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+--- Thread: Head gasket (/showthread.php?tid=5253)
RE: Head gasket - Zetomagneto - 14-11-2020
What brand of sealant was used originally ?
Clean, flat, and dry has always worked for me.
RE: Head gasket - Tony Betts - 14-11-2020
thanks guys.
when gov.co.uk let us out again. ill go get some and give it a go.
i have a couple of hot engines im working on.
thanks tony.
RE: Head gasket - David Stepney - 14-11-2020
(14-11-2020, 05:47 PM)morrisminor Wrote: What do you guys use inbetween head and gasket, nothing, grease, hylomar ?
Copper slip. Providing everything is reasonably flat, it not only ensures a good seal, but the head is reasonably easy to get off again when it (eventually) becomes necessary. I put it on the studs too.
RE: Head gasket - Steve Jones - 14-11-2020
It's a question of each to his own. I've used Loctite copper silicone sparingly on head gaskets on road and competition engines for years and years and never had a failure. I always start with a head and block that are clean and flat and am almost paranoid when it comes to the torquing down process so it might be belt and braces but it works for me and always has. I won't be changing and I know that a lot of people I respect in the A7 (and wider) world do the same. If doing it differently works for others then that's fine. As above, it's each to his own.
Steve
RE: Head gasket - Nick Turley - 15-11-2020
Ever since Steve Jones recommended 5990 I have used it.
I fully believe it is the best way as modern gaskets do not have the "give" they had when they had asbestos in the sandwich.
Head removal is not any problem.
So far I have not had any failure.
RE: Head gasket - Malcolm Parker - 15-11-2020
I have used the Loctite copper silicone since recommended by Steve and have never had any problems. Secret is to apply a very small amount, just enough to provide a thin smear. It doesn't set hard and is easy to remove by rubbing off with a cloth or your finger. I have bought two tubes over the years, simply so that I can have one in the garage and the other in the car.
RE: Head gasket - John H - 15-11-2020
Nothing to do with sealants, but this may be of interest. Shortly before he died, my late father had our Chummy's engine re-built. It was fitted for the last few runs he ever did in the car, covering only a few hundred miles. Since then, I've been running the car, and it ran perfectly until last year when it mysteriously "went sick". After trying all the usual things, I decided to take the cylinder head off to check the condition of the valves and seats. However, I discovered that the nuts were barely more than 'finger tight' and the head lifted off with zero effort! There were signs of leakage past the gasket, which was new when the engine was reassembled. I re-fitted the head with a brand new gasket, all clean and dry apart from a trace of blue Hylomar around the water jacket holes. I used an accurate low-range Britool torque wrench and stage-tightened the nuts to 20lbs in the correct sequence. After a single heat cycle, I re-torqued the nuts and they all moved a good half a flat. I subsequently re-torqued the nuts a further two more times over a number of heat cycles before the nuts finally stopped moving. So I have concluded that these modern gaskets have a lot more 'give' in them than gaskets of old, and need multiple re-torques before they become fully compacted. I believe this is why the previous gasket "failed", simply because it hadn't been re-torqued sufficiently.
RE: Head gasket - Charles Levien - 15-11-2020
Hi all, I know this has been discussed before so please excuse my asking again — I’m wondering which torque wrench to buy ie something combining accuracy with reasonable cost. I see that 27Nm pretty much equals 20 ft pounds. Some wrenches seem to have this as their lowest torque setting. Does this matter and what do you suggest please?
Charles
RE: Head gasket - Alan - 15-11-2020
Depends, and people will recommend other things but I like the “click” type as opposed to the bendy bar. I have 3 or 4 going up to 400ftlb. The one I use most is a Norbar and it’s 10 to 70 ft lb. loads of them on eBay.
RE: Head gasket - Reckless Rat - 15-11-2020
I bought a smaller 3/8" drive torque wrench from the bay of E. Goes from 0 to 50 ft lbs so ideal for head and crank bolts. The big 1/2" drive one, as said earlier, only starts at 20 ft lbs so not ideal for an accurate nip.