hard filled sbc overheats real bad

Old 08-28-2012, 08:42 AM
  #11  
bubbaf100
Member
MASTER JOURNEYMAN
 
Join Date: Aug 2009
Posts: 44
Default

If yur not too worried about weight or if was a street car dual 3 core aluminum radiators on all stock 400 blocks some filled some not just ran a high volume water pump with restricter plate on a 110 degree day driving on the back raods for a few hours cruising at 120-130 mph it would climb to 160-170 dgrees.
With a 16 fan. Idle hot or not 175-180. But I'd do what skip said first.
bubbaf100 is offline  
Old 08-28-2012, 10:53 AM
  #12  
chevyart
Senior Member
MASTER BUILDER
Thread Starter
 
Join Date: Mar 2008
Posts: 173
Default overheating

thanks guys. ill run those checks like you guys suggested. what is the best was(or tool) to check temp at the points that you mentioned. im embarassed to say i cant figure that one out. art
chevyart is offline  
Old 08-28-2012, 11:52 AM
  #13  
zipper06
Senior Member
RACING JUNKIE
 
Join Date: Jan 2006
Location: La.
Posts: 2,890
Default Re: overheating

Originally Posted by chevyart
thanks guys. ill run those checks like you guys suggested. what is the best was(or tool) to check temp at the points that you mentioned. im embarassed to say i cant figure that one out. art
Nothing to be embarressed about, i think he's talking about using an infrared thermometer. it's something we use all the time to check the exhaust header temperature on alcohol at idle if we don't have an EGT system.
Like the one pictured below on sale right now from harbor freight for $30.00, cheap but effective.

Zip.

zipper06 is offline  
Old 08-29-2012, 08:09 AM
  #14  
roadkill2
Senior Member
RACING JUNKIE
 
Join Date: Jan 2012
Posts: 628
Default

Zakly . . If you don't have one, get one . . If you're a serious drag racer you have one in your trailer and your crew chief/spotter has one in his hip pocket . . It's part of the data acquisition department. Track Temp, Tire Temp, Engine and Converter Temp when the car comes back from a round, etc . . And as Zipper said, use it to check your cylinders firing . . as well as EGT if the headers are exposed . .
roadkill2 is offline  
Old 08-29-2012, 01:25 PM
  #15  
chevyart
Senior Member
MASTER BUILDER
Thread Starter
 
Join Date: Mar 2008
Posts: 173
Default overheating

guys. im doing the changes you all talked about. here is something that may be a cause (or )effect) on this overheating. my spark plug electrodes are whiter than your teeth. way too lean. heres my plan for this and i need some jetting advice. im taking off the problem carb which was a worked 750(old style)it may have cosat me my last motor to blow, as it ran too lean and dropped valves. i have a new holley center section i added to a new 750 double pumper and i added the big accelerator pump and bigger squirters and jet extensions with notched bowls.. its strictly a race carb(no streetuse) so NO power valves. the jetting is 82 in the front and 84 in the back. i think this is close, but maybe will be on the lean side with these jets.. i know i can try it like it is, but i want it to be real close the first time and hope the carb and overheating problem is gone on the firsat pass. PS it has air bleeds in it for idle and top end but i did not touch them at all. thanks art
chevyart is offline  
Old 08-29-2012, 02:23 PM
  #16  
fast75vega
Senior Member
RACING JUNKIE
 
Join Date: Nov 2008
Location: Niagara Falls, NY
Posts: 965
Default Re: overheating

Originally Posted by chevyart
guys. im doing the changes you all talked about. here is something that may be a cause (or )effect) on this overheating. my spark plug electrodes are whiter than your teeth. way too lean. heres my plan for this and i need some jetting advice. im taking off the problem carb which was a worked 750(old style)it may have cosat me my last motor to blow, as it ran too lean and dropped valves. i have a new holley center section i added to a new 750 double pumper and i added the big accelerator pump and bigger squirters and jet extensions with notched bowls.. its strictly a race carb(no streetuse) so NO power valves. the jetting is 82 in the front and 84 in the back. i think this is close, but maybe will be on the lean side with these jets.. i know i can try it like it is, but i want it to be real close the first time and hope the carb and overheating problem is gone on the firsat pass. PS it has air bleeds in it for idle and top end but i did not touch them at all. thanks art
i had the same issue and asked the same questions... what i read and what the guys here said is that a 750 dbl pump with a front only PV comes factory with 73 frt and 84 rear. mine was at 71 front and 73 rear and ran hot and not rea good power....i jetted it to 73 frt and 82 rear and seems like big a difference
fast75vega is offline  
Old 08-29-2012, 08:57 PM
  #17  
chevyart
Senior Member
MASTER BUILDER
Thread Starter
 
Join Date: Mar 2008
Posts: 173
Default overheat

thanks fast 75 vega. the carb i am taking off is just about what you described. im going with the new center section that brings the 750 up to about 820 cfms, so the jetting isquite a bit higher.. ps im from westchester county ny and run at lebanon valley dragway near albany ny. i run an all brown 67 nova with gold bumpers. i also have a nice 75 vega that i am completing with a 408 sbc and ford rear. do you belong to out h-body forum? if you have a vega you should definitely belong. if so give me a shout and i will tell you how to join for free. thanks for info art (chevy art) on h-body forum
chevyart is offline  
Old 08-31-2012, 09:49 AM
  #18  
chevyart
Senior Member
MASTER BUILDER
Thread Starter
 
Join Date: Mar 2008
Posts: 173
Default which restrictor to use

i had a restricter in the engine(its the 3/4 inch hol disc). i also have the smaller one (5/8 and have a 1 inch one. which one should i use, keepind in mind that the block is hard filled to waterpump hole, so it passes less water through its water jackets thanks art
chevyart is offline  
Old 08-31-2012, 12:49 PM
  #19  
wazup
Senior Member
EXPERT BUILDER
 
Join Date: Dec 2010
Posts: 345
Default

Art try using the largest one. Fastvega is pretty much right on with the carb and with that start with what he said and work from there.

Have you found out if your water is flowing thru the rad.
wazup is offline  
Old 08-31-2012, 11:20 PM
  #20  
chevyart
Senior Member
MASTER BUILDER
Thread Starter
 
Join Date: Mar 2008
Posts: 173
Default overheating

hey waz will put the 1 inch hole restrictor in today. am going to race on sunday and will hopefully have a change in temp with all the little). things i have changed.. with the 3/4 inch restrictor water comes out the top of the radiator cores and into the tank(by rad cap at a steady stream(hose like appearance) stream has about a 3/16-1/4 inch diameter. thiis makes me believe the water pump is working OK. any other suggestions i will try them. i took my carb off and checked the jets(its a 750 cfm carb) and it was real bad. the front jets were only 70s with a 6.5 power valve and 80s in rear with no PV. they are now 80 with NOpv in front and 84 with no pv in rear. this should definitely give a little brown color to the spark plugs. they were firing pearly white and probably helping the car to run hot(its an almost 600 HP 377 sbc). thanks for the help you all are giving me art
chevyart is offline  

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service