Quote:
Originally Posted by HO455
No need to apologize for posting lots of information on a problem. You have done a great job troubleshooting this problem.
A couple of thoughts. I am guessing that the motor has a fair amount of miles on it from your report on how dirty the water was. Tired engines can run hot.
I had overheating problems on an old 236 Chevrolet 6 that was cured by removing the water pump and physically rodding the rusty clay that had collected in the bottom third of the water passages around the cylinders. You may have a similar situation. However it's nowhere as easy to access the passages on a BBC as it is on a 235.
And as FlyNavy says ignition timing can be a big factor. Do you have access to a distributor machine?
Have you tried disconnecting and plugging the vacuum advance hose to the distributor to see if that helps?
Pusher fans are really more of an air flow reducer and should not be used unless there is on option for a puller fan.
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Thanks HO455...I try to be informative while presenting my situation as I find it limits how many times I need to say "yeah, I tried that"...but I still worry that I might "lose my audience" if I am too long-winded. Too many times on the witness stand, I guess?
Your first thought lines up with what I was wondering about...restricted water passages...but my 1989 454 is old and new at the same time as when we had the heads off and oil pan removed (at my friends shop), the motor looked as if it hadn't had any miles put on it since new. We did not specifically look for water passage restriction at that time, but nothing jumped out at us either. I also realize that even without putting miles on a motor, the water passages are susceptible to the corrosive elements from day one...and may actually be more susceptible due to non-use (water/air just sitting in the passages) as my Suburban sat non-op for 4 years before I purchased it. Like you said, not real easy to get to the passages on a BBC...so that may have to wait until the motor comes out when the body and paint work gets done?
I haven't received the "cooling info" from Greg (FLYNAVY) yet, but I am curious about my timing...and will try plugging the vacuum advance to see...although my mechanic buddy usually sets things up "by the book" and there is no indication of pre-ignition/detonation as far as I can tell? I'm not sure if he has a distributor machine or not...but I'll ask. You didn't mention the carburetor...but I'm pretty sure it is a tad on the rich side, which should be better for cooling than being on the lean side...but I guess knowing that for positive would be a good thing as well.
I'm not quite sure what you mean about the pusher/puller fan air flow reducer situation...but I wouldn't give up my mechanical puller fan...I would just add an electric pusher fan in front of the radiator. The fan blade edge is just peeking out the back side of the shroud...but I could only get about another inch exposed IF I bought one of Hayden "short shaft" fan clutches...which I might try?
There is also the thought that 190 is nothing to complain about, and I am thrilled that I attained that "level of coolness"...so maybe I'm being a little greedy by wanting to be cooler? In any case...I do appreciate your input...as well as everyone else's!
Woody