No clearance between front cover and crank trigger wheel

[gnX405]

How much clearance should there be between the front face of the front cover and the trigger wheel?

The engine pictured is being assembled and has zero clearance, as can be seen by the scratch on the front cover. The engine is a 109 block, stock front cover, cometic front cover gasket, stock balancer and crank trigger wheel, front cover is torqued to spec, and so is the crank bolt. The crankshaft is out of a carbed 3.8 turbo, perhaps the nose on carbed cranks is shorter?

The clearance between the trigger wheel tips and bottom of the crank sensor is pretty much zero as well.

Has anyone out there shimmed under the balancer to correct this?

TIA

-john

 

[TurboBob]

did you install the "oil slinger"?

GM does have a part number for balancer shims, although I don't have it handy..

Bob

 

[LOT]

let me guess

If you put the slinger in, then I bet you changed timing chain set. Post back and may be able to help.

 

[gnX405]

Yes the stock oil slinger is installed.

And yes the timing chain has been changed, it is a Cloyes chain p/n 9-138, not sure about the part number on the sprocket itself. Could this be the culprit?

BTW I just measured the crank thrust clearance to be 0.0075" which is within stock specs of 0.003" to 0.011"

-john

 

[LOT]

seen this twice lately

Yes the stock oil slinger is installed.

And yes the timing chain has been changed, it is a Cloyes chain p/n 9-138, not sure about the part number on the sprocket itself. Could this be the culprit?

BTW I just measured the crank thrust clearance to be 0.0075" which is within stock specs of 0.003" to 0.011"

-john

Can't measure now, but I would think if it is the same front cover as came off car (or still a GM cover) then the thickness of the crank gear is less than the stock gear. I have fixed both by using an extra oil slinger and cutting it down to the FLAT which leaves you with a shim that will go through the front seal (once balancer is off) and space the ring out where it should be. Put your water pump pulley and crank pulley on then using a straight edge see if your crank pulley is back farther than it should be. Best of luck.

 

[gnX405]

Thanks for the replies.

I'll check the pulley alignment as Lee suggests.

So far I've learned the following:

GM did have a p/n for balancer shims.

There may be some thickness differences between a stock timing chain lower sprocket and a Cloyes sprocket.

A cut down oil slinger can be used as a spacer.

 

[cruzn57]

ran into the same problem

with 109, stroker, RJC girdle,
ended up cutting some shims on the lathe, .030, and grinding the front of the girdle.
spaced the WP out accordingly.
so far ok.

 

[LOT]

curious

with 109, stroker, RJC girdle,
ended up cutting some shims on the lathe, .030, and grinding the front of the girdle.
spaced the WP out accordingly.
so far ok.

As to why you would need to grind girdle.

 

[TurboDave]

Thanks for the replies.

I'll check the pulley alignment as Lee suggests.

So far I've learned the following:

GM did have a p/n for balancer shims.

There may be some thickness differences between a stock timing chain lower sprocket and a Cloyes sprocket.

A cut down oil slinger can be used as a spacer.

If push comes to shove, when/if you have to remove the front cover, you'll want to compare the thickness of your new lower timing gear with the original. The difference may show up there. May have to rethink your timing set. Or shim accordingly.

Leads one to wonder, if the cloyes gear is "thinner", where's the difference lost. On the front side, block side or a combination of the two.
You could use your dial indicator (after the front cover is removed) to check if there a difference between the chain face of the cam and crank gears.

 

[cruzn57]

timing gears were perfect

crank was perfect, only issue was girdle and TWO different balancers. both were BMS,
I ground a little material off the nose of the girdle, and shimed the balancer out.
works fine now, why would removing material from front of girdle be a problem???

 

[gnX405]

If push comes to shove, when/if you have to remove the front cover, you'll want to compare the thickness of your new lower timing gear with the original. The difference may show up there. May have to rethink your timing set. Or shim accordingly.

Leads one to wonder, if the cloyes gear is "thinner", where's the difference lost. On the front side, block side or a combination of the two.
You could use your dial indicator (after the front cover is removed) to check if there a difference between the chain face of the cam and crank gears.

Good point, I would hope that the significant axial dimension would be from the mounting face to the sprocket teeth and the overall thickness would float.

 

[gnX405]

Mounted water pump pulley and measured

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?

 

[XXQUICK6XX]

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

Steve

 

[earlbrown]

I wouldn't use the waterpump pulley as a datum point. My balancer is in the right place and the pump pulley was over .100" off (in the other direction as yours).

TurboBuicks.com - View Single Post - A day in the life of Earl....

The pump flange is just pressed on the shaft and there's no positive stop or QA from what I've seen.

 

[getchasum]

I wouldn't use the waterpump pulley as a datum point. My balancer is in the right place and the pump pulley was over .100" off

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.

 

[XXQUICK6XX]

That's too much to run a belt on. As I said before I would shim it the crank balancer that is. As in the post earlier either the crank snout is a little different or the after market timing gear pry is a different thickness and in any reason you need to get the interrupter ring further from the timings cover.

Steve

 

[bison]

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.

 

[XXQUICK6XX]

How much clearance should there be between the front face of the front cover and the trigger wheel?

The engine pictured is being assembled and has zero clearance, as can be seen by the scratch on the front cover. The engine is a 109 block, stock front cover, cometic front cover gasket, stock balancer and crank trigger wheel, front cover is torqued to spec, and so is the crank bolt. The crankshaft is out of a carbed 3.8 turbo, perhaps the nose on carbed cranks is shorter?

The clearance between the trigger wheel tips and bottom of the crank sensor is pretty much zero as well.

Has anyone out there shimmed under the balancer to correct this?

TIA

-john

Please look at the timing cover gentlemen when you are answering. In his 1st picture.

 

[LOT]

nothing if that's what it takes.

crank was perfect, only issue was girdle and TWO different balancers. both were BMS,
I ground a little material off the nose of the girdle, and shimed the balancer out.
works fine now, why would removing material from front of girdle be a problem???

His problem is the ring hitting front cover--girdle sits below cover--just didn't see the ring hitting girdle--unless different balancers have a different dia. ring.

 

[LOT]

If ring is touching cover

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