[Sun Tuned]

I got a small video of the shaft play in this one but I have no idea how to post it here.

At first I thought he had about an 800 lb oil pump in it to do that, but it was just a 60. Something ain't right that's two with less than 250 miles....

Back to Paul's thread.

[Cliff R]

My stock HEI has been in 4 different engines since the mid 1980's and never touched it till a few months ago. The mechanical advance mechanism started to stick slightly right off idle, not allowing the timing to fully return to the base setting each time it came back to idle.

I pulled the distributor, removed the shaft, took everything apart, lightly polished a few pieces and put it back together. Didn't take pics of the shaft where it rides in the bushing or the bushing but there was a very slight shiny appearance opposite the camshaft but no visible wear on the shaft. The shaft would move about .002" or so it that direction only, but not enough to worry about and the gear looked to be in near mint condition, which surprised me because it's a bronze gear running on a HR camshaft since 2009.

I've been into a lot of factory HEI's and nearly every single one of them will show a little wear at the shaft, and some scratching/scoring lines from debris in the oil, and a little wear in the direction away from the cam. This simply happens because they use helical cut gears which improve mesh area, but produce thrust up and away from the drive gear. I reject about 30 percent of them these days when the shaft is worn down even though we can put in a new bushing, so I'm constantly stealing shafts from good cores.

Seeing a distributor lower bushing fail in a couple hundred miles tells me it had major issues right out of the box. I'd be hesitant to use it again, considering the cost of an engine vs the cost of replacing it with something better........FWIW.......Cliff

[gtofreek]

Originally Posted by grivera

Joe - If you determine it's an authentic MSD dizzy, I think a new bushing may be best course of action - imagine if you bought a new dizzy and it has the same crap bearing.

Paul - how do the main/rod bearings look? Did any metal from the dizzy bearing make it to them?

The bearings and crank had no scratches at all.

[gtofreek]

Originally Posted by HWYSTR455

Yeah, I'm thinking if the lower bushing is wobbed out, the top one is too. With the shaft at an angle, I would assume it would wear the opposite side of the upper bushing.

I'm in the same boat, you could replace that lower bushing, get it together, only to find something else wrong with it. Go thru that one, fix it, eGay it, and use a new one.

Maybe the gear was too large in diameter or something? The base circle?

.

The gear isn't the problem. Engagement is perfect. Also, the top bushing is an actual roller bearing, but since it's a bearing, and it's only about 5/16" or so thick where the shaft goes through it, the shaft will cock slightly.

["QUICK-SILVER"]

Originally Posted by Va68goat

TedRamAirII,

When we pulled the motor a month ago, we inspected the oil pump and shaft. The shaft had some witness marks on it. I'm pretty new to working on cars but some of the guys thought we had a smoking gun. We switched out the oil pump and shaft, re-installed the motor and it had the same knock. We did feel around the oil pan and didn't find anything unusual. I have all the confidence that this motor will be a beast when I get it back.

5W's (or at least a few of them) should have kicked in here, before the engine went back together/parts swaped.
No reason for the pump shaft to have witness marks. Looking to see where it had touched, what it had touched and why it had touched...Could very well have had you fixed and on the road.
That's a "BIG IF" the distributor bushing is the only knock source. And was letting the shaft move far enough to get hit by the crank.

Somewhat disturbing
Clay

[napster]

I wonder if this carries over to other items from MSD. I have had five engines built and each one uses the MSD Ready to Run distributor. I haven't had a problem. Haven't heard any noises coming from the engines.

I'm having another one built. We'll see what to do when it comes to the time we dyno the engine.

Jim

[Formulajones]

Paul mentioned he's used MSD for many years in various types of engine builds and he's never seen this issue. I've used MSD quite a bit, not as much as Paul, but I have never seen this either. Can't ignore the millions of MSD products in service either, especially places like NHRA, so you'd think if there was a problem it would be more common or wide spread.

Like Paul, I'm just as interested in the UPC code.

[dataway]

I was sooooo close with this post.

"I'm going with a slightly bent oil pump drive shaft that intersects the crankshaft counter weight every other revolution. Just kidding.

Can't wait to find out what it is."

[HWYSTR455]

Originally Posted by gtofreek

The gear isn't the problem. Engagement is perfect. Also, the top bushing is an actual roller bearing, but since it's a bearing, and it's only about 5/16" or so thick where the shaft goes through it, the shaft will cock slightly.

