Reproduction Parts for 1916-1964 Chevrolet Passenger Cars & 1918-1987 Chevrolet & GMC Trucks



Visit the new site at vcca.org

Previous Thread
Next Thread
Print Thread
Rate Thread
Joined: Aug 2004
Posts: 3,469
Likes: 48
35Mike Offline OP
ChatMaster - 3,000
OP Offline
ChatMaster - 3,000
Joined: Aug 2004
Posts: 3,469
Likes: 48
On Monday, the 4th, I drove from Mid Missouri out to the Knoxville TN, area to pick up a 1936 engine from Chat member, 35Pete. I returned home the next day but did not have time to unload the engine and start the shakedown process.
A couple of days ago, I got it unloaded and perched on some blocks in the shop floor. The engine had been in barn storage for 7 years(ish) and suffered some during that time. Yesterday and today I unstuck some valves, removed a broken stud from the head and another one from the exhaust manifold.
I removed the water pump and blew some rusty flakes and dust from the water jacket, rebuilt the fuel pump, adjusted the valves , replace the distributor, and started it up. It runs great, idles perfectly with its original carburetor and has good oil pressure. I'm a happy guy and the engine will be in my recently acquired 1935 Standard Coach ( 2 door sedan), sometime in the next few days. 35 Pete also sold me a 1935 cylinder block and other parts that might restore the original engine in the car.

Mike


ml.russell1936@gmail.com

Many miles of happy motoring
Joined: Nov 2015
Posts: 23
Grease Monkey
Offline
Grease Monkey
Joined: Nov 2015
Posts: 23
Mike, Your post is very timely.
I had my '36 engine rebuilt professionally a few years back, and for the past several months it has started up and run perfectly. The car is now restored, and I took it out for a spin yesterday. The engine has probably 50 hours of running time.
As I was heading home I heard two LOUD POPS, (back fires) at about 30 miles per hour. Then the engine went dead. I pulled up, and when I tried restarting it I found that the rocker arms were not moving when I engaged the starter. My first impression was destroyed Cam gear. I took the front end off the car last night, removed the timing cover and found the teeth on the fiber cam gear were destroyed only where they engaged the crank gear. There appeared to be plenty of oil lubricating the timing gears. I also found that my distributor body had twisted about 120 degrees clockwise, and was stuck in the block. After moving the cam gear back and forth, I was able to remove the distributor, and found three teeth damaged. Also the rotor would not rotate in the distributor body. The cam gear will only rotate by hand movement using leveraged force..
I turned the oil pump with a screw driver, and it turns freely.
My question is what caused this failure?
My thoughts:
If the fiber gear failed, much more of it would be damaged.
If the oil pump froze, it would not turn.
That leaves the distributor. If the shaft seized, it would cause the distributor to immediately rotate, causing the backfires and engine failure. I am surprised that the seized shaft could cause the camshaft stop rotating.
I haven't removed the camshaft as I finished at 1:30 this morning.
Do you have any thoughts? My biggest concern is damage to the distributor gears on the camshaft.
All contributions are welcome.
sfcavco

Joined: Sep 2007
Posts: 654
Likes: 3
Oil Can Mechanic
Offline
Oil Can Mechanic
Joined: Sep 2007
Posts: 654
Likes: 3
Frozen distributor shaft would be my guess.


J Franklin
Joined: May 2002
Posts: 6,149
Likes: 42
ChatMaster - 6,000
Offline
ChatMaster - 6,000
Joined: May 2002
Posts: 6,149
Likes: 42
By your description the distributor shaft seizing would overload all components down the line and the weakest part (the fibre gear teeth) gave out. I think the valves and pistons have clearance so I think the only other nasty you may find is the distributor drive on the cam is damaged and doubt the head will need to come off.
Tony


1938 1/2 ton Hope to drive it before I retire
Joined: Nov 2015
Posts: 23
Grease Monkey
Offline
Grease Monkey
Joined: Nov 2015
Posts: 23
Thanks for your input. Fortunately I have two more distributors that work.
I took the engine out yesterday, as I have been experience oil leaks in addition the the new problem. My rebuilder made is own main bearing shims that did not surround the cap bolts, causing oil to leak around the bolt head.
Is it necessary to loosen the rocker arm, remove the side cover, the valve tappets and push rods before removing the camshaft?
steve

Joined: Aug 2004
Posts: 3,469
Likes: 48
35Mike Offline OP
ChatMaster - 3,000
OP Offline
ChatMaster - 3,000
Joined: Aug 2004
Posts: 3,469
Likes: 48
A sad story, indeed. I think you are correct that the problem started with a seized distributor. I too would be worried about the worm gear on the camshaft. Yes, you will need to remove the valve rocker assemblies and push rods to let the lifters get away from the camshaft. I just removed one yesterday and it took a little wiggling to get it done. I had the engine laying on its drivers side and pulled the lifters out of the bores enough to get clearance.
You did not say if your fibre timing gear was replaced with your engine rebuild. It is not unusual to have a failure of this type gear after prolonged periods without movement (I'm talking years). I had this happen with a Model A Ford truck.
Keep us in the loop. Good luck.
I have seen the shim packs on eBay, but not lately.

Mike


ml.russell1936@gmail.com

Many miles of happy motoring
Joined: Nov 2015
Posts: 23
Grease Monkey
Offline
Grease Monkey
Joined: Nov 2015
Posts: 23
Cam shaft out. No apparent damage to worm gear. Will take it to machine shop tomorrow to R and R gear.
It appears as though the distributor gear may be softer than cam gear. which is good.
Thanks for your support.
Steve

Joined: Aug 2004
Posts: 3,469
Likes: 48
35Mike Offline OP
ChatMaster - 3,000
OP Offline
ChatMaster - 3,000
Joined: Aug 2004
Posts: 3,469
Likes: 48
Be sure to check the tightness of the gear on any distributor you are installing. I often find loose gears on used distributors.

Mike


ml.russell1936@gmail.com

Many miles of happy motoring
Joined: Nov 2001
Posts: 19,758
Likes: 63
ChatMaster - 15,000
Offline
ChatMaster - 15,000
Joined: Nov 2001
Posts: 19,758
Likes: 63
Many of the distributor gears have a shearpin that is soft metal. It is designed to shear if the distributor shaft binds so the cam shaft gear does not get damaged. Same with the fiber cam gear which strips protects the other parts of the system if the crank or cam locks.


How Sweet the roar of a Chevy four!
Joined: Nov 2015
Posts: 23
Grease Monkey
Offline
Grease Monkey
Joined: Nov 2015
Posts: 23
Thanks guys. I see the light at the end of the tunnel!! I also figured out what the screw between the two gears is for. After finding the hole, I realized it's the oil nozzle for directional lubrication. DA!
Steve

Joined: May 2002
Posts: 6,149
Likes: 42
ChatMaster - 6,000
Offline
ChatMaster - 6,000
Joined: May 2002
Posts: 6,149
Likes: 42
While you have that part of the engine apart it would be advisable to make sure that nozzle and the oil gallery behind it are clean, they are known the block up and not lubricate the timing gears.
Tony


1938 1/2 ton Hope to drive it before I retire

Link Copied to Clipboard
 

Notice: Any comments posted herein do not necessarily reflect the official position of the VCCA.

Powered by UBB.threads™ PHP Forum Software 7.7.5