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Author Topic:   Oil pumps
Todd83C
Dirt Full Roller

Total posts: 53
posted October 25, 2005 03:17 PM  
I have seen that some people dont like the high volume oil pumps, why is that? Also what is the best weight of oil to run in a mod on alky? I ran 20-50 valvoline vr-1 racing oil in the motor last year with high volume pump and had no troubles.

jay116
Dirt Freak

Total posts: 428
posted October 26, 2005 04:47 AM  
quote:
Originally posted by Todd83C:
I have seen that some people dont like the high volume oil pumps, why is that? Also what is the best weight of oil to run in a mod on alky? I ran 20-50 valvoline vr-1 racing oil in the motor last year with high volume pump and had no troubles.


We run a high volume with our motors due to the fact that it is a roller motor. You need the oil on the valve spings to keep them cool. You can adjust your oil pressure by changing the size of the hole in the oil restrictor. We use a racing 20-50 weight oil also. There really is a need for oil up at the top of the motor for your valve train.

[This message has been edited by mod46 (edited October 26, 2005).]

TEAMPCR
Dirt Freak

Total posts: 238
posted October 26, 2005 05:32 AM  
Stock rockers (i.e. stamped steel with fulcrum ball and no rollere bearings) use the high volume pump and make sure the oil can get back to the pan. If running full roller rockers, the stock type pump should work as they do not generate near as much heat.

Todd83C
Dirt Full Roller

Total posts: 53
posted October 26, 2005 03:32 PM  
If you run a high volume oil pump and run restrictors in the block it should keep the oil in the bottom end and give a better cushing the bearings or is this wrong?

Xtreme12x
Dirt Forum Champ
Total posts: 874
posted October 27, 2005 08:36 AM  
You've got it. Always try to run a HV/HP Pump, the only time I don't run a HV Pump is on hobby stock motor's with stock pans. I built a 6" Rod Hobby stock motor for a friend that we used a HV only pump and it holds 65 cold and 45 hot. I've ran the HV/HP Pump on both of my B-Mod motors with no problems.

sc1 racing
Dirt Freak

Total posts: 419
posted October 27, 2005 10:33 AM  
isnt the job of oil restrictors to route the oil onto the camshaft and lifters. for top end oiling? anything over 30 psi is overkill..if you could actually see how much hot oil moves an 10 ps1, and how fast it moves you would see...

i use a h/v oil pump just cause my p/u tube was desinged for the h/v pump, but installed stock pump spring in it. works great with 55 on the gas 20-30 off

andykmod
Dirt Freak

Total posts: 351
posted October 27, 2005 08:13 PM  
I use high volume chevy big-block pumps and never had any oil related problems in both flat-tappet and roller motors w/restrictors, you just have to get a .125 shorter oil pump shaft from Midwest Motorsports or Speedway Motors

andykmod
Dirt Freak

Total posts: 351
posted October 27, 2005 08:14 PM  
Oh yea, As for oil, i have been using Castrol 20-50 for years with no problems.

stockcar5
Dirt Forum Champ
Total posts: 578
posted October 28, 2005 08:12 PM  
dont run restrictors. they kill your valve spring life. all the restriction you need is built into the lifters. people run their pans dry because they dont have proper flow back to the pan. open up your drain holes to the max, ditch the restrictors and you'll never have a problem.

------------------
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racer_67
Dirt Newbie

Total posts: 1
posted October 29, 2005 12:13 PM  
I have been running a M55A stock volume high pressure pump for two years now with stock rockers and hyd cam and have had no problems. I didn't take notes on oil temp but think it is lower, since the pump is not over working and bypassing oil, constanly creating heat. On another note, if using a HV pump there is a mod you can do to your pump cover to allow oil to return to the pan, as in stock form bypass oil is returned to the pick-up side of the pump.

[This message has been edited by racer_67 (edited October 29, 2005).]

Raz_900
Dirt Forum Champ
Total posts: 635
posted October 29, 2005 05:31 PM  
quote:
Originally posted by stockcar5:
dont run restrictors. they kill your valve spring life. all the restriction you need is built into the lifters. people run their pans dry because they dont have proper flow back to the pan. open up your drain holes to the max, ditch the restrictors and you'll never have a problem.


Totally agree. The pumping the pan dry thing is one of the oldest wive's tales out there.

The lifters and pushrods are all the restriction you need. A stock vs. HV will pump exactly the same oil to the top end assuming the pressure is the same. Actually, a M55A will send more up top than a M55HV with a lower pressure spring.

The difference is the stock volume pump will start to run out of capacity when the RPMs get much over 6000-6500 or so (rough estimate, depends on clearances and smoothness of the passages).



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