overheating vs severe overheating
Drifting
Joined: Feb 2010
Posts: 1,734
Likes: 267
From: Richmond Texas
Wow...great responses everybody...let me address a few...
.........Kensmith, it's a new electric fan, pulling 18 amps, 2500 cfm, puller mounted on correct side of rad. You can feel the air moving from front to back really well. But it took running it for 30 minutes with the engine off to cool it from 240 to 180.......
.........Kensmith, it's a new electric fan, pulling 18 amps, 2500 cfm, puller mounted on correct side of rad. You can feel the air moving from front to back really well. But it took running it for 30 minutes with the engine off to cool it from 240 to 180.......
Le Mans Master
Joined: Mar 2005
Posts: 7,631
Likes: 11
From: Rocklin California
Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,926
From: Washington Michigan
A properly set up L-89 isn't any more likely to overheat than a 327/300. Need to know what your timing map looks like - it matters, A LOT.
What's your initial timing setting (vacuum advance disconnected and plugged)?
What's your maximum advance (degrees and rpm, vacuum advance disconnected and plugged)?
Is your vacuum advance connected to a full manifold vacuum source, or to a "ported" source?
Is the vacuum advance working? How many degrees of advance does it add at idle when you connect it?
What number is stamped on the vacuum advance bracket behind the diaphragm (B20, B26, B28, etc.)?
What's your initial timing setting (vacuum advance disconnected and plugged)?
What's your maximum advance (degrees and rpm, vacuum advance disconnected and plugged)?
Is your vacuum advance connected to a full manifold vacuum source, or to a "ported" source?
Is the vacuum advance working? How many degrees of advance does it add at idle when you connect it?
What number is stamped on the vacuum advance bracket behind the diaphragm (B20, B26, B28, etc.)?
Former Vendor
Joined: Jan 2000
Posts: 5,593
Likes: 631
From: Brighton
Someone with the same year and BB has been talking with our tech support (John Dingman) and he says the car has an MSD ignition with no vacuum can. If the OP is that person, then no need to call me. You need to replace the distributor to get this to work right.
JohnZ wrote a beautiful article on this and it is now available to download from our website.
http://www.dewitts.com/download/timing101article.pdf
Le Mans Master
Joined: Aug 2009
Posts: 5,474
Likes: 16
From: Houston Texas
St. Jude Donor '10-'12-'13
http://www.dewitts.com/download/timing101article.pdf
Thanks for doing that article JohnZ. Nice work!
Thanks for doing that article JohnZ. Nice work!
Le Mans Master
Joined: Nov 2008
Posts: 5,691
Likes: 12
From: columbus oh
Someone with the same year and BB has been talking with our tech support (John Dingman) and he says the car has an MSD ignition with no vacuum can. If the OP is that person, then no need to call me. You need to replace the distributor to get this to work right.
JohnZ wrote a beautiful article on this and it is now available to download from our website.
http://www.dewitts.com/download/timing101article.pdf
JohnZ wrote a beautiful article on this and it is now available to download from our website.
http://www.dewitts.com/download/timing101article.pdf
Safety Car
Joined: May 2003
Posts: 4,797
Likes: 239
From: Ocean Township NJ
I hate to bring up the unthinkable, but, who rebuilt your engine? If there is any trash in the galleries it will quickly wipe out your main bearings, especially the rearmost one, causing excess friction. A number of internal problems might have been caused by improper cylinder wall honing, ring end gap, piston to wall clearance, etc etc etc. If your engine has too much friction to start with, then all of the above mentioned (obvious fixes) will have no effect. If your motor is healthy, and with a new DeWitts radiator, then it should have plenty of cooling capacity to keep temps at a reasonable level.
Has this problem been ongoing since the engine build, or has something else happened in the interim which made the problem apparent?
Has this problem been ongoing since the engine build, or has something else happened in the interim which made the problem apparent?
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Advanced
Joined: Nov 2009
Posts: 78
Likes: 1
Well, if it is cooling adequately when moving but overheats when stationary it seems that it has to be related to airflow through the radiator when the car is stationary. which means the fans. Have you tried a stock type fan either with a clutch or direct drive?
One thing that you can do that will work is to replace the water/coolant with 100% propylene glycol. You run it unpressurized (drill a small hole in the cap). I ran this in a 69 big block and it never overheated anywhere from Sears Point Raceway to stop and go traffic on 100F days. This being said, if it will cool when moving then you know that everything is OK with enough airflow through the radiator.
One thing that you can do that will work is to replace the water/coolant with 100% propylene glycol. You run it unpressurized (drill a small hole in the cap). I ran this in a 69 big block and it never overheated anywhere from Sears Point Raceway to stop and go traffic on 100F days. This being said, if it will cool when moving then you know that everything is OK with enough airflow through the radiator.
Wow...great responses everybody...let me address a few...
Kensmith, it's a new electric fan, pulling 18 amps, 2500 cfm, puller mounted on correct side of rad. You can feel the air moving from front to back really well. But it took running it for 30 minutes with the engine off to cool it from 240 to 180.
Magicv8, I will try a few of those ideas.
63split63, it's a brand new high volume water pump from Summit...seems to be working as it should...water is moving fine, just gets really, really hot.
midyearvette...Hi Peter...yep, everything else is up to snuff, but I'm interested in hearing your points on no head bolt sealer or improper bolt torque...can you expand my knowledge on those? Thanks...
Donald31176...I'll double check that.
MikeM...it's a completly newly built engine...no California involved here...
Claysmoker...Dave, I like your idea and I'll try that...want to take over this build since you have so much free time on your hands?
So where's the finished project?
