1934 v8

[JOHN ROWLAND]

New rebuild has oil blowing by the slenger at reaw of engine.about a quart in half mile. Removed pan all looks good. Help john

 

[KiWinUS]

Do you have a tube from rear main cap down into pan
It’s about 6” long

 

[JOHN ROWLAND]

Yes

 

[JSeery]

Also, over filling with oil can cause that.

 

[JOHN ROWLAND]

Could it be two much oil pressure?

 

[JOHN ROWLAND]

Oil was 5 qutshad 4 when discoverd problem

 

[DavidG]

That leaves the seal between the oil pan and the rear main bearing cap as the likely source of the problem (or the die cast insert cap for the slinger).

 

[KiWinUS]

Does your oil pan have the cap covering the starter bendix

 

[KiWinUS]

Good call by David

 

[JOHN ROWLAND]

David, oil pan seal ok. Ineed to pull the back main cap and check that out. could to much oil pressure like 60 70 lb at 30 to 40 MPH cause it. I thought it could blow by the slinger?

 

[JOHN ROWLAND]

forgot to say idling leaks none revup leaks none only going 30 40 PMH down road.

 

[DavidG]

Far fetched and not likely given recent rebuild, but it might be an out-of-round rear crankshaft journal or babbit bearing. Worth checking if you're otherwise removing the rear main bearing cap. Also worth checking would be your oil pressure at various rpm.


It sounds as though it is overwhelming the ability of the drain tube on the rear main bearing cap to drain off the oil at speed. Per chance was a drain tube installed with a check valve built in? Not original in '34, but not a bad idea unless the valve gets stuck in a closed position.

 

[jimTN]

Could be the oil pump drive gear housing cover behind the flywheel. You could rig up something that would pressurize the system and look to see where the oil is coming from if you have the pan off. I rigged up a old small tank with a tire valve stem and and outlet with an old grease gun hose to pressure up new rebuilds. would not take much capacity.

 

[Lawrie]

Blocked breather cap
Lawrie

 

[JOHN ROWLAND]

breather cap ,willcheck

 

[bobH]

That leaves the seal between the oil pan and the rear main bearing cap as the likely source of the problem (or the die cast insert cap for the slinger).

And, what if the die cast insert was left out?

 

[JOHN ROWLAND]

DavidG, going to take ball out of tube it only has a 1/8 slot by 1/2 long to drain oil out. It must have 80lb pump ,when engine was new 30lb oil pressure was a norm. Engine is new rebuild , the main bearings are inserts, had it line bord.Engine is new and tight. i agree to much oil on the rear main. Thank you all for the help, will let you know the results.

 

[DavidG]

In addition you may have to revert to a 30 lb. pump.

 

[Tim Ayers]

I'm assuming you have an aftermarket oil pressure gauge hooked up. 70lbs @ 40 mph sounds a tad high. To confirm, no leaks or issues at idle, correct?

Does a '34 oil pump have a relief valve/spring like the later ones? If so, I wonder if the oil pressure relief spring/valve is not opening correctly and causing an excess oil pressure condition to find the path of least resistance.

 

[deuce_roadster]

My understanding is that you shouldn't put an 80 lb pump in engines with only a slinger.