here's the run down: i have a Chevy 292 L6 in my '53 sedan. Mild Isky cam (don't know the cam specs off the top of my head), but its pretty mild. Langdon's cast iron headers, an offy 4bbl intake with a carter AFB 500cfm carb. timing is set to 10 degrees at about 700-800rpm. vac***e advance is on manifold. i've got a 160 degree thermostat (brand new, just put it in the other day) i've flushed the block and radiator twice in the last 2 days. no blockage anywhere. this is a '53 radiator. it starts up great. idles pretty good once it gets warmed up a bit. after about 10-15 min. of idle the temp reaches about 200-210 at just idle, with only the electric fan ****ing air. i didn't think that was toooo bad. well, yesterday i take it for a short ride. after about 10 min of driving the temp gets up towards 230,....and thats while doing 40mph! so i pull over and sit and let it cool down. once cooled i check the water level in the rad., that was fine. no leaks. the one thing i did notice was that, with the engine running, my lower rad hose is not "hardening up", like its not circulating at all. i got back home and re-flushed everything, pulled the water pump plug and looked inside to make sure the propeller was spinning as a rotated the pump shaft...thats fine (its a new water pump). filled up the block first to try and avoid any trapped air and then filled up that radiator. start it up. same thing. and i've got my temp sensor tapped into the side of the head, is this a good place for a good temp reading? its right next to my headers and carb, so i'm sure it may be hotter just in that area. the only other things that i have tied into the cooling system is my heater core and intake heat. i've racked my brain trying to figure out why its not circulating properly. any help/suggestions whould be greatly appreciated. thanks Chris
did they give you a reverse rotation pump by mistake ? if not , pull the t-stat out and see if that cures it
I've got my temp sensor in the water inlet. Was that 10 degrees BTDC? 292's like advance. Are you sure your belt is tight enough? You don't have a marine or reverse rotation pump do you? The only dumb question is the one left unasked.
thats actually a good questions, i thought about that last night. i'll pull the t-stat and see. thanks.
10 was set with the vacc. advance plugged and thats about where it wants to run best. the vacc. advance is working properlly and advancing when connected. yea, i doesn't not like to run real low, advance is the what it likes. yea, i'm gonna check out the pump cycle and see....hopefulley thats it. thanks.
oh and a fellow hotrodder i work with suggested putting the temp sensor on the t-stat housing to get an accurate water temp reading and not header, intake, block, and water reading.
FWIW, my stock idiot light temp sensor was in the head...no problems while the car was running, but it would trip the HOT light if I tried to restart it within 10 minutes fo shutting down the fully warmed up engine.
Is your electric fan pulling enough air and oriented correctly? The going down the road heat up makes me wonder if the fan is impeding flow. Can you subs***ute a regular positive blade fan temporarily? The reverse flow water pump could be an idea too. Are you getting any bubbles in the radiator? The siamesed exhaust ports run pretty hot and I have had some dump trucks crack the head, putting some hot exhaust in a void thats not quite is the water, but eventually will be, The T-stat housing is a good place to take a reading, and is a good place to trigger your electric fan. 210°-230° isn't bad for these idling, but that hot going down the road is a little warm. Another thing, maybe try richening up the carbs metering rods on the cruise step. If you have a 7552 rod set. try a 6852 set, or go a size or two bigger on the primary jets. 292s have strong vacuum, if the rods are down it could be leaning a couple of cylinders. Another thing is changing the power springs, If you have too light of ones, the rods stay down, a heavier one ( I run the pink ones myself and have them be very responsive in a 4000 lb vehicle and be even better in a lighter one. I have to hit it hard to get it to richen with the orange ones. Hope this helps you on the way.
