[Crazytrain]

I picked up a really nice T/A from a young fella a few weeks ago. I know its set up wrong. Its a 400ci with 6x heads so it pushing about 8:5 CR I geuss. He told me he has the biggest cam you can get from Summit in it which needs what like 10:5 at least? I know its wrong but my ? is would that alone make it run hot? I've already done the impellar,top hose below the cap. Timing set at 13 degrees. Has good flow thru a 4 core. Runs 200 to 220 and even at Idle gets to temp in just a couple of minutes. Has a 180 therm. and yes it works.

[ericwy]

If you are using the standard 50/50 mix of antifreeze/water try increasing the ratio
of water that you are using. A 40/60 or 30/70 ratio will make your cooling system
more effiecient since water can absorb more heat than antifreeze.

In the southern states we dont have to worry much about freezing. Dont worry about
boil over either at 15ps straight water boils at 250 degrees F. 30-40% antifreeze will
raise that temp a bit more, but also provides corrosion protection and water pump
lubrication.

Recently my engine needed some repairs that required removing the timing cover. The shop
replaced the 30/70 coolant mix with a 50/50 mix. I instantly noticed a 10 degree increase
in operating temperature. I plan to restore the 30/70 ratio befor the heat of summer arrives.

[Crazytrain]

I have about a 20/80 mix in it now I believe. It's not boiling over while it's running but does after I shut it off.

[GOAT8U2]

13 degrees of initial/base timing?

What are the rest of the timing specs, vacuum advance, total/WOT?

If you're running it as ported vacuum you're going to have a tougher time keeping the car cool.

[Crazytrain]

All I have is a simple timing light so all I have is base timing. What do you mean by a ported vacum? Thanks

[ericwy]

Ported vacuum has no vacuum at idle. As soon as the throttle is opened a little
the ported port (on the carb) will show a vacuum signal. A manifold vacuum port
will show a strong vacuum signal at idle.

Ported vacuum began to see more use during early emission changes in an attempt
to reduce NOx. Ported vacuum offers no vacuum advance at idle which means you
would have retarded ignition timing at idle, coupled with low air flow through the
radiator means it gets hot. GM engineers knew it was a problem and devised the
TVS (Thermal Vacuum Switch) that would allow full manifold vacuum to be directed
to the vacuum advance to help cool the engine by advancing ignition timing to speed
up the engine reduce retarded ignition induced heat.

Some engines like full manifold vacuum at idle others don't just depends on your
combination of parts. There have been many threads that discuss that topic.

[Crazytrain]

Thanks ERICWY I'll try the manifold vacum out today and see what happens. Thanks again

[getmygoat]

Eh, don't forget major cooling components like the radiator... Radiators get old, corroded, and don't flow as well and thus don't cool as well.

You could have it boiled out, flushed - or you might need a new one. You can get them recored with denser fins per inch count to provide more cooling capacity in the same form factor as well.

[Crazytrain]

The radiator( 4 core) has good flow and looks to be rather new. I tried the manifold vacuum today and it seemed to help quit a bit although it was a cool day here 68 degrees it ran around 180 190 at highway speed but when I slowed down it got up to 200 220. Before it would stay there though and not cool back down after the change today it cooled back off to the 180 190. It also help smooth out the idle and it just seemed to run better in general. I also put in a 160 therm. It has a 17" flex fan on it so I think maybe I need to get rid of that and go to a clutch fan. I got a private message from GEOFF and he gave me a list of things to try that was one of them. Thanks for all the replys I'll keep posting to let you know how it's working out. Any other thoughts would be appreciated.

[guccieng]

everyone has given good advice, but we're missing the main question. is a low compression motor ok with 13 initial? the answer is no. my 400 with 5c heads liked 18 to 20 initial PLUS vacuum advance to run cool. since the initial is so high, my combo liked the ported advance at idle. i would shoot for a higher initial, but watch the total closely. it may like the 5 more degrees too.

[ctgross]

Sounds like you're on the right track, some very good advice from these guys. A good clutch fan may help, just my ,but some argue a flex is better. Good luck with it and please post your results.

Where are you in HOG country? I'm just south of Hot Springs.

[Ben M.]

You've done all the great water flow checking points, but how is the *air* flow...?

[Crazytrain]

I'm up in Knob, Ar, how did you do during the ice storm? We lost power for 3 1/2 weeks. Thank goodness for our generator. I will keep posting and hope it helps someone else. Everyone has been great with all the help and I do so appreciate it very much God bless. I do have a few small gaps where the shroud should be touching the rad on the bottom and sides gonna try to fix those up next, thanks to GEOFF for that one too. Will also try the timing bump up but I did that to 16 before I asked for help and it made no change kinda worse but I'll try the 18 and and put it back on the port vacuum to see what happens.

