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Discussion Starter · #1 ·
I could use some help here. I think i screwed up, im not sure whats going on.

88 460 EFI thats going back into an 88 Bronco. First engine ive built. Fresh rebuild. .030 overbore, .010 off the deck. Heads were both cracked so it got replacement castings with slightly bigger valves (2.09 int/1.76 exh). Im running the EFI friendly cam from Comp (34-255-5), along with Comp lifters. New pushrods & rocker arms. Kaase oil pump, ARP driveshaft. Stock EFI intake/plenum, with a BBK throttle body. Its a fairly mild streetable build. The engine was in the bronco for many years and was simply wore out (rod knock). This was supposed to just be a simple refresh and back in we go, but something doesnt seem right, and i think its my fault.

So some back story:
I made some mistakes with my tune when i first set it up, and the engine saw excessive cranking before i got it all sorted and got it to run (i screwed up my ignition settings, and it took a while to figure it out, so the engine saw lots of cranking until i got it sorted and got it to actually run). Technically its not broken in yet- ive only actually run the motor intermittently for about 45 minutes to an hour over the course of approximately two weeks, because its losing oil pressure as it warms up. I have the stock sensor in the rear port on a Tee along with an electric oil pressure sender from NVU. I believe both sensors to be accurate, as they were both installed in the engine shortly before the rebuild, and were reused.

So this morning i did an oil/filter change. First batch of oil to come out, and it came out dark and had metalllic dust in it but nothing out of the ordinary (i dont think for the first oil change anyway). So then after refilling it i fired it up and was running it at about 2200 rpm to break in the cam, but after maybe 5 minutes im down to single digits on oil pressure on both gauges again. So i feel like something is wrong here. Oil is Royal Purple Break-In Oil (10w30), with Motorcraft filters.

At this point im afraid ive already damaged the motor and it needs to come back out. I was wondering if anyone has any thoughts/ideas/recommendations on stuff i can check before i pull the motor back out and bring it back to the machine shop. Maybe something i did wrong on assembly? Or do you think its fubar and i should stop wasting my time and pull it back out.
 

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I'd dump the oil out of it and take a look for more metal. If you see more metal it's just time to yank it back out. Sounds like there was some damage done but lets see what you find when you get the current oil out of it. Cut the oil filter open and look in there for metal also. You might want to cut your first oil filter open and check in that one too. It probably has tell tale signs if it did indeed kill something inside.
 

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Did you say you ran it around, and then attempted to break in the cam after the first oil change?

Next suggestion is a leaking or misplaced galley plug. Did you get them all in?
 

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Discussion Starter · #4 ·
Good questions.
Did you say you ran it around, and then attempted to break in the cam after the first oil change?
The vehicle has not moved from where it was parked when the engine was removed. So when i say i didnt break the cam in right away, its not that i didnt want to, but its that the engine didnt run well enough to be able to do so until today.

I'd dump the oil out of it and take a look for more metal. If you see more metal it's just time to yank it back out. Sounds like there was some damage done but lets see what you find when you get the current oil out of it. Cut the oil filter open and look in there for metal also. You might want to cut your first oil filter open and check in that one too. It probably has tell tale signs if it did indeed kill something inside.
The first batch of oil has maybe 45 minutes of engine run time on it, spread out over about 2 weeks. But it has a lot of cranking. It smelled of gas, and i believe it was running way too rich which was partly my fault, but mostly due to a 'possible bad' wideband O2 showing an impossibly lean condition, and the ECU overfueling to compensate (i am running a Stinger ECU, the PimpX). I was hoping my oil pressure problem was related to gas contaminated oil, but perhaps not. Friday i put a different set of fuel injectors in it along with a new wideband O2 and drained the oil. That is the oil filter i cut open, with tin snips. Lots of small metallic fines, dark in color. Kind of what id expect from rings rubbing on a cast iron wall, which is why i was assuming it is ok. (I am familiar in the difference in chips/dust from grinding/machining steel, to cast iron, to stainless.) I would think (maybe i am wrong) that if it was bearing material, the metallic fines would be more of a silvery color, and larger, almost like metal flake in paint. Yes/no? The color of the oil is difficult to describe, as its Royal Purple so even new its a weird dark color.

This morning i installed a new oil filter plus 6 more quarts of RP break-in oil, and ran it for 5 minutes before losing oil pressure again. Today the motor ran considerably better than it has any other day so i believed my tune was finally 'good enough' to get it to run to break in the cam. But after about 5 minutes at ~2000-2200 RPM i was down to 5-6 PSI so i shut it off. As the oil only has that 5ish minutes of run time on it i have not drained it yet, nor have i removed that oil filter.
I was thinking that tomorrow i should remove the distributor and run the oil pump with a drill to see what kind of pressure it builds, and compare the NVU oil pressure gauge against a mechanical one just to verify what i already believe, which is that my gauge is good and my oil pressure is bad.


Next suggestion is a leaking or misplaced galley plug. Did you get them all in?
I did the final assembly of the engine, but the machine shop installed the freeze plugs, oil galley plugs and the cam bearings. I can only assume he installed the galley plugs correctly, but i cant say for sure without removing them to inspect. If one of the flat ones was installed up front in place of one of the tapered ones, would that cause low oil pressure at the rear pressure port?? I have not hooked a gauge to the oil pressure port in the front of the engine yet.
 

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Discussion Starter · #5 ·
So i have two oil pressure sensors in the rear port on the block. The OEM sending unit, and the aftermarket one from NVU. So i removed the OEM one and hooked up a mechanical gauge there. Pulled the distributor and ran the oil pump via the driveshaft, and i see ~40 PSI on both the mechanical & electrical gauge, so that confirms i have oil pressure when cold, and confirms my electrical gauge works properly. Drained the oil, pulled the filter, cut it open, and i dont see any bearing material. Brought the filter over to the machine shop since hes only about 5 minutes away and he agrees, no bearing material in the filter.

