Oil Pressure....help

Thanks Jim, your advice is always sound. I will try what you have suggested.
The Window rattler cam was described in a recent posting, I assumed it was a recently built motor. The comment was made with a humorous tone which is hard to convey in type. Not as a dig. I always enjoy your thoughts as to engine builds and problem solutions. If I wasn't so damn poor, I would have had you build it. Thanks again Jim

 

No, that particular motor was a while ago.

I didn't take offense Jim, but it's important to others looking in on this to understand that we were not doing something "bad" here in the shop.. Hence the explaination, and my disagreement with you. We were playing the game like everyone else back then.

If folks really follow the rules, you should see these cars slow down. There were some really wild "sounds stock" cams being used.

And your right, it's tough to kid around with folks on the interent, I quit trying to do it years ago.. even to folks I know well.

Good luck, let us know what you find out.

JW

 

I realize my mistake.....you make a living doing this sort of thing, you don't need some joker making comments like I did. In humor or not. I have seen your work first hand, and it is top notch.
I took the intake off, and the cam bearings are perfect. Tha cam looks like it broke in evenly. When I took the pan loose, (I couldn't get it off even jacking the motor) the mains also looked fine. No heat discoloration. I have installed a gauge at the oil port on the motor, and it reads the same thing. Where could the bleed be coming from?

 

Some Things To Check Without Pulling The Engine;oil Pickup Tube Gasket,soft Plug Behind Top Timing Gear(unless You Put The Threaded Ones In) And The Timing Cover Gasket. Did You Take The Pickup Tube Off When You Were Trying To Get The Pan Off? Randy

 

Yup, those look just fine, and cam looks good too..

Where the bleed is coming from is the million dollar question.. and that is why I want you to test it as described..

In a situation like this, forget what you know about the engine, and don't discount any possiblity.

If there is no big bleed, then you have a pump related issue.

Just viewed as an observer, I can tell you that you are describing the classic bearing failure senario. Or a crank thrust bearing going away.

I would say that if the oil pressure is different now, than it was the first time you drove it until it was fully warmed up, then you have an issue..

While it's still in the car, use a screwdriver on the balancer hub and crank hub and check the crank end play again. Don't have to measure it, just give it the "eyeball test". If it's all the sudden .100 you will know where the problem is. You checked it on the stand, so you know what around .005 feels like..

JW

 

Bingo

BINGO! Went out and set up an indicator on the balancer. Ouch! Way to much end play. Carson had stated this earlier. Even though the thrust bearing wasn't peeled,the crank still has close to .075 end play.I will take the motor out when I get a hoist and post pictures of the bearing failure. Thanks to all who extented a helping hand. At least I know why I'm pissed now. Hopefully I can repair this with another set of bearings. It only had about 30 miles on it before the oil problem surfaced.What the heck would cause thrust bearing failure and not the bearings? I had the crank mains lined bored. Jim

 

I'm Cason:bla:

 

Larry thanks for chiming in. Look in the assembly manual. It says to put a straight edge across the gears. Then to measure the gap with feeler gauges. Think about it again ...If I put no gasket and torqued the bolts to 10 ft lbs. I would be jamming the bottom Booster plate into the gears. With a .005 gasket between the pump housing and the booster plate. Remember the gears are below that mating surface by .0045. When properly torqued t 10 ft lbs. This would give me .0005 clearance between the gears and the booster plate. Thanks Larry I always enjoy your technical postings. Jim

 

Thanks CASON.

 

Re: Bingo

What is a "ballooned torque converter" and what cause it to happen? hope I can digest this info.

 

Ya, I saw that too Larry, but I assume he means that the housing is .0045 below the seated gears. Anyone would have to notice that the housing was that scored up.. it would be pretty ugly..

And I have never seen one that the gears did not stick out..

One thing that strikes me as funny tho..

An oil pump will typically not turn freely with less than about .001 clearance. Jim States he has .0005.. from his measurements..

He used a .005 gasket.. the only paper gaskets I have seen for a Buick oil pump are .007,.010 or the TA .008. That includes the Fel-pro and Melling gaskets, as well as the old KB HV oil pump gaskets.

The only thing that is .005 is the Blue TA Mylar shim. But then again, maybe something else is out there I have not seen for paper oil pump gaskets.

To verify measurements, I always try and lock the pump up, and then work backward with the mylar shims to get it to just free up. This is an easy double check of your measurements. The TA shim kit makes this possible.

I would be willing to bet that last 10 stock timing cover/oil pump assemblies I have built had the same shims.. typically the .008 gasket, and then a .002 red Mylar shim..

Not often have I seen anything else, unless you start sanding on the pump housing.. and then the gaskets required are thicker, not thinner..

JW

 

i have a sbc on a stand in my garage now with the same symptoms. only this
engine knocked steady but did not increase with rpms. engine was hooked up
to a manual gear box. the oil pressure was low at idle and only went to 30 to
40lbs when cruising. i describe it as the crank is going north and south, since
i am no mechanic. good luck i will have a friend that knows this stuff over and we will pull it apart. jim

 

So let's get his oil pump deal straight..

Jim,

Are you measuring between the gears and the straightedge, or beween the straightedge and the gasket surface of the cover?

I think you guys are talking about the same thing, just differently..

----------

 

EEEKK...

.075 crank end play.


Welcome to the twilight zone.. possibly the hardest engine failure to correctly diagnose and repair..

So let's start at the beginning..

Auto trans converter ballooning.. I would say this accounts from maybe 10% of all thrust bearing failures, maybe 3% of new engine failures.. This is with a known good converter.. If you had one built, then that percentage can rise dramatically, if they built the thing too tall..

The check is easy.

When the converter balloons, as the name implies it "blows up" like a balloon.

The distance between the mounting pads/converter pilot on one end, and the converter pump gear engaugment lugs on the other lengthens.. This jambs the converter between the engine and the trans front pump, and typically wipes out the thrust bearing in the engine, and the front pump in the trans.

The check on this for you is simple.. unbolt the converter, and see if you can slide it back away from the flexplate, so that you can turn the converter freely. It should slide back about 1/8 to 3/16 of an inch.

if you can, the converter is not ballooned.

JW

 

If it passes this test, then describe in detail how you squared up the thrust cap in the engine, and what your end play readings were.

Also, does the engine have the stock or ARP main bolts, or does it have studs?

JW