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Overheating big block - could use some suggestions...?

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Overheating big block - could use some suggestions...?

 
Old 06-12-2019, 10:38 AM
  #81  
OldCarBum
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Could be worse!
I don't know how much worse it could be, but it could be!
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Old 06-12-2019, 10:47 AM
  #82  
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Originally Posted by OldCarBum View Post
Could be worse!
I don't know how much worse it could be, but it could be!
LOL the only thing I haven't touched at this point is the Crank, Rods, Pistons and associated bearings. Thankfully those were assembled by Chevrolet not Bubba.
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Old 06-12-2019, 10:54 AM
  #83  
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Originally Posted by BigBill94 View Post
LOL the only thing I haven't touched at this point is the Crank, Rods, Pistons and associated bearings. Thankfully those were assembled by Chevrolet not Bubba.
With everything you've found, it might be worth it to pull them, inspect everything and reassemble.
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Old 06-12-2019, 03:51 PM
  #84  
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Originally Posted by BigBill94 View Post
I've pulled the radiator, both cylinder heads, all of the accessories. Heads are going to a shop to get checked.

I'm going to sell the BeCool radiator/fans/overflow tank that were on it, I ordered a DeWitts HP series kit for my 1970. I picked up a Mighty Demon 850 CFM to replace the 950 ProForm that was on it.

What I've learned so far:

- Water pump is correct, it's a standard rotation Edelbrock Victor, P/N 8850, which is correct for my serpentine set up, it looks fine, spins freely
- Unrelated, all 4 tie rod ends were missing cotter pins!!
- The cylinder head bolt torque was all over the place, some were just past snugged down, others took a 2' piece of pipe on a 18" breaker bar to get loose. They're ARP head bolts
- The pistons (and heads) were caked with soot from an overly large carburetor not jetted properly, heads LOOK to be in great shape, wiped down the pistons with carb cleaner, worked pretty well. (Subsequently wiped them down with oil)
- The passenger side head / pistons were noticeably cleaner than the driver's side for whatever reason (Coolant getting into the cylinder?)
- It has high end steel full roller rockers on it, a Lunati hydraulic roller cam most likely as that's what's on the roller lifter crossbar.

I am going to pull the harmonic balancer and see what camshaft is in the damn thing while I'm at it. In for an ounce, in for a pound.

Guessing it will take me a couple of weeks to come back out the other side of the tear down....
You will like the Dewitts with dual fans. I have it and my 496 can idle all day in the heat.
FYI I still have the water pump to manifold bypass hooked up with no issues at all.
( Also wanted to reply and make sure I saw how this who-done-it turns out)

Last edited by scottjamison; 06-12-2019 at 03:52 PM.
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Old 06-12-2019, 04:06 PM
  #85  
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Couple of thoughts. I am running a 496 BBC, older March Serpentine, 195 hi flow stat, DeWitt radiator and dual Spal fans (controlled by FAST XFI 195 on/185 off) in FL with no issues.

1) March likes to include a "Performance" crank pulley in their serpentine kits. This is a smaller diameter pulley to slow down the accessories and increase HP. I called March and got a larger crank pulley (7" vice 5-3/4") which helped speed up the water pump (also helped with the alternator at idle). Just need to get a longer belt.

2) Spoiler. I have a '75 with the stock spoiler. I added the '79(?) L-82 spoiler extension and that really helps keep the car cool at speed.

Bottom line, in traffic fans cycle and keep car cool. Above 40 mph, fans are not needed at all.
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Old 06-12-2019, 04:12 PM
  #86  
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Originally Posted by SteveG75 View Post
Couple of thoughts. I am running a 496 BBC, older March Serpentine, 195 hi flow stat, DeWitt radiator and dual Spal fans (controlled by FAST XFI 195 on/185 off) in FL with no issues.

1) March likes to include a "Performance" crank pulley in their serpentine kits. This is a smaller diameter pulley to slow down the accessories and increase HP. I called March and got a larger crank pulley (7" vice 5-3/4") which helped speed up the water pump (also helped with the alternator at idle). Just need to get a longer belt.

