Rear Engine Plate sealing question

[steveg]

I'm about to re-attach the rear plate after removing my flywheel to replace the seal and convert to a BJ8 diaphragm clutch. Have a couple of questions, which I'd like getting experience-based answers on:

1)it looks like the only area that even needs sealing at all is the area around the rear camshaft opening. As far as I can tell, everything else is open to the air.

2)it looks as though the mating surface around the cam opening is very flat, as is the plate and therefore I'm thinking spray gasket such as Permatex Copper Spray-a-Gasket would be appropriate. Wonder if anyone's tried this in this area.

3) does anyone know if there's oil here under pressure, or is it just runoff from the cam bearing.

Thanks in advance.

 

[Dave Russell]

I would use a thin paper gasket. If you don't have one you can make one. I would also use sealer on both sides.

Frequently the replacement paper gaskets have shrunk & won't fit. If you put the gasket in a baggie with a damp sponge for a day or so, it will go back to it's original dimensions.

True, only the cam back opening is under pressure, but the vertical parting lines on the main bearing cap also need all of the sealing help they can get.

The rear plate must pull down very evenly to the block. For this reason, make sure that the gasket fills all of the mating spaces between the plate & the block.

Not all areas may need to be sealed, but the gasket needs to present a uniform thickness/shim to the two parts so that the plate is not warped when it is pulled down.

Good luck on the rear main seal.
D

 

[MarkA]

I agree...

Even though you may not need to seal the entire area of the back plate, you should still apply an even coat of sealer to both sides so that you get an even seating surface. And remember, it's a Healey. There is no such thing as too much sealer! /bcforum/images/%%GRAEMLIN_URL%%/smile.gif

Mark

 

[steveg]

Thanks for the advice, guys.

Interesting about the paper gaskets, though. Moss doesn't list them--my assumption here is that most folks don't use them or Moss would sell them.

I was interested in the spray gasket exactly because it's thin and easier to get it uniform compared to RTV or brush-on gasketing.

 

[MarkA]

Steve,

The paper gasket comes as part of the bottom end gasket set.

Mark

 

[Randy Forbes]

I agree...

Even though you may not need to seal the entire area of the back plate, you should still apply an even coat of sealer to both sides so that you get an even seating surface. And remember, it's a Healey. There is no such thing as too much sealer! /bcforum/images/%%GRAEMLIN_URL%%/smile.gif

Mark

Except when fitting the front engine plate. Too much sealer here will block the oil feed hole to the timing chain tensioner.

A lesson learned, born out of experience...

 

[MarkA]

I hate when that happens.... /bcforum/images/%%GRAEMLIN_URL%%/grin.gif

 

[bob hughes]

Guys

Just one point, when I installed the rear oil seal modification on the crank shaft, the cut away on the back plate and the metal outer seal holder resulted in me having to cut away the bottom part of the paper gasket 'cause there was nothing left. I did throw in a good dollop of Hilomar around the area to compensate for it though.

Bob

 

[Stretch]

It's been a while since I had mine apart and I don't remember the configuration exactly. But, I ended up taking the backplate off a second time because I had oil oozing out the cork insert at the crankshaft. I had the aftermarket oil seal kit installed and had a bit of the cork exposed. You should seal this area so what looks like a rear seal leak doesn't develop later. Recommend a high temp oil resistant silicone sealer.