Chvywolf

Ok Setup : 89 RS Conv, changed to holley 600. Swapped to 85 305 HO heads.

Problem: Engine will not get below 220 Degrees EVER.

Ok, before putting on the HO heads, i sat them next to the 89 heads and checked the water jacked hole and everything else i could think of. Even held up the head gasket to the HO heads and block. Both matched perfectly. Reason for the change was 89 heads were 64cc and the HO heads are 58cc with .01 smaller intake valve size. During summer, the car would always overheat. Tried it with 190 thermastat and with 170 and with none at all. Would always overheat in s&g traffic. Finaly put aftermarket electric fan running all the time(original fan burned up from running all the time. Blew the radiator cap just to let me know it stopped)

Solutions:? bigger radiator? But if so, why would changing heads from one year to another make that much a differance in heat?

Any help would be great.

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89 RS Conv 305 700R4
85HO heads
Edelbrock intake
Holley 600
Hedman Hedders and Y pipe
Flowmaster

Ski89Z28

Unless you have a 377 cu in or 383 cu in engine the radiator you have should be good enough. But i would check the timing cause I've heard people that had the timing off and it caused over heating.
Now first do you know if your water pump is good? Stupid question but I've got to start somewhere, sorry. If so since your car over heated enough to blow off the radiator cap I would first replace the cap. This is what went bad for me and before I replaced it I would always run at 220* or higher with both fans on!
I think your air dam is on and good cause you stated the problem is in stop & go traffic and not in highway.
The last thing and I don't know the answer is would going down to 58cc cause that much heat? I just don't know, sorry.

Good Luck!

Dan91Z

hmm.. almost seems like maybe there's something clogged in the water jackets in one of the heads..

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My `91 Z28 Convertible

[This message has been edited by Dan91Z (edited January 26, 2001).]

Keith5

Is that right? 64cc seems too big for a 305.



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1989 Pontiac Firebird Formula LO3 Auto
-180 degree stat
-Hooker Cat-Back
*****Possible summer '01 mods*****
Open Element, Auburn Posi, Keyless Entry, wonder Bar off the IROC, 4th gen seats, T/A tail lights

1985 Camaro IROC-Z LB9 Auto
http://www.geocities.com/krt80/

Chvywolf

Well, i know my water pump was working before i swapped heads because it ran at 170 all the time (exactly were i want it). The timming is at 12 degrees currently. I've had it from 8-16 degrees, and it still runs the same as far as heat goes. And my friends and i checked the heads completely over before we put them one so it's not a water jacket. (at least not that we saw. ran cleaner brush threw all the ports) The new cap i haven't tried yet. Will give it a shot this weekend and let you know.

Chamber sizes: Yes the 89 305 "E" engine TBI has 64cc chambers with 1.85 intake with 1.50 ex valves. This will make the stock engine about 9.3:1 compression.
85 305 HO heads have 58cc Higher flowing chambers with 1.84 in, 1.50 ext valve giving about 9.5- 10:1 compression dependong on decking and headgasket size. I'm at about 9.8:1 last i checked.

Thanks everyone. If you have anymore ideas, i don't care how crazy or how much i will kick myself for not trying them, i need them.
This is driving me NUTS.

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89 RS Conv 305 700R4
85HO heads
Edelbrock intake
Holley 600
Hedman Hedders and Y pipe
Flowmaster

[This message has been edited by Chvywolf (edited January 26, 2001).]

Keith5

My owners manual has that the L03 has 9.5:1 compression. "Basset Racing" pointed that out to me.

Chvywolf

Keith, you are absolutly right. The only reason i say it's 9.3 is that was what each cylinder came out to be on a (new)compression tester. Not trying to discredit you dude, just what it came out to be. Thanks for posting though.

