Which sealants do I need for head gasket and cylinder base?

Mad Hatter

Mad Hatter

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Can anyone advise which sealants I should use for the head gasket and cylinder base to crankcase joint. I’m thinking Granville blue for the head gasket (thin smear) and maybe threebond 1184 for the cylinder base (thin smear again). 96, R80GS Basic.

Is this correct?
 
Either Fresh clean grease lightly smeared on both sides of the Head gasket and rubber grease on base O ring

OR Nothing

Honestly Its way past necessary!

I have been doing these two options for 40 years from my Old Granda taught me (He was the Chief Engineer of N I Railway and Bus network)

BUT Do make sure that your Pushrod tube holes line up with the Barrel and your top stud O rings are neatly fitted in their recess (Dab of Rubber grease could help here :green gri )

And when you are torquing the heads up?? Especially on the later motors .................

Pay VERY close attention to the torque values :rob
 
Do not put anything on a head gasket. Ever.

It's a compression gasket. And specifically designed to be used without anything. Adding sealants or grease will affect how it compresses. Grease can burn holes in the gasket and also cause air pockets. Just make sure the mating surfaces are immaculate. If it doesn't seal, you have other problems.

The base gasket is only under oil pressure. And they don't get that hot. Any high quality high temperature RTV sealant will do. There are HUNDREDS of brands to choose from. But red or grey is usually more expensive and has higher heat tolerance.

Just read the packet/description and make sure it's correct for the application. Granville is a trusted brand.

Personally, I use Dow Corning. It's expensive and it's what BMW use. But I can't take risks as it's my job !!
 
Not going to start a battle but I disagree! I know you do this for a job and have total respect for you :thumb

but I also have been doing this since I was about 10 years old, My Granda taught me his methods and as I said he was the chief engineer for the UTA (Ulster Transport Authority 50 and 60s)

e.g. No matter what the work sheet shows Double check the diagnosis yourself

Always check your work

Keep a tidy workstation! Be methodical

I think I would like to say that Surface prep and Head gasket / piston orientation Correct Head (and rocker cover centre bolt) torqueing down, pushrod fitting, Exhaust Nut removal refit are way more important than Sealants "On an Airhead"

If by any chance you have an issue (which as an amateur the OP may have) Once you have compressed an airhead head gasket (Even worse heated it even for 5 mins running,) Using your way its difficult to get it off to be useable again once its been torqued up and sealant on the base its just messy and in reality unnecessary and you have the chance of intrusion to the oilways

The Rubber grease helps to prevent the O ring from catching and tearing and If you slide the o rings down to the smooth part of the studs and have a small pocket of rubber grease in their recess in the barrel you can bring the barrel and piston down together put them in their recesses and hook the piston into the conrod and squeeze the barrel piston assembly on down
I also I also use a very light skim of Graphogen on the Rings and piston skirts

MotoRevive said:
If it doesn't seal, you have other problems.
Click to expand...

MotoRevive said:
But I can't take risks as it's my job !!
Click to expand...

Exactly! You have a much higher standard of work than an average DIY'er and rightly so, Plus the issue of warranty

BUT you also have been doing this many many years and know the procedures and pitfalls so you build it once and it stays built :wink

Mad Hatter feel free to use whichever method you feel like using :rob

But I can assure you that a very light coating of clean fresh grease on the Head gaskets is not an issue (Providing you torque them up correctly) and I have built them all, Seibenrock 1000cc conversions, 1070 rebuilds and every combination of 65 80 and 100 airhead, plus many variants of classic japanese and cars/ vans / trucks using the light film on gaskets It doesn't make air pockets or burn

Almost as controversial as "What Oil should I use?" if truth be told :comfort

Now just you wait till you hear them groan as I say I use the fresh clean grease smear method on all paper gaskets inc the sump, the rocker covers and even float bowls :green gri :green gri :green gri

:aidan
 
I have no intention of getting into an argument either.

