A Nightmare on Cam Street

Home Model Engine Machinist Forum

Help Support Home Model Engine Machinist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Joined
Mar 4, 2023
Messages
13
Reaction score
1
Location
United States
Well okay, maybe not a nightmare, however my challenge does have to do with setting up the cam timing on a the cylinder ford engine I wrote about last month. I acquired the little engine from the engine of the man who built it and it would not run. After help from Roy Sholl and George Britnell, I installed a new ignition and hall sensor. Then the engine started and ran well. I turned it off after a few minutes and patted myself on the back. The next morning I went to start it and it started right up. After a few moments the engine stopped and would not restart.

I checked the ignition and fuel and everything was fine. Then I rotated the flywheel by hand and saw that the rocker arms were not moving. That told me that the camshaft was not rotating. I removed the timing gear cover and saw that the crankshaft gear was loose on the crankshaft. I decided to disassemble the engine to see if the valves had bent or any other damage had occurred. Fortunately there was no damage. The engine was extremely dirty inside, several rings were stuck and the valves leaked.

I cleaned up the engine, freed and lubricated the rings, lapped the valves, and started to reassemble it. There were no timing marks on the crankshaft or cam gears. So I am trying to determine if to start with, the cam should be with the lobes at the baseline when the number 1 piston is at TDC as a static or starting point. I will be grateful for any input or suggestions I receive.
 
Set the piston at top dead center. Then turn the cam until both valves are open equally. Depending on the engine they may both be barely open or your exhaust valve may have just closed and the intake is just beginning to open. find that center point. Once the cam is locked down rotate the crankshaft 360 degrees to top dead center or just before TDC. This is where the ignition should fire.
 
Set the piston at top dead center. Then turn the cam until both valves are open equally. Depending on the engine they may both be barely open or your exhaust valve may have just closed and the intake is just beginning to open. find that center point. Once the cam is locked down rotate the crankshaft 360 degrees to top dead center or just before TDC. This is where the ignition should fire.
Hello Steve, and thank you for your reply and guidance. The engine is one based on George Brinell's plans for the Ford inline 6 cylinder. The builder did not put a key in the crankshaft gear or camshaft gear, and made not reference marks. Georges plans do show a diagram for the crankshaft timing. I will do as you have suggested on the number one cylinder without push rods in the other five and try to determine the center point, lock down the cam gear and then rotate the engine by hand 360. This is what I did to set the ignition timing and the engine started and ran. That was before the crankshaft gear loosened and messed things up. I am just wanting to make certain the cam is as close as possible to correct timing before I finish reassembling the engine the rest of the way. Best regards Shelby
 

Attachments

  • 6_CYL_OHV_CAMSHAFT[1].pdf
    65.8 KB
just building that same cam now using a cam grinder i built just before having a stroke will let you know how i get on things are a bit slower now tho
 

Attachments

  • camgrinder.jpg
    camgrinder.jpg
    3.5 MB

Latest posts

Back
Top