(pics) 3900 and 3500 oilpump comparison

[SappySE107]

Where did he say they were 60V6s? He did not because they were not. I know this as fact and you can take it as such. If you feel this makes what he has said as irrelevant to your setup, by all means do it and let us know how it works out for you.

[Driver_10]

Perhaps maybe that was an assumption on my behalf.

However, he did say specificlly that they used "VVT" oil-pumps and blocks moddified for oil-jets. What other engine could he be describing?

Although there are a few other GM engines that use oil-jets, I wasnt aware that there were any other engine block designs that were compatable with the VVT "oil-pump". (unless of course hes talking about the LS3 "variable cam" blocks orsomething along those lines)

I just want my data to be concise.

[SappySE107]

It is the LS motors with VVT that he is referring to.

[Driver_10]

It is the LS motors with VVT that he is referring to.

Ahh! I see. Forgive me for being an ass then...

Well, I guess Ill start with a stock 3500 pump and test from there. Thanks for the excellent feed-back.

[gectek]

that is def what i would do. i have never made outrageous claims. i do built 660s but my shop is not interested in them enough right now to take the time to modify them with oil jets. if we were, then it would happen, believe that. katech commonly modifies the LS series of GM engines with oil squirters. that vvt pump is just too much for any purpose other than what it is intended for.

[AaronGTR]

So here's a question. For my particular problem, do you think I should try using a non-vvt 3500 oil pump, or stick with the 3400 oil pump (maybe get a new one?) and just shim the pressure relief spring? And how much do you have to shim the spring to get it up a few psi? Ideally I'd like to be able to get 60psi out of it around 1850-2000rpm like I'm supposed to be seeing.

[gectek]

i used a new melling. then used a 1/4 in washer. should shim it about 4-5 psi over normal at idle, and raise the others about the same. have not ran the engine yet tho

[IsaacHayes]

If the VVT pumps is too much, then the 3.4TDC would be way too much then....

[sprucegagt]

Sometimes you need more pressure though. I've been contemplating shimming the spring in my pump... or just replacing the pump or trying a 3500 pump. According to the manual for my 2000 GA I'm supposed to get 60psi at 1850 rpm. My pressure gauge has never shown over 50psi though all the way to redline, and when the engine is hot at idle I only get 25psi or just under. It's been that way since I installed the gauge. I've sent a couple oil samples out for analysis and they've shown higher than normal wear metals. Plus I had a set of crane gold rockers go bad on me. I'm wondering if low oil pressure is contributing to this problem. Also thinking I may want to change oil weights.

I have a feeling you are reading that spec wrong. There is no reason for a 3400 to have 60 PSI at 1850 rpm. If it means anything, my engine will only come close to 60 PSI at redline. It normally pulls 30-35 PSI at 1850 rpm and that's with Castrol 0W-30 and PF-52 filter.

[AaronGTR]

I have a feeling you are reading that spec wrong. There is no reason for a 3400 to have 60 PSI at 1850 rpm. If it means anything, my engine will only come close to 60 PSI at redline. It normally pulls 30-35 PSI at 1850 rpm and that's with Castrol 0W-30 and PF-52 filter.

I know how to read. But hey, if they happened to make a mistake in the manual and most 3400 owners don't see pressure that high, then that's another matter. But these are the exact words from my manual in the section on oil pressure testing...

"Ensure that the engine is at operating temperature before inspecting the oil pressure. The oil pressure should be approximately 414 Kpa (60psi) at 1,850 RPM using 5W-30 engine oil."

So what do most people with 3400's see for oil pressure? Like I said when my engine is good and hot my needle sits below the 25 mark, and it goes up above the 35 mark usually above 3000rpm and under heavier throttle. So probably 22-23psi at idle up to 40-42psi... as best I can tell with that gauge scale. That's still less than you are seeing spruce, which is why I suspect my pressure is too low.

[sprucegagt]

Your idle values are the same as mine.

[AaronGTR]

Hate to drag this topic back up but wanted to add something I just found.

In the "engine mechanical specifications" section in my manual, it's say oil pressure-warm: 103Kpa or 15psi at 1100rpm.

So apparently the technical writers for the manual screwed up and gave two totally different oil pressures in different areas of the manual. I'm more inclined to believe the lower number since I've never seen 60psi from mine.

[23TrackroadsterV6]

Wondering if anyone can tell what model and year the shorter oil pump is off of? I'm currently building a RWD 3.1 and am fabrication my own shallow oil pan and this oil pump would be ideal for what I need.

[Driver_10]

If your gonna modify an oil-pan then what about going with a dry-sump pump? NRC (nutter racing engines) sells brand new, "in-house", american made, CNC pumps for an affordable price. You can get a 3-stage pump with cog pulley and mandrell to fit the 660 for $588 shipped w/ 0ne year warranty.

Their 4-stage pumps are about $100 extra. Try buying the same thing from Moroso or Barnes and you'll spend $1800 for the pump alone.

[23TrackroadsterV6]

I'm just looking to stay with a wet sump, but wanted the shorter bodied pump so I can make the pan shallower than if I run a 2.8/3.1/3.4 pump.
I doubt the volume it moves would be an issue.