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Old 12-10-2012, 10:12 AM   #1
omp
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High Compression and low oil pressure

Getting my fresh motor ready for swap, yesterday I ran motor on stand with water and my oil pressure would not go above 10-15 psi.
I've search here and other stand forums for possible causes and the list below is what I will check when i get home as I'll drop the pan.

Will get a mech guage, currently have a stang sender to autometer guage.
Timing cover oil galley plugs
Rear plug I know it's good I checked it twice between runs
Clogged oil pickup
Oil pickup with crack sucking in air
Oil pump press relief stuck open
Worst case spun a bearing

It's run fine the past two weeks in the stand

Another question, I spun the motor over without power to
Coil and the motor fired and ran for a good 2-3 mississippi seconds on its own. Is this norm? I've had motors not shut off in an old 361 LTD but spooked me on starting. I have a 7.3 and I was just turn the motor over to check for oil in sensor passageway.
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Old 12-10-2012, 11:14 AM   #2
ledd72
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i think more information on the engine would help
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Old 12-10-2012, 11:44 AM   #3
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Bearing clearences are within spec?
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Old 12-10-2012, 11:57 AM   #4
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Bearings where in spec. Motor was primed several times before first start. Motor ran fine last weekend and this week

It's a .010 over 302 from a 99 explorer with gt40p heads, comp cam, FMS headers, std oil pump, 7 quart pan from explorer which I made pickup tube for.

Also read assembly lube could have blocked the filte. I
Have motorcraft filter on it.

I did use rtvin the valley but I it cure for 6 hours only wonder if it's plugged up somewhere
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Old 12-10-2012, 12:31 PM   #5
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well i would put a mechanical gauge on just to verify. and then if needed pull the pan check out your tube for leaks. if still low i would put a hv pump in.
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Old 12-10-2012, 12:42 PM   #6
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Yup will run a mech gauge tonight. Ordered a new oil screen made for 99 explorer incase my weld did not hold up it if screen is plugged.
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Old 12-10-2012, 12:43 PM   #7
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Originally Posted by ledd72 View Post
well i would put a mechanical gauge on just to verify. and then if needed pull the pan check out your tube for leaks. if still low i would put a hv pump in.
NO. a stock pump is MORE than adequate for this build. OP, fix the problem, don't band-aid it with an hv pump. those are for extreme high performance applications.
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Old 12-10-2012, 12:46 PM   #8
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Sorry I built a stock motor so stock pump was used, infact everything is factory except the cam. I read up a lot from Ryan's post with headers to the gt40/p reviews.
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Old 12-10-2012, 12:50 PM   #9
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sorry i am a fe guy where hv pumps are a given. but then again i run them in almost everything i own.
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Old 12-10-2012, 08:08 PM   #10
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Installed mech guage Cold start idle at 55-60 settled down to 40 after 3 min.
Bled line a few time to make sure but revving it gets 60 psi.
I have some diesel oil in there mixed so its a bit thick.
Blew out freeze plugs oops forgot drain water guess new brass ones go in now

What gives why would an auto meter guage give low reading with new sender. Oh well.
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Old 12-11-2012, 08:55 AM   #11
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yes at least its good to go
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Old 12-11-2012, 12:38 PM   #12
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No not really! I forgot to drain water and two of freeze plugs popped. So I'm going to run it tonight then do a tear down to check and replace all plugs.
I know brass is preferred, why? I can only think dissimilar metal they will
Expand a bit faster, rust resistance is better. If I'm good on my cooling std iron should suffice.

I can't remember if there are plugs behind timing cover?
Are those freeze plug heaters any good?
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