The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: Colsbeeza on 20.07. 2019 01:54

Title: Mess-Free Cylinder Fitting
Post by: Colsbeeza on 20.07. 2019 01:54
Last time I fitted the cylinder block, I had gasket goo spread from a---hole to breakfast time (to use an old Oz expression).
It is a fiddly business. Problem is placing gasket goo on both sides of the cylinder base gasket before fitting cylinders, getting rings inserted etc. By the time I had that all done, the goo was half dried and lumpy on both sides of the gasket. It was not a nice look!
I'd like to do it next time (next week hopefully) a little tidier. Maybe place goo on bottom of gasket only??
For those members who have done it hundreds of times, how do you do it cleanly?
Col
Title: Re: Mess-Free Cylinder Fitting
Post by: Shark on 20.07. 2019 02:37
Hi Col, I just did that job on another marque (the one beginning with T) and used Loctite 518 with no problems, it does not cure until there is no O2 present according to the label. It is rather sticky so use anything but your finger to spread it out. It has worked for me, others will be along soon with alternatives. Cheers.
Title: Re: Mess-Free Cylinder Fitting
Post by: orabanda on 20.07. 2019 07:29
hi Col
I prefer to only put sealant / goo on one side of a gasket, and lightly grease the other side.
It won't leak, and will be easier to dis-assemble.

BSAeeing you,
Richard
Title: Re: Mess-Free Cylinder Fitting
Post by: Greybeard on 20.07. 2019 09:18
I use a smear of Blue Hylomar. You allow it to become tacky before you tighten the joint.

Fitting the cylinder block I would stick the gasket to the block first. I might bolt the block to the case with a few nuts before the pistons have been added and leave the sealer and gasket to fully harden.
When I'm fitting the block for real, I wipe a smear of BH on each side, (wait a few minutes) before dropping the last inch.

Cellulose thinners cleans excess BH off the cases.

Title: Re: Mess-Free Cylinder Fitting
Post by: BSA_54A10 on 20.07. 2019 13:14
Like Orabanda,
Hylomar on the cases then gasket
Then pistons rotated up into the barrels
Then Bentonite grease on the top of the gasket & lower the barrels
That way the barrels will always strip clean.
Title: Re: Mess-Free Cylinder Fitting
Post by: coater87 on 20.07. 2019 13:28
 Grease on one side, oil the other.

 But i also installed the pistons and rings in the cylinders first.

 I wonder how many base gasket leaks are caused by voids in gasket goo?

 Lee
Title: Re: Mess-Free Cylinder Fitting
Post by: Colsbeeza on 20.07. 2019 13:36
Thanks Gents,
Overwhelming opinions that the top of the gasket should be left dry until just before lowering cylinders.
Also most are happy that grease / oil will seal well on the upper side.
Like GB, I thought that gasket goo under gasket may need compressing / levelling by the cylinder block, then raised for assembly.
That should solve the mess.!
Cheers Col
Title: Re: Mess-Free Cylinder Fitting
Post by: bikerbob on 20.07. 2019 15:32
For the past couple of years I have only used a very slight smear of grease on all gaskets both sides except cylinder head gaskets where I only aneal them, this is on both the A7 and the A65 the A65 has no oil leaks anywhere and the A7 has a slight oil leak from the back of the primary case but not the primary case gasket. Also I only buy head gaskets now all other gaskets I make myself it does take some time but if you use your existing cases as a template home made gaskets are a much better fit and I always make 2 so I always have a spare. I have had a problem recently with charging so I have had the dynamo off and on in fact I have used the same timing side gasket 3 times and it is still oil tight using only a slight smear of grease the advantage is you can remove the cases without the gaskets sticking and tearing.
Title: Re: Mess-Free Cylinder Fitting
Post by: lawnmowerman on 20.07. 2019 18:47
Wellseal for me. Apply thinly with a small brush on both surfaces and both sides of the gasket and leave for half an hour before assembly. Pretty sticky so holds the gasket in place on one face of the joint. It never goes off so does not tear gaskets on disassembly. Cleans off with thinners.

Jim
Title: Re: Mess-Free Cylinder Fitting
Post by: ironhead on 20.07. 2019 22:06
Gasket goo on one side, molycote111 silicone grease on the other side = no problems *smile*
Title: Re: Mess-Free Cylinder Fitting
Post by: hywayman on 21.07. 2019 10:24
Huge fan of Loctite MR5923 non-hardening sealer (or similar like 3J) for older castings with a light cover on both sides of the gasket.
Title: Re: Mess-Free Cylinder Fitting
Post by: chaterlea25 on 21.07. 2019 19:19
Hi All,
I stick the lightly greased gasket to the cylinder base wit a light smear of Hylomar, leaving the crankcase clean of any goo
Place some parallels on the case to keep the pistons square, ring clamps on the pistons and slide the cylinder onto the pistons
Some Hylomar can be applied to the crankcase base before the cylinder is finally lowered into place
Avoiding any mess *smile*

John
Title: Re: Mess-Free Cylinder Fitting
Post by: Peter Gee on 22.07. 2019 21:07
I use Three Bond thinly on the underside of the gasket. Then torque down the head to 12 lbs and leave it overnight. Next, Permatex Ultra Copper on  upper gasket, thin indeed...meanwhile I grease the underside of the block lightly, let the Permatex settle a bit (15 mins), then fit and apply 15 lbs again, then 18 after a few hours.

This wat the Three Bond forms a permanent plastic bond to the lower side, but the upper can always be broken easily