Make sure the pump is actually for a 292 and not one of the smaller versions. There is a difference, so I've been told. Most guys have reported a noticeable drop in temp readings by moving the sender to the thermostat outlet. Make sure the lower radiator hose has a spring in it to prevent it from ****ing shut. If the motor is a fresh rebuild, it will run a little hot until it breaks in... I have a 194 in my '53 sedan, and I have the stock 194 fan blade on it. I only have about a 1/2" of clearance, but it does fit. I would have to pull the radiator should I ever need to replace anything.
thanks so much for the input. as for the electric fan, i'm not real big on it at all. i only ran one due to clearance issues. i MAY be able to run a normal mechanical fan. thats my next thing is trash that elec. fan. i've only got about 3 in. from water pump pulley mounting face to the face of the radiator, so a clutch set-up is out. with the engine running and the cap off, yes there are some bubbles, but just barely. my fan right now is wirer to a toggle, not to temp. 210-230 isn't too high??!! i was aiming for 200-210 for a max high at idle sitting in traffic kind of scenario. yea, i knew something wasn't right when the airflow itself was not cooling it, and thats due to it not circualting through. i'm going to check out the water pump this evening. i'll move the temp sensor the the t-stat housing. thanks for all the ideas, thats just what i need!
Yes be sure it is a 292 water pump NOT for a 250 ,Because it will run hotter. The impeller is smaller on a 194,230,250. The 292s are bigger. That is another reason a 292 pump will not work in a 250/Low deck motor They will not fit into the block even. There is also a byep*** hole on the low deck water pumps.
i was hoping you would see this post twisted6! you've helped me on several occ***ions with the ole inline. "There is also a byep*** hole on the low deck water pumps",....well, i can tell you that the water pump i have it tapped on the top (which i have plugged) and it does have the byp*** for the heater core...so is that telling me i have a 250 water pump? thanks again! Chris
http://www.partsamerica.com/productdetail.aspx?MfrCode=A1C&MfrPartNumber=58169&PartType=54&PTSet=A this is the water pump i have on there now...
I am no fan of electric fans either once power levels get to a certain point however! Once the car is moving the fan is irrelevant. A couple of goofy things i have run across in my carreer .One is the fan, crank pulley combo. I build or used to build many BB mopars for a living and even a 1/2 inch of pulley diameter can be the difference beteen success and hot running engine. I used to give my customers the dimensions and tell them where to get the pullleys to use but would almost invairiably get a phone call, "car runs hot" I would go over and check and sure enough wrong pulleys. (too big on pump or too small on crank ) When i asked why these pulleys and what you were told to use I would usually get some lamebrain answer "well my buddy said that wouldnt make any difference." In fact i think the last I did I showed the guy with a calculator that the water pump was running 235 RPM slower at idle because he had not used the proper pulley on the pump. I just went to the wreckers and bought the right pulley myself, took it home and cleaned and painted it and went and installed it.(because i care about my motors like they were my children) Immediately the problem completley disappeared and has never resrfaced. That was four years ago now and car has won several shows since and is driven regularily with out any sign of running warm. So that is a possibilty you might look into . A smaller pulley on the water pump runs it faster for the same engine speed. The other and i am not totally convinced of it but have been told it is that 292s run hot when bored 060 oversize. I dont know if yours is so and i dont know if it is true but i have been told that more than once and am just repeating it. It may be a urban myth too but it is the local scuttle****. 292s were used for years on combines and that is where this info on overbore came from.
yea, the electric fan is the first thing to go. even if i have to move the radiator forward more to make room, i'm putting in a mechanical fan! the pulley thing makes total sense. could you shed some light on how to calculate that so i can check? as far as i know the pulley on the water pump is stock, but i'm basing that on the fact that it came with the engine when i picked it up. my 292 is a stock rebuild. i picked it up after it had been rebuilt had about 1300 miles on it since the rebuild. i took it to my guy to have a cam, springs, and lifters put it and he checked it out said everything was in good shape as far as a stock rebuild. crank had been balanced cyclinders were clean, stock sized pistons, etc. thanks for the input.
Just and idea. Your radiator could be plugged up. You'd never know until you pulled the tanks off. I've seen it a bunch of times. Did you take the t-stat out and run it and see what happened?
no, i haven't run it without the t-stat yet, but thats on the list. as for the radiator, i have ran a hose through it and it flows through it with no problems.
how would the head gasket keep the water/coolant from circulating? i don't see how. but i've been wrong before.
Pull the thermostat and hang it in a pan of water ,bring to boil . Does the stat open? If not there is the prob ,if it does reinstall as you need one in there. PS stat installed the right way? spring to engine. seen that happen just often enough to ask.
Your link didn't show anything. The 250 water pumps Only have two Hose openings 1 for the Rad. and the Other is the heater hose. NO other tapped holes.The byp*** I am talking about is on the Back side.
