Technical Early 283 SBC and Oil Leaks

I have a 1964-1965 Chevy 283 in my 1941 car. The motor appears to be fairly stock, including the 2bbl Rochester carb, but I have added the cast aluminum valve covers and replaced intake gaskets, valve cover gaskets and oil pan gaskets. Its hooked to a T5 and a 3.08 rear end. I have been driving it around the block for a bit and have now gone down the road to a couple different places. there has been some drips, but the few longer drives has resulted a LOT of oil dripping out the front of the motor. There is even oil sprayed under the bottom of the car. Looking under there this weekend, it looks like the oil is coming out of the front seal. I tightened the ban bolts a little (not all that loose).

This is an original draft tube type engine. I currently have a hose connecting it to the base of the air cleaner. the filler tube is a vented type. Is the venting via the air cleaner not enough? how does one know if I am building up too much pressure inside the motor?

 

Did you have leaks from the front before you changed out the pan gasket? There is a thick and thin front pan
seal. Did you use a one pan gasket or cork type with 4 pieces. The draft tube should be o.k.

 

I had never run the motor before I replaced the gaskets. Its the 4-piece, cork and rubber set. i just started looking at a new one-piece one. Might be the next step.

 

Is there a bolt where the circle in photo is?

 

I'm going to make a suggestion rather than suggest a solution. Post 3 pictures of the motor. Either your problem has been solved,

Or the motor has had its ventilation stifled. If you haven't been in the motor, show the front of the pan, back of the engine and over all engine shot. If it can't breathe to release the pressure, it will push oil out the gaskets like Ebola bleeds blood.

 

THe next thing you need to do is put a PVC valve on it. The Road draft tube with a hose on it to the air cleaner is not going to pull near enough air to relieve crank case pressure. first you need this.



This is the adapter used in the 60's to install a PVC valve on new Chevy cars up till 68 when the valve covers got holes in them. New ones are available from Classic industries.

https://www.classicindustries.com/product/153781.html

Nest you will need the PCV valve, and there is differences in PCV valves, they are not all the same. The one you need is a STANDARD MOTOR PRODUCTS V100 It has threads on one side to thread into the rear of the base of you carburetor. 6 Bucks at rock auto.




https://www.rockauto.com/en/catalog...sitive+crankcase+ventilation+(pcv)+valve,5052

This will get the pressure out properly. Then you can clean the motor up and see if you are still leaking and from where.

If you find yourself needing to replace the oil pan gasket, I recommend Fel Pro One Piece gasket part number FEL-OS34509T. It has the thin end seals appropriate for the 57 to 67 283 with the original Oil pan and front timing cover.

Ive done a ton of early small blocks and this has always been my recipe for a leak free small block. This is the exact set up i have in my 39, and it does not leak a drop. The valve covers are a whole other project hovever.....

 

Go with a one piece oil pan gasket and forget it.

 

64 I’m unsure of but 65 for sure was vented as such. Road draft hole at the back of the block went to the air cleaner. The filler tube at the front of the intake had a bung the tube for a screw in pcv valve (not to be confused with the one mentioned earlier above. Flow is opposite direction).

 

You’re also going to have to determine whether the pan has been changed

 

That is correct on some applications. The small chevy motors with the PCV in the filler tube had a sealed cap on the end of the filler tube, and the vent was the hose from the road draft tube to the bottom of the air cleaner, drawing in filtered air from inside the air cleaner. The PVC at the rear of the Carb attached to the road draft tube hole used the vented oil fil cap for and air source.

 

yes. There is a bolt in there.

 

I changed the pan, however it was supposed to be a "stock" pan, rear sump.

 

i had a '64, and it came with a pcv setup.

 

Is it leaking through the crank seal on the timing chain cover? You just mentioned “front of …”

 

Timing chain ain’t worn out and worn a hole in side of the cover has it?

 

This was my original thought, as I didn't change this seal. Looking under there yesterday, I confirmed it is NOT at the harmonic balancer.

I am pretty certain its at the front pan gasket. I just didn't know if i was pressurizing the crankcase with the current draft tube / hose connecting arrangement.

 

I have a chrome pan that was given to me, buddy couldn't get it to stop leaking from the seal. I haven't had a need to use it but the plan was to grind off the chrome and RTV the gasket for insurance if I did.
If that's the only leak, it's probably just the seal. If it's other spots as well, pressurization is a solid possibility.

 

Welcome to the club.
I'm dealing with the same issue.
'67 283.
I have changed oil pans and seals several times.
Currently has a stock oil pan.
I have had both front seals nothing so far has worked?
Have not tried the one piece oil pan gasket.
Don't remember a PCV.
I just let it drip!

 

Not to be a smart ass, but you did put a blob of sealer in the lower corners of the front tin where the two gaskets meet?

 

When you had the oil pan off did you check for dimpling around the bolt holes, this is from many years of tightening (overtightening).
They can be flattened out by supporting the outside of the pan rail and tapping down with a hammer, may need to use a small plate in between pan and hammer.

 

Only way I stopped the leaking with the chrome pan I had was to give it away and put a stock pan on

 

Don't waste your money and time using RTV sealer.

All we use at our Hot Rod Shop is Permatex Right Stuff. I can't tell you how many 50's-80's engine we have serviced in Hot Rods, Customs and Muscle cars and trucks for oil related leaks. We only use FelPro gaskets and National Oil Seals too.

 

I honestly don't remember. I recall this is needed, but don't remember.

 

The pan I used was a new, OEM replacement pan. Should have been a stock replacement pan for the 58-79 SBC. I will climb under it and measure though.

 

Leaks near the front of the engine can be tough to trace since the engine fan pushes oil all over, and you may be thinking it's a pan gasket, when it might be the crankshaft seal on the timing cover. On old engines a new crankshaft seal can leak due to a worn sealing surface on the crank. So you might look at that also to see if there's a groove in the crank. If so it may need a repair sleeve to stop the oil leak.

 

The harmonic balancer is what wears out in the front of the engine. If the front of the engine leaks oil and it's not the pan gasket check the balancer. There is a sleeve that can fit on the balancer that will stop the leak. The timing cover seal stops oil by sealing the balancer not the crankshaft.

 

AHotRod, you use Fel-Pro oil pan gasket with “the Right Stuff” on both sides of gasket ?

 

Front pan gasket thickness change occurred mid year 1974 .

 

NoelC has passed on good information. In addition to the vertical measurement the horizontal distance is different between early and later oil pans. At the top the early pan measures 5 1/2" and the later pan is 5 3/4". This is the distance at the opening where the gasket fits the timing chain cover. Also the Felpro numbers he listed are correct.

 

I did not say that.

If it's a molded silicone-rubber gasket, in the corners only.

All other gaskets, yes... as we have found that the "majority" of engine sheet metal is in rough shape, we spend the time to clean, bead blast surfaces and straighten. We have found that going to the trouble and time to correct the shapes and surfaces has helped allot in the final result.
God forbit that they have aftermarket overseas chrome and aluminum valve covers, intake manifold, timing cover and oil pans .... as they are NOT manufactured to SAE fitment standards and makes it even more difficult to seal. It's so sad that the customers who bought this "junk" assumes it's made right.