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Overheating on Hwy 350 SBC

How has this post lost sight? You're having an overheat issue and we're giving you valid reasons why. :dunno:

A heavy vehicle, stall convertor, high compression, high RPM's just don't mix. Just because you might have built the same engine for a 3500lb. car doesn't mean it's going to work in a 6000lb truck.
 
4X4HIGH said:
How has this post lost sight? You're having an overheat issue and we're giving you valid reasons why. :dunno:

A heavy vehicle, stall convertor, high compression, high RPM's just don't mix. Just because you might have built the same engine for a 3500lb. car doesn't mean it's going to work in a 6000lb truck.
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Well 2 things, hind sight is 20/20 and where there is a will, there is a way.
My buddy has the Identical engine but stroked 383 and it took awhile, but we got that engine to just rock in that truck., it had heating problems too, and we got that tweaked out finally and it still runs like new, 62000miles later.
 
Figured I'd give you my input over many many engine R&R's. You have a timing issue. Yeah it may run great however at speed you get different vacuum pressures and thus different timings. Even mechanical it will change. The fact that you have "no power on throttle" at 50+ when it's only at 215 deg tells me their is almost no other reason for the problem... Especially with a "race engine" as you claim. Do the timing. You need to probably adjust a good 6 degrees one way or the other at least. You're way off on timing though. Have a 67 stang and 68 camaro that both did the exact same things after engine swaps.

If you've checked the timing and it still does it... recheck the timing because it's still wrong. Hope this helps.
Josh

PS. If it's still doing it and are sure it's right. Drive it until it gets hot. As soon as it's hot immediately slow down and check for the fans functioning properly.
 
The fact that you have "no power on throttle" at 50+ when it's only at 215 deg tells me their is almost no other reason for the problem...
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Other that the fact that he is trying to move 6000 lbs of truck that is overgeared for the tires and over cammed and probably over carbed for the RPM the engine is turning.....

face it........ as stated before you can't throw a 10000 RPM race engine in a brick with tall gears and tires and expect it to perform at 1700 rpm....
just ain't gonna do it.......
 
Mountain_man said:
Figured I'd give you my input over many many engine R&R's. You have a timing issue. Yeah it may run great however at speed you get different vacuum pressures and thus different timings. Even mechanical it will change. The fact that you have "no power on throttle" at 50+ when it's only at 215 deg tells me their is almost no other reason for the problem... Especially with a "race engine" as you claim. Do the timing. You need to probably adjust a good 6 degrees one way or the other at least. You're way off on timing though. Have a 67 stang and 68 camaro that both did the exact same things after engine swaps.

If you've checked the timing and it still does it... recheck the timing because it's still wrong. Hope this helps.
Josh

PS. If it's still doing it and are sure it's right. Drive it until it gets hot. As soon as it's hot immediately slow down and check for the fans functioning properly.
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Well if I get time I should have my new dist in atleast, I know it dropped 10degs when I plugged off the vac advance, so that is when I pulled the cap off and found the center pins about broken off and advancing 34degs instead of the 22 it was suppose to have. Junk HEI's, they always have given me trouble, from welding themselves down to broken springs and pins and the weights flat wearing out from slaping the center.
But this engine has had over heating problems from the get go, I think I am chasing a circle, because the dist was right, and I had problems, it started out by ditching the flex fan and installing a shroud and clutch fan, then a/c was added and I installed a new radiator and electric fan with the high throttle silenoid, which is the fan is dioded off from and works awesome with the winch, 1500rpms at a flip of a switch, then it ran pretty good for about a month, then winter, now summer and I have the problem again,
there is one other question someone might have the answer too, the fuel lines I am using is the standard line from tank and I am using the old charcoal return line as a return off the pump, the tank does have a vent line if I remember right, but when you remove the fuel cap it blows out of your hand with pressure in the tank, really badly below a quarter tank. I have yet to figure that one out too.
 
Yep thats right, B&B engine, pop up pistons, large chamber heads to cut the compression back to pump gas, roller rockers, Scat crank and rods, world heads, etc, etc. RPM air gap intake, RPM Cam, 1411carb that I have ordered parts to jet as a 1407, MSD 6, just ordered a MSD pro billet dist to replace that HEI, afterburn headers, 2.5 dual exhaust, with Flowmaster 40 something mufflers. That engine was balanced at 10,000 rpms and I know the valves float at about 7800rpms,
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I know it dropped 10degs when I plugged off the vac advance, so that is when I pulled the cap off and found the center pins about broken off and advancing 34degs instead of the 22 it was suppose to have
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Wow,,,all that motor ....
with a worn out HEI in it...:rolleyes:

hhhhhhhhmmmmmmmmmmmmmm.
 
