totally good for you!

 

I have a clutch fan that was installed recently.

 

I am running a no vacuum advance dist right now and am running 22 initial with 34 total. I have no cooling problems at all. My problem was with vacuum at idle I barely made enough vacuum to pull in the advance and it was "hunting" all around at idle. I do have a vacuum advance MSD dist now along with a non vacuum and will experiment with the vacuum one soon. I will probably still run the 22 initial but run it on non ported so I get the advance at cruise and not at idle.

I will agree with Barry K (ain't that something Barry) and Lars on this on running vacuum on the street. It just did not suit my motor or I should say the dist was not setup properly or I just have not figured out the best scenerio for my motor yet.

 

you?? agree with a post of mine??
hold on, i'm writing this date down!

if you do decide to experiment with the other distributor to try out the vacuum advance, I'd suggest at that point to lower your initial timing down since the vacuum advance will throw in the additional timing at idle and low loads.
I can't tell you how much to lower it because that will depend on the vacuum cannister you use for the vacuum level your motor makes at idle and how much advance that cannister puts out, but they usually add 15-16º of advance.
At that point you would want to move your initial down to about 12º with about a 24º mechanical advance set up in the distributor.
that would give you 12º and 36º total with it disconnected than give you 28º initial and 52º w/ the vacuum adv connected when it's connected to full manifold vacuum.
That would at least be a good starting point than you can play around with the settings from there to see what your motor decides it likes.

you know, you aren't that far away, I'd like to run into you at a show and finally meet.

 

That is why I was going to try it on non manifold vacuum. This way I would not get the advance at idle only at a cruise. I tried manifold vacuum and at idle I get very little vacuum and it bounces. It would idle down fine but if it idled more than 15 seconds the vacuum would drop out and the timing goes down to low and it stalls out. The cahhister I have is for pretty low vacuum. I can't remember the number right now but it came on pretty low. I just need to get some time to play with it. My summers are mostly spent at the beach so not much weekend time to work on it.

We will have to meet up sometime. Your only an hour or so from me.

 

there are vac adv cans that come in as low as 2-4"Hg and 3-5"Hg. I can't imagine your vacuum level at idle being less than that!

The stock 30-30 cam in my '65 is considered a pretty radical cam (at least as far as a factory cam) and I still get 11-12"Hg of vacuum at idle.

Yep, only about an hour or so away. We still have family in Jersey also so come up every now and than.
my grandmother is still on the farm where I grew up in Pemberton, my wife's mother is in Delran, and my sister is in Haddonfield.

 

I get 8 to 9 inches at 900 rpm.
We are getting a little away form the post here. I'll have to talk to you later on this.

 

A few notes on this...
First, an engine operating at idle and light throttle cruise runs leaner than it does at WOT, and a lean mixture actually burns slower than a rich mixture. Thus, the lean mixture needs much more timing advance to burn completely, so the vacuum advance solves this problem.

Some notes from John Hinckley on the relationship between timing and temperatures:

"Now, to the widely-misunderstood manifold-vs.-ported vacuum aberration. After 30-40 years of controlling vacuum advance with full manifold vacuum, along came emissions requirements, years before catalytic converter technology had been developed, and all manner of crude band-aid systems were developed to try and reduce hydrocarbons and oxides of nitrogen in the exhaust stream. One of these band-aids was "ported spark", which moved the vacuum pickup orifice in the carburetor venturi from below the throttle plate (where it was exposed to full manifold vacuum at idle) to above the throttle plate, where it saw no manifold vacuum at all at idle. This meant the vacuum advance was inoperative at idle (retarding spark timing from its optimum value), and these applications also had VERY low initial static timing (usually 4 degrees or less, and some actually were set at 2 degrees AFTER TDC). This was done in order to increase exhaust gas temperature (due to "lighting the fire late") to improve the effectiveness of the "afterburning" of hydrocarbons by the air injected into the exhaust manifolds by the A.I.R. system; as a result, these engines ran like crap, and an enormous amount of wasted heat energy was transferred through the exhaust port walls into the coolant, causing them to run hot at idle - cylinder pressure fell off, engine temperatures went up, combustion efficiency went down the drain, and fuel economy went down with it."

