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Buick 231 oil pump info wanted

Discussion in 'Early CJ5 and CJ6 Tech' started by schardein, Apr 1, 2005.

  1. Apr 1, 2005
    schardein

    schardein Low Range Therapy

    Success, MO
    Joined:
    Aug 11, 2003
    Messages:
    553
    As some may know, I spun 2 rod bearings getting on it a couple weeks ago. Motor is out and new (to me) short block is on hand.

    My question is about the oil pump. Apparently you can get a "wear plate" if your lower housing is worn? Also you can get a spacer and longer gears which is a hi volume, with or without the "wear plate". I am ready to spring for a new cover and hi volume pump, without wear plate cause everything will be new, but want to tap into everyone's knowledge first.

    Both my motor and the replacement short block had the wear plate installed.

    Can anyone shed some light on standard procedure here, or offer real world experience?

    I had the RPMs up there, but I think ultimately my problem was low oil pressure. Want to prevent future occurrences, cause the right foot ain't gonna get any lighter!!
     
  2. Apr 2, 2005
    Spicolli

    Spicolli jeep geek

    So. Cal.
    Joined:
    Dec 23, 2004
    Messages:
    188
    i put a wear plate and hi volume pump on. i should be getting the engine up soon (just installing it now)
     
  3. Apr 3, 2005
    jeepdaddy2000

    jeepdaddy2000 Active Member

    Eagle Point oregon
    Joined:
    Jun 24, 2004
    Messages:
    1,132
    I've run a high volume pump in my 225 for almost 20 years with good results. Remember, high volume doesn't mean high pressure. High volume pumps are designed to move more oil at the same pressure(pressure can be changed by replacing the pressur spring). This will keep your pressure up in older engines with excessive bearing clearences. Instalation is simple. My kit required the drilling of two small holes for the instalation of the extension alignment dowels.
     
  4. Apr 3, 2005
    4x4chevette

    4x4chevette Member

    Lancaster, Ohio
    Joined:
    Dec 19, 2004
    Messages:
    133
    i installed the high volume pump and now carry 60 psi at an idle... I had 3 pounds before the install. Before the hivolume Id id a stock replacment and a 60 psi spring... I never changed the spring this time..
     
  5. Apr 3, 2005
    michigan_pinstripes

    michigan_pinstripes I'm not lost, I'm wandering

    Clarkston MI...
    Joined:
    Aug 20, 2003
    Messages:
    605
    I'm not the guru on Buick oiling systems but I have been reading up on this all Winter. This topic has plenty of "IMO's" :rofl: I'm not convinced the HV kit is worth the money.

    So here we go.... IMO, for the 225 and stocker 231's, the higher volume doesn't really have a place to go since the the passages are small. On engines where passages have been opened and main bearings drilled, it is a different story. The last generation 231 had a 5/8" block passage from the pump (previously 1/2").

    I have read many threads from harcore GN guys that say a stock setup with the critical plate-to-gear end clearance is plenty good for street cars. Also, tight mains at .0015 should produce the proper pressure. I have read that plastigage the end play may not be as accurate as a dial bore gage. (not to exceed .003 )

    The way I see it, if you drill out main bearings for more oiling, it is like flushing the toilet while you are in the shower. Then you need the high volume kit to make up for it.

    However -- Our old motors don't have tight mains anymore so will a HV pump on an old motor make up for it? Not neccessarily. IMO, a proper tolerance rebuilt oil pump assembly still will be fine. I have also read that there are many sealing issues with the aftermarket "offshore" parts on the HV kit.

    Here are your choices

    1. Silverseal makes complete "metric" (231) replacement pump assemby for about $40. No loss of sleep on tolerances. :D

    2. Take your assembly to someone that knows how to build it.

    3. Do it yourself booster plate (new wear plate) but pay attention to the .003.

    Do some due diligence on this subject! ;)
     
  6. Apr 3, 2005
    jeepdaddy2000

    jeepdaddy2000 Active Member

    Eagle Point oregon
    Joined:
    Jun 24, 2004
    Messages:
    1,132
    Early Buick V6's suffered from oversize cam bearing oil holes(there is an old fix by which the bearings are redrilled to a smaller size before installation). Couple this pressure loss with the natural widening of the clearences due to wear,and many engines have trouble maintaining pressure at idle. By moving more oil(volume) than can leak out, the pressure will come up. However the pressure will at no time exceed the pressure rating of the relief spring. This is especialy importiant not only to older engines, but to operators who run their engines at minimal RPM's during technical wheeling, even if the motor is new. I installed the pump upgrade to keep reasionable pressure at the bearings since many times my engine is forced to momentarly lug well below idle while dealing with evil situations.
     
  7. Apr 4, 2005
    4x4chevette

    4x4chevette Member

    Lancaster, Ohio
    Joined:
    Dec 19, 2004
    Messages:
    133
    Yes, this is what happened to me... I could runt hat think at close to 6grand all day long,b ut after an hour of wheeling in low lock ist gear at and ilde, I would spin rod bearings, lost 3 engines in the chevette from it.
     
  8. Apr 4, 2005
    schardein

    schardein Low Range Therapy

    Success, MO
    Joined:
    Aug 11, 2003
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    Thanks for all the replies. I will agree there is no substitute for a properly clearanced engine. I like to mic rather than use plastigage, but I do use it.
    My motor would run low pressure at idle after it was warmed up. It lost 2 rod bearings after some hi rpm pounding for less than 5 minutes.
    I have heard that one way to keep the pressure up is to use quality lifters, cheaper "loose" lifters bleed off to much pressure. I guess putting everything together here, it is best to build these engines closer to the tight side.

    I am thinking since I want to replace the timing cover/oil pump anyway, why not go to a hi volume...can't hurt.
     
  9. Apr 4, 2005
    michigan_pinstripes

    michigan_pinstripes I'm not lost, I'm wandering

    Clarkston MI...
    Joined:
    Aug 20, 2003
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    605
    Here is a source for the complete Silver Seal cover assembly here in Detroit. He is a GN guy and likes this product. Many aftermarket covers out there are not very good quality. He is a small national mail order warehouse and has excellent prices. Comes with cover, neoprene seal, oil pump assembly, gaskets. $129 + ship. Note: This is a 231 assembly but should work on 225's as I think the cover is drilled to accomodate both 14 & 20 pans.

    http://www.fullthrottlespeed.com/it...STC3F223A8820}&Cc=BUSHORT&iTpStatus=0&Tp=&Bc=

    http://www.silver-seal.com/Index.cfm?p=373
     
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