If it was in a post, I missed it..... Tell us about the radiator.

I've had a couple engines over the years that had similar symptoms. A radiator in good shape, but whose cooling fins are clogged with bugs or dirt will often cool fine at low speeds and rpm's, but tend to heat up on the open road.

A good high pressure wand usually takes care of the bug/dirt issues.
 
wasted wages said:
Wow,,,all that motor ....
with a worn out HEI in it...:rolleyes:

hhhhhhhhmmmmmmmmmmmmmm.
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It was a new NAPA reman, when the motor was built, 8000 miles and it has started to fall apart, go figure,

and its NOT by any means a race engine, the SHORT block or rotating assembly is the same, NOTHING ELSE. My race engines have massive alum. heads, victor intake, 1050 carb, girdles, crank scrapers, dry sump, electric water pump, solid lifters, 300+cams not a wennie 256 Rpm cam, oil restricters, galley is coated, etc etc, the engine is just a plain street/strip build engine using Edelbrock RPM components plus world heads, crane roller rockers, comp cam push rods, stock everything else. Its a very street able engine.
 
wasted wages said:
Other that the fact that he is trying to move 6000 lbs of truck that is overgeared for the tires and over cammed and probably over carbed for the RPM the engine is turning.....

face it........ as stated before you can't throw a 10000 RPM race engine in a brick with tall gears and tires and expect it to perform at 1700 rpm....
just ain't gonna do it.......
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While I agree however 215 deg is by no means overheating. It's "close" but not in an area where their should be any problems down shifting and gaining power. My suburban is the 8600gv model and I can say it is underpowered due to 35" tires and 3.73 gears however I've never had a problem down shifting and accelerating. If he can accelerate up to 50mph fairly easily then why not down shift and accelerate again? *shrug* Hope you check some of the things mentioned among all the members and find the reason though. Let us know what you come up with as well.
 
JPMSK5 said:
It was a new NAPA reman, when the motor was built, 8000 miles and it has started to fall apart, go figure,

and its NOT by any means a race engine, the SHORT block or rotating assembly is the same, NOTHING ELSE. My race engines have massive alum. heads, victor intake, 1050 carb, girdles, crank scrapers, dry sump, electric water pump, solid lifters, 300+cams not a wennie 256 Rpm cam, oil restricters, galley is coated, etc etc, the engine is just a plain street/strip build engine using Edelbrock RPM components plus world heads, crane roller rockers, comp cam push rods, stock everything else. Its a very street able engine.
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So let me get this straight, you have a bottom end built like a race engine then you throw stock stuff up top and expect it to run perfect. :dunno: You need to learn that every component of an engine works together in harmony to make power and run correctly. You certainly can't expect an engine with domed pistons to work correctly with a pair of stock flowing heads.

What do i know, i've only been building engines professionally for 22 years.
 
4X4HIGH said:
So let me get this straight, you have a bottom end built like a race engine then you throw stock stuff up top and expect it to run perfect. :dunno: You need to learn that every component of an engine works together in harmony to make power and run correctly. You certainly can't expect an engine with domed pistons to work correctly with a pair of stock flowing heads.

What do i know, i've only been building engines professionally for 22 years.
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:bow::bow:

:D
 
4X4HIGH said:
So let me get this straight, you have a bottom end built like a race engine then you throw stock stuff up top and expect it to run perfect. :dunno: You need to learn that every component of an engine works together in harmony to make power and run correctly. You certainly can't expect an engine with domed pistons to work correctly with a pair of stock flowing heads.

What do i know, i've only been building engines professionally for 22 years.
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I was wrong they are 72cc heads, World Products 012250-1, anyway, the compression came down to 9.78. The pistons is use what you got and I had that rotating assemble sitting under a bench and needed used for something. No longer in the mud run thing, to pricey, so a bottom end put together and paid for, why not.
 
Mountain_man said:
:bow::bow:

:D
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yea its not the idea engine built, and I dont dissagree with anyone that the motor is a half bred, but minus the pistons, compensated by large camber heads, the rest is a standard build in this area of the woods.
 
I don't claim to know everything but if you've got busted parts on the distributor then start there. If it's faulty it could very well be causing problems. Fix what's broke and if it still does it check more things.
 
JPMSK5 said:
everyone here builds 9:1 and 9.5:1 compression engines in this area, unless, it is a blown engine and they have been 7:1. All running pump gas 91octane.:confused::confused::confused:
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I was mainly eluding to the fact that I didn't think 9.78:1 was considered really high compression.
 
Mountain_man said:
I don't claim to know everything but if you've got busted parts on the distributor then start there. If it's faulty it could very well be causing problems. Fix what's broke and if it still does it check more things.
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dist overnight from summit, here tomorrow
 
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