[shaker455]

Originally Posted by gtofreek

It's not the lifters that are failing. It's the fact that the oil band is in the wrong place. That prevents them from filling up when they are on the base circle. I modify the blocks so that is not a problem anymore. Your machine shop just hasn't figured out what the real problem is, they just blame the lifters, which do have the band in the wrong place, but the lifters work fine when block is modified. These are Hylift/Johnson slow bleed lifters so they do not have too much internal clearance.

Thanks Len Caverly and our shop address that issue years ago.
Best on your return

[Va68goat]

Sirrotica,
Thanks for the reply. Everything that you mentioned is pretty much way over my head but the friends that are helping me that live near me are watching this thread..so that helps. I think we are going to pull the converter back and see if the noise is still present. Since I have a new balanced flexplate, I assume we should just install it huh? I don't know if that's going to help or not but since I have it and its balanced, I assume we just install it. I went back and looked at the dyno video and I didn't hear it either. I don't know if it's because it was pretty loud at the time of dyno though, since I wasn't there. When the motor was installed and running, we heard the knocking sound. After many hours of diagnosis and replacing parts we decided it was best to pull the motor and take a look at the windage tray. We did notice only 1 washer was used to space the windage tray when normally Paul uses two washers. We did notice some witness marks on the windage tray so we added some spacing. I think the noise from the windage tray masked the knocking noise that we hear now.

TedRamAirII,
Unfortunately, I think we have some more testing to do. I certainly wish I knew more about cars to do this myself but I do trust the friends that are helping me. I have no clue about the clearance of the oil pump shaft and the camshaft You had good suggestions..thank you.

ponchjoe,
Hopefully we'll be able to work on the car and we'll take a look at what you mentioned.

[Sirrotica]

Originally Posted by Va68goat

Sirrotica,
Thanks for the reply. Everything that you mentioned is pretty much way over my head but the friends that are helping me that live near me are watching this thread..so that helps. I think we are going to pull the converter back and see if the noise is still present. Since I have a new balanced flexplate, I assume we should just install it huh? I don't know if that's going to help or not but since I have it and its balanced, I assume we just install it. I went back and looked at the dyno video and I didn't hear it either. I don't know if it's because it was pretty loud at the time of dyno though, since I wasn't there. When the motor was installed and running, we heard the knocking sound. After many hours of diagnosis and replacing parts we decided it was best to pull the motor and take a look at the windage tray. We did notice only 1 washer was used to space the windage tray when normally Paul uses two washers. We did notice some witness marks on the windage tray so we added some spacing. I think the noise from the windage tray masked the knocking noise that we hear now.

TedRamAirII,
Unfortunately, I think we have some more testing to do. I certainly wish I knew more about cars to do this myself but I do trust the friends that are helping me. I have no clue about the clearance of the oil pump shaft and the camshaft You had good suggestions..thank you.

ponchjoe,
Hopefully we'll be able to work on the car and we'll take a look at what you mentioned.

As long as you have the new balanced flexplate by all means install it. I really have little faith it's going to cure the noise though. I feel you're in the right area, but if the noise gets cured by changing the flexplate it would be some other issue other than a crack, such as too much run out touching something on the rear side of the engine.

I'm not sure if you've tried a stethoscope, or used a rod to listen for the noise, but it sometimes will point you in the right direction. One other thing I have used to listen to automotive noise is a 1/4 inch piece of vacuum hose placed in your ear, and moving the other end of the hose around to pinpoint a noise. This method is probably better for getting you in the area where the noise is loudest, than listening with a rod or a stethoscope.

Just thought of one more thing, the welded lugs on the torque convertor. I have seen an instance where the lug was fractured. The car was a race car, actually the middle picture in my signature, 67 GTO, so with open exhaust no telling if there was a noise or not. The lug actually finally pulled a section of the torque convertor out, and caused all the ATF to leak out and burn on the hot exhaust system. One of the tack welds on the lugs could have broken off and caused a noise from the movement. Not likely, but this isn't a common noise either.

