350 Olds Motor/Heads Need Info

[joe_padavano]

HELLO:

Note that the majority of the issues with the OLDS motors involve cooling issues. From the factory, an effort was made on the Firebird/TransAm to keep coolant system pressures down by using an "open" coolant system. Although a pressure-rated radiator cap is used, the unpressurized overflow reservoir vents coolant pressure from the radiator. Attempts to defeat/improve this stock coolant system have resulted in excessive coolant system pressures and blown freeze plugs.
Some mechanics indicate "movement" of coolant visible in the radiator shows water pump activity, but this may/may not be true. Movement of coolant in the radiator could also be an indicator of combustion chamber gases in the coolant resulting from a leaking/blown head gasket. There is an exhaust gas detector for coolant systems available to adapt to radiators.
Factory engineers normally don't deviate from known good systems. The OLDS motor was dropped from production early-on. If the OLDS motor is the only GM motor to have the water pump bypass tube in place, that indicates the engineers felt an issue at hand with the coolant system on the OLDS motor. Note that the Chevrolet small block water pump takes coolant directly off both sides of the block and does not have a bypass tube. This is a dramatic departure from the OLDS design.

Mark

Sorry, but again, you need to get an understanding of how the coolant flows in the block. The pump sucks coolant in from the bottom radiator hose and pushes it into the block through the two holes in the front cover. The two larger round holes near the top of this Olds front cover are the water pump outlet holes into the block cooling jacket.

This is EXACTLY the same coolant flow path as on a Chevy motor (or ANY other GM V8). The coolant then flows through the block, into the heads, into the crossover at the front of the intake manifold, and through the thermostat into the upper radiator hose. Again EXACTLY like on any other GM V8.

Note that the Chevrolet small block water pump takes coolant directly off both sides of the block and does not have a bypass tube.

No, it doesn't. It "takes" coolant from the bottom of the radiator and EXPELS it into both sides of the block, JUST LIKE THE OLDS and Buick, and Pontiac, and Cadillac, and Ford, and Chrysler motors.

The "unpressurized overflow tank" is unique to Olds motors? Really? I guess the ones on my Chevy trucks must be something special. The pressure in the cooling system is governed by the radiator cap and the restrictions in the flow path. I have NEVER heard of any blown freeze plugs on an Olds (or any other motor) due to coolant system pressure. I even had the thermostat fail closed in my 69 Hurst/Olds and the 16 psi cap vented before anything else.

The OLDS motor was dropped from production early-on.

Really? The last Olds V8 was built in 1990 (it was also the last production car engine built in the US with a carb). The last Buick V8 was built in 1980. The last Pontiac V8 was built in 1981. You might want to check your facts.

Note that the majority of the issues with the OLDS motors involve cooling issues.

Again, news to me and the millions of other folks who bought Olds-powered cars in the 1960s, 70s, and 80s.

 

[joe_padavano]

HELLO:

Several varieties of the Edelbrock RPM line, RPM, RPM Performer and RPM Performer/AirGap. With the RPM
Performer on the OLDS350, on disassembly, I noted the "turkey tray" had contact marks scorched into the tray where it had touched the intake manifold.
This scorching again goes back to the HIGH importance of the intake manifold in carrying coolant to/from the cylinder heads and engine block. ALL of the coolant to the radiator goes through the front of the intake manifold, so the manifod gets HOT!

Again, that statement doesn't pass a sanity test. You're telling me that 200 deg coolant (even 250 degree coolant) can SCORCH aluminum? Really? News to any metallurgist I know. If the gasket is touching, the "scorch" marks are just from rubbing. The oil splashing on the bottom of the gasket (or the bottom of the intake if you don't run that gasket) is hotter than the coolant. Oh, and if the coolant at the crossover at the front of the intake is that hot, what about the exhaust crossover that goes under the carb? Sorry, but your statements are getting more and more rediculous.

I noted that the center water/coolant ports in the FELPRO fiber intake gaskets were blocked off. These could assist in cold-weather warmup if you opened them up.

News flash: Those aren't coolant holes. Those are the EXHAUST CROSSOVER holes.

An interesting note is that on the Firebird/TransAm OLDS versions, the TEMPERATURE gauge starts at 220 degrees! Gives you an indication of how HOT the factory expected these to run! My AUTOGAUGE reads 165 degrees most of the time.
Mark

Must be a Pontiac thing then, because every Olds factory coolant gauge I've ever owned starts at 100 deg F. I've never seen over 220F in any Olds I've ever owned.

 

[78 salon]

Joe, reading this guys 4 posts has realy made my head hurt. Guess that's why his title is "noob". 🙂

 

[joe_padavano]

Joe, reading this guys 4 posts has realy made my head hurt. Guess that's why his title is "noob". 🙂

Maybe it should be "boob"... :lol:

 

[DrRansom442]

try as I might I couldn't get the turkey tray to fit under my Performer intake.

:?: That's odd, which Performer? The felpro one fits just fine under my RPM small block intake.

3711, I forget who's turkey tray though - I may have to dig through the receipts. I even tried to "notch" a 5"x5" hole to clear the lowest hanging runner .... wound up just cutting the tray into nothing but the sides.

 

[DrRansom442]

aside from my Toronado, I've never had an Olds run more than a constant 210 degrees - Calais with the 260 ran a pretty constant 190-200 in 100 degree summer heat .... the Toronado had a blow head gasket (and no reverse) and I still drove it for 8 months

 

[marcar1993]

An interesting note is that on the Firebird/TransAm OLDS versions, the TEMPERATURE gauge starts at 220 degrees! Gives you an indication of how HOT the factory expected these to run! My AUTOGAUGE reads 165 degrees most of the time.
Mark

I beg to differ. Take it from a trans am owner and aficionado who has been around them my entire life. The pontiac and olds motor cars had the same gauges and the temp gauge started at 100 then went to 220.

 

[2fit661ca]

HELLO:

The OLDS motor was dropped from production early-on.

who the hell is this guy...? this is g-body forum, a forum dedicated to certain cars built between (1978) 1981-1988... One ofthose cars being the Olds Cutlass Supreme which used an OLDS V8 motor... Buick had the 3.8 V6, and Chevy had the 305 V8... OLDS had one of only 2 V8s put into the 8+ different G-bodies...

 

[jrm81bu]

OLDS had one of only 2 V8s put into the 8+ different G-bodies...

What? Might want a recount.

 

[2fit661ca]

OLDS had one of only 2 V8s put into the 8+ different G-bodies...

What? Might want a recount.

uh... plus the 301 and 260