engine is out.......again......

[Blazer406]

Also, check for cracks that run from the main stud holes to the cam bearing journals. Last fall I had a crack there. Lost all oil pressure. The bearing spun but also walked it's way out of the journal which left the oil hole in the wide open.

Will check for cracks. Thanks.

 

[Blazer406]

I have had spun cam bearings. IMO, this is not your low oil pressure problem. Granted, it has to be fixed and is not helping BUT think about it. It is spinning in the bore (and unless it has moved forward or rearward) it is covering the oil hole. The 2 eng. that I had spin bearings lost no oil pressure. When repairing this spun bearing you MUST have heads and main caps torqued to desired value when they line bore the cam journals. Buy 2 sets of 87 bearings and use all the large bearings. There is .020 difference between the front and rear bearings as compared to the 2 center bearings. The 2 center being .020 smaller dia. out side. We all over torque the mains and heads which in turn distorts the 2 center cam journals. They are unlike the 2 end journals which have a mass of material holding them true. #2 and 3 sorta set out there with very little meat supporting them. This is why I ALWAYS torque heads on before I install cam. Once inserted it MUST turn freely with 0 drag. I even have a tool to relieve the offending bearing if it has drag. If it has drag and is not addressed, it will build heat once running and GRAB the cam juornal as yours did. With a HV pump and booster plate, believe me a spun bearing will not cause such a large loss of pressure--you have this problem plus something else going on. Best of luck.

I will check everything close......

The spun bearing does appear slightly flared out on the surface of the cam journal.... I'm wondering if it had worn enough to cause more than .010 clearance.......and big clearances caused the oil pressure drop......

It appears that the edge of the bearing is on the edge of the journal... so I assume it is still centerd on the cam journal.

Regardless I will check everything good.

 

[Lee Thompson]

priming

I always prime with the intake off and I don't see any oil coming from around the lifter bores.

 

[gnxtc2]

What lifters are you using?

Billy T.
gnxtc2@aol.com

 

[bison]

I always prime with the intake off and I don't see any oil coming from around the lifter bores.

I always see some. More with some batches of roller lifters. However i never assembled one with more than a stock pump and never had an oil pressure problem. I had one that spun cam bearing number 2 and it still had good oil pressure.

 

[Blazer406]

What lifters are you using?

Billy T.
gnxtc2@aol.com

I did a poor boy hyd roller conversion.... I retrofitted my 109 with a spider... and dogbones... and stock hyd roller lifters from a 60 deg V6.....they are .842 diameter... and are the lifters the SBC guys use when dooing a poor boy conversion on a pre-'86 SBC.....

My original concern was that the flats on the sides of the lifters were going down in the lifter bore too far and causing the oil pressure in the galley to escape thru the top of the lifter bore where the flats were on the lifters....

After some fairly careful measurements... I don't think these flats are making down that far....I think I have .040 or more before the flats would get into the oil galley....

 

[gnxtc2]

I did a poor boy hyd roller conversion.... I retrofitted my 109 with a spider... and dogbones... and stock hyd roller lifters from a 60 deg V6.....they are .842 diameter... and are the lifters the SBC guys use when dooing a poor boy conversion on a pre-'86 SBC.....

My original concern was that the flats on the sides of the lifters were going down in the lifter bore too far and causing the oil pressure in the galley to escape thru the top of the lifter bore where the flats were on the lifters....

After some fairly careful measurements... I don't think these flats are making down that far....I think I have .040 or more before the flats would get into the oil galley....

Did you check if the lifter body is unshrouding the oil gallery when it comes up on the cam lobe? The two oil galleries run parallel in the center of the block. When the galleries were drilled, they broke into the lifter bores. The lifters "seal" the gallery.

I ran into this problem when I was looking for a solid roller lifter for my 109 block. This was around the time Crower came out with solid rollers for our motors. I put a Comp solid roller in the bore and placed a pencil type light in the gallery and saw light. If I recall, the bottom part of the lifter unshrouded the gallery.

I don't know which lifters you have. In the pic, the lifter on the left has the more of the roller unshrouded. This causes the oil gallery to unshround as is come up on the lobe. The lifter on the right has the roller shrouded thus keeping the oil gallery shrouded.

You also have to take into account the amount of lift the cam has as this will raise the lifter higher in the bore.

You should also check the main and rod bearings for damage. When you lost oil pressure, the mains get their oil from the lifter oil galleries and rods get their oil supply from the mains.

Pics will also be helpful.

Billy T.
gnxtc2@aol.com

 

[Blazer406]

Here is some pics of the lifters I am using... the two off by themselves are the longer 90 deg V6 and V8 SBC stock hyd. roller lifters..... the shorter ones are from the 60 deg V6....

 

[Turbo1dr]

Are you using a small base circle cam with those lifters?

 

[Blazer406]

Are you using a small base circle cam with those lifters?

Yes... to an extent.... the reason I know it is small base circle.... is I just tried an experiment by dropping some regular flat tappet lifters in the hole and priming the engine back up........to see if I got oil seepage up thru the lifter bore..... What I noticed is the lifters that were on the base circle of the cam.... went down into the bore past flush.... by probably .100" ...... so I am pretty sure it is a smaller base circle than the original cam....

 

[Blazer406]

Well... I just bailed on my poor boy hyd roller conversion..... I ordered some of the HYD ROLLER Morel's from TA Performance. I also got some 3/8" dia .080 wall pushrods coming from Summit....... after talking with several people.... the oozing oil I saw around the lifter bore(s) could be enough to take enough oil volume away... that my oil pump can't keep up...... so to eliminate this as one of my questionable issue(s) that could cause oil pressure drop.... I'm converting over to real hyd. roller lifters...

