Author Topic: sohc 750 oil pump (Read 12235 times)

ttr400 · « **Reply #25 on:** September 14, 2010, 01:46:36 AM »

Update:

Spring details.

Stock (used) taken at 25mm compression = 9 PSI, At 20mm = 13 PSI

Kit 970 spring. At 25mm = 11 PSI, At 20mm = 18 PSI

Kevin

voxonda · « **Reply #26 on:** September 14, 2010, 01:56:56 AM »

Great info Kevin,

Thanks, Rob

Bill/BentON Racing · « **Reply #27 on:** September 23, 2010, 02:36:36 PM »

K.Thanks,Bill

Bodi · « **Reply #28 on:** September 25, 2010, 08:56:34 AM »

The spring mod will allow a bit higher maximum pressure with cold oil or at high rpm. This assumes all else is good: if you have low oil pressure because of loose bearings then the pump isn't hitting the pressure relief anyway so raising the relief pressure won't make any difference.

wannaby · « **Reply #29 on:** March 10, 2011, 01:29:41 PM »

Sure would be nice to see more picks of the inline tranny cut off midget motors speacially the cut tranny side anyone know of any for sale ?? that inline straight 8 would be nice ...what is the history on it.....

wannaby · « **Reply #30 on:** March 11, 2011, 08:02:05 PM »

Found this on here ...kind of cool....

cougar · « **Reply #31 on:** April 05, 2011, 08:27:13 PM »

I've been following this thread for a while now. Ok here is a wrench thrown into your discussion, LOL ! I won't go into my past experience but let's just say it's extensive and long ranging. Having built many engines (granted mostly automotive), from my experience the idea has always been to have more Volume not pressure. This being said is there a higher Volume pump for our beloved SOHC motors? ...cougar...

cougar · « **Reply #32 on:** April 15, 2011, 10:58:57 PM »

Bump ! Ahh come on, no thoughts on the "more oil" instead of "pressure" . Anything on higher volume pumps? ...cougar...

paulages · « **Reply #33 on:** April 15, 2011, 11:50:10 PM »

I tested the PSI on my 550 pump with no PRV at all, and it was off the charts instantly. The pumps seem to provide plenty of pressure, it's just a matter of adjusting when the PRV opens. You 750 guys have it hard though with the oil pump inside the sump. The 500/550/650 oil pump makes it easy with the PRV assembly hanging right off the side. It should make for quick changes... One of these days I'll measure the spring pressure of a stock spring, then shim it in .010" increments and record the pressure changes.

I know this doesn't help you guys too much, but maybe somebody's got enough spare time to pull their oil pan over and over again and test various preload shims?

MRieck · « **Reply #34 on:** April 16, 2011, 06:06:10 AM »

Quote from: cougar on April 05, 2011, 08:27:13 PM

I've been following this thread for a while now. Ok here is a wrench thrown into your discussion, LOL ! I won't go into my past experience but let's just say it's extensive and long ranging. Having built many engines (granted mostly automotive), from my experience the idea has always been to have more Volume not pressure. This being said is there a higher Volume pump for our beloved SOHC motors? ...cougar...

I totally agree

cougar · « **Reply #35 on:** April 16, 2011, 10:52:59 AM »

Mr. Rieck; I Very Much Appreciate you agreeing with my statement of "more volume than pressure". From what I've heard, you are to SOHC 750's what Carroll Shelby is to Fords. So I hold you in the highest regards!! That being said, do you have any knowledge that you can impart to us on a way to increase the oil Volume in our beloved SOHC750's? Thank you for sharing, ...cougar...

paulages · « **Reply #36 on:** April 16, 2011, 11:15:09 AM »

Maybe I'm misunderstanding the "volume" being discussed here.. Are you talking about overall oil volume? Volume of oil passed through the pump at any given time? It seems like with the oil passageways being static, the best you could ask for is higher pressure to get it moved through the engine more quickly and greater overall volume of oil in the system so that it has more of a chance to cool before being recirculated.

