Hi my name Israel

im having a couple of delimas with my damn tpi

its a 92 25th. anni. z28 with a 305 5 speed
the car spun a bearing last year so i got it rebuilt.

when i rebuilt it installed a xr276hr-12 comp cam, was way to big and was running way to rich...

one of the reasons i took it out was because i thought that was a reason why it was over heating it goes right into the red.
i took the cam out and installed a stock l98 cam, we took heads off again an replaces gaskets, thinking the builder put them wrong. we took the time to manually set the valves. the thing is its still running WAY TOO HOT...
im just looking for advice on what it can be.

so far this are my upgrades.
ported polished stock heads, edelbrock shorties with CA emission weld off, custom true duals with slp lm1.

i have changed the fans to some from a 98 malibu still electric fans.
what could be the problem to this overheating situation...

i dont know what to do anymore..

i have changed MAP sensor IGAT sensor, an some other sensors, the car also feels heavy an kinda slugish doesnt burn out as how it use too..

im trying to get the car running right since im restoring it an repainting it black

here are some pics an a small video of when it was cammed.

this is how it use to look


during the strip down process an rebuild
ps. does not have the aluminum valve covers anymore














present, finally got it wet sanded, doors & fenders primered.


true dual slp system



the video
http://vids.myspace.com/index.cfm?fu...mp=vid_OEV_P_P

 

Just some things to check. Is you water pump circulating, Is you thermostat opening, Is your radiator plugged?

 

the car video on idle
http://vids.myspace.com/index.cfm?fu...eoid=105727677

 

forgot to mention that, water pump is fine its also brand new

i went thru 6 thermostat starting at 160-195 deg, i took the radiator to be cleaned, thinking that was the problem, but wasn't,

 

Did you go through the basics? Do the fans come on at the right temp/at all?

Those malibu fans may not be enough, a lot of guys are having great success with the Taurus fans.


Get the basics down.

 

Brand new doesn't always mean good. Anyway have you tried it without a thermostat? One more dumb question, Is your belt on right, so your water pump is circulating correctly?

 

well this is the second water pump, i doubt two of them wouldnt be good.

an yes i have an still the same crap

 

I was just going to say that. There's 2 different water pumps, one circles one way, one the other.

I believe the Corvette is the only one that has the reverse pump. Is it possible you put the reverse flow pump on it.

 

Well there isn't much left other than maybe the water jackets are plugged in the motor somewhere?

 

not that i know of i brought it from napa, it only gave me one option for it..

 

Is the belt run in the stock locations with the stock pulley system?

That could reverse the pump.

 

same stock belt system, i just disconnected ac, an smog pump

 

also how could it be reverse system if its belt drivin??

also u can see the water in the radiator circulating

 

could it possibly be the heads??

 

Depends on how the belt is routed. If like the Corvettes, it's reverse flow.

 

Your temp gauge might be reading too high. If you have no other way of checking the temp you can buy a radiator cap with a built in thermometer. They are $25 at most parts stores.
es.

 

When you disconnected that stuff you had to re-route the belt, did that cause the belt to ride on the water pump so that it has to spin the other way?

 

no because the pullies on it are still attached just hoses are disconnected

 

could it possible be the heads that got machined wrong??

 

I'm sure you already checked this but did you set your base timing? I had an idle problem and the engine ran really hot! it turned out when I reprimed the engine and reinstalled the distrutor it was a tooth off and the ecm must have tried to correct it. Once I set my base timing the idle problem went away and the engine ran must cooler
Mike

 

Correct PRIMARY water flow for your 305 is:

Lower radiator hose> water pump> cylinder block>cylinder heads>front water crossover in intake> thermostat>upper hose>Driver side radiator tank> Radiator core>Passenger Side Radiator tank>Lower Hose.

As you can see, a reverse rotation pump screws up the works!

You must have the right pump to match the water pump drive. If you have a serpentine belt, the pump turns opposite of a V-belt pump. A V-belt pump on a serpentine belt turns the wrong direction! What pump do you have?

Serpentine pump turns opposite crank rotation (counter clockwise viewed from the front) and a V-belt pump turns same as crankshaft rotation (clockwise viewed from the front). "Corvette" etc. is irrelavent, you are using sepentine belt drive, so you MUST get a sepentine drive pump! You could have a serpentine pump PART NUMBER with a NON-SERPENTINE Pump in the box, since you have had two pumps, this is unlikely.

Serpentine pumps turn backward because the pump drives off the Back (smooth) side of the serpentine belt.