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89 RS Conv 305 700R4
85HO heads
Edelbrock intake
Holley 600
Hedman Hedders and Y pipe
Flowmaster

84FTA

Blowing off the radiator cap says you obviously have some kind of faliure/blockage of the overflow. If the spring failed in the cap and it wasn't flowing to the overflow then that's where I'd start. When you overheat you should blow the cap off the resivour (depending what type of cap you have on the resivour, some blow off, some are lightly spring loaded with outlet holes).

Remember, pressure creates heat, so super heated water being pushed to the limit of blowing off the radiator cap means it's own compression was fighting it's cooling plus it slows down the water pump and the engine has to use more power (making more heat!) just to push the water pump.

Also you may want to see howmuch/any stuff has been logged into the A/C condeser and radiator. I had about a full bail of hay on my A/C condenser when I removed it.

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1984 WS6 Trans Am Hartop
Former L69 Car under restoration
1984 Trans Am T-tops
4-bolt main 350, performer intake, headers, Holley 650, T-5, hayes clutch, dual elec. fans and 3.23's.
Daily driver and restoration
13.98 @ 101

[This message has been edited by 84FTA (edited January 26, 2001).]

MrF-body

have you tried running the car without a thermostat? are you sure that it isn't running too lean? this would create really high heat conditions!

Red Devil

K, here is some silliness for you...
You are running at higher compression now, sooo... you're using 93 right?
Retard the timing down to 8º and see what you get.
Did you drop down to a colder plug?
All things to look at, probably just one or two of these will do it.

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"Question with boldness even the existence of a God; because, if there be one, he must more approve of the homage of reason, than that of blind-folded fear."

-Thomas Jefferson

Chvywolf

Haven't tried the new cap yet. Will do that tommorrow at first light. I have hooked up a air/fuel ration gage to it and tuned in the carb with no effect, and i did run it with 8 degrees with no change. Plugs are something i didn't think about. I have an Accel HEI super coil with Bosch platinum plugs. Plus running it with no thermostat on highway it gets to 220 but in stop and go traffic it will redline in about 10 min. Will let you know tommorrow if new cap works. May even try colder plugs. Thanks guys. Definitely have somethings to try now.

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89 RS Conv 305 700R4
85HO heads
Edelbrock intake
Holley 600
Hedman Hedders and Y pipe
Flowmaster

burnoutrpm

do you have the original radiator? the one with the plastic tanks? if so i have the solution! i have the same problem in the summer, spring, and fall, also winter! i have also tried everything and more than you ever want to consider! i came down to the radiatro, its never been relpaced!, cleaned but never, ever re-placed! im going to change the radiator to a aftermarket one thats a single 1 1/4 core( not becool!! and it'll be about 200$ i say its the radiator i know this for a fact i have the same thing and problem!

one mor consideration>??? do you have the air dam attached? does it overheat everywhere like mine?

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1989 firebird formula

Mods: converted from T.B.I. to a carburator 305 to a 350. Flowmater exhaust,hedman shortie hedders,202 heads,350 horse cam,bored.40 over, Edlebrock torker2 and a 600 edlebrock manual choke.

Future mods performer rpm air gap intake (polished) comp roller cam, and way better headsa 400 defintely in the works!

Chvywolf

Yes i have the original radiator. But if it is the radiator, does the 85 305 HO have a bigger one than the 89 L03? I do have the airdam. Maybe i'll just get a house window fan rig in a 120vac adaptor and throw it in the car. Shouldn't overheat then huh???



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89 RS Conv 305 700R4
85HO heads
Edelbrock intake
Holley 600
Hedman Hedders and Y pipe
Flowmaster

WickedV6

Your overheating problem made me think of something. While looking through a Jegs catalog, I saw some coolant additives. One was called "40 below", and the other was made by Royal Purple, and it was called "Purple Ice". Has anyone used them before? if so, what were your thoughts on them. I know that they wouldn't fix the problem, they would only increase the time it would take to heat up, so I'm sorry for not being much of a help.

L. Craig Conner
lonnieconner@hotmail.com

Bort62

Well burnoutrpm, I have my stock radiator with 150K on the car, and it never over heats.

