VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Timing Gear Replacement

I was cruising today at 60 mph, Temp at 180, oil pressure at 15 and then, all shut down. After getting my baby home (1940 Chevrolet - 216 engine) I removed the distributor cap to see if the rotor was turning while turning engine over, not turning. I surmise I stripped the timing gear.
Is this something I can replace or is it best to take to an engine shop?, I consider myself a fair mechanic, I have the shop manual and a Motors manual and a fair amount of time. If I do it, I will have more questions...
Thanks for any advise.
Whmarquis@aol.com

Go for it, I think on your car it is easier if you pull the front clip, both fenders and all the sheet metal from the cowl forward, along with the radiator etc. You will need to have some help or a good engine crane to move the clip.

MM
Would you mind telling those directions again for us non mechanics. Sounds like you want to remove the whole front end. What is the "front clip"?? Wouldn't it just be easier to pull the motor?

On a 1940 the radiator will need to be removed...then the balancer.Oil pan removal is necessary as the lower timing cover mounting bolts come in from inside the pan (back of front main bearing cap).Correct proceedure is to remove the camshaft and have a gear pressed on.Easy way is to leave the camshaft in the engine,split metal collar thats moulded inside the gear with a chisel.To install new gear drill 3/8" hole in center of the front of camshaft-tap threads and draw new gear on with a bolt.

Possible problems-valves may be bent due to piston to valve interference, also some push rods may have bent.To check for bent valves a cylinder leakage test could be made with the rocker arms removed or wait and do a compression test after gear is installed.The crankshaft steel gear should also be replaced...The cause of the timing gear failure is usually the oil passage behind the engine front mounting plate being plugged up and the gear running dry.The plate should be removed and the passage in the plate cleaned.

You probably can do a better job than an "engine shop" by following the shop manual and using this site.

The timing gear is usually the first thing to "go" on an old Chevrolet engine so after the new gear is installed you will be over a major failure.Will also give you a good oppertunity to clean the oil pan and pump screen.

Chevgene, Thanks - Your rely has given me the courage to give it a go, I just removed the hood and hood side panels, was going to pull the whole front end but will remove radiator instead, I'll wait on the valve check as the head was just rebuilt with new valves,etc was just completed,less than a thousand miles ago. Chev's of the 40's has a matched set of gears with the timing gear made of aluminum, good /no ? Thanks for your help...
whmarquis (Wes)

The aluminum timing gear is very durable.It was used in large trucks for greater durability.Was not used in small trucks and cars as they tend to "sing" a bit at lower speeds-worse when cold but will be no big problem.A new fiber gear will last a life time if its getting oil

I have a '40 that I have driven for about 400,000 miles and have changed the timing gear 'in the car' four times. You did not need to pull the hood or side panels except for accessibility. In addition to what Chev Nut sez I always pull the right side panel 'cause it helps to get at the lifters and engine side panel. I usually pull the grill as I could never quite get the cam far enough forward to clear the engine. If you were going 60 mph you probably have some bent push rods. I just find a nice flat surface and straighten the them with a hammer the best I can and they work just fine. I did this on a curb in a rest stop just outside Yuma, AZ years ago and ran the push rods until the next overhaul with no bad effects.

Thanks Mike, This is encouraging. I'm going to do myself.
Wes

I beleive I'm ready to pull the Balance Pully, is there a special puller for this ? It doesn't look like it's been off in a long time ...... I think you can rent a puller at some auto parts stores. Any special precautions ?

Thanks,
Wes

I just had my balancer off and on again, and used a puller to get it off. It is interferance fitted with a woodruff key to align it. Use an Impact driver (Pneumatic) to remove,and tapping a little with a hammer while in between bursts is a good idea. Use no heat as I believe there are rubber discs that are riveted in between the metal plates. When you put back on, drve from the center, hand start cog area, only - dont drive from pulley outer part. I seem to remember in service manual ther was a way to drive this back on with a special puller/driver, but I could not figure it out ,so I tapped mine on percussively. Chevy40 P.S. Buy a puller from J C Whitney or such, and you will always have it in the future.

I just checked my 216 and the bolts to mount the puller to are 3/8" 16 TPI Length will vary with puller design. Do not screw too far in as you can go too far and damage timing gear cover. I only came close!! I think Mr Mack has a good point about removing front clip on 1940. Only took me about 3 hours and a friend and whole front end with radiator attached came off. Shop manual has more details. Got to love the wide open access !!

Just a quick update to my Timing gear replacemnet, I'm back on the road, runs great, I can hear the aluminum gear, thanks to Mr. Mack, did it all myself except for the valve work and pressing off and on the timing gear. Thanks again to all who responded to my questions. It was quite an experience (and Fun). Hoping I can help someone else some time.

WHMarquis