VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 1929 Engine Rebuilder Questions

engine rebuilder called me yesterday with a few questions/concerns. thought i would post here for feedback/thoughts:

1-camshaft timing gear keyway i bought a NORS fiber one from TFS. however the keyway in it is approx 5/32 wide where as the keyway in the cam and the existing cam gear are 3/16 wide. so was wondering if we need to widen keyway in the gear or was the original one opened up to 3/16 somewhere long the line. or what are our options

2-crank gear condition has some side wear that should be irrelevant, looks like the slinger was loose at one time and grooved the front face of the gear. The main concern is that it looks like someone used a 2 jaw puller to pull the gear off at one time. There are 2 small chips on 2 of the gear teeth. does NOT look major but he would like to put on a new NOS or NORS gear if available. if not sure we could reuse it, i can get pictures if needed.

3a-crank gear spacing/gap, what is the gap / spacing on hte crank gear or should it just align with the cam gear once set ??

3b-camshaft gear washer/spacing. camshaft has been reground and ready for install. On the install the cam goes in, then the new thrust plate bolts on. question was there is a .003 clearance. engine builder was asking the proper method for setting the clearance for pressing on the cam gear. he was thinking of using a washer on the shaft behind the cam gear. but was wondering how it should be done on these older 194. he has done 216 & 235s

4-crank pulley fitment. assume that the crank gear pulley is a press fit, however mine is barely a slip fit. what tis the proper id of the pulley and od of the shaft ? thought was to find another pulley if the shaft is ok, or sleeving the pulley to press fit on the exiting shaft. but assume it would have to be a split sleeve for the keyway.

5-crankgear flinger does it sit loose on the shaft or ?? i know that the open end of the flinger, since it is a cup shape goes up against the ring on the timing cover since it spins freely. should the back of the flinger sit flush against the crank gear. the key on the crankshaft spins the flinger.

Hello BearsFan315,
There are two question 3's. With regards to question 3B, I am not aware of a spacer washer used behind the camshaft gear to set the clearance needed away from the thrust plate. So how do you determine the .003 gap that the repair manual states is required? Well, you can try a washer/spacer of the proper size that will not touch the thrust plate. That might call for reaming out the I.D. of the thrust plate. I can think of two other ways, correct or not should get the job done. Camshaft not in engine block. 1. Use .003 feeler gauge between thrust plate and cam gear while pressing onto camshaft. Camshaft in engine block. 2. Bolt thrust plate tightly to block and pull the camshaft tight against thrust plate, measure from face of thrust plate to face of camshaft. Measure thickness of cam gear at center. This should indicate how far to press cam gear on, to get the required .003 clearance. These two ways may not align the gear teeth flush and may not have the cam gear and camshaft faces flush either. The fix for that would be to shave the thickness of the thrust plate as needed. You say "new thrust plate". Do you have the old thrust plate to compare thicknesses? The Filling Station offers one thrust plate to fit all years and states that it replaces GM# 836827. The MPPL indicates this as 1932. As for the 1929-31, the MPPL indicates thrust plate GM# 835746. Why is that and what is the difference?

yes i have the old plate, and the new plate is the one from TFS.

The slinger is pushed up against the gear by the pulley. By the way the 29 oil slinger is a one year fit. One from a 30 will not work with a 29 timing gear cover. It will bind up and not spin. Art

thanks postings parts wanted/needed in the appropriate section

per my question 1 above, all the MPPL call out a no9 woodruff key, which is 3/16 width. so would guess that you have to open up the keyways since they are only 5/32 wide ?? all the cam gears i have on hand and friends have are stock 5/32 wide ??

I am not sure what size things should be but perhaps machining the key so it's stepped would solve the issue.

