I have a 1926 Chevy with a 4 cylinder 171, I’m trying to figure out the correct gear line up for the cam and crank gear.. my book says the dots should line up but my number 1 piston is down I have the 13/16 fiber cam and steel crank gear, any help would be very appreciated and I posted pics below of what I have. Thinking its actually the later 26. Thanks!
I am not sure if makes any difference but; the fiber gear is for 1927. You should be using 5/8" steel gears for 1926. Make sure your #1 intake valve is just starting to open (piston at top dead center). Remove the distributor cap and check to see if the rotor is pointing to the #1 plug wire on the cap. Remove the crank gear and turn the crank until the #1 piston is at top dead center. Re-install the crank gear.
@stephen-s-gow both gears measure 13/16 well that’s what was in the motor when i tore into it and my stupidity I didn’t take pics of the dots and where they were, my manual says line the dots up but I don’t think that’s right so what is the timing marks supposed to be because the cam is correct 15th tooth counterclockwise over has a dot but I’m thinking.. correct me if I’m wrong that the crankshaft gear the dot should be opposite of the keyway not like it is now correct? Cause See right now with the dots lined up my number one piston is down, and I don’t have the head back on it yet was just seeing if someone knew exactly where the dots should be before I go any further and I can’t find any info on that. Thanks!
The 13/16" thick gears are 1927-28. The prior years gears are 5/8" thick. Since both gears are the same thickness they should be okay as long as the keyway is in the correct position for the camshaft and they don't rub on the cover. I would check with a camshaft regrinder to be sure the keyways are same on the earlier and later shafts. Once you determine that then the correct alignment can be determined. There are diagrams in the 20s Repair Manuals that give the cam timing measurements based on the piston position. Referring to those Manuals will permit verification of the cam to crank timing. I recently helped VCCA members with '22 and '23 engines verify their their cam timing using those measurements.
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@cullen1x From what you are saying it sounds like you are using the wrong mark on the cam gear. Fifteen teeth is 90 degrees of cam rotation which would put your piston at top dead center. Try doing that. Both valves on cylinder #1 should be closed at this setting; if not then you have wrong parts in your engine. The crankshaft from 1925 - 1928 are the same. P/N 344648.
Ok, I have double checked all the numbers and everything is a 1927, so does anyone know how to set the gears where they need to be or have a picture something like that? Thanks!
Hope this may help you
@cullen1x I have no clue if it's part of the issue but your punch marks don't line up. I believe one should be on a tooth and one in the valley as shown in the pics posted by Rick. It may not matter. Someone with more engine building experience than me will have to say. Rotate the engine until #1 piston is at TDC then see where the marks are.
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Assume for now that the mark on the camshaft gear is incorrectly placed.
So, according to the pages posted by Rick above, (On the camshaft gear)"..count back (counter-clockwise) fifteen teeth, starting the tooth which is in line with the keyway (in the camshaft)."
Now, mark that fifteenth tooth (maybe scratch a line into the fibre to denote that tooth).
This is your new cam gear marking that should point to the tooth valley that is marked on the crankshaft gear.
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