2) Spoiler. I have a '75 with the stock spoiler. I added the '79(?) L-82 spoiler extension and that really helps keep the car cool at speed.

Bottom line, in traffic fans cycle and keep car cool. Above 40 mph, fans are not needed at all.
Where did you get the 79 spoiler? That might be good for mine.
I don't have the seals in yet (they just arrived) so my fans still cycle on the highway, so I want to get those on and look at removing the license plate and the better spoiler.
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Old 06-12-2019, 04:26 PM
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Originally Posted by scottjamison View Post
Where did you get the 79 spoiler? That might be good for mine.
I don't have the seals in yet (they just arrived) so my fans still cycle on the highway, so I want to get those on and look at removing the license plate and the better spoiler.
I got it from Wilcox Corvette. Not sure if it will work with the chrome bumper cars but works great on rubber bumper (73-79 w/o the pace car spoiler). It basically rivets onto the stock spoiler.

https://willcoxcorvette.com/corvette...oling-l-82-eng


Good pics in this thread.
https://www.corvetteforum.com/forums...-airdam-2.html

My car:
https://www.corvetteforum.com/forums...post1599180381

Last edited by SteveG75; 06-12-2019 at 04:32 PM.
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Old 06-12-2019, 04:41 PM
  #88  
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BigBill- in the post where you show your head, head gasket and block- think it is post #45- unless I am putting the gasket on from the photo incorrectly, it looks like your front and rear coolant passages are blocked off by the gasket. If that is the case, your front and rear cylinders are getting coolant flow only from the passages at the outer and inner side of the block and would run a lot hotter than they are supposed to. Or am I looking at the photo wrong? When I did the 454 in my convert, the head gaskets that came with the rebuild kit were wrong and the holes on the gaskets did not line up with the holes on the block/head. Fortunately I noticed before I put everything together and got the correct ones.
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Old 06-12-2019, 05:01 PM
  #89  
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Originally Posted by ronarndt View Post
BigBill- in the post where you show your head, head gasket and block- think it is post #45- unless I am putting the gasket on from the photo incorrectly, it looks like your front and rear coolant passages are blocked off by the gasket. If that is the case, your front and rear cylinders are getting coolant flow only from the passages at the outer and inner side of the block and would run a lot hotter than they are supposed to. Or am I looking at the photo wrong? When I did the 454 in my convert, the head gaskets that came with the rebuild kit were wrong and the holes on the gaskets did not line up with the holes on the block/head. Fortunately I noticed before I put everything together and got the correct ones.
I had this same concern, I have a Mark VI block, the coolant passages are different. https://www.fme-cat.com/digipubZ/Fel...%22page%22:32} On page 30.

Someone posted this which was a huge help... And I called just to make sure. Edelbrock heads are compatible with either Mark IV or Mark V/VI blocks.
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Old 06-12-2019, 05:22 PM
  #90  
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Originally Posted by SteveG75 View Post
Couple of thoughts. I am running a 496 BBC, older March Serpentine, 195 hi flow stat, DeWitt radiator and dual Spal fans (controlled by FAST XFI 195 on/185 off) in FL with no issues.

1) March likes to include a "Performance" crank pulley in their serpentine kits. This is a smaller diameter pulley to slow down the accessories and increase HP. I called March and got a larger crank pulley (7" vice 5-3/4") which helped speed up the water pump (also helped with the alternator at idle). Just need to get a longer belt.

2) Spoiler. I have a '75 with the stock spoiler. I added the '79(?) L-82 spoiler extension and that really helps keep the car cool at speed.

Bottom line, in traffic fans cycle and keep car cool. Above 40 mph, fans are not needed at all.
Interesting, I just measured the crank pulley, it's a 7" pulley.

I'm looking at those spoilers now.
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Old 06-12-2019, 06:27 PM
  #91  
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Not seeing anything that would fix the overheating (maybe I missed it).
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Old 06-12-2019, 07:31 PM
  #92  
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Originally Posted by 97C5 View Post
Not seeing anything that would fix the overheating (maybe I missed it).
I believe #5/#7 were leaking exhaust into the cooling system based on the compression check. Then I found out why that might be the case, the heads were not installed properly.
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