But you just do not reuse modern produced head gaskets. You might think you've got with it. And it may seem fine for years. But it's not a risk you should take. Of course, you don't have the risk of a water jacket leak but a badly sealed head gasket causes a lot of damage to an engine. It's not a risk you should take.

A head gasket is not difficult to remove anyway. It it's stuck to head or cylinder it's because it's been leaking and burned. Maybe because it's been fitted with grease... :rolleyes:

If you're going to work on your own engine, then do it right or don't do it at all. And if you think you're going to be pulling it apart again because you got it wrong then you shouldn't be doing it at all.
 
Gents, an interesting debate. I’m not a complete novice btw (40 years as an aero engineer and 40 years spannering my own bikes), but I was interested in whether there was any specific advice for airheads. I think what I’m going to do is use a very thin smear of threebond on the cylinder base and nothing on the head gasket.
 
Fully agree with the light coat of grease on the gaskets. On the newer bikes, there is no base gasket, just a thin bead of Dirko or other high quality high temp gasket cement. Clean faces and and clean threads matter a lot. I was putting the heads back on my new-to-me T500 and I was just about to put the sleeve nuts on the barrel studs when I took a proper look at them and found the internal threads were in a state, old grease etc. Luckily, a friend had the right tap and die (10mm x 1.25 I think) so it all looked and went on great after a bit more time spent on the prep.
 
Base gaskets. Fine... Grease or sealant is fine.

It's head gaskets that should never be grease or have sealants applied.

On modern bikes (As Binridin correctly states), many surfaces have no gasket at all. Just sealant. The sealants are so good and the manufacturing of cases is so precise these days that a paper gasket is more unreliable.
 
MotoRevive said:
It's head gaskets that should never be grease or have sealants applied.
Click to expand...

Feel free to do your jobs your way, as you well know there's more than one way to do many a job (But always the right way ;) )

Please allow us old fellas our pleasure of greasing something up and sliding it together :green gri

I don't know who or what told you that the grease burns a hole or anything else

Its a Fallacy! There has to be a defect there, to start that chain of events, end of story :rob

Same as Radiator repairs Many years ago I had to explain to a customer

Foxes Sand Quarry at Blackpool the expanded tubes and leak in his radiator were not a defect!

They were the end result of a blown headgasket over pressurising the cooling system! He thanked me when he came back as I had just saved him a £1000 on a new rad that would have done exactly the same thing in a couple of weeks

Cause and effect :rob

AS I said before My Grandad (a very respected man in the engineering world here) taught me that technique 40 years ago and I have never had any issues and I suspect that I have done thousands of engine builds and rebuilds in that time
"BUT" and I stress "BUT" I am meticulous in cleaning everything and cleaning off threads and cleaning threads out, checking for warpage, checking for valve seal etc etc and something as simple as wiping grease off the studs and applying the light coat of oil when instructed and to follow Torque sequences and values
 
Why would you grease a head gasket ??? So you can re-use it easier ? They don't stick anyway. I pull old engines apart all day long. Head gaskets do not stick.

Gaskets are made differently now. They not anything like your grand father's day.

You just don't need to add grease. If grease helped in anyway, they would come with grease on them. They are manufactured to be as good as they can be. Don't mess with that science.

I pulled this off Haynes website in case you weren't aware.

Most modern head gaskets are made from multiple layers of steel (MLS). Typically these use three steel layers; the centre layer is slightly thicker, while the two thinner outer layers are coated in rubber-like high temperature and chemical resistant polymers (most commonly Viton) which helps the contact faces seal against the cylinder head and engine block.

Earlier head gaskets were often made from composite material (often referred to as fibre head gaskets), typically graphite-based coated in a wax-like finish, and with beads of silicone around the waterways and oilways to aid sealing.

These, older, composite head gaskets are more prone to failure than modern MLS gaskets, but many MLS replacements are now available for older engines that would have been produced with a composite gasket when new.
 
