I'm about ready to give up here....

So today I finally got my '72 registered and inspected again. The car has been in the garage for almost a year now. It's running 455 with a stock '75 bottom end, and over the last year, I put '72 stage1 heads on, a new C110 cam from T/A, double row roller timing chain, new lifters, rebuilt the oil pump to T/A's recommendations, adjustable pushrods, new rockers and shafts. So here is the problem, I took the car out today to get it inspected, I stopped at the car wash to rinse off the dust, took it to the Goodyear for inspection (passed with flying colors), stopped off on the way home for a soda, and on the second to last turn from home, the oil pressure drops to 5lbs, I jazz the throttle and the gauge doesn't move, then it drops to 0 and the engine starts clattering (valve train). I don't understand it, it had 11 lbs or oil pressure at idle, hot (185 degrees) all afternoon, and 40lbs going down the road and suddenly it drops to 5 then 0? The temp gauge never got above 185 degrees and I checked the oil, it's full. After the letting the car sit for about an hour, I fired it back up and it was back up to 11 lbs idle and 40 lbs on the road. I drove it home and put it away for the night.


Does anyone have any idea what may be causing this, or what may have caused it? If it matters, i'm running 5w-30 in it, I rebuilt the oil pump, and have an adjustable pressure regulator from T/A in it.

It's getting to the point of me giving up and selling....I spent over a grand on this car in the last 3 months and I still can't drive it.


Harry

EDIT: the only time i've seen something like this, it ended up being wiped main bearings. I don't think (I hope) that isn't the case here, it was fine before... and nothing in the bottom end has changed, just the heads and cam...

 

I would dump that oil and check for metal deposits than at least put in 20w50 that 5w30 is way to thin then go from there

 

Holy **** HARRY.... Your problem sounds EXACTLY like what happened to my 350 motor a few weeks ago. It was great when I broke it in and when I decided to install it in my 73 it had great pressure as well then out of no where,I had no oil pressure. I swapped oil,cut the filter apart and still haven't found the problem. At Idle it sounded great until I touched the throttle.Then it sounded like the rockers were all loose. I have all new valve train parts and such.I did manage to find the oil pump gears were rubbing on the cavity where they go in.They were new Melling gears non Hi Volume.

 

cam bearings?

 

Ooooooo, you probably don't want to read this...........
almost every time I have heard/seen this.......spun bearing(s)

How many miles on the short block?

I had this happen to two of my Buick 350 engines.....both had approx 120-130k on them.

 

Buick oil pumps have a tendency to cavitate when the check valve hangs up for any reason.Pull the oil pump appart and check for any strange wear or foriegn matter and make sure the check valve and spring are working properly.I would also use 10w-40,buicks don't like thin oil.It doesn't sound like a bearing problem to me.

 

My vote is oil pump as well. First thing to check.

Devon

 

Thanks everyone, I'll try to get the pump apart this weekend and check for debris and see if the relief valve is binding, as well as changing the oil to 10w-40. I do have a high pressure/high volume pump kit I bought from T/A. Do you think this is worth putting in while I have it apart or should I just check and leave the stock gears,etc in place?

Thanks,
Harry

 

have you ever pulled the oil pan in the past?

it could be possible that the pickup came loose from the block and is sucking air, or is there a dent in the oil pan and the pickup found it's way stuck to the bottom of the pan.

 

Just run stock gears, the TA booster plate and adjustable regulator. The hi-volume pump will tear other things up, it's not worth it. If the stock setup doesn't get you pressure, the high vol won't either...something bigger and badder is going on.

Devon

 

You have been given some good advice. I would first, real quick, take the nut off the pressure regulator valve and with a magnet see if it slips in and out real easy without hanging. You might be able to remove it and clean the bore with brake clean and blow it out and then lube the valve and slip it back in making sure it is very "FREE". If it wants to bind, then remove the pump cover and deal with it. It sounds like it may have stuck in the open position when you lost pressure. Hopely you didn't damage bearings when this happened. I would do this and change oil and try it. If the pressure goes down a bunch when it gets hot, you may have damaged bearings, time to look inside.
Good luck,
Jim N.

 

That happened to me also, and unfortunately it was a spun connecting rod bearing. I had to replace the crank & bearings & resize the rods. I hope that you have much better luck.

 

So I got the filter off, but couldn't find my hack saw to cut it open. i also removed the relief spring and the check valve was not stuck, it came out with the spring. I ran the oil left in the filter through a strainer and didn't get any metal out if it. I'll find the hack saw and cut it open tomorrow. To be continued...........


Harry

 

use tin snips to cut the filter open, or even steal your wiifes good scissors.

 

I am a little curious of what type filter were you running?

But my question is probably mute, as I am thinking it was in normal shape - correct? I have seen 2 engines ruined by fram oil filters. The last was about 7 years ago, and fram actually stood behind it and paid for the rebuild of my buddies motor. The check valve in them gets hung up and sticks closed and oil will not flow out, causing the oil to build pressure in the filter and it would literally blow outwards to about 1 1/3 to 1 1/2 times its origonal size in diameter.

Just wanted to add that info. I hope nothing is damaged badly. Good luck,

Mike

 

Yeah - you dont want to hacksaw it open

stop by radio shack and get a good strong magnet. They sell a bar thats about 1" by 3" for a few bux. I keep it in the oil drain bucket. not everything is magnetic but ...

 

Thanks again all.

JM3 and Alan, I'll pick up a pair of tin snips on the way home tonight and use those instead of the hack saw.


Michael,

The filter that was on the car was and A/C Delco, PF24 I think the # was. I've read ALOT of horror stories on Fram filters also, I don't use them on any of my vehicles.


Harry

 

Good luck Harry,

I hope that nothing is damaged badly. It looked like you had good origonal oil pressure, then it went south.

Have you checked the screen on the pick up tube? If you do not have one, get you a 5/8" tube to help get that oil up there... I also think the 5w-30 oil is too thin for your stock bottom end. It is good for a fresh and tight new motor, but I would say at least a 10w-40 and maybe blend 2 or 3 20w-50's in there. I tell you what, I am also a firm believer in Slick-50. I have a true story that I can give testiment to on a car that I had several years ago that was ran without any oil in it for 4-5 minutes, with a Slick-50 treatment many months before and went for 50K miles more before selling it running perfect as the day I got the car.

Mike

 

I had this happen to me on my first 455 rebuild. After checking all of the above, I found a film covering the pick-up tube. It turned out being the lint off of the rags that used to make sure it was clean.