The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: gt6uk on 06.01. 2017 18:57

Title: Head gaskets
Post by: gt6uk on 06.01. 2017 18:57
I have recently been given a genuine NOS BSA top end gasket set which includes a composite ( copper/asbestos ) head gasket. How do these compare to the solid copper gaskets now available?

Steve.
Title: Re: Head gaskets
Post by: bikerbob on 06.01. 2017 19:35
I have never been a fan of those composite gaskets for me they have always failed go with the solid copper but don't forget they have to be annealed before use and you can use them again unlike the composite ones.
Title: Re: Head gaskets
Post by: coater87 on 07.01. 2017 01:22
 When I use a really old paper gasket set, some gaskets you find might seem too small. Stud holes are too close and it is all just a little wrong.

 Just use a spray bottle with water and mist the gaskets a little.

 The paper loses its moisture over the years and actually shrinks. They will get back to the original size in 10 or 15 minutes. Just dont soak them, they are paper after all.

 Lee
Title: Re: Head gaskets
Post by: KiwiGF on 07.01. 2017 10:33
I have recently been given a genuine NOS BSA top end gasket set which includes a composite ( copper/asbestos ) head gasket. How do these compare to the solid copper gaskets now available?

Steve.

I used those composite gadgets in my youth but not recently.....they obviously work ok, and are probably more forgiving of unflat heads and barrels, but if they fail, in my experience, it is usually "catastrophic" eg no compression, and often between cylinders, whereas a solid copper will generally just leak.....albeit noisily......and get you home on one and a half, as opposed to one cylinder, or none.

Just my 2 cents worth......
Title: Re: Head gaskets
Post by: bikerboy on 19.02. 2017 02:02
I have also had a composite one fail (many years ago) and it blew from the cylinder to the push rod tunnel. Having the new trendy alloy pushrods at the time it melted two of the damned things. I was in Leicester about 100 miles from home and I remember using grinding paste to lap the head on a showroom window at about one in the morning while nobody was about :)
Title: Re: Head gaskets
Post by: RichardL on 19.02. 2017 04:36
  I was in Leicester about 100 miles from home and I remember using grinding paste to lap the head on a showroom window at about one in the morning while nobody was about :)

So that was YOU!
Title: Re: Head gaskets
Post by: Tomcat on 19.02. 2017 06:35
Steve, I don't use NOS gaskets as there is better quality products available now. If you did use that head gasket be sure to use some sealant around the pushrod area. TC
Title: Re: Head gaskets
Post by: The Artful Bodger on 19.02. 2017 11:09
I have one on my Huntmaster, after having the head skimmed I torqued it down on the bench then the next day torqued it down again, it went down quite a bit. I fitted the engine in the bike and torqued it down again, it went down more.
  I ran the bike for a few miles and torqued it down again (the Huntmaster is easier for removing the rocker assembly) and it went down again. Did 500 miles and yes................ it tightened up again! After about another 1000 miles I had a slight oily-nes from the left cylinder so I bought a copper gasket ready to replace it, but being lazy decided to try to tighten it again, it went down again and cured the oily-nes
  However 4000 miles later and it's still's fine with no leaks so fingers crossed, if and when I take the head off again I'll be using the solid copper gasket.
  On my M21 I decided to use a composite gasket as the alli cylinder head had seen better days including welding a crack in the combustion area, like the Huntmaster it took a number of re-torquing sessions before it totally settled in (much easier with a side valve!) and it's been fine for the 2000 odd miles I've put on it.
Colin
Title: Re: Head gaskets
Post by: Derby Rob on 19.02. 2017 17:53
not a fan of the composite gasket,had one blow on me coming back from an MOT , replaced it with a copper one, never been an issue since.
Title: Re: Head gaskets
Post by: terryg on 19.02. 2017 20:12
Old Minis have given me grief when trying composite gaskets. That was before realising the need to run the engine up to temperature and then, on cooling, retorque the head nuts.
The best solution I found was to use annealed copper gaskets AND check torque after running at temperature.
Compared to the A10 the 'land' between cylinders on the Mini is narrow but I still prefer solid copper for the A10s.
Title: Re: Head gaskets
Post by: terryg on 23.02. 2017 08:33
There was another thread recently on carbon fibre head gaskets. The initial comments sounded promising.

