sticking oil pressure valve RV8

kokkolanpoika · Post by **kokkolanpoika** » Fri Jun 27, 2008 6:05 pm

Hi..

I have got too mutch proplem with my engine oil system.
Engine is still my old RV8 4,6 stage 3 (buildin a new 5.2 engine)
My proplem is.
I bought new oil pump base last year (from RPI) and i drived about +3000km and relief valve sticks open position this summer. (same proplem as my old base, so i change new one)

So i take the base of and install some valve lapping stuf in it, add turn the pistons couple of times, and it moves like new again. But when i go to the test drive. valve sticks again slightly open. So i take it off again, and piston looks ok, but it will stick still.. (i also measure the clearances, bore is 15.25mm and piston is 15.21mm, so clearance is 0,04mm) i notice that piston will hit the wall when it comes out where the oil flows.. It will sticks there.

So this is not funny anymore..

Can some one explain why it will stick? Oil sump is clean, bearings are ok (look at them last year)

Can i solve this Fuc...ing proplem to fit tadpole??? I dont want to anymore bought +100£ base every summer or +3000km..

Post by **katanaman** » Fri Jun 27, 2008 6:48 pm

Its unlikely to be your piston and more likely to be the bore of the pump base. They get little ridges (as in tiny) down the bore, the piston goes slightly sideways and hangs up. Your clearances will also be different when the engine is hot. Tadpole valve will sort it but unless you get the seat cut to suit it you will have lower pressure because of slight leakage. Its nothing to worry about but people get all uptight about having big (well for a rover anyway) oil pressure figures. JE engineering can supply the tadpole and do the machine work. I have often wondered if putting something like a stainless liner in would work but I have no idea what the different expansion rates would do.

Post by **katanaman** » Fri Jun 27, 2008 6:59 pm

Just found this topic on web to help exlain http://www.britishv8.org/Articles/Rover ... pgrade.htm

RoverP6B · Post by **RoverP6B** » Fri Jun 27, 2008 11:58 pm

It could well be the oil pressure transmitter rather than the oil pressure relief piston or it's bore.

Especially as you fitted a new oil pump front cover and it still does the same.

My original 3.5 would on occassions, when at normal operating temperature, the oil pressure would fall, sometimes almost to zero, then recover. The oil warning light never came on during these occassions.

When my 4.6 was fitted, a new oil pump front cover was used, but I retained the original Smiths oil pressure transmitter because I was hoping to find an original replacement.

The oil pressure fluctuations continued exactly as they had done with the old engine and old oil pump front cover.
I removed the oil pressure sender and fitted a new replacement.

Oil pressure readings were exactly as they should be, and the fluctuations were gone.

Have you replaced your oil pressure transmitter?

Ron.

kokkolanpoika · Post by **kokkolanpoika** » Sat Jun 28, 2008 6:20 am

I´m 100% sure that it is an oil pressure relief valve.. Bacause i take it off and it will stick. and bore is wear.

I have got also new pressure transmitter. and oil light stays on when i start engine. And also i have got mechanical oil pressure gauge, and it will show zero..

Contackt to RPI if buy them tadpole base..

RoverP6B · Post by **RoverP6B** » Sat Jun 28, 2008 6:39 am

Hello Timo,

Well you have obviously ruled out the transmitter.

How disappointing to have a new oil pump front cover do exactly the same as the one you replaced

Maybe this is more common on later issue oil pump front covers

Ron.

ChrisJC · Post by **ChrisJC** » Sat Jun 28, 2008 6:40 pm

I have fitted a tadpole valve to my engine because the valve stuck open.
However, the tadpole valve sticks closed with a cold engine, giving an oil pressure >60PSI !

Chris.

kiwicar · Post by **kiwicar** » Sat Jun 28, 2008 7:09 pm

can't you pollish out the ridges in the bore of the valve, make /find a piece of steel that is a closefit in the bore and is itself smooth and parrallel, get some brasso and use it in an electric drill to pollish the bore, try and keep it moving in and out as it spins so any scratches that remain are cross hatched and the valve bit shouldn't stick. I would not think it has to be that critical a fit, just the sealing face is critical. Also make sure there is a good chamfer on the back of the piston.
Mike

kokkolanpoika · Post by **kokkolanpoika** » Thu Jul 03, 2008 10:24 am

kiwicar wrote:can't you pollish out the ridges in the bore of the valve, make /find a piece of steel that is a closefit in the bore and is itself smooth and parrallel, get some brasso and use it in an electric drill to pollish the bore, try and keep it moving in and out as it spins so any scratches that remain are cross hatched and the valve bit shouldn't stick. I would not think it has to be that critical a fit, just the sealing face is critical. Also make sure there is a good chamfer on the back of the piston.
Mike

I try to polish it, but it aint do any help..

I contackt to RPI, and they don´t have anymore tadpole unit..
Contackt to Je-engineering and John H says that he can modify my old unit.. So i have to send it to him..

Thanks for advise guys..

Wotland · Post by **Wotland** » Thu Jul 03, 2008 10:39 am

Hello Timo,
Try to contact DJE, I think they have oil pump housing with tadepole in stock.