You should be a little More cautios with Dispensing bad advice. Someone May actually listen to you.


Chvywolf, When you say the Cap blew off the radiator, Do you mean Off the Overflow tank, Or off the radiator itself ?

If the spring loaded rad cap is Not Functioning properly, it will never allow the Cooling system to become pressureized, and can cause premature boil overs ( Because as pressure increases, So does the boiling point )

Now, this is Not expressly Connected to the car overheating, Because If you are observing the temperature gauge In the "red" zone, then Weather its boiling over or not, its still a problem. However, If Your car is boiling over, you are loosing Coolant, and that can lead to overheating For obvious reasons, I had a Similar problem On My Sc due to a bad rad Cap, I would boil over coolant and Not notice, and one day I massivly overheated.

It is also possible that Your Temperature gauge is Malfunctioning, Or that there is air trapped in the water jacket adjacent to the Temperature sender.

If I were you, I would spring for a new Rad cap, about 10 bucks at Most, and See what You got from there. Next time the car says its overheating, stop pull over and take a look.

Is it ? You can usually tell. Is the coolant boiling in the overflow tank ? Does the motor feel unusually warm ?

DONT OPEN THE RADIATOR, I had a friend who once did that, a trip to the emergency room later with 2nd degree burns all over his chest and he will never do that again.

If the car Does not appear to be overheated, Then I would start looking at the temp sender.

if it does appear to be overheated, Then I would suspect blockage On The radiator( the good old birds nest, faulty water Pump, stuck thermostat, ect.

I would bet 5$ that a new rad cap solves it however.




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60 Ranchero - Project ( Money Hole )
85 Sport Coupe LG4 - Daily Driver

Just another Hot Rod kid, or thats what they all tell me.
Livin' the Stereotype

327 firebird

I would have to agree with RED. If you have 9.8:1 compression you really need to be running at least 92 Octane. If you run less than that your car will have detonation, which will definatly cause overheating big time!! Also I would find out what spark plug was OEM with the engine the heads came off of and use that one. Don't use the ones the were for your old heads. I agree to with retarding your timing to 8 degree's BTDC. After all that see if your overheating has gone away.. it should

Chvywolf

Bort I'll take that bet... give me about 1 hour. I'll let you know.

327, i do use 92 octane (didn't once will never do it again) The only thin runnig the engine at 8 degrees does is make it have crappy throttle response. NO change in operating temp. I'll have to get back to you on the plugs though. Thanks everyone. Will let you know what i come up with in about an hour.

MrF-body

here is another stupid idea! when you replaced the water pump are you sure you put the gaskets on right side up? if put on upside down they would restrict water flow, right? just a guess. also, does the car have a serpentine belt? is it routed around the water pump pulley the right way??

MrF-body

just thought of something else i had a problem with once. take to shroud covering the top of the radiator off. loo down between the radiator and the a/c condensor, is it full of dirt and leaves?

Keith5

My dad's truck's radiator has 190K on it and it doesn't overheat. I have an '85 IROC(which came with the highest output engine that year) and it looks like it has the same radiator that my '89 bird has.

------------------
1989 Pontiac Firebird Formula LO3 Auto
-180 degree stat
-Hooker Cat-Back
*****Possible summer '01 mods*****
Open Element, Auburn Posi, Keyless Entry, wonder Bar off the IROC, 4th gen seats, T/A tail lights

1985 Camaro IROC-Z LB9 Auto
http://www.geocities.com/krt80/

Chvywolf

Checked water pump, shroud is gone. Everything was workong fine untill i put the HO heads on. It has to be the heads, but i don't know how. Everything matched up and the water jackets were clear and clean. Only thing i can think of is the head gasket. Maybe it's restricting the water flow. i don't know. Replaced the cap and the plugs are exactly the same for the 89 and the 85 heads according to Pepboys, autozone and discount. i give up. Thanks for all the help though. I'll just buy a 350 and save myself the trouble of spending $$$$$$ on a crappy 305. Laters and again thanks to everyone who posted. well....220 isn't that bad...is it???

