Timing Cover Fitting

[Belle427]

Im refitting the front cover this week and wondered which was the best approach.
I was thinking of a very light smear of Hylomar to both metal surfaces, proper gasket and thread sealant to bolt threads.
Does this sound ok?
I noticed on removal some black rtv type sealant under the bolt heads, not sure this is necessary?

[phazed]

Use a quality gasket, (there are cheapies around) with a smear of Hylomar on both surfaces,

You will only have to seal the threads on the lower 2 sump bolts that screw into the front of the cover as they are usually drilled through although I have seen one cover with blind holes.

[carsy]

Ive never used anything on the timing cover gasket. Always just plonked them on and never had any leaks.

Dont forget some sort of sealant on one of the long bolts that break into the water jacket.

[Belle427]

Thanks both.

[Belle427]

Just for future reference the hylomar didn't work for me. Started the engine up and I have a coolant leak.
Looks like the hylomar has allowed the gasket to squeeze out even though I let it set before tightening.
Luckily its not such a bad job and I have a spare gasket which will be fitted dry.

[phazed]

That doesn’t make sense. It must be for another reason.

Hylomar is designed for that sort of application.

[BIG DUNC]

I take it all the surfaces were clean and the remains of the previous sealant used were all scraped away?

[Belle427]

Yep everything spotless as the engine was out and on a stand
just one of those things. I'm sure hylomar is great but it was originally designed for metal to metal surfaces.

[phazed]

The product won't be at fault. I have used the blue on gaskets for maybe 20 years.

Is it possible that the gasket wasn't bedded directly on the mating surface? the surface area is very small in places.

[Belle427]

phazed said:

The product won't be at fault. I have used the blue on gaskets for maybe 20 years.

Is it possible that the gasket wasn't bedded directly on the mating surface? the surface area is very small in places.

Just looks as if its squeezed out slightly in one place. Mistakes happen, only took me 30 mins or so to get it back off so not so bad.

[N7GTX]

phazed said:

The product won't be at fault. I have used the blue on gaskets for maybe 20 years.

Is it possible that the gasket wasn't bedded directly on the mating surface? the surface area is very small in places.

Sorry to disagree but Hylomar was never intended for use with gaskets. It was originally developed under licence by Rolls Royce Aero Division. Mostly it was used on the fuel system components where a gasket would have been too intricate or thin. During the fitting or reassembly of air fuel ratio control units and barometric flow control units (very complicated carburettors if you like) the components were highly machined alloy parts and the thinest smear of Hylomar blue - there was only the one product then - was applied. It was generally excellent in those applications being combined with close tolerance parts.
As I worked in 2 aero engine bays (with perks of the job) I used Hylomar on Mini A series engines, Ford Kent and so on, where gaskets were supplied. In most, within a year and often sooner, they leaked.

Unless the mating surfaces are highly machined and torqued down correctly, Hylomar is definitely not the best sealant for use with gaskets out there.

[carsy]

Don’t put anything on the gasket.

Did you put some sealant on the one long bolt that brakes into the water jacket. I just use a high temp rtv for this and never had a leak.

[Belle427]

I used this on all the bolts

https://www.permatex.com/products/thread-compounds...

[stevesprint]

Very interesting thread as I’m in Peters camp (maybe its an age thing) as I've used blue Hylomar for years with gaskets and only had the cork sump gasket and universal gaskets (one size fits all) like the one on the right squeeze out, the gasket on the left is a perfect fit on the intermediate cover (serp).



My son also had an A series gasket squeeze out once but that was because he didn’t tighten the ‘drop gears housing’ bolts to the engine block evenly.

Iain
Thanks for explaining the history of blue Hylomar.

[N7GTX]

stevesprint said:

Very interesting thread as I’m in Peters camp (maybe its an age thing) as I've used blue Hylomar for years with gaskets

Steve, you and Peter cannot be older than me, surely?

I started playing with Hylomar in 1972

[phazed]

Red Hermatite, 1970 on Lambretta LI 175.

[Steve_D]

Indian head gasket shellac...Isetta bubble car timing cover. 1965

[phazed]

That is old!

[Sardonicus]

Never had problems using Hylomar blue with conventional gasket materials along with Wellseal etc , all old school sealants nowadays of course, Hylomar Blue Quote ..... "This product can be used to replace a traditional gasket or to “dress” it to significantly improve the performance of the gasket ......" but just like RTV sealers used correctly they get the job done used incorrectly they don't work but then what does? (neither are RTV based obviously)

Edited by Sardonicus on Wednesday 28th March 23:42

[stevesprint]

N7GTX said:

Steve, you and Peter cannot be older than me, surely?

I started playing with Hylomar in 1972

You have been play mechanic longer than me, my first car was a Dolomite in the mid 80’s which I eventually installed a Sprint engine in, hence the nick name.

In Peter and my defence it does say ‘gasket and jointing compound’ on the box

Belle427 said:

Just for future reference the hylomar didn't work for me. Started the engine up and I have a coolant leak.
Looks like the hylomar has allowed the gasket to squeeze out even though I let it set before tightening.
Luckily its not such a bad job and I have a spare gasket which will be fitted dry.

Yes it can allow the gaskets to squeeze out if you're not careful, I normally finger tight everything first then check all is ok and leave it for a few mins before slowly tightening up evenly. Sorry I don't mean to teach you how to suck eggs.