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


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Grease Monkey
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Grease Monkey
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i have spent many hours on trying to get this fresh engine running. using the procedures in the reprint service book. The best it has ran so far is about three turns.

Pistons were rusted in the block because the head gasket failed. The car was in a museum from about the late 70's. So I think that was the last time it was even running.

I had a very good machine shop do everything. all ignition parts are new. the only problem I can think is a possibility is the Advance-Retard moves a little around the center. I will have a rebuilt distributer next week, From Gary Wallace, hopefully that's the problem. I have purchased all the other ignition items from him.

I wanted to start a thread to get some more input, the only part that moves is the ring that holds the points, loosely around the center, the rest seems to be in good condition.

Filling Station - Chevrolet & GMC Reproduction Parts


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Shade Tree Mechanic
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Shade Tree Mechanic
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I see no one has replied, I don’t know if you have the same distributor as a 1917. I used a scope to actually see the no.1 piston at the top, also I put a wire ,held on with a screw to make a pointer and placed a mark on the flywheel. My other problem was that the distributor was different than the one in the manual. My spark control rod was on the other side of the one in the book so when I retarded the spark on the steering wheel it was actually advancing the spark on the distributor. When I did get it to run it overheated and then had to adjust the distributor again.


1917 490, 1928 Depot Hack, 1925 Buick roadster, 1978 Vette pace car, 2002 Z06
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ChatMaster - 15,000
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If you verify that No. 1 piston is at the top and on the compression stroke, the distributor points are set to just beginning to open, there is spark to the plugs and fuel/air mixture to the cylinders; the engine should fire and run. It takes ~ 15:1 air to gasoline and a hot spark to ignite the compressed mixture. A higher fuel ratio or a shot of starting fluid or carburetor cleaner will burn easier so a short shot of either can be of help in getting an engine started.

Running 3 revolutions suggests a fuel problem to me.


How Sweet the roar of a Chevy four!
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Grease Monkey
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After several setbacks, as far as getting back to the project. I’m back to it. A new re built distributor was fitted, then I tried to pull it down the road, it backfired badly. I made several attempts to adjust the distributor again, I realized I had no oil pressure, so I had to get a new oil pump. Once I had the pump I took off the timing gear cover. Found the timing marks to make no sense to me. I took off the crank gear and reset everything. I went through the timing procedures several times, using operation of the valves not the marks. I believe it to be extremely close but it still doesn’t really want to run. With the snow and ice outside I can’t pull it to see if I’m right. I did a compression test, about 30 psi across all cylinders.
The marks on the gears do lineup, but it’s at about midway through the intake stroke. The piston and valve relation are in the correct positions at that point though. Either way, the marks, keyways, holes in the cam gear are set up in no way like the book shows. I’ve never seen it run. You can’t buy a new cam, so I don’t know if he’s got the wrong cam somehow?
I can’t find any specifications on gap for the points?

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ChatMaster - 15,000
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The description about the alignment of the cam and crankshaft gears is concerning particularly when they "are set up in no way like the book shows." I am not aware of any cam/crank timing gear issues in 490s. There are some incorrectly marked later 4 cylinder gears. In fact the '28 Service News warns of mis-marked gears so cautions to count the teeth from the keys to determine the proper timing.

My recommendation is to count the timing gear teeth clock and counter clockwise from the key and see if that matches the mark location in the illustration in the repair manual. Also measure the position of piston and valves as described in the repair manual. If the cam and crank are not properly timed the engine will not run properly.


How Sweet the roar of a Chevy four!
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Nick, I think your camshaft gear is a replacement, which may not have the key way cut in the correct position, regarding the pictures in the repair manual. I would suggest removing your crank gear with a puller, turning your crankshaft so that the key way on the crank is in the position shown in the repair manual( approx 11 o’clock), turn your cam shaft to the position shown in the manual, so the key way is in the same position(not quite 9 o clock ) . The refit your crank shaft gear,
The cam and crank key ways must be in the positions shown in the manual. That should give you top dead centre, and the cam lobes pointing downwards , away from the cam followers, with the valves closed.
The original cam gears in the pictures are marked with the original part number 750, and is shown in both my 1922, and 1924 parts books with the key way at approx 9 o’clock position.

Last edited by jack39rdstr; 01/09/23 09:28 PM.

JACK
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I was told once that the early 6 cylinder cam gear was the same as the 4 cylinder cam gear, EXCEPT FOR THE TIMING MARK. I don't know if this is true, but given the issues you are having, perhaps someone substituted a 6 cylinder gear and timed it with the wrong mark. Just food for thought.

Mike


ml.russell1936@gmail.com

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The late four cylinder and early 6 cylinders had the same diameter and number of teeth. There is a difference in thickness between the three similar gears. A VCCA member Verlyn Husmann has reproduced metal replacement gears in the three thicknesses.


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