Replacing the Front Cover on the Twin Cam

[monoposto]

Hi,

I'm just in the process of replacing the water pump on my twin can and am confused about whether there should be a gasket between the front cover and backplate, around the area of the water pump impellor? Both the workshop manual and Miles Wilkins state that there is no gasket but, after searching the archives on here, some of the members state that there should be a gasket and that it is omitted from the workshop manual. To make things more confusing, when I removed the front cover, there was a gasket fitted around this area but the new gasket set provided does not include a replacement. So - should there be a gasket and, if so, where can I get it from?

Any advice ?

Lee

68 +2

[types26/36]

As far as I understand it Lotus fitted a thin gasket between the backplate and the block but there was never any gaskets between the front cover and the backplate, I believe Lotus only used a sealer there.
Now the cars are 30 + years old and most of the backplates and front covers are showing signs of age been distorted and the faces not so good anymore, I personally make a thin gasket for around the water pump and both sides of the timing cover and use a sealer.
Others may not agree but my engines generally do not leak so you must decide what works for you.

[alan]

i have never used a gasket, just silicone sealant and have never had a problem. the most important is to be sure there are no burrs and the surfaces are degreased 100%.this is after 37 years of working on twin cam engines
AlanB

[types26/36]

i have never used a gasket this is after 37 years of working on twin cam engines AlanB

I first worked on a twin cam in 1966 some 44 years ago, I cant remember if I fitted front cover gaskets .....probably not but 44 years ago (or 37 in your case) the castings were all relatively new and had not been levered off, corroded or generally had a hard life. Now for the sake of a few minutes making a gasket I for one will continue to fit gaskets and have piece of mind knowing that I will not have to do the job all over again.
I am not asking or telling any one to take my advice, I am merely stating the way I do it and if they want to do it without gaskets that is entirely their choice

[bcmc33]

I've just fitted the backplate and front cover using RTV - the thought of gaskets didn't cross my mind.

[rgh0]

A very small smear of silicone ( loctite Silicone RTV Gasket blue or high temp red just depends on what I have to hand) around the water pump o rings and then loctite 518 master gasket on the join between the front and back cover is what I use with good success. Loctite have an anerobic flexible sealant that will fill larger gaps than the 518 ( i cant remember the number) and you could use this if the cover is badly distorted but if its that badly distorted or damaged it probably should be straightened, welded and re machined if needed rather than try to cover the problem with a sealer filling the gaps

cheers
Rohan

[billwill]

I use a thin skim of silicone flange sealant. and it seems to be ok.

I use the same stuff to seal the water-pump podule to the front of the case.