I would like to hear more from those with experience of this relatively new development.

Anyone?
Title: Re: Head gaskets
Post by: Peter in Aus on 23.02. 2017 09:26
I have fitted  solid carbon fiber head gasket (as stated in a privies thread) supplied by Draganfly, it is still going well with on oil leaks and it has not been re-torqued since assemble over 12 months ago and has done over 3000 miles.Time will tel if it is OK but certainly looks good at present.
Peter 
Title: Re: Head gaskets
Post by: KiwiGF on 23.02. 2017 09:39
This is a tricky one, I don't expect a head gasket to fail, ever.  *problem* .So it's going to take a very long time before I would buy a fibre one.....And lots of members reporting doing lots of miles  *dunno2*

Hopefully my current solid copper gasket will outlast me (as long as I keep annealing it each head removal) but maybe that's why the carbon one was thought of...... *whistle*
Title: Re: Head gaskets
Post by: duTch on 23.02. 2017 10:07

Quote
  I have recently been given a genuine NOS BSA top end gasket set which includes a composite ( copper/asbestos ) head gasket. How do these compare to the solid copper gaskets now available?

Steve.

 Maybe they couldn't find a buyer, so went next option ?

 
Quote
      I was in Leicester about 100 miles from home and I remember using grinding paste to lap the head on a showroom window at about one in the morning while nobody was about :)


So that was YOU!

 No- it was me ..but Sparticus was not far away                         *smile*

 I'm using a copper one and am quite happy thus far, and the re-re..?..usability appeals to me



 
Title: Re: Head gaskets
Post by: coater87 on 24.02. 2017 01:51
 I remember when I was young my dad always sprayed this really thick silver paint on all his head gaskets, but I don't remember  what it was..... *sad2*

 Now this is going to bother me.

 Lee
Title: Re: Head gaskets
Post by: coater87 on 24.02. 2017 16:40
 Called my brother and he remembered.

 It was the silver paint transmission shops used to spray on rebuild transmissions to make them look "new". I dont know if they still make that stuff. He also said you could spray it onto a glob of grease and it would dry into a shell over the grease. *eek*

 My brother said quite a few of the hill climber guys at the time (early 1970s) didnt use a head gasket, just that silver paint stuff. The heads supposedly didnt leak and they got a little higher compression.

 I wouldnt try that, but at that time 1950s bike parts were probably available at the local junk yard...

 Lee
Title: Re: Head gaskets
Post by: duTch on 24.02. 2017 20:40

 The other thing about copper is that it's possible to make your own, like I did when I couldn't buy one at all (not an easy task)

 
Quote
  I remember when I was young my dad always sprayed this really thick silver paint on all his head gaskets, but I don't remember  what it was..... *sad2*
 

 I never did it,but remember hearing about it and I think it was called 'Silver Frost', at least over here- not sure if still available or had a name change as I've used similar

Title: Re: Head gaskets
Post by: WozzA on 26.02. 2017 05:47
This is the stuff I use on my gasket, never had a leak yet...  *wink2*
Title: Re: Head gaskets
Post by: jjbsa on 04.03. 2017 21:29
I have also had a composite one fail (many years ago) and it blew from the cylinder to the push rod tunnel. Having the new trendy alloy pushrods at the time it melted two of the damned things. I was in Leicester about 100 miles from home and I remember using grinding paste to lap the head on a showroom window at about one in the morning while nobody was about :)

This has got to be one of the best stories ever!!!  The ingenuity of the young motorcyclist!