Remove the thermostat, fill the radiator with water 2 inches from the top, leave the cap off, start the car: immediately go to the radiator and look at the water inside. CAN YOU SEE WATER CIRCULATING IN THE RADIATOR? Without a thermostat installed and if everything is correct, as soon as you start, you should see vigorous water circulation with water flowing OUT of the tubes in the radiator core. If water is flowing out of the tubes, then your pump is turning the right direction. If you cannot see water flowing from the tubes, then you have a reversed rotation pump or a blocked water flow problem.

NEXT, AND ONLY IF YOU HAVE WATER CIRCULATION described above, use a deep fry thermometer direct in the radiator water to measure the water temp and compare it to the temp gauge on the dash. Do not let it run until it boils or you will burn the crap out of yourself if water boils over and then blows out of the radiator. All you want to see is that the thermometer and gauge are pretty close in readings. IF the thermometer says 180, does the dash gauge show about 180 (about a needle width below 200) you are pretty sure that the gauge is good. If not, you know the problem.

I have heard of certain types of Chevy Intake gaskets that had only one set of Water crossover passage holes stamped in them, or they have a big hole in front and a little round hole for the rear of the intake. 99% of them are reverseable (Big water cutouts on both ends), but if you have a set that has only one water crossover hole, and you installed them with the large water crossover cutouts to the rear, then it is possible that the water flow is blocked from one or both of the heads to the intake crossover and thermostat housing. Again, check the coolant flow as in paragraph 7.

Do you see a lot of bubbles as the coolant flows? Lots of bubbles could mean leaky gaskets or cracked head castings. If you used the original heads from the overheating engine, did you have them "magnafluxed" or otherwise checked for cracks? 305 heads are NOTORIOUS for cracking in the exhaust ports when they are overheated!

What size radiator core? You should have at least a 28 x 18 radiator 1 inch core. How fast does the temp go up? It should take about 5-7 minutes of idling on a dead cold engine to get the temp up to 200 or so.

Head gaskets are almost all reverseable, so it is darn near impossible to screw that up. Are you using the correct year 305 head gaskets?

Hate to ask, but are you sure the thermostat is installed correctly, with the copper "pill" facing down into the water crossover?

Long and short of it, you had a hot running engine, so you had a problem on the old setup and you have not found the problem. You are looking for problems/defects with parts that you DID NOT change.

My guess is

A. Too small a radiator.
B. Cracked Heads.
C. Wrong water pump, V-belt pump on serpentine drive.
D. Incorrect head gaskets.
E. Warped heads.
F. Wrong intake gaskets.
G. Thermostat installed upside down

 

My guess is

A. Too small a radiator STOCK RADIATOR, NO MAJOR MODS FOR IT TO NEED A BIGGER ONE

B. Cracked Heads. there no water in the oil, so idk about that.

C. Wrong water pump, V-belt pump on serpentine drive. SERPENTINE WATER PUMP

D. Incorrect head gaskets. CHECKED THEM TWICE I HAVE FEL-PRO

E. Warped heads. idk

F. Wrong intake gaskets. CHECKED TWICE ALSO WITH HEADS AN REPLACED AN THERE ARE NO, WATER BLOCKAGE

G. Thermostat installed upside down[/quote] MAN IVE DONE IT EVEN WITHOUT A DAMN THERMOSTAT AN KEEPS OVERHEATING, AND IM SURE THE THERMOSTAT IS ON RIGHT SIDE


it takes about 5-15 min and goes into the red.
the bored the motor .30 over. im taking the heads to get checked tomorrow, for some reason the idiot who did them cut them around the spring an he said thats how he PORTED them???

some guys say it can also either be the block that got machined bad...


i really dont know wth to do

 

ive checked timing and timing over and over an its not that...

before when i had my cam in it was sitting at 106 centerline intake lobe
an only required 108, it was advanced an it overheated less, then for no reason it started over heating, once it over heats it looses a lot of power and torque, an turns slugish, an even backfires, map sensors, igat sensor, all sensor u can think of have been replaced..

 

okay now how do you KNOW its overheating OTHER than looking at the gauge? does it boil over into the overflow tank (try new rad cap), does it steam under the hood, anything?

my 92 rs temp guage kept pegging out in the *260 range (redline) and i hooked up a scanner to it and looked at datastream, and my coolant temp sensor was reading *219 while the guage was *260+.... and i replaced the coolant temp sensor in the process.

now again on my 92 rs, when it warmed up and got to operating temperature, it ran slugish, popped sometimes, overall poor performance. had a code 42 (open in est circuit), checked the knock sensor and it wasnt even pluged in.... plugged it in and it ran like a champ. timing was bieng adjusted accordingly to the temperature of the combustion chamber.

start with the easy stuff first.

oh and do you have a lower air dam (bolts to the bottom of core support)?

