pressure build up in lower end

Bottom End (crankcases and crankshaft)
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bibs
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pressure build up in lower end

#1

Post by bibs »

Well I'm just havin all kinds of fun.My pan pisses oil like prune juice running through an old age home............and I'm about at my wits end here.

Cotten got me squared away on a burnisher for the oil pump(36-72 S&S) so I tried burnishing the seat....no workie.
It only took me about 45 minutes to make up the tool and it came out pretty nice.
I have a brand new build here in a set of replica cases(58) stock bore 9-1 KB pistons with STD heads,shubbel style intake....shorty "E"
She sound sweet,nice throttle response.But she leaks a hellin through the breather hose.........on start up mainly.
I have overhead oil lines with a small orifice so the heads dont over oil........the overhead oiler is an aftermarket unit and it is plumbed on the top of the Cam gear cover close to the access port where the trash screen is located.On top of the oiler manifold sits a 0-60 lb oil pressure guager....and today she dang near seen 60 lbs :shock: ....She dropped down to 35 and wouldnt go any lower once the motor was warm.
I didnt(for a change)build the lower end...a shop in Wampum PA,name of KJ cycle did the work....and wud,nt ya know the owner who did the work is on vacation!!!!
I think....correct me if I'm wrong that the main issue here is the breather gear.
The holes in it are miniscule at best and I'm using 60 weight oil
or....it may be out of time by a tooth or so

I cant talk on the phone to anyone about this problem because of my hearing(loss)
Will Somebody PLEASE help me get to the root of the matter........Thanks,Dave.
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Re: pressure build up in lower end

#2

Post by john HD »

i would jettison that car oil filter and run it staight back to the tank.

it is only puking on start up right?

john
bibs
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Re: pressure build up in lower end

#3

Post by bibs »

I dont know if I follow you here JOHN....you mean run with out a filter and just go with straight lines from the tank to the motor?She pukes on start-up and while she's running...but mainly on start up.

Sounds inviting,maybe too much pressure built up in the system because of the filter?
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Re: pressure build up in lower end

#4

Post by john HD »

bibs,

try it without the filter.

a lot of car filters have check valves in them to prevent drain back. yours might be plumbed backwards and you may be pumping against the valve.

run it without the filter and see if it stops puking.

is there a steady stream returning to the tank?


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Re: pressure build up in lower end

#5

Post by bibs »

There appears to be oil returning to the tank when you give 'er some throttle....you can see it returning then.
I'll be back on here just as soon as I fire'er up and see whats going on..........Thank you John.
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Re: pressure build up in lower end

#6

Post by NationWide »

Hey bibs, did you ever get it sorted? I'm dealin with the same problem. '49 pan, stock oil pump (but later cover - no governor), stock oil lines, stock external filter (but paper element), chain oiler shut off for belt drive (hose runnin to rear chain), drippin a healthy drop of oil every 2-3 seconds and makin a huge mess. It's a fresh motor, probably about 15 miles on it now. Checked the breather gear, its timed right, good fit & no major scoring in the bore. I've been told it might just be that my rings aren't seated yet and I'm gettin blow-by past the rings. Gonna be a long break-in if I gotta keep comin home to top off the oil tank! I've been all through this forum and haven't seen any clear answer, and this seemed to be the most recent thread... had any luck?
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Re: pressure build up in lower end

#7

Post by Hauula Pan »

How old is the pump? Could be the motor is sumping as oil gets past check ball. Also Breather Timing !!!! If you have good circulation back to tank filter is probably OK. Pan motors & after market pumps don't always get along and play well together. A lot of the after market pumps put out too much pressure, especially at idle, early pans ran very low pressures.
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Re: pressure build up in lower end

#8

Post by Cotten »

bibs wrote:
Cotten got me squared away on a burnisher for the oil pump(36-72 S&S) so I tried burnishing the seat....no workie.
It only took me about 45 minutes to make up the tool and it came out pretty nice.
.......But she leaks a hellin through the breather hose.........on start up mainly.
Dave!

