thomas1976

I'm in the middle of pulling the engine, due to the oil pressure dropping as the RPM increase, it started after about only 1 year of abuse, the fel-pro oil pan gasket is broken in couple spots too.
Courrently has clevite 77 P crankshaft + rod bearings and durabond cam bearings.

I was looking for bearings and found little information about the -aluminum alloy and silicon composition- bearings.

Mainly the descriptions I found are as the following, the H series are the softest for frequently rebuilt engines, the P series a little harder and Aluminium the toughest.

Anyone using Aluminium engine bearings?

sofakingdom

iTrader: (1)

Hard bearings = bad (for most of us)

Reason being, any trash that gets into the gap between the moving part and the bearing, needs to become "embedded" AS DEEPLY AS POSSIBLE. The deeper it goes, the less it touches the crank; which is ALL THAT MATTERS.

The only time hard bearings are good, is when the crank is VERY hard, and they will be inspected FREQUENTLY.

A stock or "budget performance" type of crank in a street car does not meet this definition. Cast or forged.

In fact, for most people, this would go in either the "if you have to ask, you don't even need to know" category or the "if you needed to know you already would" category.

Alot of us have been running Clevite H mains and Durabond cam bearings for DECADES and HUNDREDS OF THOUSANDS of miles. They're perfectly fine for the vast majority of street builds.

I'd suggest in your case, from your description of your problem, examine the clearance EXISTING NOW between the pump pickup and pan sump, before tearing into any bearings. NOTE CAREFULLY that I did not say "protest vigorously about what you set it to when you assembled it"; I said, CHECK IT NOW. If I were the betting kind, I'd bet your pump pickup has rotated itself around to where it's about touching the pan, like about everybody else that this happens to.

zraffz

I run the bi metal king bearings in everything I build and never have any issues.

thomas1976

Thank you for the feed back, which one of the bi metal bearings do/did you use?


Going by this tech article http://kingbearings.com/files/Engine..._Materials.pdf the -King HP Bi-metal Bearings- and the -King XP Tri-Metal Bearings with hardened babbitt overlay- sound like the ones to chose from for a DIY built fun street/strip engine.

Of the two it sounds like the"King HP Bi-metal Bearings" are a better match for the nodular cast iron cranks, like the Scat 9000 in my engine.

Would be nice to know what numbers correspond to, "medium load high performance engines", "medium load engines, "medium-to-high load engines".
Only numbers/description mentioned is for high load engines, "Ron Shaver’s Outlaw sprint car engines under extreme service conditions: torque over 500 ft. lbs."

thomas1976

Yes Sir, the oil pump pick up was laying at the bottom of the oil pan.
I will go the "weld a brace on the pick up tube and bolt it to the pump" route.

zraffz

I've ran the cheap king bearings with a scat 9000. Good results but any polished crank shouldn't wear new bearings. I'm currently doing another scat 9000 king bearing build.

grumpyvette

WOW!
ok first question, what makes you think its bearing failure?
clearances stay the same and oil flow generally increases when engine rpms increase up to the point where the oil pump by pass circuit opens limiting the pressure curve increasing

http://forum.grumpysperformance.com/...hp?f=54&t=3536

your symptom does sound like you have lube system issues but its more likely to be related to the oil pump pick-up moving or being too close to the oil pan floor

http://forum.grumpysperformance.com/...hp?f=54&t=1800

five7kid

iTrader: (14)

Isn't that already established?

thomas1976

I have read that bad cam bearings can give similar symptoms and the engine oil was full of microscopic brass and silver flakes, I also thought that some of the rubbish oil pan gasket chunks could have obstructed the oil pump pickup.
I know how the oil pump and bypass work, but thaks a lot for all the other good information.



The rod bearings do not look too fresh anymore after only 15k miles, probably due to the plastic and rubber particles in the oil.

thomas1976

Couple more pics of the rod bearings.
I hope I'll have time to take out the crank shaft tomorrow.

thomas1976

It appears that the rear of the rear main bearing is the main source of the microscopic brass and silver flakes in the oil. Wonder why.
The front of the rear main bearing is like new.

thomas1976

Could it be that the crank is machined too rough?

The cam bearings look still good.

NagleMac

iTrader: (1)

I'd get the crank polished if you haven't done that already. When i bought my scat 9000 crank my machinist told me that they cut the crank opposite way that the engine turns. They also polish them that same way so they dont have to remove the crank from the stand and flip it around. This will end up creating a lot of initial wear on the bearing until the crank starts to wear in the same direction it spins. So he polished it correctly for me. DId you weld that pick up tube on? or just press it in? Some people use loctite when pressing them in but what i did is just put two small welds from the pickup tube to the oil pump body.

thomas1976

Thanks for the input.
I used loctite and it was a very tight fit, didn't help, lesson learned.