Gotcha.

Well, this issue seems easy enough to detect, just look at the reluctor wheel, contact will be noticeable. And I'm guessing there doesn't need to be a noticeable noise or anything, so just need to keep an eye on them.


.

[torqhead]

Nice job Paul! One of those issues that had all of us on the edge of our seats! Will definitely include thorough distributor inspections for now on when I build an engine!!!

[SRR]

This may be a long shot but when you unpacked the distributor did it look perfect? Sealed in a wrapper? Maybe it was a "copy" returned as new and somebody kept the real one. Who knows.

[dataway]

What would have been the end result if the problem was not addressed? Loss of oil pump drive? Eventual destruction of the dizzy gear (and loss of oil pump drive)? Wouldn't think it would contaminate oil too bad, would just get washed into the pan and filtered.

Maybe eventual wonky timing readings or failure of the reluctor?

[Va68goat]

Quicksilver,

Here are the pictures of the oil pump shaft.

[Formulajones]

Originally Posted by dataway

What would have been the end result if the problem was not addressed? Loss of oil pump drive? Eventual destruction of the dizzy gear (and loss of oil pump drive)? Wouldn't think it would contaminate oil too bad, would just get washed into the pan and filtered.

Maybe eventual wonky timing readings or failure of the reluctor?

I can't even begin to fathom that it didn't already have wonky timing readings. With a shaft moving around that much and beating up the reluctor wheel I see no way this thing had rock steady timing. Eventually it would have just damaged the reluctor wheel or magnet to a point the engine would have died or started severely misfiring.

I've had old worn distributors before, and timing jumps all over the place which is why I can't imagine these guys didn't catch it back when I mentioned it was a likely cause.

[Va68goat]

Formulajones,

The distributor was pulled several times but nobody caught it. I think because it was a new MSD distributor, nobody expected this.

[Sun Tuned]

These days you would not believe the stuff that has to be checked over compared to just 20 years ago. And the thing about it is it's an ongoing learning process. This stuff changes by the month the stupid stuff that needs to be looked over that never used to be an issue.

It's difficult sometimes but one just has to be patient and let the folks work through the laundry list of possibilities. I sent Paul a pic and some video of the one I had.

And you're exactly right, the guy I was working on it for sorta didn't want to believe his 150 mile new 385.00 distributor ate the bottom bushing either. And I hated to call him and have to tell him. Sorta made me feel creepy like he was thinking I was fooling with him.

These days, stuff happens. And it's almost not about checking some stuff. Some of this stuff you have no way to know to check it because 50-75 miles ago it was fine...

It's a new world folks and I am starting to not care a whole lot for the work it takes to keep up with some of the stupid stuff we are seeing these days. And having to try and outthink/outfox and figure out before it even happens.

[gtofreek]

Here's some pics of the pistons, crank, and bearings. These are typical of all the others.

[gtofreek]

One more of a main bearing.

[HWYSTR455]

Not seeing anything jumping out there, which is a relief. And actually, expected. Nice.


.

[chiphead]

Originally Posted by Formulajones

I can't even begin to fathom that it didn't already have wonky timing readings. With a shaft moving around that much and beating up the reluctor wheel I see no way this thing had rock steady timing. Eventually it would have just damaged the reluctor wheel or magnet to a point the engine would have died or started severely misfiring.

I've had old worn distributors before, and timing jumps all over the place which is why I can't imagine these guys didn't catch it back when I mentioned it was a likely cause.

The top bearing was still in good shape. Without a major rotor phasing error, the timing will be pretty steady. You would have to check it pretty closely to find it. Maybe the old 1 to 6 cyl timing check. Any engine with a lumpy cam is going to have some spark scatter when you check the timing.

Eventually the reluctor wheel would have contacted the pickup hard enough to damage the pickup coil or shear a roll pin in the shaft. If you were lucky, the dizzy would fail and the engine would refuse to run.

Worst case, it would have run until the oil pump shaft started to bind in the retainer loop that is cast into the block. That would really grind the driveshaft and make metal. If the distributor continued to operate, the oil pump shaft could bind up, twist out of position and fall into the crankshaft, with disastrous results. If you look at that oil pump shaft, you can see where it's got witness marks where its already dragging in the loop. The only time I've seen something like that, was out of my Pontiac 350 with a totally clapped-out HEI distributor.

Glad everybody was paying attention to noises. This could have lunched the motor.