Some notes on the subject from Automotive Engineer Duke Williams:

"Higher overlap (cams) increases exhaust gas dilution at idle and cruise, which slows flame propagation speed, which increases the timing requirement. Insufficient total timing at idle and low speed cruise increases EGT, which will cause more heat to be absorbed by the cooling system, which can result in high operating temperatures and, in extreme cases, overheating to the boilover point, even if all cooling system components are within their original performance range."

Further:

"Ported vacuum advance is an emission control technique to increase EGT, which promotes oxidation reaction in the exhaust, but it also increases operating temperatures, increases the tendency to detonate and run-on at shutdown, and increases fuel consumption. With a handful of exceptions, all GM pre-emission engines equipped with vacuum advance used full time manifold vacuum."

Running no vacuum advance is the same as running ported vacuum at idle - it retards timing significatly from its optimum timing point for the lean, diluted mixture at idle and low speed cruise, resulting in increased EGT and elevated engine operating temperatures.

Lars

 

You've correctly set up your non-vacuum distributor with enough initial timing to eliminate the problem. The mistake most people make is that they get a "performance" distributor with no vacuum advance, and then they set the initial timing to the "factory spec" of about 6-8 degrees. This results in massively retarded timing and inadequate spark advance at idle and cruise, causing severe overheating problems and poor overall performance. The key, which you've discovered, is that if you are going to alter the systems on your engine, you need to have enough understanding of those systems to do the alterations correctly. If you eliminate vacuum advance, you have to compensate for this by correcting your timing curve, including correction of the initial timing and total timing.

 

Every high perf (over 500HP) motor I have ever had in a vette got a BE COOL Module system with dual electric fans . I never see temps over 180 degrees even on the hottest day idling for an hour.

As far as ignition, I am no expert but I always use an MSD distributor with no vaccum advance(again,for the same type motor). I set the initial timing between 10and 12 deg. initial and use the bushings and springs to dial in about 36 degrees total timing to come in fully at about 2800 rpm or so.

Simple, stupid, for guys like me that do more body work than mechanical work , and seems to work pretty well. Now I know that if you nit pick combinations for max power there will be variations but as a baseline that has always worked well for me on the street.

 

I'll try the tune first, but before I tune I have to eliminate all vacuum leaks in the headlights by installing a new hose kit.

Then I have to weld a bung in the headers then the tune.

This will be followed by an install of the rad seals. I'll remove the condenser. The last thing I'll do is install dual SPALS.

 

Sounds like a good plan, but I would order the rad seals with the vacuum hose kit and install them at the same time.

 

I see a lot of good suggestions here, but one I didn't see ( I just skimmed the replies, so forgive me if someone mentioned it already) has to do with the cylinder heads. Have they been drilled for the steam holes in the block? If not, that is likely why its overheating (I'm assuming this is a new engine).

 

It's a used engine, maybe the previous owner knows the answer.

 

or maybe he doesn't want to bother because I told him I'll trash this engine if I can't solve the overheating issues.

I paid good money for this engine. I would hate to start over for nothing.

 

Motorhead had that tuned to a T and no cooling issues. Before you start changing carb and timing settings make sure you have no vacumn issues and all seals and front spoiler are in place. Next step would be a Dewitts radiator and electric fans. If that small block is 550 HP and you have A/C the stock radiator is maxed. The Radiator and fans are a lot cheaper than trashing the motor and starting over. JMHO

 

Your cooling system needs to be upgraded to handle 550HP, it is as simple as that. You need good electric fans and a good aluminum rad. Your rad is probably OK>

BeCool sells modular systems rated at 400, 700 and 1000HP. The reason for 3 or 4 different systems is they know you need more CFM thru the rad to cool higher HP motors or they would just have the 400HP system and sell that to guys with 1000HP motors.

Click on products, cooling and then modules and you will see 4 different
systems, each rated at a specific horsepower.

http://www.becool.com/#Products

Upgrade to electric fans and you will have many years of enjoyment out of that motor just like I did.

 

Thanks for the advice. I just get frustrated sometimes. I tend to forget that upgrades in power mean upgrades in cooling, drivetrain, suspension etc.

:o