Randy G.

Remember my '62 I purchased that overheated from a guy who found it for sale by a family of a guy who was restoring it 15 years ago but died? It had a new Al Knock interior, Targetmaster 350, powerglide, power windows, nice hard top. I installed a new Dewitt's restoration radiator and chased my tail on everything and even took the advise of everyone on hear just to make it more fun? I discovered a cracked head, swapped both of them out and it still overheated. I did all the usual things like vacuum advance, checking the counterweight advance curve, swapped water pumps, larger fan, HD truck fan clutch, sealed the radiator with foam like Frankie said, thermostats drilled, no thermostat, straight distilled water, shop fan blowing in the grill, sprayed water on the radiator with a hose while running and it just heated up. Then I posted this after running 5-6 minutes in my driveway:





So, I took the 350 Targetmaster engine out, installed a new 383 long block stroker motor with aluminum heads along with a 700R4 overdrive automatic and the only thing I didn't replace in the entire process was the old Edelbrock "Streetmaster" intake manifold. Guess what. It still got hot.

The Streetmaster's were last sold by Edelbrock in 1978 or so. They have an open plenum and short straight port runners.

I stripped the paint off of it and noticed it had a few weld repairs around one of the carb studs but looking it over very carefully I could find no hidden cracks or anything from that would suggest any problems. With this manifold the 383 had a little bit of a hesitation off idle in as you would start to accelerate up to about 10 miles per hour almost like a lean spot.

Because I knew the right manifold should have a divider in it for an automatic rather than an open plenum I decided the last straw was to buy the only lower profile aftermarket manifold that would let me close the hood without shoving the air cleaner stud and wing nut through the hood. It was the Edelbrock Performer series.

I bolted it on Thursday and drove it all over the place. The hesitation is gone, drivability is significantly improved and the water temp is down 35-40 degrees. I drove it from my shop to home on the freeway which is about 15 miles and the temp went from 185-195 with a couple of instances after sitting in traffic where it pushed it past 205. When traffic would clear it would drop back down to 185-190. Significant improvement.

I actually talked to Tom Dewitt via email last week about installing an electric puller fan before considering a manifold swap. He told me to look elsewhere because as severe as the overheating problem was a fan won't solve it. I think he was right.

So, I'm heading out the door to the Silverado Days car show to check it out, then I might head on down to Huntington Beach with it.

As far as the manifold goes, there appears to be no significant difference between the water jackets/passages between the two that would make any difference. Speculating I could say the Streetmaster may have a crack beneath the plenum that when cool is closed but as it warms up it opens and leans the engine. Other than that and the difference in air flow characteristics possibly creating a lean condition I have no clue why an intake manifold swap would cure an overheating problem. In the driveway at idle both manifolds are pulling just short of 15" of vacuum.

Who knows.


.

GTOguy

Thanks for the update, Randy. That is just plain STRANGE. 383's are a bunch of fun, so you didn't wast money in my book.

Westlotorn

Congratulations on the improvements. You worked really hard and long on this project.
I guess now you know you have a good target 350 as a backup engine.
Enjoy the new 383. How much of a power improvement did you gain?
I have seen Lean Burn conditions detonate pistons till they fractured without causing a over heat problem. Combustion Temp from lean burn will raise temperature but should have shown up with other indicators, spark plugs burned white, no light brown or gray color, detonation issues, pinging, power fade under hard acceleration ect. Memory says you were very happy with the way the 350 ran other than overheating.
Maybe the old manifold had an internal coolant blockage or it somehow pinched the thermostat so it could not function. Glad you got it fixed.

cardo0

Hey thats soom good info and thx for sharing. Wow a quirky intake! If u investigate further and find the cause please post w/some pix - it helps us all.

Well now u have a good 4 bolt block to use or build as a spare motor too. Im sure your happy w/that strocker though. Nothing wrong w/a performer intake. Weiand Action series is low profile also or if u can find an older Weiand Sealth 8016 (maybe used only now) that have a low profile and a larger rpm range to match your stroker: http://www.jegs.com/installationinst...5/925-8016.pdf. Well on the other hand maybe youve had enough of used intake manifolds?


Congrats.

SI67

FYI: Looks like the "Action +Plus" manifold for the small-block, at least, has been renamed "Street Warrior."

It's great to hear that the problem has been solved.

cardo0

Intakes are a lot like corvettes , u never have enough of them and your always looking for a better one.