Today i changed the oil out for Rotella 15W40 (this time i put in 7 quarts instead of 6), ran the oil pump via the driveshaft and got ~48psi, which id expect from the heavier oil. Put the engine back together and fired it up. Ran it at 2k rpms for 4 minutes, and in that time it dropped to about 5-6psi so i shut it down. Waited 5 minutes, fired it back up and no oil pressure at idle. Shut it off, waited another 10 minutes, and fired it up again. Barely any increase in oil pressure. So i dont think its a problem with oil draining back down to the pan.

At this point i cant see anything else i can do, without pulling the motor back out.
 

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Sounds like it is time to pull motor and break it down for inspection. Order gaskets and see what you find.
 

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Discussion Starter · #7 ·
Yeah I'm gonna get the garage set up to pull the motor. I've got to work this weekend so I'm gonna get everything ready to go to start the disassembly process Monday. I'll keep you posted, and let you know what I eventually find.
 

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i have seen before a poor oil chamfer holes on the crank will cause exactly what your describing but hell pull it out and inspect it, I took mine apart 3 time on the stand till I was satisfied i had everything perfect now after a year on a 545 blown BB 65 psi cold and 65 psi hot idle and at 55 mph it pays to be on the perfectionist side
 

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Assuming no noises yet, I'd second the bearing clearance root cause. Check bolt torques on disassembly. Check for foreign material in the cap to mating surfaces.
I came across an "overhauled" 429 (with original pistons, rods, & bolts) similar no-pressure when hot complaint. I'm confident the lack of cleaning / reconditioning the rods was the issue. The shortblock was rebuilt... original crank, rods, and block were machined or reconditioned... new pistons for 30 over bore, new bearings, freeze plugs, timing set, and new bolts. Ran like a champ.
 

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Discussion Starter · #11 ·
Thanks all. The plan is to pull the motor back out this upcoming week and get it back on the stand. Im pretty particular about things, so im sure its gonna end up getting rebuilt all over again just to make sure its right. The crank had to be ground -.010 on the crank bearings and .-020 on the rod bearings, so im guessing theres an issue with clearances there. We'll find out in the next week or two.
 

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The crank had to be ground -.010 on the crank bearings and .-020 on the rod bearings, so im guessing theres an issue with clearances there. We'll find out in the next week or two.
Did you clean all the oil passages in the crank with some brushes and solvent of some sort?
 

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Discussion Starter · #13 ·
Um....no? The crank came back nice and clean from the machine shop, so yeah...didnt know i should do that :oops: I guess i just assumed it was ok because the thought never crossed my mind. I was quite paranoid about keeping all the journals & bearings clean during assembly; definitely installed a couple bearings twice because i thought i saw some dirt on them. But i never even thought about cleaning the passages in the crank; i guess i just unwrapped it, wiped down the journals and installed it.
 

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In my experience the passages need to be thoroughly cleaned, at minimum just to check that they are clean.

Only reason i mention it a friend of mine threw a crank in a SBC without cleaning the passages and scrapped the bearings.

Not saying this is the issue but could be and always something builders have to check.

Machine shops can tell you everything is all set to assemble but it needs to be cleaned.

Cylinder walls need a lot of cleaning, even if they look clean fresh from the shop.
 

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Discussion Starter · #15 ·
Well I didn't clean those passages, so that's a definite possibility.
I did hose the cylinder walls down with brake clean and then wiped with lint-free rags immediately prior to crank/piston install. Then used a liberal amount of 30w on the pistons + rings during install. Of course I used engine assembly lube on all the bearings.
 

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That's not sufficient for cylinder walls in my experience. The honing grit is imbedded in the crosshatch and takes some detergent and a lot of elbow grease to get them clean.

Hopefully everything is ok but when you get it apart look for scuffs on the piston skirts and vertical scratches on cylinders, if there it needed more cleaning.

If there appears to be any debris or dirt that went through i would completely strip the block down and pull all oil galley plugs, get some long galley brushes and some mineral spirits and start scrubbing
 

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Discussion Starter · #17 ·
Yikes :eek: I guess I really did screw up. Ok well hopefully it's not too bad, but I guess we'll find out in about a week.
 

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I'm not trying to be an Ahole just pointing things out.

Like i said hopefully none of the things i pointed out are an issue.
 

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Discussion Starter · #19 ·
Yeah no I appreciate it. Like I said, never done this before, so if I did something wrong if rather know now, so I don't make the same mistake twice.
 

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I'll 2nd Norm... internal engine parts cannot be too clean! I prefer wiping (scrubbing) new cross hatch with an atf / kerosene mix, let it loosen and lift the machining grit, then wipe it out, using moderate pressure, with white paper towels. Repeat several times, until no more gray shows up on the white paper towel. And once more, this time letting it sit overnight before wiping the atf off and scrubbing the bores with Dawn and warm water. Then rinse and rub in a light coat of engine oil (cast iron will immediately rust after the rinse).

I also do not put oil on the rings... I do lightly oil the ring compressor. Most ppl put too much oil on the piston rings. It will eventually burn off, leaving a dark brown coating (first sticky, then crusty) on the rings and lands. Excessive oil also prevents (or delays) the rings from rotating and seating. ...this could cause poor compression or oil consumption... usually not bad enough to require another rebuild, but easy enough to prevent any problems the first time.

FWIW Instead of engine oil, there is a dry film on the market... Quick Seat by Total Seal. It is rather expensive. Maybe someone with experience can comment on it's effectiveness... or recommend if/when dry film should or should not be used.
 
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