Head Gaskets

markQLD said:
ay Vince.  me thoughts, for what they're worth, suggests that it is difficult to predict that a particular gasket will seal with a particular engine.
and,,  a particular gasket will not seal with a particular engine.
an engine is an engine,  and for me they all have the potential to create trouble.  & it's good sometimes when they don't.  ;)
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Not quite Mark.

Find recessed liners, fit a gasket with slightly thicker flame rings, flush liners will do nicely with the "dodgy" gaskets without further issues.

Protruding liners will need to be dealt with, no matter which gasket you have on the shelf.

piet
 
How the fuck should I know that, Phil? 
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see your point - but all the non Viton ones distort, fall to bits or expand to cut off oil, whereas I've yet to see a Viton one deteriorate. Original Laverda Viton "O" rings were dyed green - real colour is dark grey not black - although probably hard to tell if they are burnt to a crisp  :D :D - Regards - Phil
 
opened up a whole world of dog poo with this head gasket deal

measured liner recess on 2 barrels yesterday, clocked them with a dial gauge so is pretty accurate
1st photo, 78 Jota, shows the liner recess all over the place but can say that this set of barrels has history as the engine has broken a conrod at some stage of its life so at least one liner has been changed, can see measurement varies from 0.03mm to 0.12mm, highly doubtful that this barrel will seal with new style head gaskets
easy to tell that the conrod has let go as there is a bunch of welding on the engine cases, No 1 conrod



2nd photo, 2Volts barrel, also 78 Jota, liner measurement even on all 3 liners at 0.08mm, not a bad result



1st set of barrels, liners out, face skimmed, flange recess machined, ready to drop liners back in
what a pain in the butt this is going to be having to drop liners on every 1000 engine
1200's just became my favorite engine


 
redax5 said:
1st set of barrels, liners out, face skimmed, flange recess machined, ready to drop liners back in
what a pain in the butt this is going to be having to drop liners on every 1000 engine
1200's just became my favorite engine
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1145's for everyone  :D
 
Must say I'm a convert to big bore high comp 1200 engines.
The Mirage works out at 1126cc, with Asso high comps.
The engine feels ALIVE!!!
 
Its very close to Crispins workshop,lots of Laverda action happening there,might look into this with the locals.Whats the best option,full copper flame rings,copper coated steel or full steel flame rings at the appropriate thickness to work with the barrel depression.What material for the rest of the gasket? Number required?
 
Dellortoman said:
It might be worth talking to a head gasket manufacturer about getting some gaskets made to the right spec. Could save a lot of work modifying the liners on the 1000 engines. How about these guys in Hornsby NSW? http://www.swansonsgaskets.com.au/setup.htm

Cam
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have been using Swansons for at least 3 years for custom head gaskets to suit 82-84mm bores
also get them to make me a range of base gaskets in various thicknesses so I can raise or lower barrels as needed

 
sfcpiet said:
Phil,

I don't think the o-rings really do much in the way of sealing, reckon they're more-or-less only a sort of back-up for the gasket itself.  They won't stand the brunt of compression if the gasket lets go in one of the "corners", nor will it hold back oil pressure if there is the slightest recessing of the liner because of the overlap, as I had to find out.  More often than not, I find crumpled and deformed o-rings, even swollen ones, almost completely blocking the oil passage.

Imho, the o-rings were an attempt to keep the oil from sweating to the outside because of the early gasket mating face design, and a real problem once the liners start to protrude.  The factory tried to support the o-rings by fitting the thin walled bushes for 79-80, but omitted them later on.  I use a tiny smear of Loctite 514(?) all around the outer edge of the gasket, and if all is well in the liner dept., usually ends up completely oil tight.

