The rubberised gasket on my rocker cover has been refitted probably 20 times and had started to crack. I ordered a replacement with my last consignment of parts and a cork one was supplied.
I have learned to be gentle with the securing nuts so as not to create a leak or deform the cover and I think that's why nyloc nuts are used....They don't come loose. But it seems that the cork gaskets need a bit more torque because mine started leaking after a hard 60 mile run. Luckily I had stopped anyway as I had an urgent appointment for a different type of leak behind a roadside bush ?. I caught it just in time...Both leaks.
Does anywhere sell the better-style gaskets individually or in multiples of the same gasket?

fiat500 said:

The rubberised gasket on my rocker cover has been refitted probably 20 times and had started to crack. I ordered a replacement with my last consignment of parts and a cork one was supplied.
I have learned to be gentle with the securing nuts so as not to create a leak or deform the cover and I think that's why nyloc nuts are used....They don't come loose. But it seems that the cork gaskets need a bit more torque because mine started leaking after a hard 60 mile run. Luckily I had stopped anyway as I had an urgent appointment for a different type of leak behind a roadside bush ?. I caught it just in time...Both leaks.
Does anywhere sell the better-style gaskets individually or in multiples of the same gasket?

Click to expand...

Hi Peter, I was using a rubber item under my alloy rocker box and had the same problem as you, the rubber was going hard anyway. I have to say that I am now using cork gaskets on mine and providing I am careful it does not leak! Always make sure to clean both surfaces with something like methylated spirit (no residue) and don't on any account allow the area to become even the slightest contaminated with oil during the fitting. Also don't over do the nut torque as you can squeeze the gasket out from the sealing position. Take your time doing the nuts up a little at a time and leave it to settle between goes. Unfortunately if the gasket becomes contaminated it will only get worse as in my experience tightening it down more just dislodges the gasket from it's seat and increases the leak!!!!

Ian.

Evening Peter;
Axel Gerstle sells the the 'rubberoid' gaskets as a separate item. It is called a "valve cap gasket (rubber)", the part number is:-- 19006/1 and the cost is about E2.30 each--suggest you get a couple!
I have always advocated the 'rubberoid' gaskets, for both the rocker-cover and the sump as against the 'cork' variety.

?

Bleeding Knuckles said:

Hi Peter, I was using a rubber item under my alloy rocker box and had the same problem as you, the rubber was going hard anyway. I have to say that I am now using cork gaskets on mine and providing I am careful it does not leak! Always make sure to clean both surfaces with something like methylated spirit (no residue) and don't on any account allow the area to become even the slightest contaminated with oil during the fitting. Also don't over do the nut torque as you can squeeze the gasket out from the sealing position. Take your time doing the nuts up a little at a time and leave it to settle between goes. Unfortunately if the gasket becomes contaminated it will only get worse as in my experience tightening it down more just dislodges the gasket from it's seat and increases the leak!!!!

Ian.

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I agree 100% with what Ian says above.

Especially the part about ensuring that no oil gets between the sealing surfaces. Some people think a little oil won't cause a problem, IT WILL!

Some even apply a film of grease to gaskets - somewhere back in the mists of time this fallacy was started and continues to this day! Ask people why they do it, they'll say it helps the gasket fit better/ seal better/ prevents the gaskets sticking to a surface etc. etc. Yet workshop manuals say clean the gasket surfaces and fit the gasket dry!!

I worked in a Fiat dealership back in the 1970's/'80's. Often had to 'dress' pressed steel valve covers to straighten flanges distorted by overtightening. Once this was done, a new, preferably rubberoid type gasket was fitted DRY and gently snugged down - no further leaks! Same applied on other makes of vehicle at that time also.

One thing I discovered was why does oil or grease (which is oil in a soap) on the gasket sealing surface result in a leak....

It's due to a process called afaik 'capillarity' (I'm no scientist!!) or maybe 'wicking'. The oil film provides a path for further oil to follow. The pressure is greater inside the engine than outside, so oil tries to flow outwards. This flow increases as the engine heats up and the oil film heats up (warm oil flows better). As some oil weeps out, more oil is drawn into the space vacated between the gasket and the surface being sealed.

2 further thoughts!

If you can only get a cork (as opposed to a rubberoid) gasket, do not despair. If you do as Ian (Bleeding Knuckles) above says it will likely seal just fine. But what I do on valve covers that won't be removed for many,many 1000's miles e.g. OHC engines is to apply a light smear of Hylomar or similar non-hardening sealant to the inside vertical face of the cork gasket. Some use a shellac type gasket goo, but I'm extremely wary of this stuff. Your decision, your risk!

Where pressed steel valve covers are held down by nuts on studs sealed by fibre washers, I reckon most fibre washers are too hard to be sealed by lightly tightened nuts. There are better sealing washers available (e.g. Dowty washers- aluminium washer with a built-in inner rubber seal) but I use a smear of Hylomar sealer on the both faces of the fibre washer

or use a fibre washer with a larger bore and insert a rubber 'O' ring in the space between the threaded stud and the fibre washer

or use a rubber washer if I have one to hand.

Guys here with lathes could machine a small groove on the underside of the valve cover nuts to accept rubber 'o' rings.

