Well, I was off yesterday on a nice cruise. Everything was going great and all of the sudden boom. Stalled. Had to tow it home and this morning I pulled the distributer and found it completly ground down on 1 side. The other side looked fine. What happened here? I had the correct gear for my cam. This is a very low mileage ZZ454. No more than 200 miles. I put the moly lube on it like suggested before installation. Do I have to replace the cam? How do I prevent this from happening again? Should I contact GMPP?

Greg,

Did the dist shaft seize up or get stuck? I would contact GMPP and see what they say. I would also inspect the cam gear if you can get to the back of the engine and look down the dist hole.

Bill

Definitely contact GMPP. All those pieces that have disappeared off the distributor gear are now roaming around inside the motor.

Did not seize up. Actually, did not stop spinning but did skip some teeth which caused it to stall. I looked down the hole and the cam gear looks worn. Its not like the distributor gear but worn. It'll need to come out. I'm not too worried about the parts roaming around the motor because the filter and screen on the pump should catch it. I hope! Anyway, its out of warranty and they'll tell me that I did not follow the proper procedure for breakin on the distributor gear. I can't even find a phone number on their website.

Greg,
Stick a long screwdriver down in the block and try to turn the oil pump. If the oil pump locks up or gets real tight for some reason, it will do the same thing. Its kind of unusual for a distributor gear to fail like that, just worn on one side. Usually if there is a problem, they wear evenly all the way around until they just get too small and then give up.

Greg, sorry to hear about this.

Were you running the melonized gear or an MSD gear?

GM Melonized gear. I put my oil pump primer in and spun it by hand. It turns although when I attached my drill it made a funny wining sound at speed. I installed a moroso high volume pump. Is the original pump high volume? I still have the original and it seems easier to turn than the moroso. Could this be my issue? Perhaps I should install the old pump back in with the correct pickup along with the new cam and gear? Looks like I've got some work to do! I'm really curious about the original pump if it is high volume. Thanks for the replys. This has been a bad weekend for me obviously!

By the way, looking at the gear, it is worn all around but on one side they are sheared off. Probably got to a point and then it just ate it up.

Greg, our shortblocks are the same - my oil guage shows about 70-80 cold (but I'm running 20w-50 at the moment) at a fast idle.

Warm - idle 25-30, cruise 60lbs.

To much oil pressure will cause excessive gear wear.

I think my pressure was about the same but I wonder if the pump I installed had a problem as it is a little harder to spin. Just seems a little tight when spinning and the drill seems to struggle when priming it. Bottom line is I'll be pulling the engine, replacing the cam and oil pump.

why did you install the HV pump? it puts more load on the dist gear.

Keep in mind that there's a bypass on the oil filter, with an HV pump it open a lot during cold operation when the oil pressure is very high. You'll need to be looking at the crankshaft bearings carefully while you have it apart. Also, pieces of the gear get tossed around by windage in the crankcase and will end up getting embedded in the piston skirts and scoring thre cylinder walls.

I wonder if guys will ever get over this HV oil pump myth? It's worse than the "power valve fluttering at idle" myth, at least that one didn't wreck engines.

I wonder if guys will ever get over this HV oil pump myth? It's worse than the "power valve fluttering at idle" myth, at least that one didn't wreck engines.

LOL

and no, the original pump was not a an HV pump. An HV pump is not needed and can be a source of problems. Chevy oil pumps are not and have never been a problem area.

HV/HP pumps can overwhelm the internal pressure bypass and essentially turn into a hydraulic pump, especially when cold or if using heavy oil. there can be weird loads on the drive gears in this situation.

You'll also want to be inspecting the cam thrust area behind the upper timimg gear, it gets overloaded by the cam pulling back too hard. Many BB have been damaged there over the years. There's kits available to repair the front of the block but require milling the area smooth and flat again.

To live is to learn I guess. I thought it was necessary and just figured that is what GM would have installed. I bought the pump with the pickup installed and it matched my pan. I did not realize that HV pumps were not good. Why would they sell something that would ruin a distributor gear and cause problems? Doesn't make sense. I'll install the original next time. I'm hoping for the best regarding the grindings. I'm really not wanting to get in to tearing the entire engine down.

"why would they sell....."

because people still buy them. they're more profitable than regular pump because they charge more for them and there's no appreciable extra expense to manufacture them.

I am with Tom on this one. Put a standard volume/standard pressure pump back in there before you go any further....

I have had my 454 apart twice with this same problem. I don't know what the deal is but when I pulled the distributor one side of the gear is worn down and the other is fine?! I am running a roller cam and a bronze gear. I did not check the gear mesh the first time but I double checked it the second time before running it. This is not a GM engine a rebuilt motor. I installed, two different intakes and three different distributors and two different cams. Still the same thing worn on one side. It is either the block or oil pump on mine and I am betting on the block. I also am running a HV pump.


What do you guys think?

dump the HV pump, I'll bet the problem will just go away.

I'm going to dump the HV pump as suggested. Might as well put a bigger cam in it. But it does not make any sense that they would sell something that would cause so many problems. GM does not need these kind of issues and they are selling these pumps.

I'm going to dump the HV pump as suggested. Might as well put a bigger cam in it. .

See, there's always a silver lining!

oh come on, millions of after-market high volume pumps are out there operating with no problems. when is the last time anyone heard of a HV oil pump eating up a distributor gear like this?

speaking of myths, let's not start new ones....

GM dealers sell those pumps because uninformed people demand them. Chevy doesn't install those pumps in their engines though. think about it: 327/350, 327/375, 350/370, 396/375, 396/425, 427/435, 454/450, they sold those engines in new cars with warrantys. None of them had an HV/HP pump. Since they've been building HP engines since the late '50s, they might have noticed by now if the stock pumps were causing them problems.

Glen,

see directly above, post from 1970-cloned. that's not the only one either.