Return From Vettefest - Fingers Crossed

[Clem Z.]

Re: Return From Vettefest - Fingers Crossed

most of the time there is a crack in the combustion chamber you will find rust on the spark plug shell and if the crack is bad enough water droplets will short out the spark plug

[Ronald L.]

Re: Return From Vettefest - Fingers Crossed

Stu,
yes. Working one day, and then it gets stuck in then open or closed position.

[Paul J.]

Re: Return From Vettefest - Fingers Crossed

Stu;

It failed that day, for whatever reason. It probably closed when you turned the car off at the show and did'nt reopen when you were leaving.

Paul

[Stuart F.]

Re: Return From Vettefest - Fingers Crossed

The new Robertshaw looks almost identical to the Chinese rip off, except the thermal element is smaller on the Robertshaw (bulb on the bottom side). Just for my peace of mind, I tested the new Robertshaw in the same pan same way and it opened fine.

Can anyone enlighten me about the bypass hose on my L-76? Could it have had any effect on what took place - good or bad?

Well, going out now to mix up some more 50/50 as I didn't quite have enough to fill it again. I will run it for a static test tonight, then if that goes ok, out on the road tomorrow. I was hesitant to go to coolant right away, but I did pull the plugs and all looked normal which gave me some confidence.

Stu Fox

[James B.]

Re: Return From Vettefest - Fingers Crossed

Stu-
I hope everything is okay. I have been working with gearing formulas. With 3.36 rear I assume you have a wide ratio trans so 3rd gear is probably 1.47 and second gear is 1.88. I used 770 revs/mile which would be 205X75s.

So if that is all close, down shifting to third at 100 MPH would be 6,972 revs and shifting down to second at 80 would be 6,485 revs.

I've heard small blocks can handle 7,000 ()- probably best not to downshift at 110 MPH. JimB

[Duke W.]

Re: Return From Vettefest - Fingers Crossed

All L-76 four-speeds are close ratio regardless of axle ratio. Back when I hot lapped Kent with my 3.08 axle L-76 SWC I shifted into fourth at about 130 MPH.

He didn't overrev it.

It's real easy to set up a gear chart with Excel and do "what ifs" with gearing and tire revs/mile. No calculator necessary.

Duke

[Clem Z.]

Re: Return From Vettefest - Fingers Crossed

i let someone drive my new 64 365 HP with 4:11 rear gear and at the top RPM end of 3rd gear he shifted not into 4th but back into 2nd and nothing was hurt.

[Stuart F.]

Re: Return From Vettefest - Fingers Crossed

Thanks fellows for the additional insight and suggestions.

I started it last night and warmed it up. Seems to run fine. I even did a few higher rpm holds and it was as smooth as could be.

I'm still trying to figure what affect that bypass hose has in this. It still seems that the engine temp holds right below the thermostat spec of 180 degrees, and I know this new thermostat opens at or close to 180 as I pan tested it. This is the same condition I noticed with the other 180 (that failed) and, for that matter, the same way it acted with the former 160.

Has anyone else with a L-76 or perhaps L-84 noticed such a condition? My thought is that perhaps being as how the temperture sensor is in the water manifold on these older engines with the bypass we're not seeing the true engine temperature as the coolant is moving quickly through there via the bypass and the thermostat. I got to do a little reading on this to figure it out I guess.

At any rate, I will do some road tests today and expect it will go well, specially when I maitain my new self imposed 5500 rpm limit. Back in the day, this engine freely reved to and knew the redline quite well, even pulling the 3.36.

Stu Fox

[Clem Z.]

Re: Return From Vettefest - Fingers Crossed

Thanks fellows for the additional insight and suggestions.

I started it last night and warmed it up. Seems to run fine. I even did a few higher rpm holds and it was as smooth as could be.

I'm still trying to figure what affect that bypass hose has in this. It still seems that the engine temp holds right below the thermostat spec of 180 degrees, and I know this new thermostat opens at or close to 180 as I pan tested it. This is the same condition I noticed with the other 180 (that failed) and, for that matter, the same way it acted with the former 160.

Has anyone else with a L-76 or perhaps L-84 noticed such a condition? My thought is that perhaps being as how the temperture sensor is in the water manifold on these older engines with the bypass we're not seeing the true engine temperature as the coolant is moving quickly through there via the bypass and the thermostat. I got to do a little reading on this to figure it out I guess.

At any rate, I will do some road tests today and expect it will go well, specially when I maitain my new self imposed 5500 rpm limit. Back in the day, this engine freely reved to and knew the redline quite well, even pulling the 3.36.

Stu Fox

the bypass allows the coolant to circulate while the thermostat is closed and bypass the rad. on race engines we removed the bypass since we did not use a thermostat just a restrictor to make sure all the coolant went thru the rad. SBC have a bypass built in to the water pump leg and the block.

[Duke W.]

Re: Return From Vettefest - Fingers Crossed

The bypass allows the coolant to rapidly recirculate back into the engine to promote fast and even warmup, which is good.

In addition to the internal bypass built into the pump and block the heater system also acts as a bypass, so SHP/FI engines have three bypasses.

The larger the bypass area the faster the coolant will recirculate and the less the pressure buildup. SHP/FI engines may have had the external bypass because of their higher idle and total rev range, but I believe it was eliminated on L-79s, so possibly Chevrolet decided it wasn't really necessary.

Duke

[Stuart F.]

Re: Return From Vettefest - Fingers Crossed

Thanks again for your comments. I just returned from about an hour ride and all went well. As the temperature held and the oil pressure was up there, I gradually expanded the envelope. The darn thing seems to pull better than ever. Before I knew it, I saw 6500 (exceeding my limit). I ran it up through 3rd and then geared back down several times and it performed flawlessly. With the top down (of course), I checked as best I could for any smoke, but did not see any thing unusual. I probably need my son to trail me again to check for certain. Oddly, the temperature never reached 180, rather held steady between 160 and 180. I believe that bypass has a lot to do with that and, in fact, is probably responsible for saving the engine that day.

Thanks to all for your help with this. I believe I have learned something, some of which you could call a lesson.

Believe it or not, I have now overheated several 283's, a 350, a 305 and now a 327, and have not lost one Chevy V8 yet. In fact, they all seemed to run better after. Chevy do (did) make a darn good V8!

Stu Fox