[Va68goat]

64speed,
No, believe it or not, it hasn't been resolved. I've put less than 200 miles on this car since I got it.

Bentwheelbob,
Yeah, I think you're right. Me and my buddy's have spent well over 60 hours of diagnosis time and replacing parts. I have about $1,600 in just parts and tools since I got the motor delivered. (Rockers, pushrods, flexplate, fluids, gaskets, I also had a shop inspect the cylinder heads and I bought a bore scope.). It's been tough. If I knew more about cars, I'd have an easier time trying to figure all this out. Since my knowledge is very limited, that why I went Paul. I may try to get the flexplate installed just to rule that out before the motor goes back to Arizona. I'd hate to send the motor back and Paul can't duplicate the knocking noise. I'll let you guys know how it turns out. Thanks for all the suggestions.

[NeighborsComplaint]

Originally Posted by Va68goat

64speed,
No, believe it or not, it hasn't been resolved. I've put less than 200 miles on this car since I got it.

You got yourself a real mystery there. Change out the flexplate leaving the convertor disconnected and sorry to say, hope for best but prepare for the worst.

[chiphead]

My money is that it's still banging on the windage tray.

[AG]

The new Comps have the adjusted oil band height that is similar to a stock Pontiac, just put a set in a motor I am building now.

[jonmachota78]

Did the oil filter ever get disected and inspected? I wish you the best in figuring out the issue

[Sirrotica]

Since I've seen at least a dozen cracked flexplates over the years, it does sound like a cracked flexplate on that video. Pontiacs are less prone than chevys are, but I have seen both along with a few olds and buicks over the years.

It may not be a cracked flexplate, but the noise is consistent with one, and yes they are constant every crankshaft rotation. I've seen chevy impalas with 2 speed powerglides driven by senior citizens crack flexplates, the car doesn't have to be abused for them to crack. There is no rhyme nor reason why/when they crack, they do just crack for no apparent reason. It's actually metal fatigue that eventually finally overcomes the initial strength of the stamping.

I've seen them with small cracks and I've seen them where the whole center around the crank flange bolts is completely broken in 2 separate pieces. All that is needed a crack where the edges bind, and click against each other, and you get the noise. To someone that has little experience with engines it may sound as a rod knock, but it doesn't normally change with engine load as a rod knock does. It also is not as heavy as a rod knock.

One thing that confuses the issue is they have already removed the convertor bolts and ran it with the engine with the convertor pushed away from the flexplate. Since the flexplate has no stress on it when disconnected from the convertor, it should have gone away. So even though it sounds like a cracked flexplate it may not be that, given the detective work already done.

From the video, it does seem to be in the flexplate area of the engine, however sounds travel in a reciprocating engine and are not always what/where they seem to be. If I had to bet on it, it's not a flexplate, but the noise seems to be concentrated in that area of the engine/transmission assembly.

Pontiac did use a very fine/thin shim between the crank flange and flexplate on some applications around .010-.015 thick. If I remember correctly, I have left that shim out without any negative consequences, probably in this circumstance it would not cause the noise in question.

The noise does sound like it's from the sheetmetal accessories on the bottom rear area...………

[gtofreek]

Good post Brad. When the torque converter was pulled away and noise still present, the windage tray had a clearance issue at that time that had not been resolved yet, so that may have been the noise they heard when they pulled the TC away. Hard to say.

There has never been any metal in the oil or filter so I'm confident it's not a bearing. When I keep looking at the video's of it on the dyno, there is no evidence of a knocking noise, not even at an idle. As loud as the noise is, if it was there when dynoed, I'm confident I would have either heard it then, or in the video.

[ponchjoe]

Is there an illusion in the video? About 38 seconds in the camera comes over the pipe and shows the starter and it looks like it’s moving in time with the noise.

