oiling system

bsfc9 · Post by **bsfc9** » Mon Jan 26, 2004 8:52 pm

don, ive got a motor on the dyno trying to troubleshoot an oiling problem. is a 358 circle track motor, dry sump w/ 3 scavanges from the pan, roller cam bearings, restricted oil to the top end, spring oilers. at about 6500 the oil pressure starts to drop and is down by 15psi by 8000. through this range the oil flow stays at a constant 14 gallons per minute(we have a flow meter for this). at 6000we have 73psi and at 8000 we are at 58, this is a 700hp motor. any thoughts?

speedtalk · Post by **speedtalk** » Mon Jan 26, 2004 9:18 pm

I'd cut the filter apart to verify the engine is ok and then try another pump. If this is just the characteristics of the pump it'll probably never cause a problem.

What items do you know are not the problem? Tank, lines, etc? and why?

bsfc9 · Post by **bsfc9** » Tue Jan 27, 2004 7:10 pm

the engine shows this problem in the car with its tank and also with the (seperate) dyno tank. the lines used with the dyno tank are dedicated and have not had any past problems(engine also shows same problem in car with its lines), checked oberg on scavange side--no debris, removed scavange side filter--same, checked oil pressure on both sides of pressure side filter(framhp6) and there is a small pressure drop--removed fram hp6 and the oil pressure is a little higher but still shows the same prortional drop as before. the pump had 16-28 pulleys. now we changed pulleys to speed up the pump and it started losing pressue earlier in the rpm range(could this be a pump efficiency problem?). by the way, is 14 gal. per min. a little much, did you measure this on your cup engines?

speedtalk · Post by **speedtalk** » Tue Jan 27, 2004 8:41 pm

bsfc9 wrote:14 gal. per min. a little much, did you measure this on your cup engines?

Yes, that's high - I'm assuming regular cam bearings? That's probably all that pump will do. What is the width of the pressure section?

bsfc9 · Post by **bsfc9** » Wed Jan 28, 2004 9:33 pm

don, the engine does indeed have roller cam bearings and i say the pressure section is a 1.400(although the engine builder says its 1.100). we have slowed the pump down and now the pressure drop is less but still there.

speedtalk · Post by **speedtalk** » Thu Jan 29, 2004 1:49 am

The pump manufacture will have flow numbers, but my memory says a 1.100" pressure section is over it's head at 14 gallons and the 1.400" is border line.

I've run pressure sections under 1.000", but the engine maxed at 7,000rpm and only needed to make 35psi

In the end you may need to figure out a way to lower oil consumption - I don't know if the pump will do any better than 14 gallons.

Can you try another pump?

bsfc9 · Post by **bsfc9** » Thu Jan 29, 2004 6:36 pm

yea, trying another pump would be our next step, but i think the owner and his builder are convinced that slowing down the pump("so its not cavitating") is the answer--i will let you know what we find if we do. (i think we need a bigger pump or an engine that leaks less.) thanks again!

speedtalk · Post by **speedtalk** » Thu Jan 29, 2004 8:44 pm

Yes, please let me know.

bsfc9 · Post by **bsfc9** » Sat Feb 07, 2004 10:42 am

don, we installed this pump on a different engine that has never displayed oiling system problems and we observed the same behavior. this pump must not be correct for the application.
what kind of gal/min oil flow have you seen in a roller cam bearing application and in a non-roller cam bearing engine?(i understand there are other variables{spring oilers, etc}just some general parameters)--thanks

speedtalk · Post by **speedtalk** » Sat Feb 07, 2004 11:12 am

Glad you figured out the problem.

When you put the pump on a different engine, did it still max out at 14gal?

Roller cam bearings take about 3gal of consumption out of the motor - assuming the bearings are NOT pressure fed.

bsfc9 · Post by **bsfc9** » Mon Feb 09, 2004 9:16 pm

don, it flowed more than 14

with a similar drop in oil pressure. now i have heard that an engine with roller cam bearings will flow 8-12 gph. would you consider this accurate?

speedtalk · Post by **speedtalk** » Mon Feb 09, 2004 11:27 pm

bsfc9 wrote:now i have heard that an engine with roller cam bearings will flow 8-12 gph. would you consider this accurate?

That's exactly right. I think most of our engines were 10 gals. Are the roller cam bearings being pressure fed? If so, that would explain the difference.

bsfc9 · Post by **bsfc9** » Tue Feb 10, 2004 9:34 pm

don, the roller cam bearings in these engines are not pressure fed, only splash. i am not too familier with pressure fed roller cam bearings.

speedtalk · Post by **speedtalk** » Tue Feb 10, 2004 9:58 pm

bsfc9 wrote:i am not too familier with pressure fed roller cam bearings.

I just wanted to make sure someone didn't make a mistake and drill a hole in the bearings. How about spring oilers that are not restricted? I'm just taking a stab at it.

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