Inliners International Forums General Discussion Engines 292 Swap Done...Low Oil Pressure?

Phase one of my 292 swap is complete. Engine in and running. Was really excited to fire it up but started to get a little nervous after running it a bit. Oil pressure starts at about 25 psi but dropped really low...maybe 5 psi (at low idle), once engine was to temperature. I have the stock dummy light as well as a AutoMeter gauge connected and it was low enough to light the red dash light. Talked to the speed shop that built the motor and he asked me to remove the break-in oil and try the thicker (15w-50 synthetic w/ zinc for flat tappet cam) to see if pressure increased. I did that and it is now measuring about maybe 10 psi at low idle.

Still seems pretty low, but I did find a few threads (at least one of which was on this forum) indicating these engines run low. The thing that worries me is that the drop is so substantial from cold to hot. Just thought I would ask the community here and see if I can get some input from those who have 292's and can comment on their experience. Many thanks!

That pressure is too low. Especially with a fresh engine.
Does it sound noisy? Like lots of lifter type sounds?

The inner 2 cam bearings can fail on a new engine, then they hemorrhage oil around them causing a oil pressure loss.

It is one problem to think about.
Here it is in more detail. Near bottom of my page. You may be able to see if it a problem using a scope or good mirror thru the fuel pump hole and look at the cam bearing.

https://www.12bolt.com/tech-tips.html


Cam Bearings
Keep in mind when changing cams to pay attention to the bearings. Here is a abbreviated article from King Bearings on Cam bearing failure.
Structures and Materials of Camshaft Bearings
The typical structures and designs of camshaft bearings are presented. The most traditional design of camshaft bearings is a steel tube with a layer of lead based Babbitt alloy applied onto the inner surface (bush type camshaft bearing). The bearings of this type may be supplied in semi-finished (un-bored) condition. Then the bearings are bored after installation in the engine. However, the precision (bored) finished type is more popular. A relatively thick and soft Babbitt layer provides good conformability of the bearing. The material allows fitting its shape to misalignments. Babbitt also has very good embedability, which is important for bearings operating with contaminated oil. The main disadvantage of Babbitt bearings is their low load carrying capacity. Babbitt alloys are soft; therefore they have low fatigue strength. Also, the fatigue limit of the lining is directly dependent on its thickness: the thicker the layer the lower its fatigue limit. Since the Babbitt lining is relatively thick, its fatigue strength is low (~2,000 psi). Bi-metallic camshaft bearings, with a lining made of aluminum alloy, have a much greater fatigue strength of at least 5,800 psi. The bearings are split shells type, rather than bush. King Engine Bearings manufactures camshaft bearings made of aluminum/silicon alloy: K-788 . Their load capacity reaches 8,000 psi.


A bimetal structure with an aluminum alloy lining is the best solution for camshaft bearings. Aluminum alloy is not too hard, therefore it has good conformability. Also, it is stronger and more wear resistant than Babbitt. In contrast to a tri-metal structure, aluminum alloy bimetal bearings have superior conformability, and can tolerate far greater wear since they do not have a thin overlay. The thickness of the aluminum lining is approximately 0.010”. If the load applied to camshaft bearings exceeds the fatigue strength of aluminum alloys, tri-metal materials having a copper based intermediate layer and very thin (up to 0.0008”) soft Babbitt overlay are used. Tri-metal materials have greater load capacity, but their conformability and maximum wear are limited by the very low thickness of the overlay. Once the overlay is locally worn out and the bronze intermediate layer is exposed, seizure of the bearing by the steel journal becomes very probable. Since misalignment and excessive wear due to oil starvation are typical causes of camshaft bearing failures, tri-metal construction is rarely used in the design of camshaft bearings.

King Bearings are made using the K-788 Aluminum/ Silicon Alloy. These are the bearings I recommend.
Pictures of failed cam bearings. Notice how the soft babbit flows over the oil hole.

I am with Tom here. Way too low for a fresh motor. I know you don't want to hear this, but with the time, money and effort you just put into that swap, the last thing you need is a failure of the motor after just a few miles. If it were me, I would probably want to take the motor out, get it apart and see what is causing this issue. Something is up and the only person who will ultimately pay the price is you so better to go through this aggravation now rather then later.

Thanks for the quick response guys! Was hoping the answer would be "that is totally normal for a 292" but I guess that is just how it goes. Yes, the valve train is much louder than I would expect it to be. Almost sounds like a diesel. I posted a picture and video of my valve train (link below). In the photo, you can see that the middle lifter is off axis (not centered on the spring) and the roller appears to be wearing already. Also, things wiggle a little more than I expect (see in video). Seems like possibly more evidence of the cam bearing as you mentioned.

https://www.flickr.com/photos/webarone/albums/72157703233838425

[img]https://www.flickr.com/photos/webarone/45011254164/in/album-72157703233838425/[/img]

The side movement is controlled by the pushrod. You may need to use guide plates.
How about a sideways picture showing the roller on the valve stem?

The oil pressure or lack of is a different story. You have to figure it out. I would expect 40 psi at idle on a new engine (cold) or higher. No lower than 30 hot at idle.

I added some side shots to the album. Please let me know what you think. Thanks

[img]https://www.flickr.com/photos/webarone/43925053970/in/album-72157703233838425/[/img]

Talked to the machine shop and they agreed that I need to pull the motor and bring it back to them. Very depressing.

Na, just some teething issues. Take a deep breath, better to solve this issue now than to have a catastrophic failure later.

Any chance this could be due to not enough oil? Running with the 5 quarts inserted by shop but the pan is the deeper 292 pan which might take 6 quarts???

No. There is adequate oil at 1 qt low.

Try the 6th quart and see if it helps.
I run Valvoline Racing 30 weight in my 292. But I live in a hot climate. [Southern Arizona] In winter I have run 20W-50.
My Oil Pressure Gauge reads about 40 PSI.

You were right. Cam bearing was toast. Machine shop replaced bearings and added notches to new bearings to improve oil flow and they repolished all bearing surfaces. They also decided to shim the spring in the oil pump to increase pressure. He said it was getting about 60 psi with a driill. I am a bit nervous about this. Does this sound wise? Or at least not going to now cause a new problem??? Thanks.

You shouldn't need to shim the pump. High vol. or even high pressure puts more stain on the dist.& gear. I race mine and don't use anything other then a Stock pump and Have plenty of oil pressure.

I agree, but the shop already did the shim and I picked up the engine and did not think about it until I got home. Would prefer not to have to call them and potentially argue about whether or not they made a mistake and drag then engine back down there again. If it is a major concern, then it is probably worth it but if only a minor concern and something that might only create an issue far in the future then might just keep it as-is. Thoughts?

What kind of pressure would be expected in a fresh build with standard vs. high volume pumps? My engine has 2000 miles on the build and runs a hair over 50 psi at idle and around 60 running. Too much?

I'd say you're okay. My Jeep Cherokee runs at 60 psi down the road and 30 to 40 while idling, and it has 202,*** miles on it. My 292, have only cranked it over, it has 30 psi cranking oil pressure and it has 155,*** on it.