kimo1965

See Update at the bottom of this post -- Sorta long story, but here goes. Had my 427 rebuilt by what I thought was a reputable machine shop. It's a 67 4-bolt main. Had align-honed, new H-Beam rods, new pistons, bored with a deckplate, all new bearings, went with a hydraulic roller cam and roller lifters. I asked the shop to prime the engine before I picked it up. Well, the shop guy said he primed it but he could not get oil up through any lifters, pushrods, rockers, and he thought it was the weight of my oil (20w/50) . He said to keep an eye on it when I started it to make sure oil up top.

Changed to oil to 10W30 and started it, sounded very dry up top. Pulled the valve covers and no oil at all after running a couple of minutes. Bone dry! Could not run the engine in with no oil up top. Pulled the intake and back lifters on each side. Spun the oil pump with a drill for several minutes through an old distributor housing we have rigged up for priming...no oil coming through the 2 passages where oil enters the lifter galley in the back of the block. The oil apparently enters these passages from the rear cam bearing. The oil gets to the rear cam bearing from a passage between the rear cam bearing and the rear main bearing. Can't see where the rear cam bearing can be installed wrong with the groove in the block, but who knows?? Any thoughts?

Had posted in C3 section before but wanted to check with you guys. Already pulled engine again and am ready to take it back to the daggone shop. They obviously should have never let it leave the shop with that issue!! Several of us are perplexed as to what would cause this. I think I should see and feel a lot of oil flowing out of the passage into the rear lifter valley when those back ones are removed and I can feel the oil hole in the passage with my finger shouldn't I? Funny thing is, is that when I did have it running for a couple of minutes the oil pressure on the gage was pegged at 80 PSI, which seemed a little high with a standard pump. Maybe there is a blockage and sending abnormally high PSI.

One final thing, I see no galley plugs missing at the rear of the block and the ones behind the timing gear are installed (which I think would lead to low or no oil pressure, right?) Thanks, Jim

UPDATE - the shop has had the block for 2 weeks now and will supposedly look at it tomorrow. The only weird thing we found when we disassembled the block was the rear cam bearing was installed with the hole not lined up. All oil passages were open. Wondering if any of you engine builders out there know anything about whether installing the rear cam bearing with the hole not line up is proper? I will give another update early this week with the shop's results. Jim

LSUvetteguy

Do a thread search on this common problem for older BB's that have been rebuilt. The cam on 396's and early 427's must have a goove cut in the rear to allow oil up to the lifters. You should also check to make sure the bearing is lined up correctly. Good luck.

Dicecal

Mossy66

Check this thread:
http://forums.corvetteforum.com/c1-a...uestion-4.html

Last page, post 61 from JohnZ explains the situation.

You say you have a '67 block though?

Good luck!
Gerry

kimo1965

Thanks guys. I had known about the 65-66 grooved bearing issues on big blocks. My block is dated April 67. So, from John's post it looks like the rear cam bearing still has to have the bottom hole lined up right? Then the oil goes around the groove machined into the block around the rear cam journal and into the 2 passageways? The machine shop seemed to think that it did not matter how the rear cam bearing was installed b/c when oil went up, it would still go into the groove b/c of the hole leading up there and even if the hole were blocked by a misaligned bearing, it would sstill be forced into the grooved. Does this make sense? Thanks for your help. Jim

rgs

On the 67 block, a misaligned bearing would starve the cam journal, not the lifter galleries.

A friend of mine use to limit the upper oil flow when he ran full roller rockers and lifters. They would install orifice plugs behind the standard plugs. When you pull the engine again, remove the rear oil gallery plugs and check for restrictors. They still should have had some flow though. Maybe when the shop cleaned the block they plugged the restrictors.

Mossy66

I am not an expert here, but what you said in your last post makes sense. What about the lifters you are using. Are they the correct ones for your application? Could there be some mis alignment that causes the oil passage to be blocked by the first lifter, like if it's too high or low in the lifter bore? I read about a problem like that here before.