[screamingchief]

If it's running hot @ idle,I'd be looking at stuff like pulley ratios,and airflow across the radiator for my answers.

If it's running hot going down the road,then there are some other culprits to look for.

If it's running hot doing both,the list grows even longer yet.

We need good descriptions to give good answers.

I seriously doubt the cam is the culprit though,not directly that is.

Tuning the combo for the cam,yeah could easily be that,look into the carbs fuel curve tuning and such,as well as finding what it likes in respect to the ignition timing.

One thing that comes to mind is this era of GM cars often came equipped with a "baffle" that mounted underneath the radiator,that baffle was there to stop the air from going thru the radiator and then feeding back into the clean air ahead of the radiator.

These baffles are easily damaged/lost on these low slung cars,so that may be worth looking into too.

But again that is mostly a low speed issue,not a concern when the car is going down the road @ speed.

[sixt8bird]

How about running too lean and having restricted exhaust.

[Crazytrain]

No restrictive exhuast have Ram air 3 manifolds and 3 inch side pipes. Not sure about it being on the lean side Thanks......... Why do People drink then come on hear to answer ?'s go to the bar if you want to start a fight. Again GEEZ.................

[screamingchief]

Originally Posted by Crazytrain

No restrictive exhuast have Ram air 3 manifolds and 3 inch side pipes. Not sure about it being on the lean side Thanks......... Why do People drink then come on hear to answer ?'s go to the bar if you want to start a fight. Again GEEZ.................

Bringing your pent up animosity over here to this thread is on you bubba.

I did'nt start any $#!t here,I just gave straight forward advice to try and help you fix your problem.

And what do I get for my time & effort?

I get static because your all bent outta shape over a few smartass comments from another thread,,,well grow some skin man!!!

I asked you to tell us specifically when and how it is running hot,that's cooling system diagnosis 101 if you ask me.

You want a circle jerk of misinformation here,just keep holding any & all valuable information back,you'll get exactly what your after,trust me.

I was the first one in this thread that mentioned checking the fuel curve tuning.

I also pointed out a few other things the others overlooked that could be @ issue.

You metioned you checked that the upper hose is below the cap,well guess where that fine advice came from in the first place.

Dont want my help,fine by me.

Good luck,you'll need it.

Your on your own.

[sixt8bird]

It can just be the cam with his combo as a friend of mine had a 428 that ran cool, then he installed an old HO Specialties cam and it ran real lopey, would heat up no matter what. He then went to a 2802 cam and it ran great again. No overheating issues.
Me on the otherhand have never had heating issues on any of my cars. They all run at around 165-170 tops.

[performerrpm]

i think a good clutch fan is in order, ive never had a flex fan pull enough air to keep anything cool, at idle they dont pull in much air at all because of the design of the blades - idle isnt fast enough- and at highway speeds they straighten out and probally act as a barrier keeping the fresh air from coming in and going out, seems they really only work good from a high idle to maybee 3000 rpm, i tried one on my 400, then the 350 in my truck and temporarily on my 455, never was they succesful in keeping temps down, only bennefit is that they look cool

[Crazytrain]

Originally Posted by screamingchief

Bringing your pent up animosity over here to this thread is on you bubba.

I did'nt start any $#!t here,I just gave straight forward advice to try and help you fix your problem.

And what do I get for my time & effort?

I get static because your all bent outta shape over a few smartass comments from another thread,,,well grow some skin man!!!

I asked you to tell us specifically when and how it is running hot,that's cooling system diagnosis 101 if you ask me.

You want a circle jerk of misinformation here,just keep holding any & all valuable information back,you'll get exactly what your after,trust me.

I was the first one in this thread that mentioned checking the fuel curve tuning.

I also pointed out a few other things the others overlooked that could be @ issue.

You metioned you checked that the upper hose is below the cap,well guess where that fine advice came from in the first place.

Dont want my help,fine by me.

Good luck,you'll need it.

Your on your own.

Okay you did give some advice on this post but it just so happens that I read your other post first and came here already ticked off. So thanks for your advice. On the other hand everyone here in not a expert on cars and knows everything to write to explain a problem. If I did I probably could figure it out on my own. I came here to learn from others as I'am a novice to the motor world . I appreciate those who have given me answers without judgement as it has helped me greatly. Thanks