What would cause an oil pump to hydrolock?

[forcefed86]

So this is a continuation of my last issues here....

http://www.dsmtuners.com/forums/cyl...or-initial-fire-up-big-problems-help-pls.html

Basically The car runs and idles now and will do so without issue for hours. I putted around the block and idled in the driveway tuning etc for 60 minutes plus earlier this week.


Although after the car has warmed up there is a slight lifter tick that is not present when cold. I have confirmed this is not an exhaust leak. If I cruise at 40 or so for around 5 minutes the engine will slow itself down and lock up. I put in the clutch and coasted into a neighborhood. Once cool the car starts right up and I drove home.

I have confirmed many times this is not a bearing/ring issue. I believe somehow the oil pump is hydro locking? What could cause this?

If the oil pressure relief could not open for some reason would this cause it?

I was planning on pulling and inspecting it.

Thanks

 

[donniekak]

What pistons, and ptw clearance.

 

[forcefed86]

What pistons, and ptw clearance.

STD bore JE pistons. The ring set had a little over 5k on them. So they had to be in spec.

I pulled the oil filter housing and ported the housing it appears to be working correctly. The oil gauge in the car is up around half way on initial startup. Drops about an 18th inch when warm. More pressure than I had last time around.

But I did just notice MMCD is saying my oil pressure is only 10psi or so when warm? Is this normal? Doesn't the MMCD get the oil pressure reading from the same spot the gauge does?

So I tapped into the oil port right next to the turbo supply. Confirms my low pressure. MMCD is showing 7.8psi when warm. My gauge started at 20 so I'll have to tap it with another gauge to confirm it is that low. Jumps to around 30psi when I rev it. I'm sure this is my issue. Not sure how I used a new topline oil pump.

I did use the oil filter housing off a junkyard motor. Could the relief spring be to weak? Could I try shimming the relief closed? Or am I pretty much screwed? When I primed the motor with my hand drill it literally initially shot oil a foot in the air adn teh factory gauge shows much higher than my previous engine did.


Anyone have any suggestions? I don't see how this could happen. Also if it was losing oil pressure I'd think the head would be the first place so the cam journals would show some sort of rubbing or wear correct? I pulled the journals and they looked good as well as the bearings.

*********************UPDATE*************************

Ok so I got a nice calibrated gauge. Motor warmed up to 200 or so.

Tapped oil source at the oil cooler port. 32 or so PSI at idle jumps up to upper 60's reving to 2000 or so. All seems good there.

Used the same gauge at the head. Tapped oil source right next to the turbo supply. Pressure is around 7-10 (fluctuates a bit) when I blip the throttle to 2k or so it jumps up to around 18 and stops.

What could be starving the head of oil?

 

[BogusSVO]

how thick is your head?

the oil passage from the block to the head could be to shallow? or do you have the 1g 6 bolt block with the 2g 7 bolt head? if you have this combo and did not ream out the head bolt holes you may not have enough oil flow past the head stud into the head.

read this..
http://www.dsmtuners.com/forums/newbie-forum/341028-4g63t-head-oil-port-mod.html

and this
http://www.dsmtuners.com/forums/cylinder-head-short-block/341885-oil-port-mod-2-4g63t.html

 

[forcefed86]

how thick is your head?

the oil passage from the block to the head could be to shallow? or do you have the 1g 6 bolt block with the 2g 7 bolt head? if you have this combo and did not ream out the head bolt holes you may not have enough oil flow past the head stud into the head.

read this..
http://www.dsmtuners.com/forums/newbie-forum/341028-4g63t-head-oil-port-mod.html

and this
http://www.dsmtuners.com/forums/cylinder-head-short-block/341885-oil-port-mod-2-4g63t.html

Thanks for the reply.

It is a 1G head w/ studs. Head pulled directly from my last motor worked fine installed on this motor. I don't believe my oil pressure readings are that off. Looks in spec. HLA is regulating pressure down and that is the reading I'm getting. around 7-10psi. The numbers I was picking up from the MMCD were off. Looks like it's reading well into the negatives with the car off. I've got some sort of PTW or ring issue it has to be.

On my other thread it does seem my FWD oil port is clogged. Not sure what would be causing that or how to go about cleaning it. I shut off the engine immediatly so maybe I just didn't wait long enough for oil to come out of the FWD port.

 

[NOSLO2PT0]

I used a new topline oil pump.

That's your problem right there!

 

[slowgsr]

=the oil passage from the block to the head could be to shallow? or do you have the 1g 6 bolt block with the 2g 7 bolt head? if you have this combo and did not ream out the head bolt holes you may not have enough oil flow past the head stud into the head.

I have a 7 bolt 2g head on a 6 bolt 1g block, I DID NOT ream the head bolt holes.. I have no problems. (with L19s)

The head dosen't need a ton of oil pressure, lets keep the oil in the pan where it needs to be people!