Timing and Cooling Issues

[trukman1]

I think I'd try a 1/8th inch hole first. LOL!

 

[trukman1]

My '67 had an over heating problem. I chased coolant parts till I was about to pull my hair out. Then had the idea of going old school. I advanced the timing till it stumbled, backed off till it ran smooth and locked'er down. Never had any more problems. Can't remember what the timing ended up at though. I've gotten a lot of flack for doing that but when I first worked at a garage the guy who owned it told me he always set the timing that way since the recommended timing in the manuals were for new vehicles and engine wear over the years makes that irrelevant. I know you said your engine was new but thought I'd throw this out there. YMMV.

 

[Snoots]

The stat NEEDS an air bleed hole drilled into it along side the valve area, the stat is closing then no HOT coolant can flow across the sensor bulb so it goes into cooking mode, when enough hot coolant gets to the bulb it opens up again!
Thank you MADE IN CHINA! This is an old problem from way back with cheap stats
Just drill an eight inch hole and the temp WILL Stabalize

OLNICK

I use an .060 drill bit. I'm guessin' he meant 'eighth'.

 

[QBuff02]

My '67 had an over heating problem. I chased coolant parts till I was about to pull my hair out. Then had the idea of going old school. I advanced the timing till it stumbled, backed off till it ran smooth and locked'er down. Never had any more problems. Can't remember what the timing ended up at though. I've gotten a lot of flack for doing that but when I first worked at a garage the guy who owned it told me he always set the timing that way since the recommended timing in the manuals were for new vehicles and engine wear over the years makes that irrelevant. I know you said your engine was new but thought I'd throw this out there. YMMV.

Often times I've found that the best way to set timing is by ear or "feel". You can dial it in with a light but sometimes it just takes that little nudge one way or the other of the distributor to get it just right. When I bought my truck a few years back there was NO timing pointer on the engine, so I literally HAD to set it by feel. Took me about 15 minutes to tweak it by ear and when I got done with the timing and carb adjustments it would start right up cold, hot, summer or winter it didn't matter. Ran it that way for almost two years before I pulled the engine and rebuilt it. It does have a timing pointer on it now and when I first set the new engine up I used the pointer and a timing light but I fine tuned it by ear and feel after that. i'm about 6 degrees beyond my initial setting of 10 degrees btdc with the light and its been living by "feel" at 16 btdc with no issues since. Doesn't matter the temp it fires right up every time and the performance is spot on. Sometimes you just gotta go with your gut.

 

[Dirtboy]

Wasn't there 2 different timing tabs [on the timing chain cover] depending on the year? I think there's only 1 harmonic balancer, but having the right timing tab is critical. The fact it's running hot and you're after-firing, [backfire is actually through the carb], indicates the timing is way late. Also when it gets real hot there's the possibility of detonation or ping.

If you have the valve cover off for #1, rotate the engine and intake valve should've just closed as you're coming up on the timing mark. Stop on the mark and pull the distributor cap to verify where the rotor is pointing.

If the cam timing is off that could also be an issue..

Update: was on target. I started advancing the timing until the stumble went away and using my timing light figured out I was at about 50*. I thought WTF??! Then started checking and the 12 o'clock timing tab is 40* advanced from the 2 o'clock tab.... long story short, the remanufacturing company put an early model timing tab on a late model block/harmonic balancer. Timing issue is gone but it still runs about 210. (Which is in the middle and where the truck ran before.)

 

[Tonyg123]

Check and recalibate your timing tab to balancer. Youll be surprised how may tabs and balancer dont line up on tdc

 

[SirRobyn0]

Yeah, from what I’ve read a bad t-stat is quite common.

Depends on the brand Stat the most common one at parts stores is junk. Mr. Gasket is glorified junk. A/C Delco T-stats are great and 99% of parts stores can order them.

Jesus christ, an 8" hole? Lol

Ok, I'm sitting in the living room "watching TV" with my wife, when I read that, then I had to explain to her what I burst out laughing. Thanks a lot lol.