SBC Oil leak

[Stefan]

Hi

I have a small oil leak at the front left corner of my SBC that
I have been trying to find for days now. I have narrowed it down
to the area at the front of the block near the mounting for the
mechanical fuel pump. The sump, timing cover and fuel pump blanking
plate bolts have all been checked and torqued appropriately
and the whole area cleaned. The oil keeps re-appearing (slight spray)
but I just can't find where it is coming from. Does anyone know
of a book with a picture of the oil galleries? Is there a gallery
that runs into the water pump? Do the two unused holes (for a mounting
bracket) need blanking? Any suggestions?

Hmpf, another cleaning session and a trip round the block....

[paul]

Hi there I've also had / got an oil leak (more of an oil mist leak)and I traced it back to the rocker cover gasket on my engine (new 97 Goodwrench)it seems in there wisdom they leave the mating surface as cast and it's a b*gger to seal tried everything with no avail But this will all disappear when I fit the Dart heads as they are machined
cheers
Paul

[Stefan]

Thanks Paul,

It is indeed more of a spray than a leak which is probably why I am having
so many problems finding it. I guess it could come from a little further afield
so I'll take a look at the rocker cover gaskets. My leak is too much for me
to ignore 'til next winter, and the cylinder heads are going to have to last
at least a year (although you have just given me my second good reason to replace them :9 :9).

[dave]

Hi Stefan.
Do you have a PCV valve fitted on your engine?
If not and you have a pair of push in breathers instead this could be causing the problem as the breathers do not extract the air from inside the block quite as good as they ought to and the pressure that builds up can cause a fine mist of oil to blow out of the front crank seal putting oil everywhere with no obvious sourse.
Also there are two tapped mounting bosses on the front of the block in the area of the fuel pump, one of these is a through hole directly into the fuel pump housing and if you don't have a bolt in it (preferably with some PTFE tape wrapped around it)it will also leak oil.

[Stefan]

Dave

I do have a PCV so I'm expecting no probs there, The damper is also completely clean so I don't think the crank seal is the source. But I don't have either
of those holes blanked so that is another likely source.

I have got a couple more pointers now, ta guys, will let you know what I find.

BTW Dave, any comment on my Spax collet post?

[nbracken]

I too have oil leaks from the top end of my SBC bought new in 99 - I think both are from the inlet manifold - back and front - I will try and fix with silicone seals when I get round to taking it off - have heard it is better than using the gaskets at across the front and back of the inlet manifold.

[dave]

Hi Stefan.
Sorry mate, can't help with the Spax collet issue as Dax now use Gaz shocks and i can't remember what the part no. is for the Spax ones that they used to use.
This might seem a silly question, but have you called Dax and spoken to Peter Walker? If anyone knows, he will.

[DanH]

I'll bet that Dave is correct in suggesting that the original poster's leak is coming from the threaded hole on the lower front side of the engine. The hole is frequently bored through to the passage that houses the mechanical fuel pump rod and will leak if there's not a sealed 3/8 inch bolt or plug in the hole. I had the same experience with a 350 chevy when I forgot to plug the hole at the rebuild.

I will also second the advice Nigel had concerning the use of silicone sealant instead of the gaskets to seal the front and back ends of both Chevy and Ford intake manifolds. I've never had a problem after using a nice bead of silicone, but virtually every engine using the gaskets seems to show at least some seepage after some mileage.

Dan

[mikey]

Shock Absorber numbers- Spax G18AP 13027 should allow you to order a collet from Spax.
Mike.

[Stefan]

I have used silicone for the intake manifold and have no problem there at all. I think you guys are right - the oil seems to be coming from the unblanked hole at the bottom. Need to find a bolt that fits now...