72 LT-1 engine rebuild encountered a few questions

[Robert D.]

I am rebuilding my feb 72 built car CKY designated engine and have a few questions. First I have re-installed the correct water pump and harmonic balancer and my pulleys don't look like they will work.


i have 3858533 BJ pulley on the balancer I think this is correct?
and I have 3991423 BW for the water pump...I don't think this is correct?

what are the correct ones and are there other applications that they were used on to aid my search?

also, I have two windage trays. The one that was on the motor I have re-installed is the shorter style in the photo and I also have another one that has two more bolt holes and extends over an additional main cap. Can anyone shed some light on the differences and correct application for my car?



thank you for any assistance
Robert

[Robert D.]

Re: 72 LT-1 engine rebuild encountered a few questions

Here is what the pump and balancer look like... the valve covers, carb and intake are just there for paint and not being used

[Larry M.]

[Robert D.]

Re: 72 LT-1 engine rebuild encountered a few questions


Thank you,

robert

[Larry M.]

Re: 72 LT-1 engine rebuild encountered a few questions

Robert,

The water pump pulley on ours is 3991423 BW. Sorry, but I'm not able to view the number on the lower pulley.

You may already have a copy of the Assembly Manual for your car, but in case not, the two attached scans may give you some help.

Larry

[Patrick B.]

Re: 72 LT-1 engine rebuild encountered a few questions

That water pump looks longer than the water pump used on a 70 LT-1.

[Mark E.]

Re: 72 LT-1 engine rebuild encountered a few questions

Robert,

Why do you primer the engine?

[Robert D.]

Re: 72 LT-1 engine rebuild encountered a few questions

Robert,

Why do you primer the engine?

I used eastwood it was a high temp etching primer? I don't want flaking after pulling the motor?

[Joe L.]

Re: 72 LT-1 engine rebuild encountered a few questions

That water pump looks longer than the water pump used on a 70 LT-1.

Patrick------


The1970 and 71+ small block water pumps are different. The 71+ are slightly longer.

[Joe L.]

Re: 72 LT-1 engine rebuild encountered a few questions

I used eastwood it was a high temp etching primer? I don't want flaking after pulling the motor?

Robert------


The problem is that the primer will cause the finished paint to look too "thick" and "smooth". Most engine paints are self-priming. If the engine surfaces are clean and oil-free, the paint will not chip off. If the engine surfaces are not clean and oil-free, even with the primer the paint will chip off.

[Joe L.]

Re: 72 LT-1 engine rebuild encountered a few questions

I am rebuilding my feb 72 built car CKY designated engine and have a few questions. First I have re-installed the correct water pump and harmonic balancer and my pulleys don't look like they will work.


i have 3858533 BJ pulley on the balancer I think this is correct?
and I have 3991423 BW for the water pump...I don't think this is correct?

what are the correct ones and are there other applications that they were used on to aid my search?

also, I have two windage trays. The one that was on the motor I have re-installed is the shorter style in the photo and I also have another one that has two more bolt holes and extends over an additional main cap. Can anyone shed some light on the differences and correct application for my car?



thank you for any assistance
Robert

Robert------

GM #3858533 is the correct balancer pulley. I do not recall the correct water pump pulley and I can't check my references because I'm out-of-town. 3991423 might be the correct one, though. Your application also used a single groove, add-on water pump pulley which served as the AIR pump driver pulley.

The windage tray you have installed is correct. The longer but otherwise similarly configured tray was not used on any pre-1975 Corvette. It was used on 1975 and later with L-82.

[Robert D.]

Re: 72 LT-1 engine rebuild encountered a few questions

Robert------


The problem is that the primer will cause the finished paint to look too "thick" and "smooth". Most engine paints are self-priming. If the engine surfaces are clean and oil-free, the paint will not chip off. If the engine surfaces are not clean and oil-free, even with the primer the paint will chip off.

Thank you. At this point it is what it is. I've spent a fortune on Eastwood paints that really don't go very far.

[Robert D.]

Re: 72 LT-1 engine rebuild encountered a few questions

Any ideas what would cause my pulleys not to line up? I just ordered the 3991425 BX add on since I know it's not with my smog system. Ill double check my notes on the water pump.

[Joe L.]

Re: 72 LT-1 engine rebuild encountered a few questions

Any ideas what would cause my pulleys not to line up? I just ordered the 3991425 BX add on since I know it's not with my smog system. Ill double check my notes on the water pump.

Robert-----


It could be that the harmonic balancer is not on far enough (i.e. the snout is not seated on the crank sprocket) or the water pump hub is not installed at the correct spacing.

The 1971-82 Corvette waterpump pulleys have VERY limited other applications. They were not used on any other passenger cars. They may have been used on some MD/HD trucks.

[Robert D.]

Re: 72 LT-1 engine rebuild encountered a few questions

So I called and verified (car is in Maine while apart I'm in pa and have been running back and forth for the build)
Water pump number is 3991399. H261 with the thicker output shaft the pump that was on before was incorrect and different height

balancer pulley 3858533 BJ
water pump 3991423 BW

the balancer is new and pictured here it's dimensions are correct I'm wondering if the shaft on the crank part is different?