So, you think the problem isn't sumping?
Please elaborate upon "But she leaks a hellin through the breather hose.........on start up mainly."

You are not running a breather filter, are you?

....Cotten
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Re: pressure build up in lower end

#9

Post by steinauge »

Excessive breather gear endplay can certainly cause oil out the vent .Before pulling the timing cover I would plumb around that oil filter -IE run a hose straight from the return fitting on the pump to the return fitting on the tank and try it again.Run the engine 15-20 minutes at road speed,shut it off,let it cool and restart.If no oil leaks out it was the filter.those filter setups have caused endless trouble.
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Re: pressure build up in lower end

#10

Post by NationWide »

Stein,
Thanks, man, I hadn't thought about breather gear end play... makes sense though. Too much end play = too much oil???
I by-passed the filter yesterday, no change. Guess it's time to pull the cam cover again! Before I do though, I wanna look at a pump body in hand to see how the chain oiler passages go. The stock screw didn't seem to bottom, so I made a longer tapered brass screw and saw no improvement, but maybe I'm not closing off the hole in the way I should... any comments?
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Re: pressure build up in lower end

#11

Post by steinauge »

Are you maybe filling the lower end by way of the pressure relief passage in the case? That is a not unusual problem on engines with old style cases and 68A or 68B type pumps.I am not familiar with the S&S 36-72 style pump.I have 2 S&S pumps here at work and both have the pressure relief outlet on the back of the pump as per 73 up HD pumps.Another thing may be the location of the pick up hole in the end of your breather gear-it must line up with the corresponding hole in the breather gear bore in the case.Sometimes in aftermarket cases it isnt quite right and that will cause the problem you describe.
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Re: pressure build up in lower end

#12

Post by RICOCHET »

By replica cases do you mean aftermarket like STD or some other? With that pressure as high as it is I'm thinking there's a problem involving differences between the case passsages, oil pump and cam cover. Is any oil getting to the top end at all as seen by removing a fitting at one of the heads. Something like what Steinuage just said about oil being routed elsewhere than where it should be. If aftermarket cases and especially replica cases it's hard to tell exactly what year passages were drilled into them, some are for original type pumps and some are done to later pump requirements and anywhere in between. If you've exhausted other possibilities you might check all the passages and routing.

ricochet
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Re: pressure build up in lower end

#13

Post by NationWide »

Thanks Stein, Ricochet. My cases and pump are the real deal, factory HD... I don't know what else to do but pull the cam cover & pump, check breather endplay and anything out of order with the pump (wrong gaskets? or a tear b/t the feed gear cavity & the chain oiler hole?). Maybe the cases were drilled for a later pump - I'm gonna try & trace all the passages and make 'em make sense. Any other ideas in the meantime, or while I got 'er in pieces?
Got my hands on another pump body and tested my shutoff screw with shop air - it works, so I'm 99% sure that oil's comin from somewhere else.
Took 'er for another little slimy ride today... gawd it's nice out, & she runs GOOOOOD! It's killin me!
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Re: pressure build up in lower end

#14

Post by Pomike »

I had something similar on my '65. It turned out to be the oil pump gasket had torn on installation, and that will make the mess you are talking about. Dumped oil everywhere into the motor, and primary, then got pumped out by the breather. I don't know if this helps, but sometimes we can overlook something.
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Re: pressure build up in lower end

#15

Post by steinauge »

By squinting hard at the picture it appears the oil pump is aluminum.If that is so and the cases are 1958 models unless your pump is for a 68-72 you are likely filling the lower end by way of the pressure relief hole in the crankcase.All the 73-e92 pumps have the pressure relief outlet on the back of the pump.The rod feed gallery in the 73 up pump will line up with your oil pressure relief hole in the pan cases and fill the gearcase area right up thus causing your problem.If this is occuring the solution is to plug the hole in the case.HTH
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