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#1
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Engine temp concerns
Ok, got a head scratcher here. A stroked 400 to a 461. My old cam and head combination was 9.5:1 #46 heads flowing 250CFM with the SD Stump puller cam. I had a short snout stamped impeller water pump that I clearance the divider plate on, and this engine would NEVER get above 180 deg. Now, I have swapped to Kauffman D-ports flowing 305CFM,10.6:1CR using the "Old Faithful" cam, and I have changed to a long snout cast impeller water pump. I also clearanced the divider plate, but this darn thing wants to stay at 200-220. It may be running a little lean, but I did some carb work on it today which improved it a little, but it is still running warmer than I like. I am running only water in the system right now, with a regular 180 thermostat.
Timing is 10 initial, 32 total Any suggestions on where to start looking for the problem?
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461 Cu. In. Pure Pontiac Power: 1969 Pontiac GTO - Back On Top - Popular Hot Rodding Magazine Last edited by 69*Goat; 05-25-2015 at 10:05 PM. |
#3
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Ok, did some investigating when I got home.
Timing: The total is 30, not 32. That is W/O any vacuum advance. If I hook it to ported vacuum, I get 36, if I hook it to manifold, I get 42. I have a vacuum leak on the carb where the choke can /pot is bolted to the carb. I bet that is affecting what the ported vac on the carb is pulling. It is only pulling 5-7 inches of vacuum just off idle, where the manifold is pulling close to 20 inches just off idle. Until I get this sieve of a carb changed, or fixed, there is not much more I can look at.
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461 Cu. In. Pure Pontiac Power: 1969 Pontiac GTO - Back On Top - Popular Hot Rodding Magazine |
#4
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My understanding is that ported vacuum line should give you zero vacuum and thus zero advance at idle.
Also, 20" is a lot for your combo at idle. Others will chime in I'm sure. I have 12" and less of a cam as I recall.
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Adam __________________ 1964 LeGTO 469, M21, 3.42 __________________ Sold: 1968 Pontiac LeMans Convertible See it go HERE |
#5
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I'm about at my wits end with the temp issue. I have gotten the carb mixture right, I have the timing set at 32 deg total without vacuum advance, and I have the vac adv hooked to manifold vacuum. This is a new engine, i have put 100 miles on it, and after getting all of the above adjustments done the temp did drop to between 195-200. it is not getting above 200 right now. As I stated before, my old Iron headed set up never ran hotter than 185, all day long it would stay at 185. The CR with the iron heads was 9.5:1, and I know that it was running lean. My new aluminum headed set up has a CR of 10.6:1 and the AFR is where it should be.
Is the new setup the culprit? Could the cast impeller water pump be pushing too much water through the system? and not allowing it to sit in the radiator long enough (That was one suggestion given to me) I am going to go home and pull the thermostat housing and see what I see. I do remember when I pulled the engine apart for the new upgrades that the thermostat was wedged in the water crossover at an angle which was allowing water to get past the thermostat basically making it a restriction instead of blocking it off and waiting for the thermostat to open. You guys have any suggestions?
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461 Cu. In. Pure Pontiac Power: 1969 Pontiac GTO - Back On Top - Popular Hot Rodding Magazine |
#6
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I'm certainly no cooling expert. But I've read that 12-14 initial and 34-36 total will usually run a few degrees cooler than 10 & 30.
And, are you using an adjustable vac can, so you can reduce the vac advance from the high intake vac advance numbers numbers ? Are you running the same advance numbers you were with the other engine ? I didn't see it mentioned, but are you using the same fan, shroud, and rad as before ? I'm just assuming that with the extra energy generated by the lager engine, it will just naturally produce more heat. So, you may need to upgrade the entire system--bigger radiator, more fan power, etc. The question of tranny cooling lines, usually comes up. If the fluid is routed thru the rad, that warms the coolant. And if an aux cooler is used and is directly in front of the rad, that will slightly increase coolant temp, by heat transfer and making it harder to pull air thru the rad and the tranny cooler. Hey, ALL these little things can add up to cooling problems. Anybody have any luck with a GOOD pusher fan in front of the radiator, or AC condenser if you have one, as a helper for slow speed situations ? I read that one guy bought one and it hardly blew any air at all. Another cooling question. I read that an electric fan from a Lincoln Mark VIII, will suck 5000cfm of air, on high speed. Anybody tried one ? http://www.hotrod.com/how-to/engine/...ooling-system/ http://www.ebay.com/bhp/mark-viii-fan Last edited by ponyakr; 06-10-2015 at 05:05 PM. |
#7
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I pulled All of the A/c Components off several years ago.
