Timing on '55 850

[JohnWayne]

Guys... I set my timing tonight & she's runnin better. I just have one question on the degree reading on the flywheel. I had the smoothest idle @ about 650 - 750 rpm @ 15 degrees. So thats what I left it @. Is this ok? My manual says to set it @ 5 degrees while running @ 475 rpm. But I just couldn't get it to idle that low (Still need to go through the carb).

 

[Bob]

Late timing will cause the engine to run HOT... even the exhaust manifold will be noticeably hotter than normal.

Early timing will cause "spark knock" when you lug it. (BAD for the pistons!)

If it runs well, and you're not seeing either of the above scenarios, you've got the timing darned close.

However, it certainly wouldn't hurt to get the light on it again and see where it's at when you it it to idle down a bit more.

Did you watch the timing mark (with the timing light on it) to verify the mech advance is bringing up the timing as the engine speed is increased?

 

[JohnWayne]

Yep... When I started out with the light, I just kept seeing the word 'out' on the fly wheel. But then after I got it to idle down I started to see 25... then 20... then down to 15 @ about 650 - 750 rpm. I had a hard time keeping the rpms steady that low. but I just wasn't sure what degree I should be seein @ that rpm. I'll get'er dialed in with a new coil and plug wires, adjust the carb as per the 'shop manual' and then time it again & go from there.

 

[john_Bud]

What's the compression on each cylinder? Poor cylinder seal, low compression, may be the cause of the bad idle. It can also be from a vacuum leak. Idle it down and then spray WD-40 in a mist around the carb and manifold. The other could be weak spark.

jb

 

[JohnWayne]

I checked compression last year when I bought it. I had all three cyl. within 4 psi. I can"t remember the exact reading... someting in the 120s or 130s.
I replaced the coil today. Bypassed the resistor that was before the coil. Put new (metallic core)plug wires on & got it to idle pretty good while I timed it. 475rpm @ about 5 degrees seemed to run better. Then I dialed my carb in as per my shop manual. Purrin pretty good. Now I just gotta fix my oil leaks & I"m field bound!