------------------
89 RS Conv 305 700R4
85HO heads
Edelbrock intake
Holley 600
Hedman Hedders and Y pipe
Flowmaster

87RS402

Is it possible that you are running a V-belt water pump on a serpentine setup? Running the water pump backwards would cause it to run hot for sure.

327 firebird

220 isn't that bad... its livable but higher than I would like it. The only thing I can think of is that you said the fan shroud is missing. Also make sure the air dam under sthe bumper is there... it directs air up to the radiator. The only other thing I can think of is for some reason your CR is above 10:1 (someone put different pistons in there?) Where using 92 Octane isn't enough need about 100 or so VP race fuel. But I doubt this in your case. I've heard of it happening with people who have 350's and put on the 58cc 305 heads... but since yours is a 305 it shouldn't happen unless someone screwed with the pistons or milled the head or block???

8Mike9

Were the heads fluxed before install?

Red Devil

Swap out to a colder plug. I love the Bosch, and it is usually the only thing I use. That said, there is always a but, and here is mine...
Bosch plugs run a tad hotter so they can do their self-cleaning thing, using these plugs in a higher compression situation as yours can cause some problems, esp. with iron heads. Pop those bad boys out and run some good ol' AC Delcos at one step colder, make sure you have a 60/40 (water/glycerine)or 50/50 mix (and maybe invest in a bottle of Water Wetter) and then let us know.

Keith5

I think I might have something here. You said that you cc'ed the old heads at 64cc's. An L03's chamber is about 58cc's. That is what you should have had in the car factory. 64cc heads are on 350's, is it possible somebody put a 350 in your car before you owned it? And the 305 HO heads don't flow enough to cool the 350 block?

slayer2000

iTrader: (1)

are you sure your choke is adjusted correctly? I had a 455 poncho that usaully ran 210 or so when I got it. about a week after I started driving I rebuilt the Q-jet and set the choke to factory specs. never over heated again.

82 TRANS AM

Sounds like a bad head gasket (i know they are new) or a cracked head to me. And no, all the electric fans you could fit in there would'nt help.

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Kenney
82 Trans Am WS7 notchback
83 Trans Am WS6 T-tops
72 Vista Cruiser 455
90 Olds Trofeo
80 K-10 w/snow plow
Painter @ Chevy dealer
GM junkie

Black Beauty

no..its not a 350...he had a TBI...b4 he threw the holley on there.
as far as the over heating...could it just be the higher compression?? is your lower and upper rad hoses good....lower one can collapse sometimes. have you flushed radiator? cleaned fins? overheating problems can come out of nowhere...could have been a coincidence that you changed the heads...so dont rule that out. good luck.

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Rick
90 Camaro RS 305 TBI
400 small block, Hooker 1 3/4 LTs, Random Tech Cat, Hooker aero chamber cat back on the way!!
TH700-R4 with Trans-Go shift kit (corvette servo here...but not installed yet)
MacEwen Motorsports White Gauge Overlays
14" K&N X-Stream Open Element
GTS Headlight and Taillight covers
5% Limo Tint all around
Classic White Chevy Bowtie sticker on rear window
http://www.geocities.com/esvalenz

Man if my camaro were a rice-rocket all those mods would give me what...easily 50-60 hp!!!

"Just because I've done it, doesn't mean I knew what I was doing!" - Me

Keith5

I know he had TBI before. My TBI motor has 9.5:1 compression and should have 58cc heads. The HO had 58cc heads, and 9.5:1 compression. That's why I asked if somebody had put a 350 in it. Some 350's have 64cc heads.https://www.thirdgen.org/messgboard/Forum11/HTML/000714.html



[This message has been edited by Keith5 (edited February 04, 2001).]

86TpiTransAm

Take the heads off and have them magnafluxed for cracks!! A cracked head would definitely cause an overheating problem! It makes sense.... the car was running fine with the other heads, then you swap heads and it starts running hotter! Sounds like a cracked head to me!

