Oil Pressure Problems

GTXJim · Post by **GTXJim** » Sun May 25, 08 10:25 am

Started the motor up yesterday for the first time previously it has only done dyno time in the States since I've owned it I have had pro gram main caps fitted, big roller cam, roller lifters, dragstar style sump and a remote oil filter. it has a mellings dual pickup oil pump and was taking ages to prime up, but had it spinning over on the drill showing 40psi fired the car up pressure slowly drops off to 0 spoke to Blue and Dunc and they both said about the big dual lines draining back, so fitted some different lines same prob did this about 5 or 6 times best we had was revving the engine 4,000/5,000rev's and only had 25/30 psi.
The bearings are the ones that were in it as they are fine all checked for clearance the lifter bores have bronze guilds fitted and it has Indy heads with external oiling. Any ideas I'm off to Broklands now to clear my head

Blue · Post by **Blue** » Sun May 25, 08 12:31 pm

Before getting too carried away, try another gauge to be certain you really do have a problem. I'd take a look at the relief valve in the pump next, make sure it is not jamming and that it fully closes. If the spring looks like it has been cut down (compare it to one from a stock pump) that could be your problem. Some American racers run very little oil pressure to save HP. If that's not it, I'd strip the pump and look for wear or damage.

mopar_mark · Post by **mopar_mark** » Mon May 26, 08 10:44 am

With the oiling system on my B1, I had issues in so much as that the oil would bleed down & I had to manually prime to get the oil pressure back.

I used to physically pour oil down the oil feed line which fed the pump & the same time prime oil pump with drill in reverse mode.

I wouldnt expect to get more than 30-40psi when using a drill. Once pressure was there, I would start engine & pressure would be back to 60-80psi.

I didn't have a problem if motor was used regularly, if not pressure would drop after 2-3 days and I would have to go through the same procedure.

Yours is a slightly different scenario as you can achieve 40 psi when manually priming, but oil pressure is falling off when motor is running.
I had a problem when I couldnt get oil pressure manually & turned out to be faulty gauge. It threw me for a while, as gauge was working fine, never showed any problems or fluctuations.

When you got the 40psi manually & ran the car, oil pressure dropped to 25/30psi. When you switch off the engine, does the engine maintain/hold the oil pressure or is it falling off fast.

If it were me I would be:-

Try alternative oil pressure gauge, I have a new one if you need to borrow.

As it s only 4 bolts, Remove oil pump & check all is OK with rotors, pump to block '"O" ring seal or gasket is good. I used to run a KB Pump, so may be easier to check if working than what you have ?

Re install pump, without oil lines, spin oil pump using drill & check output pressure.

If pump OK ,re install oil lines & pour oil down the main main oil pump feed pipe & tighten all oil lines.
I still have a KB pump if you want to try, assuming you have room ,it will be a straight swap

Not sure what oil filter system you have, I had a System 1 so could easily check if was OK. If unable to inspect,I would change for another filter. For cranking purposes I would even consider by passing the oil filter to try & eliminate the problem

GTXJim · Post by **GTXJim** » Mon May 26, 08 11:39 am

Cheers Guy's, thanks for the advice, I've also heard that the big pump can supply too much oil to the Indy heads with the external oiling and almost fill up the valve covers so considering putting an adjustable oil pressure relief valve on. But in the mean time will check gauge then pump then every thing else, so should be fun this week.

Anonymous · Post by **Anonymous** » Wed May 28, 08 5:58 pm

How big is this big cam, and who's roller tappets are you using ?

Cannonball · Post by **Cannonball** » Wed May 28, 08 6:17 pm

Slick wrote:How big is this big cam, and who's roller tappets are you using ?

yes slick, dident dave have a similar prob because off the lifters ????

Blue · Post by **Blue** » Wed May 28, 08 6:43 pm

I remembered Dave having a problem with that and suggested it, but apparently Jim's block has had the lifter bores bushed so there is no oil feed to them.

GTXJim · Post by **GTXJim** » Wed May 28, 08 7:15 pm

Hi Slick, the lift is 690 the lifters are comp cams, but all the lifter bores have been bushed.
But have another problem, checked one of the main caps this afternoon and found this!!!

Pete · Post by **Pete** » Wed May 28, 08 7:19 pm

Ouch!

Another case of first class American machining and assembly?

latil · Post by **latil** » Wed May 28, 08 7:29 pm

Looks like the clearances are too tight,there was muck in the gallery and as for the scratched journal,who knows.What a pain.

Guy · Post by **Guy** » Wed May 28, 08 9:24 pm

Is that a result of the earler lifter problems, which journal was it??

Cannonball · Post by **Cannonball** » Wed May 28, 08 11:08 pm

thats a bummer jim
pull it apart n start again,

GTXJim · Post by **GTXJim** » Thu May 29, 08 9:23 am

Sure is Dunc, Motor's coming out on Saturday, I may get away with a polish on the crank haven't checked any of the rod bearing yet.
The funny thing is me and my Brother used to throw engines together and never had a problem, this one I've been over careful with, double checking everything HO HUM

Cannonball · Post by **Cannonball** » Fri May 30, 08 12:41 am

GTXJim wrote:Sure is Dunc, Motor's coming out on Saturday, I may get away with a polish on the crank haven't checked any of the rod bearing yet.
The funny thing is me and my Brother used to throw engines together and never had a problem, this one I've been over careful with, double checking everything HO HUM

you will get there fella, good luck

Pete · Post by **Pete** » Fri May 30, 08 8:47 am

Good luck Jim, I am sure you will get it out for the Nats.

Please tell us what you find.