SBC Guys - top end oiling issue qns.....

If you have, or can get one of these:



...or make one of these,



Then you could run some pretty exhaustive tests on your oilflow with worrying about motor damage...

Just a thought.

 

rat, these guys know more about the old stuff than I do, I'll be the first to admit, I'm a race engine builder. That said, Ive been thinking about what you guys have posted regarding the groove in the distributor, and your not milling the intake.
Now, do you know what about reading a contact patch? Yes like in a ring and pinion but now only on your distributor and cam gear. We do this all the time with race engines, and set the distirbutor up with a slip collar or if it has one, we then check the gear pattern and set our pattern up with the slip collar by altering its verticle installed hieght. We use manifolds sometimes that are very one-off and there is no consistancy in block deck hieghts either, so this dimension is critical and must be part of the building process.
How does this apply to you? Well with this pattern checking, you might see that it is indeed the groove in the disrtibutor body that is causing the problem because it is up way to high on the gear pattern. This might be a blessing in disquise, because the oil pump drive might just be barely engaging on to your distributor end shaft.
If this is the case, you can chuck your distributor body in a lathe, and turn off the collar and install a slip colar, and your done, TR

 

not only having a soft plug drop out, but knocking one in too far will cause simular problems. the oil will still pass through, but will be restricted, and at rpm's the top end oiling system will be starved. make sure you didn't drive a plug in too far, even a couple milimeters will make a huge difference

 

rat, if you check your pattern you need some Prussian Blue or gear marking compound. This is diffrent than Dykem or machinist blueing, I'm sure you know which is for layout work, If there is something you dont understand regarding the slip colar or gear pattern checking, just ask, I have lasagna cooking, and was typing fast, TR

 

I hear ya fellas and TR, dave me some of that lasagna brother hahaha !!

I just can see how it can be if the dist cutting off oil flow if the lifter are pumped up and stay pumped up at dile and on the fwy.

Tonite I'll have a play with the dist height and see what I can nut out.

BUMP...

Rat

 

personally thats why i think its soft plug driven in too far... just personal experince

 

I may be dreaming but do they make two driffent sbc cam bearings? Early and late modle?

 

yes, they had different journal sizes between early and late model small blocks

 

Does your engine have a wide rear cam bearing, or a narrow bearing? If narrow, it may not have been installed far enough to the rear of the block and is allowing oil to freely flow into the end of the rear cam journal and then drain through the two oil relief holes in the rear cam journal. This can be checked using a "leak-down" test.
This improper rear cam bearing installation does occur, however infrequently.
BTW, cam bearing oil hole alignment is not nearly as critical on SBC as it is on rocker-shaft oiled engines. The 3 o'clock position is considered the standard in the engine rebuilding industry.

 

i cant remember but i think the lifters get oil from the rear cam bearing if the bearing is driven in to far or not far enough it would uncover the groove in the block and cause an internal leak. could possibly be the problem

 

Jimbo, he has mentioned several times that he threaded them all and used sealant, not sure what soft plug you are referring to, unless I misread all his posts...

I used to work in the small engine industry, and the Kohler OHV engines used sbc lifters. With that said, there was a service bulletin on the lifters at one time, about some manufacturing debris left in the lifters and that was causing issues. Kohler did not use hollow push rods though, so top end oiling was not the symptom. Take a couple of the lifters out and disassemble one or 2 and see if there are any metal pieces in them. I would expect the pieces to be too large to go through any of the holes in the lifters, and might be blocking the exit... with that said, it is a long shot that only half the lifters would be affected, and you happened to put them all on the same side. I would recommend removal of the other valve cover and making sure ALL of them are oiling, as the splash from one may be oiling the rockers of another. If you find any chips, replace all the lifters, it should save that headache down the road.

 

Ok here's the update fellas....

Grabbed a buddy's HEI and measured the base /grooves. Turns out my dist was under in OD size .050" compared to his so we figured what the hell, drop the HEI in it and see what happens.

Put in the HEI and presto....oil to the rockers. Musta been internal leakage around the dist shaft allowing the oil to escape around it an not pressurise the pass side pushrods/rockers.

Oil pressure has gone up to over 50psi hot and 30 at idle.

Problem solved thanx to all who offered advice/input - learn something new everyday

Rat

 

Whooo-hooo

 

I should have caught this problem. I tried to spin the oil pump shaft with out using a distributor housing and had the same problem. It would only oil one one side of the block. When you looked down in the dist hole you could see the oil gushing out of the oil passage. I installed the dist housing and the right side started oiling.{using an old dist with out the gear on the dist}

I also thought a 283 had a grove cut in the cam shaft on the rear bearing that affected the oil pressure.

 

Great!

 

Cheers rat, no we wait for the mandatory video of the smokey burnout, TR