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Author Topic:   help with 377
regal 22
Dirt Full Roller

Total posts: 28
posted July 13, 2005 03:47 PM  
;ast week posted topic about valve cover leaking. found out sun morning it was steam coming out of valve covers, water purging out of radiator when running. this is frustrating because water never rose above 180 deg oil press fine motor did not loose power, pulled off of track when i saw smoke from under hood. the new motor lasted a total of 12 laps, when I had this motor done in the winter and ran it in the spring it lasted 6 laps and exploded a piston. my spare motor is a bone stock 400 bored 40 over, still runs but wont last more than 10 laps before running hot, I have a 30 x 19 alluminum rad less than a year old good water pump and use a 3/4 in restrictor, i run my timing at 32 deg total advance. I guess my question is am I doing something wrong with tuning, or am I missing something, or obviosly am i working with junk? by the way the guy who literally wins every week at my track says "400 and 377 s are for drag racing they can't hang in dirt for reliability " is he right?

x13jc
Dirt Freak

Total posts: 390
posted July 13, 2005 07:53 PM  
a friend of mine runs a 377 in his late model and revs the **** out of it all the time.7200-9200 rpm!!!!!!!!it runs awesome! Its all in how its prepped and built.

RACEINMUD
Dirt Freak

Total posts: 323
posted July 18, 2005 05:02 PM  
I run a 400 SBC. Alum Rad. Stage 1 waterpump, gutted therm. 4 blade fan 1/2 out of the shroud. Decent air box to the rad. I use distilled water and that hyper green stuff from checker. On hot nites gets to 210-220 but climbs up AFTER the 25 lap main. I would go thru each area of your cooling system and ck if something is a little off. I did have to open up my nose piece more than others. 4 5X10 square holes instead of two. But it seems to be working fine. Let us know. Race

driver27
Dirt Maniac

Total posts: 194
posted July 19, 2005 06:33 AM  
Seems your radiator has been on a couple of blown motors. The tubes in it have ovaled out decreasing airflow thru the radiator. This is becasue of the soft aluminum seem compression from the motor, thats why your 400 runs hot. You need to replace it.

smyle
Dirt Roller

Total posts: 13
posted July 19, 2005 01:12 PM  
quote:
Originally posted by driver27:
Seems your radiator has been on a couple of blown motors. The tubes in it have ovaled out decreasing airflow thru the radiator. This is becasue of the soft aluminum seem compression from the motor, thats why your 400 runs hot. You need to replace it.


I agree you should check the fins on the radiator if you can not see though them your tubes have swelled from a blown head gasket.

bubba0six
Dirt Maniac

Total posts: 146
posted July 19, 2005 09:10 PM  
call me stupid, but i thought that this is what radiator caps are for. To release preassure so damage will not accur to the radiator, and of course to fill.

[This message has been edited by bubba0six (edited July 19, 2005).]

leapinlizard
Dirt Freak

Total posts: 402
posted July 20, 2005 08:11 AM  
Yeah that's right. The boiling temps of water goes up with pressure. Increasing the boiling point of water saves damage from air pockets that occur when the water boils out. Radiators are cheaper than engines.

driver27
Dirt Maniac

Total posts: 194
posted July 20, 2005 08:50 AM  
Radiator caps cannot release pressure fast enough to save the tubes from ovaling if they see compression and pressure from the engine. How many PSI does a good race motor make...well over 250 or so, whats your cap rated at....20 -22 psi or so. How many cubic inches in a motor...350 or so...you try to bleed all that air out of the overflow tube if the cap lifts. Caps only work if water temp gets too high thus building pressure slow enough that the cap can release it. Trust me on this one. Put a smoking cigarette in front of your radiator, if the tubes are swelled it will barely pull the smoke thru the fins, if a all. Now try this on a rad that is known good, it will pull all smoke and pull the ash right off the cigarette. Poor folks got poor ways, but it works. Ovaled tubes from blown motors cause all sorts of cooling issues in dirt track cars casue the rad will cool some, but without sufficient flow past the tubes, it will eventually heat up.

bubba0six
Dirt Maniac

Total posts: 146
posted July 20, 2005 03:28 PM  
quote:
Originally posted by driver27:
How many cubic inches in a motor...350 or so.

about 43 per cyl. Im not saying you are wrong or anything I just find it hard to believe that racing radiators are that poorley designed. It would seem to me that Griffin and others would take into consideration that race engines blow head gaskets pretty often, and they would build their product accordingly or they would not be around long!

regal 22
Dirt Full Roller

Total posts: 28
posted July 20, 2005 07:38 PM  
i thank everyone for their replies, first thing is yes my rad has been through a lot, last year I had a 350 that split a new copper radiator thats when i bought the Howe, after a race the hoses would swell up real bad. Maybe I should lock the centrifical advance on the dist, and set timing at 34 deg like another racer suggested, I took the plugs out, 13572and 4 light brown 8 fouled and 6 had metal melted from tip to electrode,autolite ar 132 . I am not positive but I think that was the cylinder that has a sleeve? I realize I might not be most qualified to work on a race car, but it is a labor of love, that is driving me to the poor house. just want to race! any suggestions are greatly appreciated. thanks!

driver27
Dirt Maniac

Total posts: 194
posted July 21, 2005 06:26 AM  
ok I stand corrected, assuming its 43 ci per cylinder, and only one cylinder is leaking at 5000 rpm, thats 215000 ci per minute that would have to be vented. Think a quarter inch hose bib (rad overflow vent) can do that?

Not trying to argue, simply stating that aluminum radiators run on blown engines where cylinder pressure is vented to the cooling system, will oval the tubes and become significantly less efficient. Its really got nothing to do with design, just the properties of aluminum, its a soft metal and the tubes are thin. It is easier to bend than you would imagine.

All im saying is its something to keep a very close eye on.

smyle
Dirt Roller

Total posts: 13
posted July 21, 2005 08:41 AM  
quote:
Originally posted by bubba0six:
I just find it hard to believe that racing radiators are that poorley designed. It would seem to me that Griffin and others would take into consideration that race engines blow head gaskets pretty often, and they would build their product accordingly or they would not be around long!

All I know is a friend of mine blew a head gasket at the beginning of the season and after that his new motor would over heat. Upon in spection of his radiator the fins were all crushed from the swelled tubes (I think it was a Griffin).

bubba0six
Dirt Maniac

Total posts: 146
posted July 27, 2005 08:14 PM  
The more i think about it the more i think it is ****. when you blow a head gasket between cyl. and water jacket all of the compression from the cyl. is not going to go into the radiator. your valves are still working and releasing preassure through the exhaust, also the preassure is only going to build so high.... have you ever hooked a compression gauge to your engine it will only go so high 130psi or so. with this said. if your compression is, lets just say.... 150psi your exhaust valve is gonna vent probably atleast 80 percent of that, which leaves about 30 psi on top of the 15psi that is already in your cooling system that equals around 45 psi, im pretty sure that my cap and quarter inch puke tube can take care of getting rid of that, before the tubes in my radiator swell. and the reason im arguing the point is that over the past few years i have blown 4 head gaskets with the radiator that i have in my car and the darn thing still looks new, not even a sign of ballooning. and it still cools great!!!

driver27
Dirt Maniac

Total posts: 194
posted July 28, 2005 06:30 AM  
suit yourself.

Only offering suggestions, and from past experience. Seems a few on here agree, a few dont.

It can and does happen, perhaps you were just lucky. Good luck to ya.

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