Time to post this and go try a few of these things out...Nick
Kensmith, it's a new electric fan, pulling 18 amps, 2500 cfm, puller mounted on correct side of rad. You can feel the air moving from front to back really well. But it took running it for 30 minutes with the engine off to cool it from 240 to 180.
Magicv8, I will try a few of those ideas.
63split63, it's a brand new high volume water pump from Summit...seems to be working as it should...water is moving fine, just gets really, really hot.
midyearvette...Hi Peter...yep, everything else is up to snuff, but I'm interested in hearing your points on no head bolt sealer or improper bolt torque...can you expand my knowledge on those? Thanks...
Donald31176...I'll double check that.
MikeM...it's a completly newly built engine...no California involved here...
Claysmoker...Dave, I like your idea and I'll try that...want to take over this build since you have so much free time on your hands?
So where's the finished project?Time to post this and go try a few of these things out...Nick
Pro
Joined: May 2010
Posts: 560
Likes: 2
From: North Las Vegas Nevada
DT
Former Vendor
Joined: Jan 2000
Posts: 5,593
Likes: 631
From: Brighton
Not nececessarily the root cause. If this is indeed the car Mr. DeWitt referenced and it has no vacuum advance, then while the car is moving and the engine is above idle, the timing is advanced by the mechanical advance, but at idle the mechanical advance may be adding no timing at all (when a vacuum advance would be doing its job) and you get an overheat situation.
DT
DT
Melting Slicks
Joined: Sep 2003
Posts: 3,050
Likes: 2
From: Orange Ct
Not nececessarily the root cause. If this is indeed the car Mr. DeWitt referenced and it has no vacuum advance, then while the car is moving and the engine is above idle, the timing is advanced by the mechanical advance, but at idle the mechanical advance may be adding no timing at all (when a vacuum advance would be doing its job) and you get an overheat situation.
DT
DT
Advanced
Joined: Nov 2009
Posts: 78
Likes: 1
Valid point and certainly true. However, I had a 69 with a LS6 crate motor with roller cam...no vacuum advance and no overheating. Didn't the L88 cars have no vacuum advance as well?
Not nececessarily the root cause. If this is indeed the car Mr. DeWitt referenced and it has no vacuum advance, then while the car is moving and the engine is above idle, the timing is advanced by the mechanical advance, but at idle the mechanical advance may be adding no timing at all (when a vacuum advance would be doing its job) and you get an overheat situation.
DT
DT
Le Mans Master
Joined: Mar 1999
Posts: 5,401
Likes: 986
From: Itasca IL
Nick,
Sorry to hear you are having problems with the new build.
It has been obscenely hot in Chicago this summer. I drive my L-68 almost every day. On 90+ degree humid days, the car will reach 190-195 at the upper radiator hose while standing still. At speed it drops down to about 180. It never gets hotter than 195, no matter what. Cooling system is 100% factory configuration, with brand new fan clutch and fresh coolant. I think you have either a problem with airflow AND/OR a timing problem.
As JohnZ asked, please tell us more about your timing configuration.
Out of curiosity, why use and electric fan instead of maintaining the OE setup?
Sorry to hear you are having problems with the new build.
It has been obscenely hot in Chicago this summer. I drive my L-68 almost every day. On 90+ degree humid days, the car will reach 190-195 at the upper radiator hose while standing still. At speed it drops down to about 180. It never gets hotter than 195, no matter what. Cooling system is 100% factory configuration, with brand new fan clutch and fresh coolant. I think you have either a problem with airflow AND/OR a timing problem.
As JohnZ asked, please tell us more about your timing configuration.
Out of curiosity, why use and electric fan instead of maintaining the OE setup?
Pro
Joined: May 2010
Posts: 560
Likes: 2
From: North Las Vegas Nevada
But if you just swap out a vacuum advance distributor for pure mechanical, and still set initial timing per the factory specs for that engine, and don't curve the distrubutor to compensate...
DT
Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,926
From: Washington Michigan
Former Vendor
Joined: Jan 2000
Posts: 5,593
Likes: 631
From: Brighton
As far as Electric fan go, I happen to like them but let me explain.
The original engine driven design was fine and when everything is set up right there should be no reason to go with electric or flex fans.
Electric fans can move a lot more air than the stock system and the more air through the core, the more heat rejection. In problem cases when you need to boost the cooling system beyond the normal range, electric fans are the answer. I do not believe in multiple systems such as the OP using flex fans with electric fans.
Team Owner
Joined: May 2006
Posts: 37,671
Likes: 1,115
From: CA
I think we may have lost the OP. I too would like to hear more.
As far as Electric fan go, I happen to like them but let me explain.
The original engine driven design was fine and when everything is set up right there should be no reason to go with electric or flex fans.
Electric fans can move a lot more air than the stock system and the more air through the core, the more heat rejection. In problem cases when you need to boost the cooling system beyond the normal range, electric fans are the answer. I do not believe in multiple systems such as the OP using flex fans with electric fans.
As far as Electric fan go, I happen to like them but let me explain.
The original engine driven design was fine and when everything is set up right there should be no reason to go with electric or flex fans.
Electric fans can move a lot more air than the stock system and the more air through the core, the more heat rejection. In problem cases when you need to boost the cooling system beyond the normal range, electric fans are the answer. I do not believe in multiple systems such as the OP using flex fans with electric fans.
I should have looked before asking, i see you sell them but are they tested for accuracy?
jack
Last edited by 66jack; Jul 23, 2010 at 12:07 PM.
Melting Slicks
Joined: Dec 2004
Posts: 2,021
Likes: 84
From: Florida
Nick,do you have a heat riser on the exhaust system.If you do check to see it opens all the way.That will make your motor run hot,It happened to me.When i relized the problem a quick fix and problem solved .Bob W