Gerry

kimo1965

Gerry, I checked what you said and they are the proper lifters. Plus I pulled the back 2 on each side altogether to see where the oil enters first towards the lifters and no oil. So, if no oil is getting to the very first lifters it would seem that rules out valve train components. Thanks, Jim

rongold

What is the exact casting number and casting date of the block--is it a 3904351 or some other # ??? The 3904351 block has the groove behind the rear cam bearing--HD truck and/or marine block, maybe not. Maybe you have some HD truck or marine block that has no groove and needs a grooved cam. Is the rear bearing journal on your cam grooved ??? I have a grooved block and a grooved cam, and contrary to what some people say, I do not get an excessive amount of oil up on top. The limiting factor is probably the size of the hole in the side of the valve lifter, not the amount of oil in the galley.

rgs

Here's a link to a set of restrictors Jegs sells. If the engine builder didn't take out the hex plugs when they cleaned the block, they would not have known they are there.

http://www.jegs.com/i/JEGS/555/23610...oductId=751002

rongold

It looks like those restrictors take the place of the 2 rear galley plugs, and if they are in there, the possibility of BOTH of them being clogged is remote. The possibility still exists that his block is not a Passenger/Corvette block and does not have the groove behind the cam bearing.

Frapps

In the last year I have had two sets of brand new lifters fail to pump oil to the top. Each time I had to argue with the machine shop that supplied them that this was not my first square dance and that I did in fact know what I was talking about. Hard to convince people of this because historically the lifters never fail to pump, well U.S.-made ones anyway.

TWO sets, all sixteen in each!!!! Go figure. Some shops can test them on the bench.

Good luck.

Mossy66

Sorry Jim,

I missed the part of your original post that said you pulled the rear lifters to check for oil flow.

midyearvette

pull the rear welch plug and see if the rear brg is installed too deep...the holes in the bearing must line up with the rear groove designed in the later blocks...i have seen some brgs installed too shallow and the brg actually misses the groove....i think you have an obstruction in the galley....the holes in the rear brg really just oil the rear cam journal anyway on the later blocks...are you sure it's not a 942 block or earlier??..good luck.....

knight37128

What block do you have?

Forget about when it was cast. Need casting numbers to tell which block you have.

kimo1965

[QUOTE=rongold;1572263230]What is the exact casting number and casting date of the block--is it a 3904351 or some other # ??? The 3904351 block has the groove behind the rear cam bearing--HD truck and/or marine block, maybe not. Maybe you have some HD truck or marine block that has no groove and needs a grooved cam. Is the rear bearing journal on your cam grooved ??? I have a grooved block and a grooved cam, and contrary to what some people say, I do not get an excessive amount of oil up on top. The limiting factor is probably the size of the hole in the side of the valve lifter, not the amount of oil in the galley.


Ron and others, my block is a 3904351. I am going to pull those 2 plugs at the back of the block and see if there are restrictors. I don't think so. I am fairly certain that the block is grooved around the rear cam bearing. The cam does not have a groove and the rear cam bearing he used is not grooved. From John's pic in the other thread, it looks as though the correct bearing should only have one hole in it, right? I will be back in a few after I run out and pull those rear plugs. Thanks, Jim

kimo1965

[QUOTE=rongold;1572263398]It looks like those restrictors take the place of the 2 rear galley plugs, and if they are in there, the possibility of BOTH of them being clogged is remote. The possibility still exists that his block is not a Passenger/Corvette block and does not have the groove behind the cam bearing.


Ron, I just pulled the 2 rear plugs. No restrictors. Just the standard plugs, maybe 3/4 inch long. Not long enough to block the 2 holes. When I pulled them, I could shine a flashlight and see the 1st lifters on each side. Jim

midyearvette

[QUOTE=kimo1965;1572268297]pull the WELCH plug the big one behind the cam....if the cam brg does not cover the groove..there is your problem, if not..blocked oil passage...

kimo1965

[QUOTE=midyearvette;1572268344]Sorry Frank, I see what you mean. How do I get that thing out? Isn't it right up against the rear of the cam? Usually when I have pulled freeze out plugs, I knock them in on one side and then grab them with pliers and wiggle them out. Would this one come out the same way, and is there room for me to knock it in and get it out like that? Thanks Jim

midyearvette

[QUOTE=kimo1965;1572268407]i guess you cant smack it in without buggering something up because the cam rides close to it but try something like an ice pick or small punch on the sides....get the thing out of your way..i know it may be a long shot that the brg is in too far or too shallow but let's hope....good luck sorry for your dillema...you will get there....