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Author Topic:   over heating
laptime
Dirt Roller

Total posts: 12
posted May 29, 2004 06:43 PM  
i got a chevy 350 bore 30 over i had the heads check and the block ,new water pump ,fan , fan shroud. 2 core aluminum radiators, new cap, we set the timing from 38
all way down to 25 and still get hot, then we change the heads , also carburetor, hade a 180 thermostat took that out and put all the restrictor in from 1 inch to 9/6 still runing hot we also added some redline to get
i even change the wt gauge can anyone please help me out with this i was also just told that the guy that build my motor knock
in 2 freeze plugs in the right side of the block would that make it over heat it over heat at idle and 3000 rpm
thank you for everthing
harold

Racefan20k
Dirt Roller

Total posts: 18
posted May 29, 2004 08:03 PM  
Do you have a fan shroud, what size of radaitor, ever thought about an eletric fan to help cool it down a bit, I would look at the obvious before you tear into the motor or mess with the timing

racer17j
Dirt Forum Champ
Total posts: 5390
posted May 29, 2004 08:31 PM  
What do you mean by knocked in 2 of the plugs??? Elaborate on that a little bit. That might be a problem restricting water. A lot of the 355s that run around here run a 5/8 restrictor. What kind of water pump? What kind of fan?

laptime
Dirt Roller

Total posts: 12
posted May 30, 2004 07:55 AM  
we have a good FAN SHROUD, the fan is a 16" NYLON FLEX FAN, there was no vac,leak but theres 2 freeze plug inside of the block that
they didnt get out when they put the new one in, the water pump in a stock one for chev 350 and it was also been replace so now just about everthing is new on this motor and still runing hot it take about 5 min and it is setting on 210 at higher rpm it still go up to 200+ in 5 min no mater what i have done
ty for everthing you all trying to do for me

blackbart
Dirt Roller

Total posts: 16
posted May 30, 2004 08:06 AM  
Had the same problem with overheating and found that the flex fan straightened out at higher rpm's and did not pull any air through the rad. Switched to a four blade solid fan (older chev half tons have these) with a significant amount of pitch and now will not go over 190 while racing. I don't like the sounds of the old freeze plugs in the block though.

racer17j
Dirt Forum Champ
Total posts: 5390
posted May 30, 2004 08:40 AM  
the plugs are white and iam going to get a new fan to day from a friend and try that

hobby39
Dirt Maniac

Total posts: 112
posted May 30, 2004 10:04 AM  
I friend of mine was having basically the same problem a few years ago he was trying everything when someone sugested that he check to see if someone knocked the freeze plugs in so he stripped the block and shook it and there was what sounded like freeze plugs ratteling around inside. the local engine builder said that the block was junk because he never had any luck getting them out and it wauld always overheat. just what the local engine builder said hope you have better luck. Just my 2 cents.

19J
Dirt Freak

Total posts: 370
posted May 30, 2004 12:50 PM  
Two things. Yes get rid of that fan. Never buy anything that says High Performance Flex Fan. that means junk. Get a solid fan. It dont have to be 4 blade. Some may argure but a 5 or 6 will work just as good. And you can get them out. I pulled apart a buddys motor and his dad left one in when he built the motor with a lil jiggling and a claw hammer and screw driver i got it out. I just pulled it out like a nail. That could also be your problem but i would try the fan first.

laptime
Dirt Roller

Total posts: 12
posted May 30, 2004 05:56 PM  
ok now i got a new 18inch fan today and i can feel the air flow there the rad. but at idle it is getting 200 still but no higher now and also at 2000 to 3000 rpm its drop to 190 now so went getting some where now
i have a thermostat that has been gutted should i try a restrictor to drop it down more or just live it where it is and what size should i try if needed also thank you for all the help
43 pure stock
harold

racer17j
Dirt Forum Champ
Total posts: 5390
posted May 30, 2004 07:05 PM  
yes the fan is at 1/2 way in and out of the shroud i will also try the jets as well onece again thank you all some much
43 pure stock
harold

Leadfoot#8
Dirt Full Roller

Total posts: 44
posted May 31, 2004 10:19 AM  
What kind of radiator??? A racing 2 core or a stock 2 core??

laptime
Dirt Roller

Total posts: 12
posted May 31, 2004 02:42 PM  
It is a racing 2 core

ruggs66
Dirt Maniac

Total posts: 193
posted May 31, 2004 03:39 PM  
do you have a spring in the lower hose?

just squeeze the lower hose & see if you can collapse it.

[This message has been edited by ruggs66 (edited May 31, 2004).]

laptime
Dirt Roller

Total posts: 12
posted May 31, 2004 04:47 PM  
yes i got the spring in both hoses

ruggs66
Dirt Maniac

Total posts: 193
posted May 31, 2004 04:55 PM  
when you set your timing is it at idle Or total timing when at 3000+ rpm?

