[GT182]

Make sure you get a pump with impeller vanes that are at least 3/4"s high. They will improve flow and stop cavatation of the coolant. Check as many pumps as you need to to get the correct vaned impeller.

If it were me, I'd use an adjustable vacuum can. I wouldn't run with out vacuum advance, but that's up to you. IMHO it's not a good idea to not have one hooked up... no matter what cam you have. Maybe for drag racing it might be ok, but I don't think so for street use. The cam in my XX 400 is not the stock cam [hotter cam installed], and I still need to run the vacuum advance to keep the timing as it should be... which keeps the engine running cooler ad temperature down to where it should be. I'm sure there are others on here that will agree.

[Tripower455]

Originally Posted by GT182

Make sure you get a pump with impeller vanes that are at least 3/4"s high. They will improve flow and stop cavatation of the coolant. Check as many pumps as you need to to get the correct vaned impeller.

If it were me, I'd use an adjustable vacuum can. I wouldn't run with out vacuum advance, but that's up to you. IMHO it's not a good idea to not have one hooked up... no matter what cam you have. Maybe for drag racing it might be ok, but I don't think so for street use. The cam in my XX 400 is not the stock cam [hotter cam installed], and I still need to run the vacuum advance to keep the timing as it should be... which keeps the engine running cooler ad temperature down to where it should be. I'm sure there are others on here that will agree.

Normally, I'd agree with you, but with my current combination, running the vac advance does nothing but make the engine runs worse. I'm not sure why. The distributor/can is brand new and holds vacuum fine (I have had them go bad too).

The heat problem predates my cam, and distributor change.

I've got an Evans pump. As soon as the coffee kicks in, I'm gonna go install it and see if that's the issue.

[GT182]

I'd say is you're running a cam that is too hot for the street, unless you're drag racing only. Vacuum advance is neccessary and without it it's making your car run hot. I'm not trying to be a smarta** but there's only one fix for that. Hopefully you know that by now.

What carb are you running that has no port for the vacuum advance, or is it just plugged?

[Tripower455]

Originally Posted by GT182

I'd say is you're running a cam that is too hot for the street, unless you're drag racing only. Vacuum advance is neccessary and without it it's making your car run hot. I'm not trying to be a smarta** but there's only one fix for that. Hopefully you know that by now.

What I know, is that the lack of vac advance is not making the car run hot.

Lots of guys are running fine on the street without it. It's definitely a tool in the "getting it to run cooler" box, but not the panacea for running hot. Every combo is different.

FWIW, mine ran roughly the same temps with or without it, with both cams in this engine. I ran it for 5 years with a Crane 621 HR (222/229) with the vac advance connected to manifold vac, and now have an SD Old Faithful, which is certainly not too much cam for my combo 9462, 290 cfm KRE Dports) by any stretch of the imagination. The old cam liked about 10 degrees of vac advance at idle, this one definitely doesn't.

What carb are you running that has no port for the vacuum advance, or is it just plugged?

Rochester 2 GC. Jet "circle track" 500 CFM, which has no "ported" vac port. Neither did the stock tripower center it replaced. The only option with my setup is full manifold vac.

[GT182]

Originally Posted by Tripower455

What I know, is that the lack of vac advance is not making the car run hot.

I don't buy that statement at all. It is necessary for correct timing which in turn is a part of whether the car overheats or not. You best ask someone like George Kujanski if it's important or not. And I've never ever seen a carburated car or truck gas engine that didn't have vacuum advance. Funny how we always checked that to make sure it worked way back in the 60s when I started playing around with cars with friends, relatives and garage mechanics.

But them again I guess I'm not smart enough to know the difference. Good luck to ya.

[grandville455]

I posted in my other Thread about what i found today.

[Tripower455]

Originally Posted by GT182

I don't buy that statement at all. It is necessary for correct timing which in turn is a part of whether the car overheats or not. You best ask someone like George Kujanski if it's important or not. And I've never ever seen a carburated car or truck gas engine that didn't have vacuum advance. Funny how we always checked that to make sure it worked way back in the 60s when I started playing around with cars with friends, relatives and garage mechanics.

But them again I guess I'm not smart enough to know the difference. Good luck to ya.

OK, I am a liar.

I haven't been messing with this engine for almost 6 years.

I guess I haven't tried:

Vac advance, no vac advance, a little vac advance, a lot of vac advance, 2 different distributors, different mechanical timing curves, initial timing, total timing, main mixture, idle mixture, different sized pulleys, tightening up impeller clearance on the divider plate, mechanical fans, shrouds, shroud seals, electric fans, aluminum radiators, copper radiators, double checking the temp gauge, moving the temp gauge probe into a spot where it is in the water flow etc. etc.

The one constant in every case is that it has run hot, around 210-220 at speed. The best it'll do is 195 or so, but it has never run anywhere near the thermostat rating.

The only thing I haven't changed in all this time is the water pump, so that's what I'm doing next.

I realize you're trying to help, and I appreciate it, but I assure you that in this case, the vac advance isn't the problem!

[grandville455]

Tripower check out my other thread on engine temp

[Formulabruce]

Originally Posted by GT182

I don't buy that statement at all. It is necessary for correct timing which in turn is a part of whether the car overheats or not. You best ask someone like George Kujanski if it's important or not. And I've never ever seen a carburated car or truck gas engine that didn't have vacuum advance. Funny how we always checked that to make sure it worked way back in the 60s when I started playing around with cars with friends, relatives and garage mechanics.

But them again I guess I'm not smart enough to know the difference. Good luck to ya.

Not to steal thread, but wonder where this "religion" on vac advance and heat came from?
Vac advance only works just off idle and till mechanical kicks in as the vac drops off. This can make smooth acceleration if the initial timing isnt set very high, and can keep car from stalling upon hard De acceleration. Basically just keeping a little more rpms at a hard stop, which could I suppose cool more and reduce a tiny bit of heat soak. Its insignificant.
Most guys are NOT running Vacuum advance because they have bigger than stock cams, requiring an initial advance of probably 14 degrees. This basically eliminates any need for an advance, no matter HEI, points, or MSD ignition.
I am interested on the relation to heat, your theory , Thanks!
PS ever car I played with had them too, back in the day..

[Skip Fix]

Thought I'd add in here-before the PSN noticed my old sender was weeping coolant between the plastic and the center brass. Temp was always right on the gun. Bought a new BW sender now reads 225 on the gauge when it is only 175. So senders even the same brand and new can be a POS.

[GT182]

No idea Bruce, but all I can say is it worked. Everything else checked out ok before I change the vacuum advance can. And it's has nothing to do with religion.

[Formulabruce]

For the early 2nd gen Firebirds guys use the TP-5 sender for gauge correction, bought at Napa. Thats to get it ballpark

[grandville455]

Well after some more investigation, looks like i may have been way lean on cruising, and also my dist center plate one pin was broken loose. I will get these things fixed and report back.