Peek HP was at 5,400 RPM, peek torque was at 3,600. One question I had was about the oil pressure. It was recorded by the Dyno throughout the run. It started at 60 psi at 3,500 RPM (the lowest RPM the Dyno recorded data) on one run it went down to 42 psi and on the other it went dwin to 32 psi at 5,800 rpm. Is this a reasonable pressure for a Pontiac engine? This is my first Pontiac build. Thanks for your input.
Thanks, better (lower RPM's) than I thought for those kinds of numers.
I personally would be concerned with your oil pressure numbers. Pontiac engines should have 60 PSI above 2500 RPM's. Dropping pressure as RPM's go up is not what you want.
I would discuss this with your dyno man to make sure it was not an equipment fluke. If it is not, then I would be looking for a cause. The rule of thumb is 10 PSI for each 1,000 RPM.
Read this article: https://www.pontiacdiy.com/pontiac-v...-system-guide/
There could be a number of reasons. I am going to just ramble on and throw out ideas to consider.
1st, poor quality oil filter not flowing enough. Butler Pontiac recommends a Wix oil filter.
What oil pump did you use? I used a Mellings 60 PSI pump on a 400 build and had problems. On my present 455 build, I began with a Mellings 60PSI pump. It has a courser quality screen ( larger holes) than the fine screen mesh on the 400 build I did. I feel the fine mesh may have contributed to my problem. Anyway, I then purchased the heavy duty oil pump plate. This is thicker and is designed to provide anticavitation. You can see it and read the description here: https://www.tinindianperformance.com...il-pump-plate/
At the time, Butler Pontiac had a Pro-pump they offered, but only for an 80PSI oil pump. They eventually did put out a Pro-pump for the 60PSI oil pump -so I bought this and will use it on my 455.
What oil pan? If you used a deeper pan, did you get the matching pump pick-up tube/screen? You would have also wanted to check the clearance between the bottom of the pan and bottom of the pick-up screen. Too much space can be a problem as well as sitting too low and not enough space.
Windage tray or screen?
Was the pick-up tube secured in any way to the oil pmp so it could not fall off? If the pick-up tube/screen were to fall off, oil pressure can suffer.
I assume you purchased a new oil pump drive shaft? Never use the factory one. You want an aftermarket hardened pump shaft. The factory piece can break. You can get a simple inexpensive one from most any Pontiac parts supplier or step up and get something more rugged. I went with this one from Nitemare Performance: Standard sleeved & hardened oil pump driveshaft Bear GF
R used one and as I recall, you have to check your clearances on that larger end sleeve. He has others as well as the oil pumps & oil pump plates.
That said, I would talk with your dyno guy first. I assume the engine is still out of the car? It would be easier now to pull the pan IF needed than once you get it in the car and could have to take it back out.