Greetings folks. I purchased a chevy c10 a while back and have the truck nearly finished only to come upon a strange problem that has me baffled. As it turned out the engine in this truck was a 1957 283 power pac. I figured that was a pretty sweet little sbc so I sent it out to a machine shop and had it bored and completely rebuilt. About half way through the run in it developed a substantial oil leak and after inspection it appeared to be coming down the outside of the block. After the flywheel slinging oil everywhere we decided to pull the pan and install a new rear main seal as well as new intake and valve cover gaskets. No oil was leaking around the distributor, oil sending unit or vent tube but there was oil on top of the block back by the bell housing. Anyway it was all back together and checked and rechecked and upon start up oil begins to drip steadily as before. What in the world am I missing! I have had several other gear heads look it over and no one can really tell where all that oil is coming from, i'm about ready to say the block is cracked but the machine shop say no. Any advice would be helpful it runs like a top but pumps the oil badly.
before the intro police get you,,you should post a introduction,,just a heads up. HRP http://www.jalopyjournal.com/forum/showthread.php?t=44274
Most suspect would be the seal between the back of the intake manifold and the block. If you used the rubber seal that came in the gasket set I would bet on it. Throw it away and after cleaning the surface run a bead of black silicone sealer about a 1/4" along the sealing surface, both front and back, then gently set the intake manifold in place and install the bolts. The early blocks had a series of holes drilled in the block and the rubber seal had small tits on it that was supposed to hold it in place, it didn't work then or now and they leak if you don't seal them. If yours is an early block with a road draft tube it could be leaking where the tube fits into the block.
You've had several other gearheads look it over and none of them can tell where it's coming from. And you think somebody on the internet can find it.
there is a small freez plug type oil plug (1/4") on the back of the block, on the drivers side, for one of the oil galleries. It is about half covered by the rear of the cylinder head when you look down, about in the middle. Had the same thing happen on my 327. You have to pull the head and reseat, or replace it. there is a pic on this link http://www.carcraft.com/techarticle...ck_chevy_torque_monster_for_2500/viewall.html
Check the plugs at the back of the block and make sure the main seal lip is facing the correct direction. I hope you had some oil pressure through all of this.
This is why I asked. The position of the engine in the engine bay makes it very difficult to see anything back in there and this gives me a good spot to focus on. The draft tube is fine, it doesn't seem to be leaking at the intake but the stock gaskets in the set were used. This is the first early chevy I have rebuilt and they aren't your average small block. Thanks for the heads up I'll head over to the into thread.
Hurst style front mount. The truck was in a barn for 15 years and honestly I didn't look real close and assumed it was an original 283. It originally came with a 6 banger and somewhere along the line this 57 PP entered the picture. Loads of oil pressure, in fact thats a concern 55 at idle. Heres a pic of said hot rod truck:
If I can determine the oil is coming from inside the bell housing then the transmission is coming out and I will check the plugs. In 57 there were no threaded plugs but steel plugs like freeze plugs on the back of the block. The machine shop tapped all those smaller plugs and installed threaded inserts. I have used this guy before and he is very good but who knows at this point.
Wow nice work, that reminds me of my grandfathers truck (1963 short fleetside). Two tone white on baby blue. He transplanted in a 327 back in like 1967 and that thing ran. Later in life I had a '65 Custom Cab stepside and transplanted in a 327. Used to leave mustangs at stop lights wondering WTF just happened? I think they staked in the oil gallery plugs in the 283. 55 psi at idle should be fine. Bearing clearances, oil pump, oil, and gauge set-up can alter the readings a bit
I have never had it done , but a friend had a shop do a smoke test to find a hidden leak. Maybe that would find it . Jack
Rear cam soft plug, been there, done that.........twice, thinking it was the rope rear main seal. It was't installed at all! Most times it's just cocked a little. Butch/56sedandelivery.
Did you put the gasket between the distributor and intake manifold? It should not leak much oil but it is a possibility.
I'd pull the distributor and spin the oil pump with a primer; you can make one out of an old distributor, if you can't borrow one. That way you can pressurize the oil system, without the engine running. If the leaks is just as bad, it'll likely be the cam or galley plugs. If it doesn't leak, then likely the main seal; that needs rotation for it to leak. Try short cranks with the starter motor. Dan.
If its a '57 283 with a road draft tube and the rebuilder didnt put the baffle back in the lifter valley that could cause it to leak from the draft tube. Right next to the distributor where it goes in the block. The fit between the block and the little can and the can and the tube are pretty poor. It the baffle isn't in it will blow oil. Its possible the previous owner removed it too. If thats the case the rebuilder may not have known it needed one. A lot of folks have never even seen that baffle.
If memory serves me correctly on 283s your oil pressure sender is located back in the area that you say the leak seams to be coming from ... could be an easy fix...
The before pic looks just like one my younger brother had in the eighties. He had one with an early block 301, pop-tops, camel bumps, .505 lift erson solid, C3BX, 3 speed and 4.11's. I had my satellite, bone stock 383 car except for G60 McCrearys, 4.10s, the factory 11" converter, a hemi grind, headers,home-made underhood cold-air package, and a factory cast iron intake with the septem milled out. Flat tore him a new ass. I ragged him mercilessly about what a pig it was. Sure wish I had the motor and trans now from it now...
The engine shop just did the machine work...cylinder bore, new freeze plugs, polished the crank. I assembled the engine and installed the baffle in the valve train galley as it was when I removed it. The very top of the engine is dry. No oil around the distributor, oil pressure sender or intake. It may very well be that plug on the drivers side partially under the head.
If the top of the motor is clean that means it will most likely be the rear cam plug or one of the galley plugs. If the leak is inside the bellhousing, you will need to pull the transmission to fix it anyway so try this. Pull the trans, clean the back of the block real good with brake cleaner or laquer thinner, turn the key on and get under the truck, jump the starter solinoid wires to start it up and watch to see where it leaks. If you have a buddy around you can just have him start it once you are under there. Make sure you set the brake and chock the tires before crawling under.
Ok engine is pumping oil out of the back of the pan and the rear main seal (again) also it appears the filter cannister is leaking. The guy at the machine shop suggested going back to the original rope seal instead. Of the updated rubber seal. I'm beginning to wonder if the crank is out of round? I don't know but I my give up on this engine and sell the parts and pieces and get a crate motor!
I don't know, I still think it may be worth re-checking the old road draft area. We transplanted an early 283 into my friend's 67 C10 and it was leaking everywhere. I can't remember how we fixed it, but the issue stemmed from having a mish-mash of early and late parts bolted together. Rope seal might not be a bad idea either. Crate motors are easy and cool, but not much beats a 283 when set up right.
If the main seal area has what looks like knurling marks it's pretty much a rope seal deal rubber seals won't like it.
Sell it? Sounds like an easy fix, but you have a little work to do. You wouldn't happen to have an oil filter adapter on there?
The Jalopy Journal