 

did all of that car is over heating nasty u can see and hear water boiling in the coolant tank and like bubbling in the block after you turn it off

put three different temp sensors, same thing.

does have air damn and all of that

 

ok, so have you tried a new radiator cap? lol

 

Could the engine be running too lean causing an overheating condition? Did you scan it and look to see what might be happening in terms of fuel enrichment? Low fuel presure might cause the vehicle to run lean.

Is the engine overheating in open or closed loop?

If you scan it you can verify the accuracy of your temp gauge.

The way I found my problem was I disconnected the distributor connector and noted how the vehicle ran with out the ecm controling the spark.

Just a few random ideas here...


Mike

 

lol yes ive tried about every thing that could go wrong, put one that has like a lil red trigger to release the steam or something..

water does rotate, thermostat works, everything is connected gone over it about 4 times, timing is right, head gaskets are correct, intake are correct, idk what else to do...

 

thanks but i highly doubt that the reason, before it broke down, i put an aftermarket fuel regulator an a bunch of stuff, its running good, now becuase we manually set the heads, since one hadnt set yet, spark plugs are a yellowish goldish color, doesnt smell like gas or anything when it DID HAVE THE CAM, it DID smell to rich an valves were pich black and same with spark plugs


thanks for the help

 

MAN IVE DONE IT EVEN WITHOUT A DAMN THERMOSTAT AN KEEPS OVERHEATING, AND IM SURE THE THERMOSTAT IS ON RIGHT SIDE


it takes about 5-15 min and goes into the red.
the bored the motor .30 over. im taking the heads to get checked tomorrow, for some reason the idiot who did them cut them around the spring an he said thats how he PORTED them???

some guys say it can also either be the block that got machined bad...


i really dont know wth to do [/quote]

SORRY about the thermostat Question, but I had to ask! I am sure you are not an idiot! I only ask because I have seen VERY GOOD mechanics make this mistake! I have done it once myself! !!

OK, At least you KNOW that some things are right! You can have Cracked heads and have very little or NO water in the oil. The first sign of cracked heads is combustion gas pressure being forced into the cooling system and displacing the coolant, causing hot spots! It is a vicious cycle!

Block "Machined Bad"? ? ? what does that mean? If you had it bored 30 over, that is not enough to cause problems. Did it overheat before the bore job? Did the guy who "ported" the heads bore the block? BTW, find someone else to check your heads! If he thinks "cutting" around the springs is "porting" he has not a clue and is very dangerous! You need a COMPETENT person to look at the heads! Surely in Vegas, there is someone smarter that that guy?

I forgot to ask the Obvious, What kind of fans are you running? If they are electric fans are they both running? If a regular belt driven fan, it the thermostatic clutch working properly? If it takes that long to get hot, I am suspicious of the air flow through the radiator. Does it get hot when you are driving it as well or only when you idle standing still? My 85 El Camino has a 30 over 305, EQ heads, Hybrid Speed Density TPI, 29 X 19 1" core aluminum radiator and Mark VIII Fan. It will idle for about 5-7 minutes before it heads over 220 and for the red zone! I never let it get above 220 so I turn the fan on and in about a minute it is under 200 and in about another minute it is down to 180 and the thermostat closes! I think that the stock ECM turns the fans on at 220 and off at 200.

You MUST HAVE very strong air flow across the radiator, even on a stock engine or the temps will get away from you in a hurry. Keep in mind that the Mark VIII fan moves about 4500 CFM when you turn it on, so my car has a TON of airflow across the core. With the original, belt driven fan and the original stock engine, the car would not idle when sitting still for long without getting hotter than I liked. I never liked the fact that the car never cooled down when idling and sitting still When you drove it, the car cooled right down, and never got hot so the radiator was doing its' job, it was a simple airflow issue! Your fan MUST pull a lot of air over the core when sitting still or the car will eventually overheat.

You are 100% SURE that the radiator is COMPLETELY open? I have seen radiators that are partially blocked and caused this problem. It is possible to have water flow through part of the tubes and have a significant number that are blocked, thus reducing the capacity of the radiator.

Check Air Flow from the fans and make sure that the Radiator is 100% open!

Hope this helps!

 

I would check that whole thing was flushed out but I think it might be a good possability that the heads are warped though if they have been heat cycled many times. also if it still had the catalytic converter on it check that it isn't plugged normally the only reason you cut around the springs on heads is to install a different type of springs. I don't really see a way that bad block work could be the problem at least not just getting bored .030 over if it ended up being the case I would not go to them again unless it was a new hire that did it and he quit already.

 

get a aftermarket themometer. and check if yours if working right

 

AutoZone rents a cooling system pressure tester, get it and see if your cooling system is able to hold pressure.

Pump it to 16psi, should hold that for over 15 minutes. Let us know what you find.