No clearance between front cover and crank trigger wheel

[LOT]

slinger thickness

don't have an extra one but I cut one down a few days ago and if I would guess around .040. Looking back I should have measured it. My friend had a new eng. built, assembled and delivered--we notoiced the zero clearance before installing--since I had seen this before I knew a slinger would get it out where it would clear so didn't measure slinger. I also found one on bone stock eng. on tear down once but it had disappeared.

 

[TurboDave]

I installed the water pump pulley and checked the axial location relative to the crank pulley. The crank pulley is recessed quite a bit when compared to the water pump pulley. Looking at another engine that I have, the crank pulley is slightly proud. In order to center the two the crank pulley needs to move out 0.090"

Here is a photo with the straight edge square on the water pump pulley face. Keep in mind that the engine is upside down in this photo, the crank pulley is on top. The gap between the straight edge and the crank pulley was measured with feeler gages.

Does anyone know what the thickness of a stock slinger is?

Interesting.... You don't suppose something similar could be going on between the cam and crank timing gears do you??

 

[LOT]

first

Interesting.... You don't suppose something similar could be going on between the cam and crank timing gears do you??

First time I ran into this was a few years ago. I had always used Rollmaster timing sets and they are RIGHT. This time I bought a cam KIT which included a generic timing set. Once I found the rubbing problem I removed the timing set and found that the crank gear actually had a recess machined in it where the balancer would sit in.

 

[cruzn57]

My timing chain is a rollmaster

engine work was done by Zimmerman,
I checked the cam/crank alignment, as I'm using Danny B cam retention,it was straight up.
on my BMS balancer it was making contact with timing cover and girdle, so I removed as little as I could to gain needed room, I cut a spacer on a lathe .030, and assembled it, had to adj the crank sensor slightly, but its spot on now.
I asked Mike Zimmerman if he had seen this before, he said yes. its no big thing.
just another issue to deal with when you modify your engine.

 

[gnX405]

Put a feeler gauge in there and you should get the thickness of the shim you need.

Steve

I did that and reported that in my post.

X2 I change a water pump once on a stock untouched engine & noticed a difference. Ended up having to shim the pully on the water pump to get it correctly spaced. My thoughts were that the aftermarket water pump was a different thickness.

Like Lee's advice on cutting a slinger down....will have to remember that if ever needed.

This is an AC Delco pump from nos4gn (hey look, it's true, we can say nos4gn now without it being blocked ), which I agree with you could be off. Makes me not want to check the other front end accesories (A/C compressor etc) for alignment. Thankfully there is a bit of distance between pulleys so the belt has room to flex.

Ive seen this and had to shim the balancer out. I saw a factory installed shim one time on a tear down when replacing a timing chain. Ive also had to cut the back of crank pulley to get proper alignment. Factory alignment is not that good in most cars.

Like Bob eluded to, there are stock GM shims.
I found the following in the GNTTYPE.ORG technical section: Crankshaft Balancer Spacer "seal" .030" (max. .060") 25523377
I guess there are .030" and .060" shims? Dunno. I can't find anywhere that carries that part number.

It is also too deep into crank sensor--may or may not be rubbing sensor.

The clearance to the sensor is pretty much zero.

Interesting.... You don't suppose something similar could be going on between the cam and crank timing gears do you??

I'm not positive, but I don't think so. Once I remove the crank pulley I will use a set of picks through the seal ID and pull on the crank sprocket to see how freely it slides forward with the chain on. This will at least give me an indication as to whether or not there is a gross miss-alignment between the two sprockets. I don't want to break the front cover seal if I don't have to. As others have mentioned, the problems seem to be forward of the teeth and several have installed spacers in front of the sprocket.

I wonder how much the crank pulley should be shimmed. 0.090" would align the pulleys and provide mondo clearance for the trigger wheel to front cover and sensor. It would probably not have any ill effects on the crank signal, as there would still be plenty of trigger wheel material passing through the sensor.

 

[TurboDave]

Shimming it .090 shouldn't present any ill effects. But in order to shim it, you're going to have pull the front cover. At that time you'll be able to see the relationship between the two sprockets, and this will tell you whether your shimming needs to be in front of the crank sprocket, or behind it, or a combination of the two.
If the two sprockets are mis-aligned vertically like your pullies, when pushed back then the timing chain may not live as long as you like.

I know you don't want to pull the front cover, but if it were me, I would want to know how the two sprockets are aligned (fore-aft).

 

[gnX405]

in order to shim it, you're going to have pull the front cover.

Why? The shims would be the same OD as the portion of the pulley that passes through the seal.

 

[TurboDave]

Why? The shims would be the same OD as the portion of the pulley that passes through the seal.

True. I forgot about that detail.

 

[gnX405]

An update

Today I talked to the machine shop that built the long block and found out that the timing sprockets were re-used, and just the chain was replaced.

So the only thing that has changed in the stack-up of the components is the crank itself. Remember this is a crank out of a carbed turbo engine.

The keyed pilot hole on the damper is probably deeper than the crank snout is long which allows for the timing sprocket (and slinger) to be held in place by the face of the damper when the bolt is tightened. I think that's how it works but will verify it over the weekend.

That said, I believe the reason the damper is recessed so far back is because the crank face that the timing sprocket seats against is recessed farther back than the original crank. The real way to measure this would be to reference off the thrust bearing surface and compare this to the original crank which I still have. Taking this measurement on an installed crank may not be feasible. I will, however, be able to measure the two sprockets in an effort to determine how thick the shim needs to be behind the sprocket.

I'm going to have to pull the freshly painted timing cover afterall

 

[LOT]

I doubt !!!

Today I talked to the machine shop that built the long block and found out that the timing sprockets were re-used, and just the chain was replaced.

So the only thing that has changed in the stack-up of the components is the crank itself. Remember this is a crank out of a carbed turbo engine.

The keyed pilot hole on the damper is probably deeper than the crank snout is long which allows for the timing sprocket (and slinger) to be held in place by the face of the damper when the bolt is tightened. I think that's how it works but will verify it over the weekend.

That said, I believe the reason the damper is recessed so far back is because the crank face that the timing sprocket seats against is recessed farther back than the original crank. The real way to measure this would be to reference off the thrust bearing surface and compare this to the original crank which I still have. Taking this measurement on an installed crank may not be feasible. I will, however, be able to measure the two sprockets in an effort to determine how thick the shim needs to be behind the sprocket.

I'm going to have to pull the freshly painted timing cover afterall

First off I believe the specs. on the turbo crank and non turbo crank to be the same. Second I ? why the shop would change the chain and not change both sprockets as the top sprocket has plastic teeth. I still say the timing set was changed and the bottom sprocket is different. I also ? why not just pull damper and add the necessary shim through seal hole to get the correct or as close as possible alignment. From the factory they are NOT even near perfect. You may be over thinking (engineering) this small problem. You are right in that the bottom sprocket goes up against the crank shoulder --the balancer goes over or past the end of key--then slinger--then the 230 ft. lb. bolt. Keep us posted.