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Friends 'low' oil psi 340, only about 10,000miles
#31717
10/22/06 03:20 PM
10/22/06 03:20 PM
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Joined: May 2005
Posts: 803
Oklahoma
Mopar72Man
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Oklahoma
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Friend of mine has a rebuilt 340, stock bottom end, x-heads, upgraded cam and what not. He has about 10,000street/some strip miles on it and it seems to have, what i would consider, low oil pressure. he is running 15w-40 with a little lucas stabilizer ( about 1/4 of a bottle) and cold cruise is 65psi cold idle is around 50 hot idle is 15 hot cruise is about 40 (~3,000rpm) and might get up to 50 if he runs it through the gears. is it just me, or is that kinda low for a 'low mile' mill, he is concerned? Crank was turned .010, had new rod bearings and half-grooved mains with a melling hi-volume pump. Nothing fancy, and the clearances and such were not checked at the time. Any suggestions? Maybe a quart of 20w-50 in the 15w-40 help keep it up? 
72 Challenger - will be sublime, little 340 904, 8 3/4" - Under Construction 
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Re: Friends 'low' oil psi 340, only about 10,000miles
[Re: Mopar72Man]
#31718
10/22/06 03:27 PM
10/22/06 03:27 PM
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Joined: Jan 2003
Posts: 6,389
Abilene, Texas
fastmark
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master
Joined: Jan 2003
Posts: 6,389
Abilene, Texas
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By any chance did he put a new MP front cam thrust plate on the motor. My bud did and it has a groove that oils the timing chain that is way to big and he had oil pressure like you stated. Changed it back to the stock one and it was fine. You can plug it with a oil galley plug as well. Correction, you plug the oil galley behind the plate on the drivers side.
Last edited by fastmark; 10/22/06 03:30 PM.
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Re: Friends 'low' oil psi 340, only about 10,000miles
[Re: fastmark]
#31719
10/22/06 03:28 PM
10/22/06 03:28 PM
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Joined: May 2005
Posts: 803
Oklahoma
Mopar72Man
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Quote:
By any chance did he put a new MP front cam thrust plate on the motor. My bud did and it has a groove that oils the timing chain that is way to big and he had oil pressure like you stated. Changed it back to the stock one and it was fine. You can plug it with a oil galley plug as well.
Nope, stock thrust plate with a summit racing timing chain.
Thanks
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Re: Friends 'low' oil psi 340, only about 10,000miles
[Re: Mopar72Man]
#31720
10/22/06 03:31 PM
10/22/06 03:31 PM
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Joined: Jul 2006
Posts: 4,319
Puyallup, WA
StealthWedge67
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Puyallup, WA
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Boy, wouldn't he be feeling better right now if he had checked his clearances while assembling the motor! 15psi is enough to keep the bearings happy at an idle. but the discrepancy between as little as 15 & as much as 50 sounds odd. Personally, I'd run it until I had to tear into it again, then next time around, double check all bearing clearances.
I'll be interested to hear others take on oil pressure fluxuation like this. Some may say it sounds fine. For what its worth, my 110,000 mile original 1966 383 bottom end assembly shows 40 psi at idle and about 43 at cruise with 10w-40.
LemonWedge - Street heavy / Strip ready - 11.07 @ 120
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Re: Friends 'low' oil psi 340, only about 10,000miles
[Re: sleepyhead416]
#31722
10/22/06 05:10 PM
10/22/06 05:10 PM
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Joined: May 2005
Posts: 803
Oklahoma
Mopar72Man
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Quote:
I'd say make sure they put in the oil plug in by the dist drive.
if it was out, would it still hold those kind of pressures that it does when cold? he said it is definately in however.
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Re: Friends 'low' oil psi 340, only about 10,000miles
[Re: sleepyhead416]
#31724
10/22/06 07:14 PM
10/22/06 07:14 PM
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
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I Live Here
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Columbia, CT
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It's too low. The only way to "know" is to pull it, pull the pan, and peak in there.
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: Friends 'low' oil psi 340, only about 10,000miles
[Re: Mopar72Man]
#31726
10/22/06 08:21 PM
10/22/06 08:21 PM
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Joined: Mar 2003
Posts: 4,848
Memphis
HemiRick
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Memphis
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This is plenty of pressure.....10 lbs per 1000 rpm is all that's needed any more is wasted HP
Take care,
Rick
68 Coronet R/T 440 & 68 Charger 528 Hemi,and 5 Challengers! 6 cyl, 318, 360, 383, 451
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Re: Friends 'low' oil psi 340, only about 10,000miles
[Re: topside]
#31730
10/22/06 08:58 PM
10/22/06 08:58 PM
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Joined: May 2005
Posts: 803
Oklahoma
Mopar72Man
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Quote:
First thing I'd do is try another gauge; then cut the oil filter open and inspect the element for bearing material.
Could be bearing clearances too large, oil being aerated, maybe the filter going into bypass. Sounds like the oil has to be cold (thicker) or the pump spun up to maintain oil pressure, which sounds like an internal (pressure) leak. It doesn't sound fatal, but it doesn't sound right, either; mine have always idled hot with at least 30PSI with a stock pump and regardless of mileage.
thanks for the reply. I think i have another gauge he can toss on there. Whats the best way to cut the filter open? Do we need the whole filter cutter tool, or can we just zip it in half and peek in there? Could it be possible the oil pump is bypassing itself or something wierd? 
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Re: Friends 'low' oil psi 340, only about 10,000miles
[Re: sixpaktoogo]
#31732
10/22/06 09:30 PM
10/22/06 09:30 PM
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Joined: May 2005
Posts: 803
Oklahoma
Mopar72Man
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Quote:
Had the same problem years ago with a rebuilt 340. Ended up being that the engine had one factory oversized lifter bore! Check the front of your block to see if it is stamped with (I believe) a diamond. If so, you will need to bush which ever lifter bore(s) back to standard size inorder to use your lifters.
thanks, there were no symbol stampings on the block when he had it hot tanked before the rebuild.
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Re: Friends 'low' oil psi 340, only about 10,000miles
[Re: HemiRick]
#31733
10/22/06 10:05 PM
10/22/06 10:05 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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I agree with Hemi Rick and Mopar Joe, 10 psi for every thousand min, get the lucas out, try another gauge to be sure, if you are still worried try a oil analysis. btw what oil pump is he using?  and why use the diesel oil 
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Re: Friends 'low' oil psi 340, only about 10,000miles
#31734
10/22/06 10:14 PM
10/22/06 10:14 PM
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Joined: May 2005
Posts: 803
Oklahoma
Mopar72Man
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Oklahoma
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Quote:
I agree with Hemi Rick and Mopar Joe, 10 psi for every thousand min, get the lucas out, try another gauge to be sure, if you are still worried try a oil analysis. btw what oil pump is he using? and why use the diesel oil
thanks. it is a melling high volume as mentioned in the initial post. any many many people run diesel oil..it still has zinc (anti-scuff for our flat tappet cams) that most of todays motor oils now lack (since not many flat tappets runnin around and the rollers dont need it)..
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Re: Friends 'low' oil psi 340, only about 10,000miles
#31736
10/22/06 10:17 PM
10/22/06 10:17 PM
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Joined: May 2005
Posts: 803
Oklahoma
Mopar72Man
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Quote:
What oil filter are you using? 
maybe somewhat related.
he's ran a wix/napa gold forever, the last time he changed it was on a sunday and the local napa was closed so he just grabbed a bosch. There is a bosch currently on there..
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