sbc question

Hey guy and gals i have a quick question. my car has a sbc in it. i just pulled it do to a horrible oil leak. i have been thinking front main seal all along. i know it's coming from the front of the motor. well when i got it out and on the stand i noticed oil dripping from a bolt hole. could this be my issue? when i put the motor in the car it was a hurried thing and i had never actually had a sbc on a stand or anything. so i am thinking this is my issue. either way i am going to regasket the whole motor and change a bunch of stuff i would just like to solve it before it leaks all over the place again. here is a pic any help would be greatly appreciated.

 

Yep, very common that guys leave that open and it pukes oil

 

yeah, you need a bolt to seal up that hole. The fuel pump push rod goes right past the hole, it's open to oil.

 

suppose to have a bolt there, other wise it leaks from the fuel pump push rod.

 

That bolt hole runs into the side of the push rod for the fuel pump, if it is left open a small amount of oil will come out of it. You need to seal it with a short bolt, with a little sealer on the threads of the bolt.dont use a long bolt, because when you tighten it , you will lock the fuel pump rod, then you will have another problem.

 

Wow thanks for the fast response! Gotta love the hamb!

 

What year sbc is it, I don't have that problem with mine, mine is s 74

 

When the engine came from the factory there was a short bolt in that hole with a lock washer under the head. When a fuel pump is changed your supposed to take that bolt out and remove the lock washer and replace the bolt tightening it very carefully as it contacts the fuel pump push rod. This will prevent the push rod from dropping into the cavity that the pump lever operates in when the pump is removed. Then you remove the pump, install the new one without the hassle of having to rig a way to hold the push rod up while installing the new pump. After the new pump is bolted securely you remove the bolt, reinstall the lock washer and tighten the bolt securely. Simple, huh? Those SBC guys really knew what they were doing didn't they?

Frank

 

Right on Frank.

And that 74 should be the same way!

 

Umm... don't want to be a smart ass but he has a fuel pump block off plate on there...

 

Make that a Short bolt =3/8 nc x 1/2 inch. Too long of a bolt will hit the fuel pump pushrod.

It really makes a mess when that bolt is missing doesn't it? No need to ask why I would know that or that the short bolt that holds the alternator bracket to the intake is just the right length to work great in there.

 

Yep we missed that but a guy still wants to use a short bolt in that spot.

 

Ok,
Frank, I just looked at my 2 other older sbc and you're dead on, I totaly forgot about that. I have a 1964 283 and a 1963 327 and the both have that bolt in place, the 350 in the coupe is a 1974 block and doesn't have that bolt.

 

My next question is, What year did that change? I'm just curious
Or is that just a 350 thing?

 

The block has the 2 bolts on each side as they were motormount points on the early ones.

 

I have a '72 350 block and it has that bolt. I read in a rebuild manual about how to use it to hold the fuel pump pump rod, like fab 32 said.
Red

 

All small blocks that have a fuel pump push rod have that hole...
That being said, I have seen a few without the bolt in place leak like a gushing oil well!
And have seen 2 that went thousands of miles without the bolt and never leaked a drop, until one day, out of the blue...puddles..
It appears that a plug of sorts can build up behind the short bolt( some kind of oil residue) and seals the hole...until somebody flogs the car thru the gears...Both cases above happend imediately after a manifold/header swap..(gotta flog ER>> test drive it right ?? LOL
Dave

 

Quick fix!

 

And then the guy that replaced a bracket while he lost a bolt. Then he put a bolt in just long enough to seize the fuel pump pushrod.
He did better than the guy that had the fuel pump pushrod for an EARLY 4.3 V-6 that had one floating around in his toolbox and took a while to figure out it is shorter than a std SBC piece. Me.

 

If the push rod is not in there LOTS of oil will pass through. peace

 

Somewhere along the way GM decided that they didn't need to drill and tap the holes that originally were for the motor mounts on 55,56 & 57 Chevys. Guys threw a fit when they couldn't use the later engines in an early car without having to drill and tap the blocks. Shortly there after they started drilling and tapping them again.

Some of the engines like the one Glendale has or the one I have may have originally had a bracket that fastened on with that bolt and that is why the bolt ended up missing.

 

Changing gaskets makes no sense if they are not leaking.

 

If you already have new heads/valve covers/intake /and cam you will?

 

This is a perfect topic... I just came back from the Mooneyes Christmas show and I opened my hood to find oil all over the crossmember.. Sure enough it looks like its coming from the hole next to the fuel pump. I have around 6k miles on the motor since the rebuild and it never leaked before!!! It's weird that it suddenly started to gush...

 

older ones used the holes for motor mounts..mid 70's vans use those holes to mount the power steering pump bracket.
when running no bolt hole camel humps and needing to run power steering that style pump comes in handy.