That's just my brain working here though.. I'm probably missing something obvious.

cougar · « **Reply #37 on:** April 16, 2011, 11:37:28 AM »

Hello paulages; I understand your wondering about this. I can't explain the exact process but here is what I can say from my experiance. Having replaced the regular oil pump in automotive engines, if you put a standard oil pump beside a High Volume you'll notice that the area where the oil is being pumped from is approx. 1/4" to 1/2" thicker. This added thickness in this area gives you more volume of oil with each rotation of the pump. This increased oil volume in itself increases the oil pressure in the passageways. I hope this helps. ...cougar...

paulages · « **Reply #38 on:** April 17, 2011, 11:22:26 AM »

Quote from: cougar on April 16, 2011, 11:37:28 AM

Hello paulages; I understand your wondering about this. I can't explain the exact process but here is what I can say from my experiance. Having replaced the regular oil pump in automotive engines, if you put a standard oil pump beside a High Volume you'll notice that the area where the oil is being pumped from is approx. 1/4" to 1/2" thicker. This added thickness in this area gives you more volume of oil with each rotation of the pump. This increased oil volume in itself increases the oil pressure in the passageways. I hope this helps. ...cougar...

Yeah, that's what I was wondering. Only a given amount of oil can pass through the galleries without either dropping or raising pressure... seems like raising the pressure by changing when the pressure release valve opens (with a shimmed or thicker spring) would also be increasing the volume, assuming that the pump is actually capable of pumping higher volume/pressure than it does stock.

In the car pump situation you're talking about, it sounds like the first pump was likely pumping at full volume. It seems as if the SOHC4 pumps actually produce more volume/pressure than the PRV actually allows into the gallery, hence the heavier spring fix.

MRieck · « **Reply #39 on:** April 17, 2011, 12:02:14 PM »

Quote from: cougar on April 16, 2011, 10:52:59 AM

Mr. Rieck; I Very Much Appreciate you agreeing with my statement of "more volume than pressure". From what I've heard, you are to SOHC 750's what Carroll Shelby is to Fords. So I hold you in the highest regards!! That being said, do you have any knowledge that you can impart to us on a way to increase the oil Volume in our beloved SOHC750's? Thank you for sharing, ...cougar...

Wow...thanks but I'm no Carroll Shelby.

I think you explained it pretty well. As for knowing how increase the volume there isn't anything I can think of aside from changing rotors which would make a new body necessary..
I've never been a big fan of turning the oil pump faster which is what the high pressure units do (by changing the drive gear).

MRieck · « **Reply #40 on:** April 17, 2011, 12:03:02 PM »

BTW....there will be an all new oil pump on the market soon for the 750.

voxonda · « **Reply #41 on:** April 17, 2011, 12:07:44 PM »

Quote from: MRieck on April 17, 2011, 12:03:02 PM

BTW....there will be an all new oil pump on the market soon for the 750.

Well Mike, that would be good news! Keep us informed...

Cheers, Rob

Doctor_D · « **Reply #42 on:** April 17, 2011, 12:55:54 PM »

Subscribed.

bwaller · « **Reply #43 on:** April 17, 2011, 02:08:53 PM »

Well leave it to you to save the day Mike. I'm all ears on this news.

wrenchmuch · « **Reply #44 on:** April 20, 2011, 06:05:51 AM »

Quote from: MRieck on April 17, 2011, 12:03:02 PM

BTW....there will be an all new oil pump on the market soon for the 750.

New oil pump ? If you need commitments for purchasing let me know .

Sam Green Racing · « **Reply #45 on:** April 20, 2011, 08:10:46 AM »

I wonder what secret Carroll Murphy is hiding.

Sam.

MRieck · « **Reply #46 on:** April 20, 2011, 09:20:14 AM »

Quote from: SamCB750A on April 20, 2011, 08:10:46 AM

I wonder what secret Carroll Murphy is hiding.

Sam.

I don't keep secrets Sam....you know that. I'm hoping to have my hands on one in 3 or 4 weeks.

Sam Green Racing · « **Reply #47 on:** April 20, 2011, 11:28:18 AM »

8)Cool Mike.

Sam.

wannaby · « **Reply #48 on:** April 20, 2011, 12:25:42 PM »

So when ya say new pump do you mean an external pump or just some kind of beefed up original type pump.

cougar · « **Reply #49 on:** April 20, 2011, 02:55:14 PM »

Mr. Rieck; Yes please keep us updated on the new oil pump for our beloved SOHC750's. And as always we love to hear from you . ...cougar...

News:

Author Topic: sohc 750 oil pump (Read 12235 times)