Thread: Oil pressure woes

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First post...try not to beat me up too bad!

355 SBC, fresh build. Only thing NOT new is the block. Block was line bored/honed/cnc squared off the mains and bored .030/decked to 9.000. It an old 1969 010/020 block, 2 bolt with ARP studs. Machine shop installed cam bearings with lube holes in at 3:00/7:00 (dual hole brg), not sure what bearings they used.

Rods mic'd out at .002-.0022" (king race bearings)
Mains .002-.0025" front to rear (sealed power HP coated series)

After 30-40miles, mains are now at .003-.0035"

M55HV pump with pink/purple spring. MSD billet dist with O rings removed. Front lifter galley plugs removed, tapped and allen plugs installed. Center plug is flush so not too far in. Block deburred and lifter valley return hole flash removed.

running straight 30w oil.

cold pressure idle in P is 60#
170-180f idle pressure in P is 38#
Idle pressure in gear 25# (1000rpm idle)

After a hard run (7400rpm pull), came to stop and 0psi oil pressure. confirmed with dummy light on dash and autometer mech oil pressure gauge. Brought engine up to 1900 = 20-22#

Cruising under stall 2200-2800ish 38-40# of pressure. Stop again...0psi.

Pulled motor out, pulled main caps bearings look great. Pulled all the rod caps, pushed piston down to check thrust side insert...look brand new. Pulled pump plate and gears, poured oil directly into pump output port, pressurized with 70psi of air pressure, no gurgling or obvious leaks. Once all of the oil has been pushed out by the compressed air, can feel air coming out between main caps and crank counter weights. Checked pr valve in pump half, seems ok, wasnt stuck and didnt have any trash in it. I have not pulled the cam yet, was trying to minimize down time and cost of course. HG for this motor are not cheap (have to have .051"). Any ideas? Im about ready to pull the intake, valve train, and see if there is something wrong with the cam bearings. Figured they would hiss with compressed air if they were whooped. Running out of options at this point. Blocks never been froze or overheated since ive owned it.

Im leaning towards cam bearings as my springs are set to 220# seat pressure and not sure what bearings the machine shop used.

How did you measure the bearing clearance????crank mains grooved??

Why did you remove the o rings on the distributor???

7400 rpm??????? road or dyno???? Chassis dyno???? What cylinder heads??? Roller or flat tappet cam?????? Solid???? Rocker arm set up???????

Is the welch plug in the passage above the oil pump???

what oil pan system and pickup?? how far is pickup off pan bottom???

Why idle so high rpm?????

Im not sure what you mean by this is your problem. The mains are a little loose now IMO and .001 undersized bearings are in the works but this is a race motor. Rods seem spot on for the crank pin diam.

Also, based on the oil schematic for the Gen 1 block, the cam bearings get oil first. I understand what your saying as a whole system. Also, I tried 10-30, 10-40 as well and no difference in oil pressure.

With that much clerance you should run 50w oil

Originally Posted by jerry clayton

What oil pan system and pickup?? how far is pickup off pan bottom???

That was my first question. Assuming conventional pump pickup, how far is it off the bottom of the pan? 3/8" to 1/2" suggested. Check with clay.
.

So I asked you 14 questions and not ONE answer???

Did you restrict oil flow to the lifters/rockers??????

Jerry, I have tried to answer your questions with 2 replies yesterday and all I got was a window saying "post pending moderator approval"

Its all moot point now, #3 cam bearing is wiped out. This block originally had a main journal that had either shifted .015" down or it was machined wrong back in 69. Regardless I had the block line bored/honed. That corrected the irregular wear on the main bearing, but guessing the center of the core has shifted and the center cam bearing hole is not line up any longer.

As for your questions.

Mech solid roller .600 lift, 1.5 rocker, 220# on the seat
Milodon 7qt pan with matching pickup tube, .375" from bottom of pan
7400 on the road driving the car (1-2 upshift)
Yes plug in block under rear main cap
Idles high because I have timing locked at 38 and any thing less it will die. If I lower my base and add swing to the dist, i can fatten it up and it idles @ 700rpm. I lock timing as thats where it runs best from stall to shift light
Removed O rings as block is not chamfered and it kept shearing them. Already had intake on..
Micrometers and telescopic snap memory gauges. Measured this time with crappy ole plasti gauge since already assembled. Lets hope this post actually shows up.

Test Test test.....LET ME POST!

Ok, I dont know wtf is going on, but Ive tried posting 4 times and all I get is "post will not be visible until moderator approval"...

Regardless, i tore it all the way down. Cam bearings are sacked out. #3 1 hole bearing installed at 6:00 is wasted. Cams ok thank god.

I had this block line bored due to #3 main journal being machined wrong, but now I guess it was core shift and the cam bearing is also out of place. Either way, on the hunt for a new block. Will transplant all my stuff over to it once bored/squared/decked/mag'd.

As for the questions:
No oil restrictors in back of block, installed npt plugs in lifter valley drains and drilled them to .250 to limit some windage but not redirect all oil to front/back. Front galley plugs are npt allen, not press in type.
600 solid roller, 1.5 rocker, 240# seat pressure
7400 driving on road 1-2 upshift
Milodon 7qt pan with matching pickup, .375 off of the bottom of pan
Clearances checked with Brown and sharp mic's, and telescopic snap memory gauges during assembly
Plug in block under rear main cap
Idle high due to 38 locked timing and leaner AFR. If I fatten it up to low 13s on WB I can idle it down lower and it wont die in gear. Car has spent a lot of idle time in garage, hence the 13.9AFR setting but it lugs in gear due to tight converter...its out now and getting loosened up.
No O rings as block isnt chamfered and it kept shearing them no mater how much lube or how delicate I tried to be.

the #3 &4 cam bearing bores are smallest holes-did they install a #2 or 5 bearing? That would of been too tight and would kill bearing-cam turns 1/2 crank rpm and is primary oil recepticant-----(oils first)

On new block chamfer that dist hole and use the O-rings, also since your using rollers put restrictors in lifter gallies.
Don't bother trying to reduce windage as you really need as much oil slinging around as you can get.
Make sure that the oil is draining back from upstairs--------

Put 50w race oil in it

Im really not sure what the machine shop did. This motor has been a mess from the get go. i dropped the block, crank, rods, pistons off to be balanced, pistons pressed on (yeah should have got bushed rods), block hot tanked, cam brg, freeze plugs, mag, bore, cnc square n deck...the norm. The pistons are wiseco forged .125" dome 4cc that are .015 taller on pin height than a std 350 piston. 5.7 eagle rods... Well when i dropped it off I told them I wanted it Zero decked and that the pistons were taller than std. they called to confirm a week later that 9.015" was what i wanted it decked to and I agreed since it was going to be cnc squared off the mains after line bore/hone. Well Idk what their issues is but I picked it up and they decked it to 9.000....So after running .051 head gaskets and tearing it down, I have witness marks on the combusion side of the pistons. Heads are dart pro 1s with the fast burn chamber so there is a portion of the combustion chamber thats closed in on the opposite side of the quench. Piston rock when its cold is causing this tight tolerance issue and Im just tired of this block all together. Not to mention when they plate honed it they stripped out a head bolt hole and freaking heli coiled it. I called them out on it all and they pretty much said "sorry bout your luck and dont come back"...typical dirt track machinist mentality. If I was a local they may have done something about it. Lesson learned.