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MG MGA - Head gasket blown

Hi all, I have blown my head gasket between cylinders 2 & 3. I have an electric fan fitted no mechanical fan temp has briefly touched 220f in traffic, the rad did need topping up (must remember to top rad up). Did a compression test last night cyl 1 was 135, 2 was 65, 3 was 60 and 4 was 130psi. So I will need to replace the gasket, Payen has been mentioned, can I get away without having to skim the head? I also have a new gasket which has been in my garage for sometime its grey in colour both sides any ideas?
Thanks Dave
1500
Dave Swinburne

It depends whether the head / block are still flat across the blow - if they are in any way eroded then a skim is required.

The silver coloured gasket is OK but the Payen resin one is to be preferred and has additional resin around the outside of the water passages that are a known leak point with the traditional flat gaskets.
Chris at Octarine Services

Thanks Chris, head will be off today to see what the damage is, hopefully just a new gasket will be required.
Dave
Dave Swinburne

I always get a kick out of this guy! Resurfacing his head with out a 10 ton milling machine! Put a striaght edge on the mating side of the head. Use a set of feeler gauges to see if you can slide them through the area that gave way on the head gasket.
If you an see light it needs resurfacing. If you have a shop that can do it right away, go for it. If not you can try this.


http://www.youtube.com/watch?v=mc_gaGAf2pk

HIS HEAD IS ALUMINIUM. Yours would take longer!

GOODLUCK!
Steven Devine

Head off, blow in gasket dead centre of middle two pistons. Head and block in very good condition just a light clean required. Payen gasket on order. This may of happened because I did not re-torque after x miles? should you torque after rebuild? (50lb)
Thanks
Dave
Dave Swinburne

I would always retorque after first hot run, though Payen say it is not necessary.

For customer engines that I am not fitting I use the stronger studs and torque to 55 ftlbs so there is a greater margin for any consequent compression of the gasket or stud stretch.
Chris at Octarine Services

I retorqued after about 100 miles, and the gasket blew some 2000 miles later. Same place - between 2 and 3 cylinders. Gasket was the one that came with the engine rebuild set.
Now I have fitted the PAYEN one with the black stuff on it after checking the head and the block. And I have retorqued with the engine warm.
Peter.
P. Tilbury

While the head is off it would be a really good time to check that the engine studs do not have any pulled threads.
Keith Lowman

Engine all back together and started first turn. Head studs looked in good condition {should be only done 3k miles since rebuild} Torqued head to 60ft lbs as studs were marked with the number 22 as stated in the manual. See photo of Payen gasket on head.
Thanks
Dave

Dave Swinburne

Hi there
All the advice above is valid. When I had the same problem, I was advised to look at the bottom end. Increased compression on top, put increased pressure on bearings. I was very glad to look at my main bearings, they show copper colour - totaly worn out.Most likely saved crankshaft,rods,block or all three + big big hole in my valet.
Martin
sharpeys

This thread was discussed between 02/07/2013 and 10/07/2013

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