Big block 440 suddenly lost 30 PSI oil pressure.

[mopar 3 B]

Are you quite positive the cam shaft is still in one piece?

 

[cryplydog]

#4 cam bearing...if it has spun, looking at your rocker arms, they would not get oil. The two oil ports, one for each side, are fed oil through the #4 cam bearing...as long as the bearing holes are lined up.
If you have the oil pan off, look over the pickup tube, to see if there's any cracks, or if it's loose.

What I intended to mean is that it is possible to spin and spit out the #4cam bearing fore or aft of the journal and it's not to far of a stretch to imagine that happening

 

[dvw]

Have you run it with a new oil filter? What type of filter? Wouldn't be the first time I've heard of one being restricted. 30 psi would be a hell of an internal leak. Tried a second gauge? If there really is excessive oil in the area you indicate I'd be looking for a cracked main web. Look closely to where the oil is coming from. Up by the cam bearing? Or out of the #5 main bulkhead? If it's cracked the oil flow to the #5 main would be leaking through the casting itself. Certainly not unusual to see a cracked main web.
Doug

 

[Banjobird]

Wow, all you guys impress me with your good responses! I'm trying to think what would gush oil above the #5 main bearing and I've got nothing. I've never run the oil pump with a drill & no oil pan before. How are you oiling the motor while you spin it over with the drill???

1. Geez... I'd still check all the bearings, but I would expect some type of knock if I spun one.
2. I hadn't thought about the cracked lifter bore idea, but that would make sense.
3. Miller's idea about the #4 cam bearing might make sense for a loss of oil pressure, but you'd have to re-install the pan & fire it up full of oil (or look for bad rocker damage & again I'd expect at least a "tick")
4. 3B makes some good points.

Wow, that's a tough one

With pan off, I placed the pick-up tube in a bowl of oil and then ran the drill. Didn't take much to find problem. See final result in full post below.

 

[Banjobird]

Ok, found the problem. I removed the intake manifold and valley cover. #5 cam bearing is spun and has migrated forward unloading oil passages. Pulling engine now and machine shop says if block is damaged, they will line bore the rear cam bearing journal and install a bushing. Says the cam should not be damaged due to it being much harder than the soft babbitt cam bearing.
Thanks everyone for the great suggestions and interest in my sudden failure. What bites is having to pull and teardown a brand new motor out a just finished 3 year build with all new body and paint. Oh well, thats hot rodding and hopefully it will be back together soon.

 

[Dennis H]

Do I not understand the cause? Builder?

 

[bearman]

Sorry for your troubles. But what a great attitude for you. Good luck hope not to heavy on the wallet. But like you said its hot rodding

 

[khryslerkid]

You caught that in time! Could have been worse if you weren't paying attention to whats going on. Good catch.

 

[PurpleBeeper]

Ok, found the problem. I removed the intake manifold and valley cover. #5 cam bearing is spun and has migrated forward unloading oil passages. Pulling engine now and machine shop says if block is damaged, they will line bore the rear cam bearing journal and install a bushing. Says the cam should not be damaged due to it being much harder than the soft babbitt cam bearing.
Thanks everyone for the great suggestions and interest in my sudden failure. What bites is having to pull and teardown a brand new motor out a just finished 3 year build with all new body and paint. Oh well, thats hot rodding and hopefully it will be back together soon.

First, I'm very glad you found the problem & thanks for updating us. Second, you "might" consider replacing the cam bearings with the motor in the car. I believe you can replace them, even #5, if you take of the grill, radiator, etc. You probably don't have to pull the heads off, just the timing cover, cam, timing gear. I've never installed my own cam bearings, but it might be possible....your call.

 

[oldbee]

Thanks banjo, now I’m wondering about a core shift? Heard it talked about, never seen. Hmmm

 

[dvw]

If the bearing spun, the block is damaged . It will require repair. It must come out.
Doug

 

[5.7 hemi]

If it has to be lined bored, engine has to be at parade rest. Plus the bearings should be fitted to the cam and it much easier to do with the engine out of the car.

 

[bm02tj]

A lot of big block cam bearings need a little tlc with a bearing scraper and someone that knows how to use it
your builder did not have cam turning with his finger so it grabbed the bearing

 

[5.7 hemi]

Agreed!^^^^^

My machine shop asked for my cam when they installed the bearings so it would spin freely.

 

[Dennis H]

Agreed!^^^^^

My machine shop asked for my cam when they installed the bearings so it would spin freely.

Research on my end agrees. Now we have a cause. No intention to smear builder. Here to learn.

 

[miller]

Glad you found it!
Hard lesson. Just slapping those cam bearings in don't cut it. Like mentioned, every one I've dealt with, always needed a little hand work to make it do what it's supposed to do. Mechanic's scraper is your friend!

 

[wyrmrider]

that cam bearing is always tight
I understand that there is a long standing typo on the size
I have a tool to size all 5 at the same time in a line
remember the factory bores after install- or they did
but you can and must use a bearing scraper
the spun bearing did not get involved with a lobe or lifter did it?
there may be crap in the head feed holes and other holes
I was hoping for a rocker shaft plug
but- better than a cracked / broken lifter bore

 

[cryplydog]

I have checked several old cams that I checked journals in the lathe centers with Starrett indicators for straightness and finally found one that was acceptable and while it was chucked up I took a thin abrasive cutoff wheel in my porting grinder and cut a horizontal groove in all the journals about .100 deep, then I took a 4"hand grinder with a 80 grit. sanding disc and relieved the cam journals to about 3/4"ahead of the .100 deep horizontal cut while increasing the depth down to the cut. this relieved area is the leading side up to the cut so to turn it clockwise it is a cutting tool to slide in to the newly installed cam bearings. make sure to deburr the cutting edge. You now have a cam bearing burnishing/reaming tool to take off the high spots you get from pounding them in the block. I have a snapon cam bearing installation set and an older Blackhawk set that I prefer to use and have used several others over the years but the end result seems to always be the same "cam won't go all the way in". I always deburr the leading edge of the bearing bores and look/feel for any irregularities and correct them, then I slightly champher the leading edge of the bearing and wipe/wash all with laquer thinner and use wd-40 etc.and spray bore before driving the bearing home. If you encounter a loose one then replace with another. My opinion is you never have a perfect set/fit. I also have a home shop made hone from 1"shaft for the bastards that are non compliant. It's also easy to turn down a pc. of shaft to fit your rod inserts over and hold them with a hose clamp for champhering for the radiused stroker cranks. As for bearing knives, piss poor tool. Good luck all

 

[coloradodave]

If it has to be lined bored, engine has to be at parade rest. Plus the bearings should be fitted to the cam and it much easier to do with the engine out of the car.

That's pretty funny, Zack...

 

[wyrmrider]

cryplydog does very similar to what I do
not perfect because you are indexing off the front and rear journals but all and all all 5 line up and are the right size (or larger)
There are also wider bearings that can be fitted- some bearing sets have really narrow bearings- junk