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Discussion Starter #1
Hello all!!

It has been far too long since I have been able to spend the right amount of time on this board!

Anyways, I pulled my 77 out of storage yesterday, and took it for a 25 mile spin. Pulled it into the shop, put fresh oil and filter into it, and me and the wife were off to Grandma's for Easter supper. I romped on her (the car, not the wife) a couple times, and I noticed as my RPMs went up, my oil pressure dropped rapidly. I had about 60psi at 2600rpm, dropped it into third and took the rpms up to 5500 or so. As they were climbing, my oil pressure went up to about 80, and started dropping very quickly, to the point where I aborted the run, and as soon as I came off the throttle, oil pressure returned to normal.

This engine has one summer on it, and I was already pissed to find that the rear main started leaking over the winter. It's a 97 Vortech block, Engine quest 165's with some work heads, RPM Airgap intake, 750 edelbrock, roller cam and rockers, headers, and a Richmond 5 spd transmission. Not that much of that will make any difference, but lending some background for the experts.

My only conclusion is that the filer I am using can not handle the pressure, and is slowing oil flow, thus killing pressure. I used to use only Wix or Purolator, and this time I used a Fleetguard (the cutaways and micron ratings were the best). Should I change out this filter and see if this cures things? It's never done this to me before (that I know of, usually too busy watching the tach), and I'm really not too keen on changing engines again...I like this one! The oil pan, pickup, etc have all been checked and un adjusted. Oil was Shell 5w30, 5.5L (approx 6 quarts).

Sorry for the long post, and I appreciate any help!!
 

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Does the pressure drop if you are in Neutral and revving? That will take the oil sloshing to the rear of the pan under acceleration out of the question. Do you have a high volume oil pump? If so it could be sucking the pan dry at higher RPM's. Is the new oil filter considerably smaller than the old ones you've used? It may not be able to filter and return as much oil as a larger one would at higher RPM's. Just a couple ideas for you.
 

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ok.. type of pan, type of oil pump, is the pickup welded, or braced to the pump.....

did you block the oil pressure bypass in the oil filter mount?...

if you have the stock adapter.... then your filter is not the problem.. in a typical sbc.... the oil filter is a passive filter...not a full flow filter.....
 

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Discussion Starter #4
Excellent ideas, for sure. As for the neutral revving, it doesn't drop. The engine revs fast enough, that even if it did, I don't think I'd notice it as I'd be at redline before the gauge would register any difference. I put in an extra half quart to be sure that I had enough oil. I have a truck dipstick, and the place that sourced me the pan didn't keep the p/n, so we can't tell it it is an extra capacity or not. It is a high volume pump, and that's the other reason for the extra half quart...I really don't want to suck the engine dry.

On our way up to the shop, I romped on it twice, and didn't notice the oil pressure do anything wierd, however, that may have been because I wasn't watching it as intently as I was after the oil change.

The filter is the same size as the one that I removed. Thanks for the quick response, and all excellent ideas so far.
 

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Discussion Starter #5
I had a place in Edmonton build me the engine. I had sold my condo, made a couple dollars, and was on the road non stop with my job at the time, so I got them to build it rather than do it myself. The place that builds these engines has about 3 teams they build funny car motors for, so I figured a mild sbc would be no problem, and up until yesterday, it was!

As far as I know, the bypass is not blocked off. And as for how the pickup is mounted to the pump, I really couldn't tell you :eek: . I think i may have to take the car to them and have them take a look at it...although I'll make sure it's under warranty! I'd just rather avoid the hassle because it is a 60+ mile drive one way, and I am not too keen on driving it too far without this being rectified.

Good to know about the oil filter too. Thanks!
 

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One thing about Top fuel engine builders....... their engines only have to last... 30 seconds..... then its time for a rebuild!
 

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i would change oil and filter again, using the brand you had before the problem. when you drain the oil watch to see if its very thin and smells like fuel.. if it has a strong gas smell you may have a carb problem and its getting into your oil. this happened to me several years ago and had same symptoms as you have now..
 

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Discussion Starter #8
i would change oil and filter again, using the brand you had before the problem. when you drain the oil watch to see if its very thin and smells like fuel.. if it has a strong gas smell you may have a carb problem and its getting into your oil. this happened to me several years ago and had same symptoms as you have now..
Excellent advice. That was my next plan of attack. I noticed too that the rear main started leaking a bit after storage, so fuel getting into the engine is definitley not out of the question.




One thing about Top fuel engine builders....... their engines only have to last... 30 seconds..... then its time for a rebuild!
Wish I would have though about that when I chose them to build!!



The other thought I had, was perhaps I do actually have an extra capacity pan, and am a quart or quart and a half low. I am concerned about overfilling though. Any thoughts on that theory? Thanks again for any and all advice!!
 

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Assumption:!

Sound s like the system is working correctly as long as oil is present in pan.

You could have a oil return problem. Top end of engine is holding the oil. Drains back to the pan are not adequate.
I have seen this in aftermarket heads, in some cases they have a small return holes.

I have also seen (more than once) pickups suck to the bottom of a oil pan.

Also, the pickup itself could be off the pump, and at high RPM the pump starves for oil.

And one easy fix, dipstick could be wrong, and your running low on oil. I have seen this a lot!

Just some things to think about.


What I would do now!

Drain the oil, take a wire (coat hanger?) stick in oil drain hole to see if you feel the pick up moving around. Some times you can tap on the bottom of the pan and heard a loose pickup. (Oil drained)

If you do not find any problems with the pickup. Add a extra quart of oil to see if this fixes the problem.

Rear main leak? This is rare with a one piece rear main seal.

IMO
AL
 
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