404 block hole

Edmund

Member
Fellow Frogger
Joined
Jun 17, 2012
Messages
185
Location
Johannesburg, South Africa
Hi folks I just noticed that my current 404 doesn't have a hole on the side of the block(tiny needle size hole) on the block itself just close to the inlet manifold, I've asked around what it's for and I was told it's for fuel overflow, I've had fuel percolation on my car, done a carb rebuild, needle and float are all good but it still percolates and there's always fuel stains on the block just below the inlet manifold but moreso on the side of the inlet manifold. I just wonder if the absence of this hole could contribute to percolation?
 
Are 404s meant to have a bakelite spacer under the carby ? In 504s they insulated the carby from heat.

If so, and yours is missing, that would account for the percolation.
 
Edmund,
you are correct, about the hole to drain away excess fuel. As for percolation, I have no idea. If it helps, I couldn’t find the hole when overhauling my engine. My guess is it had closed up with crub build up. Am lead to believe it is quite small.
Dano
 
Are 404s meant to have a bakelite spacer under the carby ? In 504s they insulated the carby from heat.

If so, and yours is missing, that would account for the percolation.
No this is a tiny hole on the block itself(not the inlet manifold) but you brought up an important issue about the bakelite spacer, I didn't 504s had them, 404s actually had a gasket by the inlet but I have an 1800 504 engine and I used a paper gasket(those oil resistant ones) between the carb and inlet, maybe it's not a good heat preventer but I'm told these originally used an O-ring instead of bakelite spacer
 
Do you mean in 404s, Graham ?

It's been a few years, but in 504s I seem to remember it being in the block...

Edmund, try making a spacer. I mean, what else could possibly be causing percolation ?
 
Do you mean in 404s, Graham ?

It's been a few years, but in 504s I seem to remember it being in the block...

Edmund, try making a spacer. I mean, what else could possibly be causing percolation ?

The old 404 block I have does not have that hole but 504 blocks (at least a '76 one) do.
 
There is a 3 mm hole in the bottom of the integral manifold in the head which connects to a groove in the gasket face with the center pair of head bolts passing through it. This is drained through a 0.8mm or so hole in the block between the center pair of cam followers. if it's blocked up the car can be a pain to hot start, but it has no effect on cold starting. There are words in the factory workshop manual.
 
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