[dataway]

Originally Posted by ponchjoe

Is there an illusion in the video? About 38 seconds in the camera comes over the pipe and shows the starter and it looks like it’s moving in time with the noise.

Yeah, it does look like that doesn't it.

[NeighborsComplaint]

Originally Posted by ponchjoe

Is there an illusion in the video? About 38 seconds in the camera comes over the pipe and shows the starter and it looks like it’s moving in time with the noise.

I saw that too but thought it was the camera searching for focus. Seems like a lot of runout in that flexplate too.

[Va68goat]

NeighborsComplaint,
Honestly, I painted the flexplate because I didn't know any better. I'm very new to these old cars and I painted it. I have the inspection cover but it's not on the car. I'm assuming the alignment dowels were lined up. Don't laugh too loud because I am new to these old cars but is it even possible for the dowels to NOT be aligned?

400 Lemans,
I don't know remember if I took that picture the way it was in the car but when we work on the car next weekend, I'll keep an eye out where the reinforcing ring is. Could that cause the knocking sound?

I really do appreciate you guys chiming in and giving opinions and suggestions.

[NeighborsComplaint]

Sometimes the dowels get misplaced and the trans gets installed without the dowels in place, using only the bolts to align the trans input shaft. As the bolts are typically a slip fit, the possibility of misalignment and wear to the convertor and pump can occur.

The dowels are beefy 1/2" steel pins that are pressed into the trans bell housing flange and usually remain there when the trans is separated from the engine. If the dowels are not in place, the minor misalignment could cause the knocking/scuffing you are hearing loading one side of the pump or stator. Elongated convertor mounting holes in the flexplate can have the same effect.

[Sirrotica]

Ring gear starter interference is entirely possible, or a weak return solenoid spring allowing the Bendix gear to interfere from not returning fully. One would think that if the Bendix was touching the ring gear it would be intermittent because the starter isn't going to stop at the precise point each time. I didn't pay close enough attention to the video to know if it's a GM direct drive starter, or a gear reduction mini starter.

I suppose that after the engine is running, loosening the starter to block bolts would gain enough clearance to eliminate the starter rubbing the ring gear. If I were looking for the noise I might just try that next, only take a minute or two to test that theory. I have seen starter shims end up touching the ring gear also when they are shoved into place, one shim will sometimes twist out of line from the others. Instead of straddling the innermost bolt it will twist towards the rear, contacting the flexplate inadvertently.

The only other area I would be concerned about is contact from the torque convertor inside the bellhousing area, but if you're going to repeat the disconnected torque convertor test, you'll cover that area.

From my previous experience I don't believe there is any problems in the lower end of the engine, and oil filter dissection has pretty much taken the bottom end out of the equation. Paul IMO, seems conscientious enough to make sure the engine was done correctly before he shipped it, plus he said no noise on the dyno so some other variable in the car that wasn't present on the dyno, stands likely to be the source of the noise.

[ponchjoe]

Why did Pontiac use the shim behind the flexplate? Aside from flywheel clearance could it be to dampen flexplate noise? Is there any risk of noise from the flexplate being directly in contact with the crank? Is clearance in the bolt holes on the flexplate where it could move back and forth?
Sorry, more questions than answers, just to help exhaust all possibilities .

[Sirrotica]

Not all Pontiacs had the shim, I've put a good many of them together without it and never had any ill effects not using it. Pontiac is the only manufacturer that I have seen use a shim between the flexplate and crank flange, and I have no reasonable explanation of why they used it in some instances, and not in others.

It may have been just a way to take up for manufacturing lateral tolerances, I can't say for certain why it is used in some applications, but not all.

[NeighborsComplaint]

2nd post I have seen where the owner painted his flexplate. Why? With an inspection cover in place, you can't see it and the starter gear is going to chew the paint up on the ring gear anyway.

[NeighborsComplaint]

Were there alignment dowels in the trans when you bolted it up to the engine?