What i would do is spray some starting fluid on the intake where it meets the head while the engine is at idle. Just a couple light sprays. If the idle suddenly goes up, you have a vacuum leak, causing you to run lean which inturn is causing you to over heat. trust me, it happened to me! On a 261 inline six, with a original Fenton intake and re pop Fenton headers. later, once i found that out i had the grind the headers a bit so they would let the intake sit flush against the head. Just an idea, hope it helps!
sorry, see if this one works... http://www.partsamerica.com/product_images/img/a1c/58169.jpg but from what you said i must have the correct water pump...
Starting fluid? good way to start a fire. when it hits the Hot exhaust. you can also use a propane torch With Out the flame just the gas(so i have heard but never tried that myself) i have used carb cleaner or heavy soapy water The soapy water you can watch the bubbles get ****ed in. But anyway Yes that is a 292 pump Some also had a plate over the impeller fins. Which have been known to work better. But I would have the Rad checked out.
Doesn't have anything to do with coolant circulation. It's the hot combustion g***es leaking into the coolant that causes overheating. You'd see bubbles in the coolant, more pressure in the system than usual, but a better test is to buy the tester that shows if you have combustion byproduct in the coolant. all good suggestions, lean mixture (vacuum leak) wrong water pump, clogged rad, closed thermostat, I'd look at timing, as well. Don"t guess! Do diagnostics. Check the operation of everything that could be causing this problem, don't just change parts someone tells you "might" be the problem!
yea, i understood how it would affect overheating. but thanks for the full insight on it. as of last night i checked for vacuum leaks(not with starter fluid),...everything is fine there. re-checked the radiator, as far a flow....as i said before, with it drained and disconnected i can run a hose through the top of rad and it flows just fine. re-checked timing, i'm at 10 degrees(w/vac. advance disconnected) @ about 800rpm. carbs not running too rich. i moved the temp. sensor to the t-stat housing to get it away from the exhaust ports. trashed the electric fan! removed the t-stat(temporarily) just to see if its flowing at all....it IS flowing, it just doesn't seem as though that bottom rad hose is getting "hard" enough...but you can feel water running through it. my heater hoses(away from heat of engine) are getting warm,...so i know its at least flowing some. and after all that i ran it for about 15min (off and on) and my temp gauge barely got above 180 at idle. granted i know some of this is the location of the temp sensor...i think that the head location for the temp sensor was too much "other heat" getting picked up as well. and talking about the head gasket... thats part of my problem, i don't feel as though the cooling system has enough pressure. i do have to tiny bubbles that come up when running that engine w/the rad cap off...i just figured that was water/coolant circulating...i'll see what i can find out about trying to find out about combustion byproduct in the coolant. thanks for that info! thats what i've been trying to accomplish is finding the actual problem and not just replace parts and hope i get lucky... thanks again! Chris
yea, i've always used cabr cleaner or wd-40... but yea, i'm still not convinced its the radiator, but i may still get it checked or replace it. thanks.
~i'm bumping this back up one more time to see if anyone has any other input. i've come to the conclusion that due to bad temp sensor placement and a bad t-stat(was not opening) i made myself paranoid. so tonight i'm gonna run it around the block and see how it does. thanks everyone.~ as of last night i checked for vacuum leaks(not with starter fluid),...everything is fine there. re-checked the radiator, as far a flow....as i said before, with it drained and disconnected i can run a hose through the top of rad and it flows just fine. cracked open the pet-**** valve at the back of the block to make sure there was coolant there...thats all ok. re-checked timing, i'm at 10 degrees(w/vac. advance disconnected) @ about 800rpm. carbs not running too rich. i moved the temp. sensor to the t-stat housing to get it away from the exhaust ports. trashed the electric fan! removed the t-stat(temporarily) just to see if its flowing at all....it IS flowing, it just doesn't seem as though that bottom rad hose is getting "hard" enough...but you can feel water running through it. my heater hoses(away from heat of engine) are getting warm,...so i know its at least flowing some. and after all that i ran it for about 15min (off and on) and my temp gauge barely got above 180 at idle. granted i know some of this is the location of the temp sensor...i think that the head location for the temp sensor was too much "other heat" getting picked up as well.
Besides testing the coolant. If your thinking a head gasket issue take a compression check/Leak down Test.
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