[orion1]

Still having our overtemp problems, I thought we should nail the timing down to make sure that isnt the problem? Runs fine, just hot! Rebuilt 289 with about 400 miles on it, Edelbrock rpm cam, intake and 4 barrel carb. Could someone jot down the "timing by ear" procedure again? I think our harmonic balancer has slipped. We have Tri-y's and dual flowmaster 3 chambers so it may be a bit tricky to hear it ping but I would like to try this method. One other item, if timing is the cause of the overtemp, is it too far advanced or retarded? TIA

 

[Guest]

Timing by ear is advancing the timing until the engine starts to pink (knock) and then retard a little.
The best way to do this is to advance the timing little by little until the engine starts to pink when accelerating uphill from 30 to 50 mph in top gear. When the engine starts to pink, retard ignition until there is the slightest trace of pinking under this kind of load. The engine has to be on normal operating temperature to achieve the best results and you should use the same grade of fuel as you always do.

Ignition that has been advanced too much could cause an overheating engine. I don't think that timing that has been retarded too much would cause overheating. It does create a perceptible power loss, though.

 

[camachinist]

Likely the usual heat produced by a fresh engine....

What's the overbore?

Does the overflow just fill up or does it puke out?

Even with Flowmasters, you'll hear detonation and feel it too...trust me....not pleasant..

Water under the bridge but determining and marking TDC on the damper should be part of every engine building procedure.....it's not too late to do it on yours, just a little more work...

Then time it with a timing light....most professionals and racers do it that way...

Usually, excessive advance will scare you off before things get hot enough to melt pistons and peg temp guages...FWIW, my D-coder actually ran cooler as I advanced the timing if I didn't goose it enough to start detonating...
Retarded timing definitely contributes to overheating...that's the battle I fight with the D-coder....retard it enough so it doesn't ping under WOT and it runs warmer...
Oh, well *G*

Pat
http://albums.photopoint.com/j/View?u=1570936&a=11937754&p=42910787.jpg

 

[orion1]

The overbore is .030 and it is pretty fresh, only about 400 miles. Doofus award here I think, I was going to take out the thermostat completly this afternoon and see how it ran. Looked into the t-stat cover by-pass outlet and found a piece of crap that was blocking the flow probably 90%!! Must have been some crap from the old heater core or something in the cooling system that decided to jam in there. Put my 160 t-stat back in and took it for a couple of "hot runs" and the gauge never went past half way! Yes, I'm happy as a pig in sh--!! Thanks all for your input!!

 

[camachinist]

HAHA!! Glad it was something simple....good for you to find out so quick...

Keep us posted on further developments...the good kind! *G*

Pat
http://albums.photopoint.com/j/View?u=1570936&a=11937754&p=42910787.jpg