Mad Hatter said:
Gents, an interesting debate. I’m not a complete novice btw (40 years as an aero engineer and 40 years spannering my own bikes), but I was interested in whether there was any specific advice for airheads. I think what I’m going to do is use a very thin smear of threebond on the cylinder base and nothing on the head gasket.
Click to expand...

That is the perfect way to do it. :okay
 
Ted if you don;t like my methods then that is fine but don't try to take the piss out of me! :blast

I have worked upon many more varieties of internal combustion engines than you are ever likely to!!

By your own admittance, You have 20 years of Experience

I have over 40 from Small 2 stroke motorcycles, to large commercial vehicles and even Jet Turbine driven generators and High volume water turbines

And Yes you have annoyed me!

MotoRevive said:
Most modern head gaskets are made from multiple layers of steel (MLS)
Click to expand...

When you get one for an Airhead Let me know

But you pull these old engines apart all the time, you know there is no such a thing!

Normally I turn the other cheek, but You are just being an annoying twat now!

Just so you know! I respect your method of working but kindly do the same for me!!

:stopbeing
 
DrFarkoff said:
Ted if you don;t like my methods then that is fine but don't try to take the piss out of me! :blast

I have worked upon many more varieties of internal combustion engines than you are ever likely to!!

By your own admittance, You have 20 years of Experience

I have over 40 from Small 2 stroke motorcycles, to large commercial vehicles and even Jet Turbine driven generators and High volume water turbines

And Yes you have annoyed me!



When you get one for an Airhead Let me know

But you pull these old engines apart all the time, you know there is no such a thing!

Normally I turn the other cheek, but You are just being an annoying twat now!

Just so you know! I respect your method of working but kindly do the same for me!!

:stopbeing
Click to expand...

Oh Jesus Christ. Grow up. I am not taking the piss out of you at all. Nor am I trying to wind you up. I just don't agree with what you're saying. We can disagree right ? Don't start insulting me. I'm almost embarrassed by even replying to this but I never back down from an someone calling me a twat when they've never even met me. So I'll play your game. Lockdown does strange things to us all.

So yeah, I've been doing this for 'only' 20 years. But six days a week. 365 days a year usually. 9 hours a day. I've done the training, been the seminars, worked in the dealerships, taken the exams and now I run my own workshop.. And i've also got thousands of engine builds under my belts for 2-stroke rotters to £50,0000 race bikes. And you know what.. I've never had a head-gasket leak since I was 18 when some old timer told me "I've been doing this for 60 years" told me to reuse my old one.

However, I think arguing talent is crude and 'Willy waving" is pretty pathetic. But then, you did call me an annoying twat. Really professional of you.

I appreciate you have a lot of "years' under your belt and that's incredibly valuable and I respect that A LOT. But as soon as you started talking about re-using head gaskets, I just assumed you were a backyard hammer swinger. Yeah, I know plenty of people re-use them on old airheads and get away with it. It's just really bad-practice. For me engine building is like surgery. Do it right or just don't do it.

I also know plenty of people who have been pulling engines apart for 60 years and still use a sledge hammers because that's what they were taught. And they say shit like "I've been doing this for 60 years, you can't me how to do it" As they condemn another engine to the scrap bin" They've just been wronger for longer.

I also know guys who have been working in the trade for less than ten years who are absolute gods at their trade. They make my head spin and they could probably work for Nasa in their spare time..

So don't try this "I've been doing this longer than you bullshit" It's lame. Time means nothing. It's what you do with that time and it's how you apply that knowledge.

So I repeat. I'm not trying to take the piss out of you. Not at all. I just don't agree with you. I've not going to post again on this thread. It's embarrassing for two grown men to argue like this.

So peace out.
 
Gents, apologies if I’ve accidentally caused this spat. If we ever get out of lockdown the three of us should meet up and have a beer��������
 
I would follow the example of Jim Cray and use DreiBond applied Very carefully on the cylinder base.

Otherwise you will get oil misting after some miles.
 
I see no mention of knocking out a gasket from a cork sheet. :D
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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