Vette Threat

Well for those who are following my 393 project here's the latest update:


Everything, including drivability was looking great. She's pulling very hard, I have over 500 miles on it now and I was going to dyno it/time it this weekend but despite the rain I did notice one "little" problem. At 4900RPM my oil pressure drops to about 25PSI. Ease off, it jumps up to about 65 again. This is not g-force related.

I asked John, my engine builder and he tells me the pump I purchased from him back in 2006 is not a high volume pump. I am running the stock pan but I have never heard of this issue using a stock volume pump. I'm pretty sure when I asked him at time of purchase, he told me it was a high volume and high pressure pump so I'm getting suspicious about the whole thing.



He did also inform me of another little tidbit: My stock windage tray did not fit due to the H-beam rods hitting it so he left it off!

Gee that was real nice of him to let me know this now.

Monday, I'm ordering the Canton 240T pan, pickup tube and while I'm at it I'm thinking of grabbing a new oil pump, the Melling 10554 just in case there is one of those "new casting" pumps in there.

I am also still seeing some oil consumption (1qt in 400 miles )and some light blue smoke if I hammer the throttle. This only happens at WOT or close to it. The rest of the time as far as smoke goes shes fine, even half throttle. I'm thinking no windage tray on a stock pan, together with a high volume pump should be what's causing all this, especially the 4900RPM drop off in pressure.

The pump will only take 2 days to get here through Summit but I don't know who can ship me the Canton pan the quickest. I really would like to get this done before the season ends.

Wish I had some better news but that's where I'm at now. I feel confident some strong dyno and MPH numbers will follow but obviously I have to solve this oiling issue first.


Any opinions on my windage theory?

AGENT 86

Do you want my opinion of your engine builder I can't believe he gave it to you without any windage tray.

I spoke to the Melling rep at a trade show, 2 years ago. I was quizzing him on the problems they were having with their castings, when he grabbed one of these and stuck it in my hands.
Now that's a nice pump !!

Vette Threat

Oh I'm pretty upset alright....it's only the oiling system right? If I knew I had no tray I would not have bothered with the stock pan.

If it turns out he also went against my request of a stock volume pump........:

car5car

It should not smoke. Find out if it is rings or seals, maybe it is just one cylinder. Check your receipts if you have one about pump. Maybe you should ask your builder why your engine is smoking.

Churchkey

A windage tray would not have an effect on oil consumption or pressure. The stock tray gets in the way with a change in stroke. They are nice to have on a performance engine however unless your running over 5K rpm all the time they have little effect on anything.

You need to seat the rings. Do ten full throttle runs from 2K to 4K letting it decell in gear between pulls. Use the highest gear in the trans you can without getting a citation for reckless driving. Drive it easy for 5 minutes afterwards to get everything back to normal temps. If your going to on a dyno you can do it then.

Your pressure problem is a bit strange. At rpm's over idle once the pressure gets up to where the pump is running with the by pass spring operational it maintains pressure & may change just a bit depending on engine & oil temp heat. Engines with racing clearances at the bearings & excessive side clearance on the con rod big ends need a high volume oil pump.

Dropping the pan & changing the pump is a good idea. You can check for a loose oil pump before you remove it. ALso measure the the distance from the oil pan mounting surface on the block to the bottom of the pickup then check the depth of the oil pan to see if the oil pickup is within 1/2" of the pan bottom.

The oil pump pickup: If the pump has been changed to a high volume unit the pick up needs to be modified. The end of the pickup tube in the pan needs to be cut at a 45* angle & the edges flared out a bit. This will eliminate starvation at high rpm's.

Since the oil pressure changes exactly at a particular rpm you could have some strange electrical problem effecting the gauge reading. The oil pressure sending unit may have been damaged. This can be check by installing a mechanical gauge if the drop in pressure at 4900 remains after you service the pump.
Good luck.

Vette Threat

He's going down the road of...check you PCV, breathers etc etc.....Give me a break.

No LT1 I have ever touched, yet alone any other engine, has smoked at WOT and I REALLY took my time putting this together. It's a long shot but I think it has to do with the oiling system. Since that's the only flaw I can see at this time, I'm going to try that first.

Vette Threat

I can say that now the smoke is limited to WOT or close to it where as at first it would happen at other times as well, so I know it's getting better. I have about 500 miles on it and I'm starting to worry. I have been handed some pretty "half a$$" LT1 shorts to install into cars in the past and they never smoked like this.

I'm having a hard time believing that after 500 miles the rings have not seated enough to be smoke free. I'm not saying it's impossible, but it's not what I'm use to seeing on other peoples engines.