The "copper" rings were only copper-plated steel, probably for corrosion resistance.

piet
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Two questions:

1.  Should I avoid using the o-rings if there is the risk of them swelling and blocking oil passage?

2.  Would it be worth asking the plating shop to put a new gasket into their copper-plating bath?  It might build up enough copper on the flame rings to make them thick enough to deal with a recessed liner.  I assume the gasket material is waterproof.
 
redax5 said:
have been using Swansons for at least 3 years for custom head gaskets to suit 82-84mm bores
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I reckon if they've already been making gaskets for 1200 liners, then it should be pretty easy to adapt their pattern for the 1000 liners. Basically only a different diameter (and slightly thicker) flame ring.

But if they need a drawing, I have all the dimensions and locations of stud holes for the 1000cc gasket plotted in a CAD file (from when Motoddrob made the copper gaskets) so I can create a drawing for a composite gasket pretty easily.

Cam
 
Phil in an earlier post added something about moving some holes

I also had the "O" ring holes moved diagonally 1mm outwards to ensure a good width of flame ring where hole impinges on the ring

Some input re optumum material?

I have one of Piets thicker gaskets coming to maybe use as a template?

 
Just get them to supply some adhesive holes separately and you can stick them wherever you like  :D

I have one "good" gasket left at home. The flame rings on an identical one I sent to Greg were 1.38mm thick, but I dunno how thick the rest of the gasket is. I'll measure the other one when I get home this evening.

Just a thought on moving the o-ring holes outwards, wouldn't that put the o-rings in the wrong spot and make it more likely for them to squeeze into the oil gallery?


 
Dellortoman said:
I reckon if they've already been making gaskets for 1200 liners, then it should be pretty easy to adapt their pattern for the 1000 liners. Basically only a different diameter (and slightly thicker) flame ring.

But if they need a drawing, I have all the dimensions and locations of stud holes for the 1000cc gasket plotted in a CAD file (from when Motoddrob made the copper gaskets) so I can create a drawing for a composite gasket pretty easily.

Cam
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obviously if they have been making gaskets for me for last 3 years then they must already have a drawing on file, most likely the one I sent them
need to measure what thickness their gaskets are, they are thinner than a standard gasket, 0.7mm from memory, work well on flush barrels

 
So what does all this mean for engines already rebuilt, asks he with interest?
 
My copper ringed gasket measures 1.05mm thick on the gasket part and 1.35mm thick at the flame rings. I've not done any research into head gasket design, but I'd expect that 0.3mm difference should be enough to tolerate a reasonable range in barrel recess (something like the variation that Red's photo showed) and still have some crush on the flame ring when torqued down.

Davo, if an engine is running OK, has good compression and not burning or leaking oil, then I'd recommend the "if it ain't broken, don't fix it" approach.

Cam
 
I know this sounds like a bodge, but would using a copper or steel ring, sized to fit the recess, work? 

Reason I ask. is that I have two new gaskets with steel flame rings that are flush with the composite material.  Not keen to disturb the barrels, as they are in good order.

Tom
 
Davo said:
So what does all this mean for engines already rebuilt, asks he with interest?
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checked your engine build photos, can see one photo that shows the head gasket in place and it has writing on the gasket so you have an old style gasket installed
all will be good

 
Bewdy, got enough drama at the moment without additions.

I did look through the rebuild photos before posting but couldnt find a clear view of the top of the barrels so was just wondering, like.
 
final result after a bunch of stuffing around, RS will not need to worry about his new head gasket, within 0.01mm from flush
if these new head gaskets don't seal at 0.01mm, well stuff em, will do something else



 
That should work fine. I've been setting the sleeves up like this for several years and haven't had any problems with the gaskets I've gotten from OCT. I had a couple of 750s in last year with protruding liners and after heating the barrels up and letting it all cool off with weight on the liners themselves they went back down where they needed to be. Better to check before removing material that needs to be there. I also mark the positioning of the sleeves if they are not going to be bored later. I made this mistake once and found the bore which was round before was afterwards a bit pear shaped. After an hour of fumbling with the damned thing I got it back to where it started and the bore was round again.

Tom
 
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