That is the most common solution used for that kind of issue. Your machinist should have mentioned that.

we talked about a few options, opening up the keyway, machining the key, etc... jsut wanted to validate the keyway size was correct. maybe someone opened the keyway in the old cam gear to match the key width.

went back to the rebuilder on friday to go over plan of action

he is going to broach the cam gear keyway and ensure it is centered to keep timing aligned, i was able to get a new crankshaft gear from Gary W, he had a batch made a while back and had one on the shelf, ended up working the oil thrower in the press and on the bench to get it back into shape for reuse, he is going to use the shim method to set the cam gear and ensure alignment with the crankshaft gear. we are going to bore out the crankshaft pulley and then make a sleeve to ensure a press fit onto the crankshaft.

i need to drop off the timing cover gasket so that he can put the front together once the gear & pulley are ready. this way he can validate clearances.

should be in the next few weeks depending on time it takes to machine the gear & pulley.

dropped off the timing cover gasket and hardware this morning with the builder.

got a call from the rebuilder last night as he had a few questions, so went by this morning before work to take a look and see what we could do.

he pressed on the NOS Cam Gear i had, and the holes in the cam gear to tighten the bolts on the camshaft thrust plate was wider offset, not enough room to get the required bolts in there and NO clearance to tighten them up if you finagled them in. so opted to enlarge the holes to allow access. bolts go in, can tighten them down, but can not turn the cam, because the bolt heads rub and hit the backside of the cam gear. seems that this cam gear has a larger shoulder/raise area on the rear then the original. the shoulder/raised area is nearly as wide as the gear. so machining the head down would barely leave any head on the bolt, machining back the shoulder/raise area on the back of the gear to clear the bolt head i feel would compromise the gear as a whole.

options are to find another fiber gear with a smaller shoulder/raised area, or try the aluminum aftermarket one which has a smaller shoulder/raised area.

Is it NOS or NORS? Is there a difference between front side and back on the gear? While a different gear may work I think it would be good to know WHY the NOS gear did not fit.

Sorry has to be a NORS, as it was not Chevrolet, box says 'Colorado Gear MFG Co Denver'
was one i ordered while back from TFS, i ordered the NORS RW-593

supposed to go back over in the morning to look at solutions

If you got it from TFS I would suggest you give Steve a call . He probably has sold more of that part and may have a solution. Also it may prevent others from running into the same situation.

i contacted Steve just waiting for a return

Hello BearsFan315,
If you compare the picture of your fiber camshaft gear against the picture of TFS fiber camshaft gear, in my observation, they do not look the same. I may be wrong. Your picture of RW593 does not show the large access holes, for the thrust plate bolts. TFS RW593 picture does show large holes. Do you have the original camshaft gear to compare to your fiber camshaft gear? If you were to copy TFS's picture of RW593 and a picture of your RW593 side by side, I'd like to see that.

I talked with Steve and he agrees that the gears may not be for the same application. the ones for the 29 should have the recess in the backside for the bolt clearance along with the larger bolt hole areas.

discussed a few options, as he has 29-32 version that he checked and it is different then the one that i have. going to send this one back to TFS per his request. Great customer service as always. so will be going by engine shop this afternoon or monday to pick it up and get it back to him.

Engine is about 95% complete, well short block anyways. i will be doing the top half myself, as the head was already rebuilt, machined flat, and ready to go. so hopefully in the next week it will be done. i am hoping for end of January to have it back to my house so i can do the top half.

will try to get some pictures when i go by the shop :)

for those interested, here are some pictures of the NORS vs the Original out of the 1929 Engine

Dimensions for you dimensionally inclined:

DIM................ORI.........NORS
-----------------------------------
OD.................5.94........5.94
Bore...............0.87........0.87
THICK..............0.88........0.86
BOLT HOLES.........1.11........0.65
DIST BC............3.12........2.79
FRNT DEPTH.........0.12TPR.....0.20
FRNT SHOULDER......ANGLE.......2.00
REAR DEPTH.........0.40........0.28
REAR SHOULDER......2.00........2.31
Shoulders are top flat only, does not include the radii

top of gear views

back of gear views

stacked for comparison