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1986 Trans AM
305 TPI
4 Wheel Discs
9 bolt Borg Warner Rear
Completely Stock
Soon to upgrade to a 383 stroker w/TPI, Hedman Shorty Headers, 64cc Pocket Ported Worlds Product Sportsman-II heads, ported intake, comp cam, TPIS air foil, Adjustable Fuel Pressure Regulator, and 24 lb/hr SVO injectors!
Current project: Keeping my car running until I get the money for the above mentioned project! :-)

oldschoolrodder

I know that you said you have checked your water pump. I just want to say that I had the same problem last summer. Fought it almost all summer. Switching thermostats, temp sensors, whole nine yards. Even opened the radiator to check for coolant flow and yes...there was flow. Couldn't be the water pump. The camaro would run 220 and up at idle, cool off just a tad while driving, heat back up on idle. Just seemed crazy. So, I relpaced the water pump. It has ran nice and cool ever since. Doesn't hurt to fulsh the system at the same time either.

oldschoolrodder

Forgot to mention, once I purchased a new temp sensor. Found out that the darned thing was faulty as it was reading down instead of up. So the computer was recieving info from the sensor that all was cool and didn't see the need to kick on the electric fan.

The ODB

Chevywolf,
Are you still having the overheating problem? I will try to help if you give some more info about your car. Is the head swap really the only thing you did? and did you notice the temp change immediatly after the swap?
Any background on these new heads that you can give? like what they came from and if they were worked on or ported at all.
Please describe your exhaust system, your distributor, if you have a different than stock hood or front spoiler, and how you went about your rocker-arm adjustment after the head swap.

Just for the record I have a 350 in my garage with milled #416 heads (about 54cc's) that ran perfect on 92 octane, and stayed about 160F degrees.
In my camaro now is an 11:1 compression 383 using a 4" moroso underdrive crank pulley, and a 7.5" underdrive waterpump pulley (about 120% underdriven for waterpump). And I still use the factory 1986 radiator. The car usually runs at 160F degrees or cooler.
Needless to say I think that some of the guesses are off the mark a little. However, it is always good to have more ideas to choose from and I'm willing to add mine if you still want to solve the problem. Just supply as much info on the car as possible.



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*I do custom performance mods on Edlebrock Performer carburetors (dualplane intake mods in the works),
White 1986 Irocz, 305/383 with Edlebrock Performer-RPM intake and Performer #1407 carburetor, +110hp shot of crack, 700R-4 tranny, 3.25:1 rear, Mcreary Road-Stars, SLP-stainless 1.75" shortie headers & Y-pipe, single 3" Borla exhaust, Linginfelter-TPI camshaft part number 74216 pulls 17" vacuum solid. Cam specs 213/219 @.050 114-LSA, .462/.470 lift @1.5:1 ratio. MSD-6AL, billet distributor, multi-retard, blaster-3 coil, and RPM switch.
N/A runs 10.9 @124,
Crack-runs 10.3 @135
haven't run at track since Oct-99

ausrs

this is one that you may not have thought of either how about next time you are out at the car start it up and see if the radiator hose( inlet ) is sucking in when you accelerate i had a car that did that once and it drove me nuts till i tracked it down
just a thought

I ROCK

Replace your upper and lower rad hoses, rad cap, and thermostat, clamps, etc. Your guage probably works since the cap blew off. However the senders for the computer and fan are different from the guage sender and each other. You did check the water pump? Take off the (new) rad cap and start the engine cold and watch for bubbling. Do the plugs and set timing to 6. If none of that helps you're probably looking at pulling the heads or getting that 350!