65-StingRay

That's great - I love a happy ending.,
I remember your previous posts.
It's almost unbelievable a manifold change could cause such a huge difference.
Glad the perseverance paid off.

65-StingRay

Randy G.

I'm sure there is some sort of not-so-complicated explanation. Like I said, the water passages in the front of the manifolds around the thermostat housing and between the heads are nearly identical between the old and new. And it was holding good vacuum. I just retested vacuum tonight after messing with the TV cable adjustments on the 700R4 and the new manifold is holding just short of 15" which was exactly what the old manifold was getting, meaning an internal vacuum leak is unlikely.

tuxnharley

That's a really strange outcome, that the intake swap could make such a difference in the engine cooling.

I'm wondering if maybe there was some kind of restriction to coolant flow in the old manifold? Possibly an internal casting flaw - core shift, flashing remaining untrimmed, offset cooling passages to the heads, or ????

Was the passage below the thermostat housing clear through back to the coolant runners?

Did the gaskets line up properly on both sides between the intake and the heads?

It seems like it has to be one of those sort of things, given that the vacuum was the same in both manifolds?

Randy G.

I looked for obstructions, casting flaws, misalignment of the manifold to head by inspecting the intake gasket witness marks when I took the old one off, and even checked the thermostat area to make sure there was no reason the thermostat wouldn't work correctly. I even swapped the temperature sending unit from one side to the other just in case it somehow was obstructing the water passage. All of this is why I never bothered to replace it thinking "That ain't it!"

Gary's '66

Same could be said for women.

Gary

LouieM

The strangest case of overheating I've ever hard. Glad you solved the problem, but I wonder what actual condition of the manifold caused the problem.

jim lockwood

Randy,

In the interest of doing good science, you could reinstall the old manifold and verify that the overheating problem returns.

But if it doesn't, well.......

Jim

tuxnharley

Hey, sorry, I didn't meant to appear to be questioning your analytical abilities. It's just that I have enjoyed following your two threads about this problem, and have been intrigued as to what the cause was. This all has left me feeling like a murder mystery without the "who done it" ending!

If it was me, I'd either be going into that old manifold with my fiber optic inspection tool in every passage way - or just throwing it away without even looking, in case that didn't show anything either and thus made the mystery even worse!

I mean, it's GOTTA be some kind of coolant flow obstruction, right? What else could it be given the circumstances?

Randy G.

LOL.

I thought about this:

For sale. Edelbrock "Streetmaster" aluminum intake manifold. Has a couple of repairs as evidenced by the welds around a carb stud, is a design that was discontinued in 1978, works real well for about 7 minutes, and was last seen in a dumpster in So Cal yesterday. $666 or take over payments.

Just to toss another wax log on the fire I did change the thermostat back to a 180* when I put the new manifold on. It's a new Echlin from NAPA, and I drilled two .125" holes in it to allow it to *burp*. It originally had a new 180*, drilled it, then I changed it to a new 160* drilled, and now it's back to another brand new 180*. If you remember I also (just for fun) ran it without a thermostat and that didn't work. Maybe the 3rd thermostat fixed it.

Now maybe I can start cleaning up the wiring mess and detailing it along with everything else. I'd like to put a stock looking air cleaner and ignition shielding on it as well. Don't yell at me over the plastic fuel filter. It's outta here as well.

tuxnharley

That could be a candidate for a "Best of Craigslist" award!!

dmaxx3500

could have been a ''reverse'' water pump,would have run fine till you put a load on it---`-``

OLDED

Assuming that the new 383 has different cam specs and more aggressive initial and total ignition timing, a lot of the Streetmaster overheating could have been in the timing curve in the old engine. Retarded timing causes overheating.

Randy G.

The manifold was on both engines and both overheated similarly. I am using the original single point tach drive distributor which is set with 34 degrees total timing at 3,500 rpm with the vacuum advance disconnected using advance weights only. At idle it's at 9 degrees w/o vacuum advance. Hook up the vacuum advance to manifold vacuum and it idles with 25.5 degrees total. I have a B26 can on it. Everything I've ever known shows best idle timing for lower idle temps all in is 26 degrees at idle. BTW, the manifold vacuum at idle is 14" which I thought was pretty good considering the hydraulic roller cam that's in it.

Westlotorn

Enough of the Cooling Issue nightmare.
How the heck does the new 383 run.
Are you happy with the changes.