thedroid

I have built a 429 SCJ 4 Bolt DOOE-R heads, Flat tops, Comp XM 278 cam, Pro Magnums roller rockers, 3/8 Pushrods, Stainless Valves, Comp 924 springs, Stealth, Holley 750 vac sec, Milodon 10 Qt oil pan, high volume pump etc. The engine is in a Glastron CV 23 with pretty tite Berk JE, pump Loader and Place diverter.

I had it out for dial in on Sunday an run it up to speed after checking for leaks etc.

The thing ran great- 56-5800 on my crappy old 78 vintage tach, and buried the cheap 65 MPH speedo.

The big question is why would the oil pressure fluctuate between 60-80 psi at high rpm? I have read other threads where the 10 qt pan should only have 8 qts to keep the oil from whipping up and getting aerated. I have only 8, maybe 9qts in this engine now I am concerned about keeping a steady flow of oil in this engine. Any advise?

Thanks
thedroid

Paul Kane

'droid,

A number of things can cause oil pressure fluctuation, which makes it hard to diagnose over the internet. It could be several things within your oiling system or symptoms of a result of your oiling system, such as aeration (as you noted).

You can certainly experiment with the oil level in your oil pan, by adding more quarts or reducing the number of quarts of oil, but be very careful when you do this and pay close attention to oil pressure and engine sounds.

The first thing I would do is try a different oil filter/oil filter brand...certainly a large low restriction filter due to the amount of oil that the oil pump is wanting to deliver at the sustained 5000+ rpm. If you have a regular ol' orange Fram filter, I strongly recommend you change it immediately regardless of oil pressure symptoms. Start with a filter change first.

Tell me more about the way your oiling sytem is designed, do you have a remote oil filter? Etc.

Paul

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thedroid

Paul,
The block has all of your oiling tricks as shown on your website. I did not go to the extent of painting the lifter galley as many people do. But I do have a remote oil filter as the 1 qt Wix 51515 would not fit between the factory pad and the stringer on this application. I have run a pair of 1/2" rubber lines to the remote filter and it is mounted about 36" from the block. Is there any problem with the filter in the horizontal rather than vertical orientation? What filter do you recommend?
Thanks for the input.
thedroid

Paul Kane

The Wix 51515 is a fine filter.

I don't know for certain whether mounting it horizontally is acceptable or not, but think that you should absolutely experiment with running the boat while the filter is mounted in the vertical position, as (perhaps) having it mounted horizonatlly may allow air bublles to get built up/trapped and then pass through the system after a big enough collection of air gets pushed through.

There is also the anti-drainback flapper, although again I am not certain that operating the filter horizontally would have anything to do with your abnormal oil pressure behavior.

What kind of oil pan do you have?

Paul

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thedroid

The pan is a Milodon 10qt with a built in windage tray and hinged baffles. The pickup came with the pan ad is about 3/16" from the bottom and I have verified this when assemling the engine.

thedroid

Paul.
I will also try to rule out a faulty sender/bad gauge/electrical grounding issue. I have mechanical gauge that I can tee in and see how it is performing against the 30 year old electrical gauge.
thedroid

Paul Kane

I run that same oil pan on my jet boat, sometimes up to 5400-5500 rpm (usually 5200-5300rpm), and it works well for me.

On the other hand, I know several other people that run that oil pan and they all have oil pressure problems. They also run their jet boats to an rpm point that is higher than mine, such as 5700 and higher (just like you). They each changed to a different pan and the oiling problems went away.

This does not necessarily mean that your oil pan is the culprit. But if you look at the pan design, the gating is not that great (oil can still escape down one side of the pan), and the zeus'd in windage tray does not cover/seprate the entire sump/bottom of the pan from the windage area of the crankcase.

No disprespect to Milodon, as I use a LOT of their parts in my boat engine. I suggest you look at the simpler things first (such as the filter positioning) before you jump and pull your engine to swap pans.

Paul

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thedroid

Paul,
Thanks for the response. I'll follow up with what I uncover on the river this weekend.
thedroid