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Base: 89 Iroc-Z LB9 auto 2.73 posi
Exh: 3" Dynomax muffler, 3" Pipe in place of cat
Ign: GMPP 8MM wires, Accel cap&rotor, AC Plugs
Fuel: Cleaned and flow-matched injectors, afpr, !air pump&diverter valve
Sound: Clarion deck, Kicker speakers and amps
Suspension: KYB Shocks, BMR Strut Tower Brace
Misc: TB Bypass, Synthetic Oil, Flexlite Transmission cooler,
free mods, flow tech headers on the way,
engine swap and 4th gen seats in the works...

82RECAROTA

burnoutrpm

ok i this is off the subject but.. i went to the website you mentioned chywolf and your right it was just the t.v. out of adjustment it doesn't op from 2nd to 3rd anymore thanks a milloin!!!

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1989 firebird formula

Mods: converted from T.B.I. to a carburator 305 to a 350. Flowmater exhaust,hedman shortie hedders,202 160 (882) heads,.447/.447 lift 222@.050 duration speed pro 327/350hp cam 350 .40 over (356) Edlebrock torker2 and a 600 edlebrock manual choke (1405)

Future mods performer rpm air gap intake (polished) comp roller cam, and way better headsa 400 defintely in the works!

Chvywolf

First, Burnout, Glad i could help out with the trans.

Second, ODB Specs are:
1989 305 L03, 85 (numbers checked) HO heads were not fluxed before install. Edelbrock Performer RPM intake, Holley 600 vac sec, 84 HEI Dist w/Accel HEI Coil and 8.8 mm spiral core wires, hedman hedders and Y-pipe, hollow cat, flowmaster 4 stage muffler, 170 degree therm. 700R4 trans cool threw radiator(stock) I think thats it.

Third, I'm not calling anyone a lier, but from what i have seen and i will call chevy tommorrow to conferm this, the 89 TBI had 64cc chamber with 1.85 int 1.5 ext, the 350 TPI had 72cc with 1.96, 1.50. So as far as i have seen and read, no it is not a 350. If it was, it would be in the machine shop getting bored, strocked, painted, in prep for the blower and NOS.

Sorry but it just keeps getting longer, anyway, The last thing i changed was the heads However, and this is just a theory. If a water pump was going bad and the water jackets in the HO heads were a little smaller, would that make the water pump even worse???? If so, that thing is getting pulled when the car gets back from the paint shop. Laters and thanks for the interest and help. Oh yeah, the choke has been removed.

Chvywolf

[This message has been edited by Chvywolf (edited February 06, 2001).]

taliesian

I had a heating problem in my 84 z-28, it would over heat if it ran less than 1600 rpm, it was really bad in trafic. I had replaced my stock radiator with an autozone 3 core, it was alot bigger so my lower shroud would not fit. after noticeing that air was not being pulled untill 1600 rpm, I got out the dremel and fixed my shroud to fit since then my car has only rarely gotten over 170 degrees. if you are over heating at low speeds/idle I would get a shroud and see if that helps

Keith5

Called the dealership yet?

Chvywolf

I called the dealer and the kid working at the parts counter was so flusterd at my question that he gasped for 30 sec, then put me on hold and it hung up bout 20sec after that. Make a long story longer, he couldn't answer my question. So i emailed Chevy tech. Will post there answer when i get it.

And to answer the shroud question or comment, Shroud is exactly as it was when i got the car. It only over heats when NOT moving. Sitting still in the car, it will overheat. Moving will cool it down. I'm getting my old heads ported and putting in bigger valves and putting them back on the car. I've had it with these heads. Thanks everyone for your help. But it has to be the heads, thats the only thing i can think of and haven't changed. Laters all.

442guy

heres a huge reason the car would constantly overheat. third gens have tiny grills, letting little air thtrough the radiator. to fix this gm installed plastic black airdams directlyu underneath to force air going under the car up into the rad. could it be possible this is broken off?

Chvywolf

Possible, Yes
Is it? No

Red Devil

Does this mean you swapped out to colder, regular plugs? It's the only thing you have not posted, and this can significantly cause an overheating problem.

Chvywolf

No, haven't tried the colder plugs yet. Will do that this weekend.