NagleMac

iTrader: (1)

Oh ok. you dont really need to make a brace. Welding it to the oil pump body works fine.

bwiencek

DANG - that's a lot of trash inside the pump - that along with the pickup falling off would explain the wear you're seeing. As for the thrust bearing - do you have a manual transmission with a HEAVY pressure plate or are you sure the converter was seated properly in the trans (if it's auto) - if not then I'd really check the thrust measurements on the crank and have it polished like someone mentioned. I'd also check into why there was so much blue stuff in the pan if it was the gasket I'd be finding out what caused it to break down - if it's typical blue silicone from assembly - well then - lay off the silicone!

As for the pickup - if you're not absolutely confident in being able to weld THIN material then I recommend a bolt-on brace like the one below to everyone - they're cheap (about $10) and available at most parts stores and save engines.

thomas1976

I have the rebuilt 700r4, that this engine destroyed in only 2 days wen it was stock. Before this rebuilt one, I had 2 garbage Level 3 transmissions from P.A.T.C. https://www.thirdgen.org/forums/tran...level-3-a.html including their garbage 2000rpm #5X power raptor lock-up converter.

The crank shaft end play was 0.024 in. wen I pulled it out last week.

The blue stuff is the Fel-Pro 1 piece rubber oil pan gasket that has become brittle and started to completely disintegrate, after 2 years of service.

I was planing on fabricating the oil pump pick-up brace, but that one you posted looks great! Where can I buy it?




Today I decided to polish the rear side of the crank shaft that was tearing up the thrust bearing, I used a small polishing wheel. In the first pic I was up at aprox the same hight of the oiling hole, in the second pic it was finished.
For the rest there are no scratches, so I will let the silicon in the aluminium bearings do the fine job.

I am replacing all the bearings with the Sealed-Power A-Series aluminum bearings, for experiment.

bwiencek

I've not had that bad of a thrust wear problem in an automatic equipped car unless someone installed the converter wrong (even then it usually takes out the pump on the tranny too...) so I think you're on to it with the crank needing polishing - it looked a like there were waves left in it from the first pic?

I haven't seen that happen to a 1-pc gasket before - wonder if they changed rubber compounds or something? Was it only the 'inside' disintegrating?

The pump brace can be had from most parts stores. O'reilly I think is where I got the last one - ask for a Pioneer 839061 - they'll either have them or be able to get them from the local warehouse. Otherwise most of the mail-order 'speed shops' sell them too (summit, jegs, speedway, etc.)

thomas1976

Maybe the P.A.C.T. garbage transmissions and converters did the trick.
Otherwise it is the 5700-5800 rpm shifts that killed it before I noticed the oil pressure dropping, I also cruised around for a litle over a half year with the oil pressure problem.

The gasket was tearing in to pieces everywhere.

I noticed when a big tear came sticking out on the drivers side, I then temporarly cut it off and filled the gap with silicon.

thomas1976

Couple pics of my DIY oil pump pickup brace and the additional bolt to keep it at the correct distance from the oil pan.

bwiencek

Looks like that should hold it in place - interesting way to space the pickup - never done that with a properly installed pickup - it shouldn't get loose enough to get to the bottom of the pan - plus the 'half cover' helps space it out and keeps it off the floor of the pan so it can continue pulling oil. I have used the high-volume units on aftermarket pans with a fully open screen and a tab to keep them off the floor...

Is that the plastic pump drive retainer in the pic DSC01031 145ko.jpg showing signs of cracking or is it just a line on the pic? I always use the "HD" pump drive with the steel sleeve in any performance application - prevents the shaft from wandering or potentially disengaging if the cheap plastic sleeve fails. (although the distributor should keep the shaft held down enough to keep the drive in - it will just start to wobble at high RPM's and could wear the pump or distributor...)

thomas1976

I already had the pickup installed properly + loctite, fall off the HV pump, from reading around on the internet it seems this is very common and the higher the rpm the higher are the vibrations it has to withstand.
I did not invent anything here, I read that most people that use the brace also use some sort of "spacer" to make sure the pickup stays in the best position.

The line you see reflecting on the Steel Sleeve of the HD Oil Pump intermediate Driveshaft, is the reflection of the engine block.

thomas1976

Engine is back in, everything seems back to normal, will report back if I take it apart again.
Personally I'm very curious how the bi-metal aluminium bearings are going to work out.

During the oil change, after the first 20 minutes of running, I was able to shoot some picks of the oil pump pickup and "spacer" bolt.