5K Oil Pressure Issues

[TOMMYS Ke 11]

Ok here we go! 5k block,dished pistons machined to flat tops,block decked to suit,4k head,isky chevy lifters,430lift cam,fully balanced,datsun 12a push rods,new oil pump,all new bearings big end,mains,cam,all meassured 1.5-2.5 thou clearances. Now for the problem this is the third cam & lifters we have put in in 12 months all been the same and getting very pissed of. Start up cold 60-70 psi oil preasure once warms up drops back to 8-10psi at idel 1000rpm. Running Penrite 25-70 extra 10 oil,has any one out there had same/similar issues as this? would like to here from you so as we can sort this problem out.

 

 

Cheers :- Stuart (Thomas dad).

 

 

 

 

 

 

 

 

 

 

 

 

 

[Feral4K]

Yep! my oil pressure at idle was virtually non existent, but at max revs was around 70 psi, i think cam overlap causes the oil pump to

cavitate so to speak ( therefore " frothing" the viscosity of the oil) i fixed it by using LUCAS OIL STABILISER hello oil pressure

mine never chewed up cams but? Hope this was helpfull.

[TOMMYS Ke 11]

Hi there Feral4k was this on a 5k solid lifter conversion? thanks for your information.

 

Cheers :- Stuart (Thomas dad).

[Evan G]

double check your timing chain tentioner bolt tightness/sealing surface

[Feral4K]

No stuart its a 4k solid setup, 300+ duration, 500+ lift powerband 4500 to 9500 twin 40s bigport, springs, arp headstuds and rodbolts,

balanced, elec ignition, pacemaker 4/1 extractors, oil pump mod, now being built for methanol and giggle gas....

[wagn]

Is the oil pump shimmed? could try that to up the pressure

Also is the thicker oil your running ideal for a fresh built motor?

[CorollaNut68]

Crappers! it's a world wide epidemic! I've just noticed mine doing the same thing here in the last few days...70-80 cold..practically nothing at idle warm...Castrol20-50....

I can't remember for sure now but it seems like it used to be at least 20 or so at idle...I just looked down the other day as I was parking and it was way down, like 5, oil level was good but I changed it anyway...still low pressure, stays up ok while driving, but this pump has got lots and lots of miles on it, thought maybe that was it.

[GJM85]

It's a very very basic systematic and there isn't much that goes wrong. It's either the pump, the sensor or the gauge.... Q

Edited April 19, 2013 by GJM85

[kickn5k]

Ok here we go! 5k block,dished pistons machined to flat tops,block decked to suit,4k head,isky chevy lifters,430lift cam,fully balanced,datsun 12a push rods,new oil pump,all new bearings big end,mains,cam,all meassured 1.5-2.5 thou clearances. Now for the problem this is the third cam & lifters we have put in in 12 months all been the same and getting very pissed of. Start up cold 60-70 psi oil preasure once warms up drops back to 8-10psi at idel 1000rpm. Running Penrite 25-70 extra 10 oil,has any one out there had same/similar issues as this? would like to here from you so as we can sort this problem out.

 

 

Cheers :- Stuart (Thomas dad).

 

Just to clarify this thing is brand new top to bottom. New bearings(all of them), new "shimmed" oil pump and pretty sure Stu put a new aftermarket gauge and sender in it.

Also after some telephone convos I'm pretty sure he's bolted a mechanical pressure gauge right into where the sender goes.

 

 

Edited April 19, 2013 by kickn5k

[GJM85]

I'd run it for 5 minutes and pull the rocker cover. If its wet..... You know it's not the pump.

[GJM85]

Otherwise you might consider a bigger sump.

[GJM85]

I'm thinking the block is too short... so the rocker ratio is thrown out, putting excess pressure on the lifters, which is loading up the cam & labouring the oil pump.

 

I'm running a standard 5k block 20 thou overbored (not decked), with shallow dish pistons (not machined), 4k head and the Datsun/chev lifter/rod conversion. The same setup but my block is 5mm taller. With the Tighe 104 cam (.423" lift) the adjustable rocker gear was at the end of its tether.

 

Where'd you find the extra 5mm for the rocker adjustment?

Edited April 19, 2013 by GJM85

[GJM85]

I reckon you should shim the rocker pedestals to counter whatever you took of the block.

[TOMMYS Ke 11]

Hi there Gavin thanks for your information but we don't have any problems with rocker adjustment , still have 4/5 mm left. We are currently looking at blocking the oil feed gallery to the lifters and push the oil to the top end to see if this helps? it is something that Blown 5k from New Zealand has done in the past we will keep you all informed as to our progress.

 

Cheers:- Stuart (Thomas dad).

[GJM85]

Doesnt sound right to me bud. Only other motor ive heard of of going through lifters and cams like this are small block fords and they are all hydrauluc. Big problem with them is valve seat pressure and cam degreeing not oil circulation.

Id still be questioning the accuracy of the gauge.

Edited April 19, 2013 by GJM85