I had a friend set his timing only at idle & it was getting too far advanced whem at race speed..

carolinafast
Dirt Full Roller

Total posts: 72
posted May 31, 2004 04:59 PM  
190 doesn't sound so bad to me if it will stay there under race conditions
also agree ...those fans are junk
and a gutted thermostat is what we run
good luck

laptime
Dirt Roller

Total posts: 12
posted May 31, 2004 07:50 PM  
timing was set at 38 at 3000 rpm
but i like to say thankyou all once again for everthing
harold
43 pure stock

Leadfoot#8
Dirt Full Roller

Total posts: 44
posted May 31, 2004 09:57 PM  
I run the big hole washer,,,,tried the 5/8 middle size and she runs hot....put the big one back in and runs alot cooler.

Eric Pattridge
Dirt Full Roller

Total posts: 48
posted May 31, 2004 10:42 PM  
I run a two core aluminum, 17" fan (steel), timming is set at about 32adv. I also gutted the thermostat. Was having problems of getting a little hot. Took duct tape and taped up any open areas between radiator and core support (sides and bottom). Also taped up areas around fan shroud (if shroud doesnt cover all of radiator). Basically made it to where air flows strictly through the radiator and out fan shroud. It seemed to help. Temp didnt get above 190 even down here in hot south east Texas.

Raz_900
Dirt Forum Champ
Total posts: 635
posted June 01, 2004 07:22 AM  
190 - 200 is about perfect.

Believe it or not, you'll make best power around 200 degrees (say from 190-210). The hotter the coolant, the better the effeciency of the motor, less wear and less friction from the oil. Cold coolant (below 180) just accelerates cylinder wear, increases drag from colder oil and absorbs more combustion heat that could have been HP to the rear wheels.

Asssuming you have the right jetting, timing and fuel, leave it run at 200. Mine runs best between 210 - 220.

Oh.. and the fan was the whole problem if it droped to 190 after throwing it away. Flew fans are pretty useless.

laptime
Dirt Roller

Total posts: 12
posted June 01, 2004 12:04 PM  
i did get a new fan and jets are right now idle 1000 rpm and run about 200 but no more at 300 rpm it is about 190 no cooler so was going to get that a try this week i hope everything come out good for me this week but like to say thankyou all so much for takeing time out and helping me goodluck to you all this weekend and god bless you all
harold
43 pure stock 43

flatfoot27
Dirt Maniac

Total posts: 103
posted June 01, 2004 05:23 PM  
Laptime, You deffinitely want that motor around 210 to 220 when you are racing. They absolutely run the best when they are warmer. But here is somtething that I ran across a few years ago. We had a 350 that was doing just great and the season was just about half over it really started to run hot. I mean when we racing it was running 240 to 260. We did everthing possible, same as you have and it still ran hot. We made it to the end of the year and we tore it down we found the wrist pins were seizing up and every one of the pistons were shot. It took the wrist pins out and tore the bottom of the pistons up. Don't know what caused it, but we didn't save one piston out this brand new motor. We was told by another motor builder that the pins were not pressed in properly, but like I said, don't know. Hope you have better luck.

laptime
Dirt Roller

Total posts: 12
posted June 01, 2004 06:44 PM  
hey flatfoot27
iam going to give it a try this weekend and see what happen and if it at 210 or 220 iam going to live it right there but if it run hotter then that iam going to take it out and look at that didn't even know that would do it but thankyou for the help
harold

Scoot
Dirt Forum Champ
Total posts: 517
posted June 01, 2004 08:32 PM  
I dont think this was mentioned, I've heard you will run cooler if you run distilled water in your radiator. Has anyone tried this? and does it work? I've not had to try it so I cant honestly tell ya.

------------------
Scoot
Smith Racing Team
870-365-5989

rfb320
Dirt Maniac

Total posts: 150
posted June 02, 2004 08:47 PM  
all I have ever ran in my car is distilled water and it runs about 200 to 210 at race time. I also have a good shroud with a 5 blade solid fan and 5/8 washer. I can come off the track and let my car sit and idle and the temp actually drops. it will drop the gauge all the way down in about 15 minutes.

racer17j
Dirt Forum Champ
Total posts: 5390
posted June 02, 2004 09:14 PM  
distilled water and a cup ful of fabric softener.

I started off having problems this year and decided to make some changes. after putting in a moroso aluminum water pump, a 4 blade fan and a 160 degree thermostat, the thing ran at 80 degrees all night.

This week i'm trying it without the thermostat and hoping to get it up to 190-200

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