P.S. Please don't even mention using silicone type sealants in an engine when I'm in the room 'cause I'll break out in a cold sweat and start shaking!

Al.

fiat500 said:

Does anywhere sell the better-style gaskets individually or in multiples of the same gasket?

Click to expand...

I just had a quick look in my gasket box and I have quite a few 500 & 126 rocker cover gaskets if you are looking for some ?

Or you can get silicone gaskets. I'm going to try one of those

Ooop'S sorry Al but I'm using silicone gasket sealant around the spigot area because I have a 1mm support plate (it also gives me the correct piston height) and it needs sealing on both sides!!!

Ian.

What I was orginally getting at was that given the choice, I will always go for the Ruberoid type, which I think are the original fitment anyway; so Toshi please expect a message.

I am aware that many people mistakenly overtighten them and that this can not only cause leaks but may distort the cover. It was my timidity that caused my leak. So the cork ended up fully saturated with oil all over and as a roadside repair it wasn't apppropriate to clean it properly.
I have since degreased everything without further tightening or dismantling and after another 160 miles there are no leaks.

I understand the problems that can be caused by over-generous use of low-quality sealant, but there are applcations in modern vehicles, gearboxes in particular, where the factory choice is a premium quality silicone sealant. With this in mind I have very successfully (so far) used it on the 500, instead of the regular gasket, for the timing-cover, the distributor and the gearbox end-cover and centre-line joint.

the hobbler said:

Evening Peter;
Axel Gerstle sells the the 'rubberoid' gaskets as a separate item. It is called a "valve cap gasket (rubber)", the part number is:-- 19006/1

Click to expand...

Thanks Tom...found it....out of stock. I think that's how I must have chosen the corker.

fiat500 said:

What I was orginally getting at was that given the choice, I will always go for the Ruberoid type, which I think are the original fitment anyway; so Toshi please expect a message.

I am aware that many people mistakenly overtighten them and that this can not only cause leaks but may distort the cover. It was my timidity that caused my leak. So the cork ended up fully saturated with oil all over and as a roadside repair it wasn't apppropriate to clean it properly.
I have since degreased everything without further tightening or dismantling and after another 160 miles there are no leaks.

I understand the problems that can be caused by over-generous use of low-quality sealant, but there are applcations in modern vehicles, gearboxes in particular, where the factory choice is a premium quality silicone sealant. With this in mind I have very successfully (so far) used it on the 500, instead of the regular gasket, for the timing-cover, the distributor and the gearbox end-cover and centre-line joint.

Click to expand...

Peter, you're quite right about the use of silicone sealant in some applications where no gasket is used, as an alternative to a gasket or situations as described by Bleeding Knuckles (Ian) above. Just keep in mind that gaskets have thickness and substituting sealant may result in less end-float on shafts/more pre-load on bearings etc. Not usually a problem though.

I was referring to the type of situation you mention above where too much sealant is used and gets squeezed out inside the engine to possibly cause havoc. Many times I've removed an oil sump (oil pan) to find strings of silicone sealant, having broken off elsewhere in the engine, almost completely blocking the oil pump inlet screen!!! One little stray speck of sealant can wreck motorcycle engines if it blocks a small oil feed hole.

That's what gives me the shakes.

I've often wondered if instead of using a rubberoid (which I think are great and iirc first appeared on Fiats?)) or cork gasket on e.g. a valve cover if it would be possible to lay a thick bead of silicone sealant on the valve cover sealing flange and level it evenly using a former/guide, then leave it to set, to give an even thickness/width of 'sealing' strip similar to the rubber type gaskets/seals used on many e.g. Japanese car valve covers. This would result is a gasket that was re-useable and sealed well. Might be a good idea to fit small spacer dowels (I've used short pieces of brake pipe or metal fuel pipe depending on size required) over the mounting studs so that the valve cover could be adequately tightened down without squeezing out the soft 'gasket'

I'm now going to lie down with a cold compress on my brow and listen to a relaxation cd until the shaking ceases because someone mentioned SILICONE SEALANT

Al.

Bleeding Knuckles said:

Ooop'S sorry Al but I'm using silicone gasket sealant around the spigot area because I have a 1mm support plate (it also gives me the correct piston height) and it needs sealing on both sides!!!

Ian.

Click to expand...

:yuck: :yuck: :yuck: AhhhhAhhhhAhhhh

Did you know that the wet type cylinder liners fitted to Jaguar V-12 engines were sealed at the lower spigot with a smear of Hylomar sealant. Iirc Hylomar was invented by Rolls-Royce for use on aircraft engines?. (I like Hylomar!).

In the above application I think I'd use use a semi-hardening sealant such as Red Hermetite, but to each his own.

Al.

Long, long, ago (all the good stories start with this!),

mechanics often made their own gaskets.

There used to be sheets of different types/thicknesses of gasket paper and gasket material available to suit different applications e.g some had reinforcing fibres, some were heat resistant, iirc some even contained asbestos

These sheet materials were stocked by industrial supply houses, engineering factors and motor factors especially those which supplied truck workshops.

A new or used valve cover gasket could be used to trace a pattern on some suitable sheet material and holes punched out by a hole punch or a sharpened metal tube. Punch the holes before cutting out the gasket.

Just an idea if you ever have difficulty getting hold of a suitable gasket..

Al.