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Tristared V4 Fan
United Kingdom 186 Posts | Posted - 14 Apr 2014 : 16:16:29
| Does anyone have advice for fitting copper head gaskets?
I have had enough of buying inlet manifold gaskets.
Thanks,
Ed
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rsimps V4 Guru
United Kingdom 1616 Posts | Posted - 15 Apr 2014 : 08:07:54
| I always start by having the block and head ground finished to a very good finish. If the guy is using a miller forget it, it needs to be surface ground. I then coat both sides of the gasket with three layers of Hymolar spray gasket, leave for it to go tacky then fit as normal. Torque up in three stages leave over night and then check the torque the following morning. But I tend not to use copper gaskets as people have problems, the XP items are now made of aluminium as loads of people have trouble. I would try to get some Wills rings made, which is what I use in the 2 stroke engines. The other option is to get a small groove machined in the head to take a piano wire that will nip the gasket down around the bores. | |
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Borstlap V4 Fanatic
Norway 333 Posts | Posted - 15 Apr 2014 : 08:35:07
| The last series gaskets that came from XP were made of brass in stead of copper, resulting in big problems for users as they were much too hard. I was told once by an engine tuner that copper gaskets should be heat treated to make them softer. This makes them more able to shape after the surfaces they get in between.
RSIMPS, where did you buy the spray gasket? I have 2 sets copper gaskets lying in wait, but I don't have spray gasket. Years ago I found a spray can type in the US, but never got to order one.
Alex. | |
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rsimps V4 Guru
United Kingdom 1616 Posts | |
Tristared V4 Fan
United Kingdom 186 Posts | Posted - 15 Apr 2014 : 17:54:01
| ....hmmm - I see.
Is it Malbrads that do standard gasket opening to 94mm?
Many, many thanks as always. | |
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Woody V4 Guru
United Kingdom 2758 Posts | |
Tristared V4 Fan
United Kingdom 186 Posts | Posted - 16 Apr 2014 : 12:20:46
| ...you have to take the inlet manifold off to get to the heads?
Gaskets can't be used twice? | |
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rsimps V4 Guru
United Kingdom 1616 Posts | Posted - 16 Apr 2014 : 13:18:39
| Thats right Malbrads had some 94 flame ring gaskets made. I think Swedepeed were looking at using more std type gaskets as they were finding the old copper rings get so hot at high compression that they cause pre-ignition. Personally Wills rings all the way for me, if they can cope with a imp engine at 9000+ rpm they can cope with a Saab unit. You can also get away with reusing them a few times long as you dont disturb them. If anyone needs a head ringing, give my friend Andy a call at Shringley Engineering, he has the race proven tooling to groove the head | |
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Derek V4 Guru
United Kingdom 2187 Posts | Posted - 17 Apr 2014 : 11:33:12
| quote: Originally posted by Tristared ...you have to take the inlet manifold off to get to the heads?
Gaskets can't be used twice?
With a V engine, if you skim the heads to get a higher CR, the inlet manifold should be machined to match up, as the inlet ports will be further down into the V. Not much lee way with a paper gasket. | |
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melle V4 Guru
United Kingdom 3830 Posts | Posted - 17 Apr 2014 : 17:21:52
| What's the exact problem Ed, did you fit them and don't they work as they're supposed to do? I still haven't installed mine.
1970 96V4 "The Devil's Own V4" 1977 95V4 van conversion project 1988 900i 8V | |
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Tristared V4 Fan
United Kingdom 186 Posts | Posted - 21 Apr 2014 : 13:03:59
| The cooling system becomes pressurised when the engine turns over. I've detected coolant on the number 3 cylinder spark plug. This doesn't happen with all the others pugs are in, so by powers of deduction the issue lies somewhere around there...
There isn't much more to report at this time as I've yet to strip the engine down.
I suspect that the problem is that the heads were milled to correct flatness when the larger valves were fitted, and not ground flat (the inlet manifold was also dealt with accordingly).
As stated - I'll know more next weekend when I take a look.
It's all a learning curve...
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Woody V4 Guru
United Kingdom 2758 Posts | Posted - 21 Apr 2014 : 19:56:46
| Saab do not recommend machining the inlet manifold if the heads are skimmed, but advise that the top of the block under the manifold is machined. Granted if you only have taken the heads off that isn't practical but you have to be sure the manifold is trued properly before machining.
When you put the heads on originally, did they torque down evenly? No grabbing on the threads? As the heads are off, wind the head bolts in until they bottom and check the distance between the face of the block and the underside of the bolt head. This measurement needs to be 2mm less than the depth of the head. Cut the bolt if too long. If they dont wind down evenly clean up the threads on the bolts and the block. | |
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Tristared V4 Fan
United Kingdom 186 Posts | Posted - 09 Oct 2014 : 18:59:03
| First attempt at fitting the gaskets was dry - without sealant, this worked on first engine start up. On the second start up the left bank failed to achieve compression, even after checking and taking the head bolts up to 90lbs.
Second attempt was after the gaskets had been annealed - taken to cherry red around 650c. All the surfaces were scratch finished and coated in 4 layers of Hylomar blue spray on gasket sealant - mounted whilst the outer layers were still wet, as advised from a number of sources. Head bolts were taken up to 70lbs. Same result - start up was at first successful but then sudden compression of the cooling system, again the left head and no change after checking head bolt torque.
From what I gather the design simply doesn't like them, or at least not on a 93mm piston. I think there isn't enough material between the combustion chamber and the crescent shaped water ports.
It is my belief that the engine requires a gasket with a high level of compressibility, which of course the standard design is.
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melle V4 Guru
United Kingdom 3830 Posts | Posted - 09 Oct 2014 : 20:21:08
| Thanks for sharing your experience. I for me can't say what's gone wrong as I don't have any hands on experience with fitting the gaskets. I've had 25 sets produced, but I have the impression very few have been used yet. I'm looking forward to hearing more knowledgeable people's opinions on this matter.
I can't really see how there could be more material 'between the combustion chamber and the crescent shaped water ports', but I might not understand correctly which water ports you mean. The basic shape was copied from an original gasket, this was laser cut in board for test fitting, unnecessary holes were removed and finally the outline of the gasket has been optimised for fit and for cutting.
1970 96V4 "The Devil's Own V4" 1977 95V4 van conversion project 1988 900i 8V | |
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StefanM Starting Member
Sweden 34 Posts | Posted - 10 Oct 2014 : 07:40:25
| Copper gaskets works fine if you skim the head and block to a very superior finish. It will more than likely fail if you just use them as replacement gaskets on a engine in situ. They hare to hard to compress and there is no room for iregularitys in the surface and it does not matter how hard you tighten the bolts. They are to few to make any difference. | |
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Tristared V4 Fan
United Kingdom 186 Posts | Posted - 13 Oct 2014 : 14:42:40
| Well, this very well maybe the case – though short of having the mating faces mirror finished I’m not sure how much better I could have made them.
StefanM – if you have any experience and more importantly photos of fitting copper gaskets then I for one am all ears (and eyes).
Here is an image that references what I mean. On a standard gasket I assume that the flame ring must compress creating a gas tight seal whilst still allow the surrounding material to do the same to seal the coolant path ways.
This isn’t a fault with the design of the gasket. I just believe that there isn’t enough material between the water gallery and the chamber for a seal to work with copper.
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