Head gasket replacement.

[mechwanabe]

Hello BCF members.. Need advise on 66 AH MKIII head gasket replacement.. Is it true that the engine needs to come out in order to be able to do a head gasket replacement?
I know there are some very (almost impossible) difficult to reach intake manifold nuts and who knows what else..
Any advise, I need to replace the head gasket because of oil in the coolant..
Thank you.. for any info.
66 AH

 

[tahoe healey]

No. The head comes of easily. Protect the fenders well and the radiator. I used a movers blanket you can get at Harbor Freight cheap. Best to have two people lifting as the hood support gets in the way and that puppy's heavy. Have a place to put it before you remove it (0ne with wheels is good). You should have the head ground smooth and flushed while you have it apart. Check valve seats and BE CAREFUL TO PROTECT THE OIL BANJO!

 

[Bob_Spidell]

...
I know there are some very (almost impossible) difficult to reach intake manifold nuts and who knows what else..
66 AH

I believe you can/should remove the head with the manifolds still attached (you won't have to remove them unless you want to install new gaskets). Remove the carburettors at the manifold--no fun but doable--top nuts are easy but you'll have to reach underneath to get the bottom nuts (I use a stubby half-inch end wrench). Disconnect the exhaust downpipes at the manifold flanges from underneath (I use a half-inch deep socket on a couple of ratchet extensions).

It'll be heavy; you might want to remove the bonnet and use an engine hoist.

 

[red57]

Not to rain on your parade but I would do some more diagnostics before pulling the head.

If you have oil in the coolant but no coolant in the oil, you may have a "block porosity" problem. It is not real common but I have had two blocks develope this problem. The issue is the natural porosity of cast iron. There are some oil passages that are very close to water jackets and with years of rusting in the water jackets the iron becomes thinner in these areas and oil under 40-60psi can seep thru the iron into the water jackets....40+psi oil vs 7psi water = oil wins so you will usually see oil on the water but not water in the oil. (conversely with a blown head gasket you will likely see water in the oil also)

Moss and others sell a 'oilway repair kit' for this problem. The kit consistes of stainless steel tubes that you apply a sealant to and press in to line the oil passages with. I tried one of these kits several years ago but it did not work for me. One problem is that you need to totally disassemble the motor to a bare block - both for the machining and installation of the tubes and so you can clean thouroughly after installing the tubes. Second problem is that my machine shop was not able to pressure test after installation of the tubes so I assembled the motor not knowing if the problem was corrected or not and, in my case, it was not.

However, I have run my engine with this oil seeping into the water for a long time before replacing the block - I just had to flush and clean the cooling system every 500 miles or so - I would add laundry detergent to the water, run until hot, drain & flush. Sometimes it took a couple of rounds to get it clean, then fill with water & drive. One plus is you don't need to add water pump lube

To your original question, yes the head can be removed by itself but I recommend taking the hood (bonnet) off and using a hoist - these heads are increadibly heavy to lift off by hand.

Dave

 

[mechwanabe]

Thank you for the advise.. So far it looks like the manifolds intake/exhaust should come out with the heads. And, then remove the manifold from the heads if needed ?

 

[Bob_Spidell]

Thank you for the advise.. So far it looks like the manifolds intake/exhaust should come out with the heads. And, then remove the manifold from the heads if needed ?

Not unless you suspect a leak, or plan to skim the head, or just want to replace the gasket on principle. Wouldn't hurt to re-torque the nuts.

Trust me, you won't run out of work to do on this car.

 

[Keoke]

To your original question, yes the head can be removed by itself without removing the engine but I recommend taking the hood (bonnet) off and using a hoist - these heads are incredibly heavy to lift off by hand.----KEOKE