Gearbox gasket/sealant for alloy gearbox

[56Lotus]

I'm after a recommendation for a good gasket sealant for an alloy gearbox. I'm running an old MGA gearbox in my Lotus and the front cover leaks into the bell housing. I've tried just the paper gasket and paper with Hylomar Blue but it still leaks and to change it is an entire engine out job. I think one issue is the cutch fork pivots are part of the cover and therefore the cover is put under strain when changing gear and this breaks the gasket seal?

I'm after a recommendation for a good, strong/flexible oil resistant gasket compound to use with or without the original paper gasket.

Thanks in advance

Jon Adams

[CrutyRammers]

RTV silicone sealant.

[paintman]

Silicone sealant as suggested.
Might also be worth a bit of loctite on the bellhousing to gearbox bolts just in case they're working loose.

[Sardonicus]

Be very careful deleting gaskets they may also be included in fitting length for lay-shaft/main-shaft running clearance calculations etc on old school paper gaskets I prefer Wellseal but make sure you follow instructions and faces are grease and oil free before closing joints, RTV combined with paper gaskets dont normally work to great IMO

[Lotobear]

I would strongly endorse Wellseal and/or Permatex Aviation Nr 3 gasket cement. The Permatex is like a thicker version of Wellseal

I've just rebuilt and very leaky Lotus TC using these products and think I have now got it oil tight at last.

On close fitting metal to metal flanges (Lotus TC timing cover for example) I used Loctite 518.

I have used RTV before and had mixed success

[stevieturbo]

Any good quality RTV should be fine, or some sell them as a flange sealant.

Loctite do various products too, look through their specs.

[Lotobear]

RTV may well work fine but the sealants I mention are tried and tested on classic engines and are known to work.

Personally I would go with the original paper gasket and use Permatex No 3 on both faces. I was put on to this stuff by a guy in Oz who's been building and racing Lotus twincams for over 30 years. It's very forgiving and stays soft, taking up heating and cooling cycles very well in addition to the usual foibles found in old engines

[Krikkit]

I think Loctite 5922 is designed to boost existing sealing as well, rather than complete replacement.

[Sardonicus]

Lotobear said:

RTV may well work fine but the sealants I mention are tried and tested on classic engines and are known to work.

Personally I would go with the original paper gasket and use Permatex No 3 on both faces. I was put on to this stuff by a guy in Oz who's been building and racing Lotus twincams for over 30 years. It's very forgiving and stays soft, taking up heating and cooling cycles very well in addition to the usual foibles found in old engines

I like Permatex products if a little harder to get in the UK but Realsteel sell them RTV as its uses but in this instance not for me

[PaulKemp]

Reinzosil universal sealing compound from Victor Reinz

[Dr mtree]

Try some Threebond 1215 also known as Yamabond. It’s the best gasket free sealer I’ve used and many of the Subaru enthusiasts swear by it for sealing the crankcases.

[Sardonicus]

PaulKemp said:

Reinzosil universal sealing compound from Victor Reinz

Thats a good sealer inc Elring Dirko S the sealers of choice on the RV8 when using no cork sump gasket

[99hjhm]

Dr mtree said:

Try some Threebond 1215 also known as Yamabond. It’s the best gasket free sealer I’ve used and many of the Subaru enthusiasts swear by it for sealing the crankcases.

It was used by Prodrive on all the Subaru WRC engines and transmissions and everything they have done since.

In this application would favour gasket with Wellseal or Permetex Aviation, just make sure the castings are flat and free from burrs and imperfections.

[adam quantrill]

I cut a hole in my aly gearbox by mistake and repaired it with liquid metal, this held the oil in for a few years until it blew up due to my driving style ;^)

Anyhow you could rough up the surface and apply that over the crack,

[cptsideways]

Toyota FPIG its what they're boxes used from new, lasts forever will fix any oil weep, its the best gasket stuff I have ever come across. You can buy it on Amazon or your local dealer.