[knighthawk]

'69 Cutlass, 350, 2bbl, I rebuilt the motor using Mundello's pistons, .030, 10.25 flat tops, and his version of the ''thumper ''cam. During the cam breakin period, the engine overheated ( may have cracked something ) anyway, the engine STILL over heats, temp goes up to thermostat ( 180 ), then shortly steadily climbs higher. I don't know how hot, but ""Ralley Pak'' temp gage don't have numbers, but 1/2 way when thermostat opens, then creeps to 3/4 way.....timing is at 5 degrees, rad has 3 rows, ( been in for ,many years, but looks clean , water pump is about 2 years old, and maybe 1000 miles, It did NOT over heat last year, before I rebuilt the motor ! Need help !.....thanks.......called Mundello (Lynn) this AM, he said I needed to put a restrictor plate in , in place of the thermostat ?????????????

[richard stewart 3rd]

Hi
Are you getting any signs of overheating, such as steam coming from the rad or elsewhere,
A boiling sound when the engine is shut off, puking from the rad?

Why is your initial so low 5*?
Rich

[knighthawk]

1st time it did it ....all of the above.....since then i shut down before that

[cobalt327]

Originally Posted by knighthawk

...timing is at 5 degrees...

And this is a major cause for the engine to overheat. You should use plenty of advance during the break in procedure. The thing is, if you are breaking in a cam, you CANNOT idle the engine AT ALL, so the timing will be an estimation.

The rotor rotates CCW- so turn the distributor CW to advance the timing- BTW- this is wrong all over the interweb, like the "BoxWrench" site- animations and all.

I think that after you dial in a hunk of timing you'll find it runs much cooler. Move the distributor CW about 1/2 the distance that separate two adjacent distributor cap plug wire terminals, that'll give you an additional 22º of timing. Don't worry about this being too high- the engine will stand a lot of advance when it's running w/o any load on it.

[knighthawk]

why in you pictures , is, ford has #5 as first cyl when #1 is actually the first one ? So, what is the timing supposed to be AFTER it's broke in ?......................My book said 6 dgrees, so I figured 5 would be safer, till it gets broke in . Guess I was wrong ????

[protouringchevelle]

I ran a thunmpr cam(the small one) in a sbc 350 and it wasn't happy unless i ran 26 deg initial timing and recurve the mechanical advance for 10. At first i had base timing set at 10 and it wanted to overheat at idle if left long enough. When i upped the timing it fixed everything...over heating at idle, sluggish of idle performance and the smell of rich at idle. In the end i still changed cams but the timing change made a huge difference.

[knighthawk]

26 sounds like alot ! I believe you, but, I have a hard time thinking'' advanced'' or early timing can make it run better..... I just can't see where it firing thatearly, 26 before top dead center, seems like it would really kick back ! But maybe, like you say , it's due to the cam ??????

[oldbogie]

Originally Posted by knighthawk

'69 Cutlass, 350, 2bbl, I rebuilt the motor using Mundello's pistons, .030, 10.25 flat tops, and his version of the ''thumper ''cam. During the cam breakin period, the engine overheated ( may have cracked something ) anyway, the engine STILL over heats, temp goes up to thermostat ( 180 ), then shortly steadily climbs higher. I don't know how hot, but ""Ralley Pak'' temp gage don't have numbers, but 1/2 way when thermostat opens, then creeps to 3/4 way.....timing is at 5 degrees, rad has 3 rows, ( been in for ,many years, but looks clean , water pump is about 2 years old, and maybe 1000 miles, It did NOT over heat last year, before I rebuilt the motor ! Need help !.....thanks.......called Mundello (Lynn) this AM, he said I needed to put a restrictor plate in , in place of the thermostat ?????????????

A radiator that's been in for many years is probably not cutting it with a restored motor putting more BTU's into the coolant. What counts in radiators is the corrosion and crud that collects inside the tubes. The fact that it gets hotter the longer it runs is a strong indicator that coolant isn't flowing thru the core.

If the thermostat is functioning properly as if it's not opening it could restrict the flow like crud in the core tubes would also do it could cause a similar reaction. Before you get caught up in restrictor plates, take the thermostat out put it in a pot of water on the stove with a candy thermometer and observe what it does and when it does it. Or just take it out and go for a drive, if it's functioning but the radiator isn't it might take a while longer to get up to the overheat point, but once there the temp gauge will behave exactly as it has been.

Bogie

[cobalt327]

Originally Posted by knighthawk

26 sounds like alot ! I believe you, but, I have a hard time thinking'' advanced'' or early timing can make it run better..... I just can't see where it firing thatearly, 26 before top dead center, seems like it would really kick back ! But maybe, like you say , it's due to the cam ??????

It IS due to the cam.

Short version: When there's a lot of overlap the incoming fuel/air charge gets diluted by the previous cycle's spent gasses, almost like an EGR valve does- except this is at idle. The lean mixture this created needs a lot of lead time to burn, hence the need for so much timing BTDC.

Is the cam broken in yet? I had been thinking the overheating was during the break in stage- not while driving out on the road. In any event, you need a lot more initial timing than what you had. Just be sure the total timing doesn't exceed the max for your engine.

[toofast415]

Everyone has good and valid points. But IMO I would start with some easy things first. Could be as simple as an air lock/air pocket in the cooling system. Yes timing will have an effect on temp.

If you have access to an infared temp gun you can find cold spots within the radiator.

Just my $.02

Good luck!

[knighthawk]

I did get the required 20 minutes break in time, but then also was first overheating period. I made ''a rookie'' mistake when I tried to do the 20 minutes,, treid to fill the rad, with the thermostat in , no rad cap on,, to get the all the air out, that's when it got hot on me. Also everytime I run it now, it still gets hot, ie; I had it up to normal op temp, took it down the road 1/2 mile, when I got back, it was getting hot again............ Timing issue; OK, that makes sense now, I think I'll call Mundello's tommorrow to see what timing he recomends......... I'm also taking the rad in to a shop tommorrow to have him look at it ......thanks