JackDidley

Leaky valve guides can make a lot of smoke and consume a lot of oil. I once had a similar problem with s new motor and it seems, the better the rings seal, the better it sucks oil down the guides. The oil pressure thing may be because you got low on oil. When you drop the pan look at some bearings.

BLOCKMAN

Interesting I am a big advocate of plate honing the cylinders on performance engines, street and strip, circle track, marine.

The cicrle track engines we build never have to wrap their breatheres with rags but I see alot of engines that were not plate honed and their breathers are wraped because of blowby and even after 2 years of running they are still blowby issues which tell me the rings still have not seated HMMM

We seen on the dyno when a guy has his engine dynoed and at WOT its not hard to see if the engine has ring seal or not and you can't believe the smoke that comes out of the breathers when their not plate honed.

On stock engines your not dealing high cylinder pressures, Due to higer compression and cams that raise dynamic compression then ring seal becomes more and more important.

Do a leak down test as we have seen new engines that have had 16% or more leak down because things were not done right and causing more pressure in the base will cause the oil to foam.

I don't know what your build is but if its the one in the pic it looks like you spent some good money on your build. And if its a stroker sometimes to much oil in the pan will cause this if the crank is getting into the oil it will whip it up. And not having no windage tray maybe most of your problem here or I hope as far as oil pressure.

99% of our street builds we use the Melling select standard voume pumps and no problems so far and they also have 10% more volume pump as well.

A quart of oil in 400 miles something is surely wrong, But valve seals and intake gaskets would bother more at idle with more vacume.

Good luck hope its a simple fix for you.

mseven

sorry to hear about that, I would surely want a windage tray (I would suspect you are using dino oil for break-in). I have a melling select pump and the canton pan you mentioned, which work very well and no problems. With the canton pan you might want to rtv the entire surface of the gasket to the pan though.
hopefully the lack of windage tray is the problem.

Vette Threat

Yes it is the engine in my avatar and yes it was plate honed. I never see any smoke at idle or deceleration and this is actually the second time this short was done. The first time was for excessive oil consumption.

I stressed to the engine builder, who does have a good rep around here, that I would not tolerate that level of oil consumption or smoking again. Now at least the smoke is limited to heavy throttle so there is an improvement but still not good enough that's why the only common denominator I see was the lack of a windage tray.

Is it not possible that the extra volume of oil is overcoming the rings from having too much oil whipped up to the cylinders that normally would be controlled through a windage tray?

Vette Threat

I'm using Royal Purples break in oil.

JackDidley

Its not the oil pump. I have used HV pumps in many motors. They do not cause smoking. They do not suck the pan dry if the returns are flowing. You do need a tray under the crank. Have you looked at spark plugs ? They can tell often point you in the right direction.

larry00

Strange but Hi volume good / hi pressure bad on oil pumps.
Short of running out of oil the only other reason I've seen oil pressure drops is bearing related but not at a certain RPM.
Your on computer sensored guages ?
Internally Balanced ? Good Ballance Job on the Engine ?
If you are going into the pan you might want to look at the bearings.
Me thinks I would for the peace of mind.
I have a 383 LT 4 H Beams stock windage [ motified a bit and high volume pump and no oil use or smoke nor does the pressure vary above idle.

cv67

Wonder if the pump is too close to the pan and youre getting some cavitation?
Fwiw the Melling select pump appears to be a nice piece. Holding it next to the standard Melling its obvious the difference in castings. For $60 upgrade seems worth it.
Which spring did he use?

Vette Threat

Don't know what spring he used but I should find out Monday. I just figured while I'm there, throw in the pump I wanted for piece of mind.

I'm not blaming the HV pump alone, assuming it is one. I'm just speculating perhaps the combination of no tray, stock pan, HV pump and the H-beams is still enough to get some oil past the rings at this stage of the engine break in.

BLOCKMAN

Like I posted before try a leak down test at TDC on the cylinders and see if there is any problems as it would be a good starting point and if you over 7% leak down on them some thing is wrong in the ring seal department.

Or even they may have used low tension rings who knows.

5abivt

When you pop the pan down you can get a good look at the cyl walls. I would be pretty upset about the windage tray too. I mean if a stock LTx has one...

I have my old canton pan, pickup and hv pump lyng around. As you might know what happened to my motor the pan does have a few dings. If i remember right just 1 went through the pan if you know how to weld or know someone who can you can be my guest to take the thing from me. i would have re-used it but I went with a jeff johnston billet fab pan with a titan gerotor billet oil pumpfor my 370 sr build. the pan has been welded to stop previous leaks and the rails have been hammered flat so it's straight. Let me know if you'd like it.
I know you wouldn't want anyones 'crap' on your motor just thought I'd mention it. If the little hole can be welded imo its a 100% good pan.

5abivt

here's a few pics Jim,

BrianCunningham

Ouch!