The block is going to the machinist today....

 

[gnxtc2]

Check your clearances in the pushrod holes with the 3/8 pushrods. You might have to clearance some holes. It would've been easier if got some 5/16 in a heavier wall from Smith, Manton or Trend.

Billy T.
gnxtc2@aol.com

 

[Blazer406]

Check your clearances in the pushrod holes with the 3/8 pushrods. You might have to clearance some holes. It would've been easier if got some 5/16 in a heavier wall from Smith, Manton or Trend.

Billy T.
gnxtc2@aol.com

Well... I am running stock type iron heads.... the holes looked huge with the 5/16" dia ones I was running.... I just figured as big as the hole looked.... 3/8" wasn't but 1/32" on either side of the pushrod.... .031 inches ...... I will still check it good when they get in...thanks for the tip.....

 

[Lee Thompson]

Imo

You and your machinist need to put your heads together and see if you can tell how much putting .020 larger OD cam bearings in #2 and 3 is going to restrict oil flow to # 2 and 3 main bearings. I would drill those 2 mains .030 bigger than they are stock. Best of luck.

 

[Blazer406]

Going to revive this thread.

I fixed the cam bearing.... per Lee's recommendation.... by installing a #1 bearing in the #2 cam journal bore. My machinist had to bore the hole slightly to get the new bearing to fit. When I stuck the cam in there, it didn't turn freely . I took a sandpaper wheel on my die grinder....and began to message the bearing a little. After one or two tries.... I decided to "color" the cam journal with a sharpie magic marker. I slid it in and out a couple times.... then looked on the journal to see where it was rubbed off..... I again clearanced the bearing ever so slightly and got it to turn nice and free. I reinstalled the cam and finished the motor up... and primed it up. I put it back into the car..... same freakin thing! ...... no hot idle oil pressure. 80 psi cold idling..... then the hotter it gets..... the lower the pressure goes..... until it is like 20 psi idling....after about 20 min of sitting idling. You can take an easy stroll around the block and ease back into the driveway, check the pressure idling..... 0!

Someone asked about the oil pump..... so I decided to tear into it..... it was installed and built when the motor was rebuilt about 100 miles ago. It was a high volume piece with the booster plate. Per Earl Brown's suggestion, I ditched the high volume stuff..... did his mods.... and set the gear endplay down to like .001 - .002...... put that back in there........ primed it up before installing the cam sensor...... cranked it up........80 psi cold........ after 30 min idling.... and a trip around the block...... same thing.... 0 psi at hot idle.

Well.... the car sat (I was mad at it) for about 6 months. I finally got aaround to pulling the motor tonight. It is on the stand. I will probably tear it down maybe Sunday afternoon.....

On my list to inspect closely:

1. Check for cracks in main webbing between main stud holes and cam journal.
2. Check pickup tube for cracks.
3. Check cam bearings real close and try to measure bearing clearance.

I will probably try and prime the motor before I tear it down completely.... and see if I see anything. It is going to be difficult to spot it with the engine cold.... cause it has good oil pressure then......

Anybody with any other ideas to look at?

 

[turbo nasty]

Was the engine/top end making any racket during 0 oil psi?

How old type is your oil psi gauge and sender?

What weight oil?

 

[Chuck Leeper]

A bit of "history"...
Some yrs back I built a 109 for my streeter. I made the mistake of buying a "ported/polished" ft cover from 1 of the "famous" Buick guys...BAD CHOICE!!
Seems that the oil psi did the exact same thing as this engine is doing.
[Cost me an engine B4 it was found.]
We took the pump apart when I got it, as it was full of packing peanuts. Cleaned it, packed it w/ vaseline..
Next was the engine failure.
A call to the "famous" parts guy... "Sorry, you took it apart/no warranty."
Engine back out, pump taken apart, bluing applied to the cover... WALA! The porting was so far out, that the gasket contact surface was reduced to a point that the pressure was returning into the intake side of the pump...COLD=good. HOT= zip.

 

[87action]

front cover

I can understand porting the front covers for the purpose of truing up oil passages, but why at mating surfaces?

 

[Blazer406]

Was the engine/top end making any racket during 0 oil psi?

How old type is your oil psi gauge and sender?

What weight oil?

Engine is definately noisey in the top end (valvetrain) when it is showing 0 psi.

Gauge is a small 100 psi liquid filled (originally bought for fuel pressure) gauge I got from summit... with the 1/8" NPT male end..... I have it screwed directly into the pressure port (I installed a tee in the factory brass block to create this extra port I needed) on the front of the engine. I originally bought the gauge for a fuel pressure gauge to put into the end of the fuel rail..... but never installed it...... when I put the engine in the car....I decided to install it in an extra port down below the turbo.... so I could monitor the oil pressure on initial startup.....

I do have a new gauge that mounts inside the car I was going to install..... but the valvetrain noise seems to confirm that the gauge is telling the truth.

Oil is 20W50 now I think..... been 6 months since I put it in there. I started with 10W30 and changed it to 20W50 to "try". I even bought some VR1 SAE50 oil to try.... but decided against it because if it did work.... it was just a bandaid covering the real problem.... and I might as well find and fix it.

 

[Chuck Leeper]

That will

I can understand porting the front covers for the purpose of truing up oil passages, but why at mating surfaces?

happen if you "tru up" the ports so far out, that they get into mating surfaces.