noticeable oil in the water or vice versa. Having had the fan belt come off and now fitted a new one and checked the Dynamo ( see my previous post about Dynamo with a mind of its own ). I decided to check the compressions although the car is running very well and the engine is smooth, What I found was the following whilst HOT -- from the front cylinder back -- 160 - 120 - 117 - 155 lbs. So now I am going to have the cylinder head off. Totally dismantle and grind in the valves. Bought a new gasket set from AH spares. What I would like to know is there anything else I should do whilst the head is off? We are going measure the head on a flat surface and skim if required. I believe the original manual suggests that the head is torqued to 60 lbs ? Is this correct as I had heard that 100 lbs is correct, but I do not want to risk the studs snapping. Are there any clever tips to stop this happening again, as I believe this is a typical Healey 100 problem. Thanks John

 

[RandyHicks]

Yes, this is a common problem. I corrected the issue by installing the Denis Welch 100-4 Competition Head Gasket. #CENG401A

No leaks about 6 years now.

 

[PeterBL]

It works for me. 5 months no more leaks.

 

[pan]

I torque my cylinder head to 65 foot/lbs. I use Hylomar on the gasket and check the torque three times following the sequence in the workshop manual. Standard gasket - no leaks (so far) in several years since it was last off. Check for cracks while the head is off. The head could be warped but try not to skim too much off the surface if you can avoid it.

 

[Keoke]

Baring that the head is not warped.
British Car Specilties has a kit to resolve this problem.

 

[TonyR]

Without a doubt, purchase the Denis Welch head gasket. It must be fitted without a gasket goo and can be re-fitted again if required.
The modern day copper gaskets are junk!

 

[OWD724]

Thanks for all the replies so far. OK, so now discovered that the old head has several cracks around the base of the valve seats. Also the head needs skimming as the gasket shows large leaks in between the two middle cylinders. So by the time they are repaired, it will not be worth the money spent. So have ordered new 'fast road' Aluminium head, studs, nuts, washers and steel gasket from Denis Welch. All very expensive, but since it is my birthday today, I thought the car deserves a present as well !!! . I will post another reply when we have fitted it -- hopefully next weekend, if it arrives.

 

[CanberraBJ8]

HAPPY BIRTHDAY then, and I am envious of the new head!

 

[pan]

Don't toss out the iron head! Even though we can now obtain replacement cylinder heads, an original head is repairable & precious.

 

[OWD724]

OK, so this is the story so far -- I have now had the Denis Welch fast road Head fitted. The old original Head was cracked across the valves and the gasket gone. the compressions were 155/117/120/160. The new Head was relatively simple to fit, except we made the mistake with the rocker post studs of not sealing them properly at first so water was coming into the head. The answer when winding the studs in is to ''be brave'' with your strong hand torque with the spanner and use proper heat resistant silicone sealer. We did a pressure test on the water system up to 7lbs and all was OK. I am not using a thermostat as the car warms quickly and in the winter I put on a grill muff. We did the hot compressions and they are all 172lbs +/- 1lb. The car already has high compression pistons and high lift camshaft and H6's. Initial drive at the weekend, seemed to be very smooth but not that more power until I rev'd it to 3500, then I noticed a real difference -- so much more pull and torque and a much faster. So very pleased so far -- also still barks and pops out of the exhaust, which annoys the locals !!!

 

[simon1966]

Thanks for directing me to the thread. It will be interesting to see what I find in a few weeks when the engine comes out.