(pics) 3900 and 3500 oilpump comparison

[gectek]

read please

some people thought that because the VVT required more oil (due to some of them now also having the piston squirters) that they could use them like a performance pump for their engines withough VVT but maybe with piston squirters added (maybe not).

this means that in either case if the engine did not have VVT whether the squirters came in the block, were machined into it later, or had none, the result was the same.

we talked with melling personally, and they let us know the 411. if you still choose to ignore fact, then that is fine. i am not trying to make you upset, but if you build it, i would like to see it live.

[Driver_10]

i would not say what you are saying really. i am not speaking from just a whole in my head.

i will give you the experience that the LS engine world has provided to me. the normal LS engines are standard cam style like the 3400 and early 3500. the later styles are VVT. some people thought that because the VVT required more oil (due to some of them now also having the piston squirters) that they could use them like a performance pump for their engines withough VVT but maybe with piston squirters added (maybe not). in either case, that pump was just entirely too much for the engine. all types of catastrophic faillures occured including oil sump starvation, oil aeration, bearing wash, oil pump seizure, excessive leaking from oil seals. those are just a few. one guy even had a piston hit a valve due to high rpm and bearing wash causing the rod to lift, the bearing hit the rod, and it ruined the entire engine.

just my .02

Im installing oil-squirters into my block. The stock, "non-vvt" 3500 pump only accomodated the one set of jets at the rear of the block. With the addition of two more sets of jets, I will need to at least match the flow-rate of the VVT3500.

Dont need anymore than that and DEFINITELY need no less.

[gectek]

i would not say what you are saying really. i am not speaking from just a whole in my head.

i will give you the experience that the LS engine world has provided to me. the normal LS engines are standard cam style like the 3400 and early 3500. the later styles are VVT. some people thought that because the VVT required more oil (due to some of them now also having the piston squirters) that they could use them like a performance pump for their engines withough VVT but maybe with piston squirters added (maybe not). in either case, that pump was just entirely too much for the engine. all types of catastrophic faillures occured including oil sump starvation, oil aeration, bearing wash, oil pump seizure, excessive leaking from oil seals. those are just a few. one guy even had a piston hit a valve due to high rpm and bearing wash causing the rod to lift, the bearing hit the rod, and it ruined the entire engine.

just my .02

[Driver_10]

Finally someone who gets it!

I will agree that if you are setting up a loose motor you may need more flow. But with a 3900 pump already flowing more than a 3400 or 3500 pump I don't think a DOHC pump is necessary.

If you are going for 7500 RPM then a high pressure spring may be in order since the stock one will bypass at about 55 to 60 PSI. Running 7500 RPM will require pressure around 80 PSI (if you follow the 10 PSI/1000RPM rule) and I believe that even with a loose motor you will still only need a stock pump. But if you want to increase the volume then take small steps, don't just buy the biggest pump that will work.

Quite true.. However, I am also modifiying the block for oil-jets. My LX9 come stock with only one set of jets on the rear two cylinders. Seeing as the VVT3500 oil-pump supports 3 sets of oil-jets stock, I figured that it would be the perfect candidate.

[geoffinbc]

Pumps can only produce oil flow, NOT pressure.

Finally someone who gets it!

I will agree that if you are setting up a loose motor you may need more flow. But with a 3900 pump already flowing more than a 3400 or 3500 pump I don't think a DOHC pump is necessary.

If you are going for 7500 RPM then a high pressure spring may be in order since the stock one will bypass at about 55 to 60 PSI. Running 7500 RPM will require pressure around 80 PSI (if you follow the 10 PSI/1000RPM rule) and I believe that even with a loose motor you will still only need a stock pump. But if you want to increase the volume then take small steps, don't just buy the biggest pump that will work.

[Driver_10]

oil shear will also break down the additives faster and cause oil overheating....i doubt he has that.

If oil pressure is low at part idle and drops considerably at high rpms, then excessive sheering is the most likey cause. Had his pressure been low yet stable from 2000-redline, then I would diagnose the pressure relief spring.

You have to remember that an engine's oiling system is a regulated "oil-leak". The looser that an engine gets over time, the more oil will "sheer" away and leak off at the clearances between the berrings.

You can shim a pump much to your heart's desires and still not get adaquate oil-pressure IF there isnt enough flow passing through the clearances to form restriction and build pressure.

Pumps can only produce oil flow, NOT pressure.

[gectek]

oil shear will also break down the additives faster and cause oil overheating....i doubt he has that.

[Driver_10]

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.

Youve probably got a lot of oil-sheering from loosened clearances.

[AaronGTR]

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.

[Driver_10]

Don't get obsessed with cranking out huge oil volume. The oil jets have poppet valves and will only open at a certain pressure. They will not bleed off pressure at idle. All of the stock pumps easily make full pressure by 2000RPM there is no need to go bigger. If you do you are just wasting power and introducing heat and air into the oil when it gets forced through the pump bypass and back into the pan.

Volume is a bit important for this motor. This motor is being built to red-line at 7500 w/ 7200 shift-point. The tollerences were made to be looser which also translates to higher oil-sheering rate.

I dont need to boost the oil-pressure as much as I need the additional oil-flow. Shimming the oil-pump relief-spring can do more damage than good too. If pressure is increased "too" much, then the babbit material can seperate from the face of the berrings and cause catastrophic failure.

[gectek]

shim the spring = more pressure

[geoffinbc]

Don't get obsessed with cranking out huge oil volume. The oil jets have poppet valves and will only open at a certain pressure. They will not bleed off pressure at idle. All of the stock pumps easily make full pressure by 2000RPM there is no need to go bigger. If you do you are just wasting power and introducing heat and air into the oil when it gets forced through the pump bypass and back into the pan.

[1988GTU]

hrmmmm....

[SappySE107]

Sorry for the delay. I think you know which is which:P

[SappySE107]

The 3500 is the same as the 3400 as far as oil pump looks. The 3.4 DOHC is a bigger version of that. I will get some pics in a sec.