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461 Cu. In. Pure Pontiac Power: 1969 Pontiac GTO - Back On Top - Popular Hot Rodding Magazine |
#8
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Quote:
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Karl |
#9
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461 Cu. In. Pure Pontiac Power: 1969 Pontiac GTO - Back On Top - Popular Hot Rodding Magazine |
#10
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It was rebuilt then....This is what I mean about it being new/not broke in yet. I've even read that one of the guys on here had a rope seal that was too tight and it caused high temps.....
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Karl |
#11
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Wow... BOP seal here.
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461 Cu. In. Pure Pontiac Power: 1969 Pontiac GTO - Back On Top - Popular Hot Rodding Magazine |
#12
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That is NOT POSSIBLE if you have the proper thermostat and a correct-size thermo housing/water outlet. This is the first thing to inspect and repair. |
#13
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You said previously that the car doesn't get above 200. I'm not hearing a problem in there.
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1965 Pontiac LeMans. M21, 3.73 in a 12 bolt, Kauffman 461. |
#14
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Oil pressure decreases 5-7 PSI at that temp, and that bothers me... Call me anal... :/
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461 Cu. In. Pure Pontiac Power: 1969 Pontiac GTO - Back On Top - Popular Hot Rodding Magazine |
#16
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Get a laser temp gun and check the temps going into the radiator and coming out of the radiator. Also check temps where you sending unit is to verify that it is still reading correctly.
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#17
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#18
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Quote:
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Karl |
#19
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200* at idle or 200* doing 65 down the road.
Idle is usually effected by air movement through the rad and air in the system. Highway speeds is either air is not going through the rad, but around it, or coolant movement. If my car is running 195* and I am going down RT 15 here (Huge 4 mile downhill 55 MPH highway), the second I put it in neutral, the temps shoot up to over 205*. Almost instantly. I have the Lincoln Mark VIII electric fan set-up. Then when I get to the bottom of the hill, throw it 5th gear, the temps shoot down to under 170*. As soon as the RPM's of the water pump increase. Also where is your temp sensor? In the coolant crossover? Keep in mind that spot is where the engine is putting out the hottest coolant back to the radiator. New T-stat? (although the t-stat only regulates the MINIMUM operating temperature.) Air sealing kit around rad? Down flow or cross flow? Down flows seem to have issues if the rad hose is higher that the return inlet, air gets trapped. Lower rad hose have the spring in it? Are you sure that you burpped all of the air out of the system? Mechanical or electric gauge? ANd yes, if you are getting vacuum at the ported line at idle the carb has an issue.
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1967 Pontiac Tempest 2dr HRDTP Coupe 468 C.I. 500 HP 5 speed = FUN!!! 1990 Chevy Suburban R2500 Daily Driver 1986 Volvo DL245 Wagon.. Project car!!! The Burb Files |
#20
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200-205 at idle sitting at a light. Highway@65 190-195
Idle is usually effected by air movement through the rad and air in the system. Highway speeds is either air is not going through the rad, but around it, or coolant movement. If my car is running 195* and I am going down RT 15 here (Huge 4 mile downhill 55 MPH highway), the second I put it in neutral, the temps shoot up to over 205*. Almost instantly. I have the Lincoln Mark VIII electric fan set-up. Then when I get to the bottom of the hill, throw it 5th gear, the temps shoot down to under 170*. As soon as the RPM's of the water pump increase. Quote:
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No special sealing kit around rad. Quote:
Ha!!!! No spring!!! Quote:
Electric No vacuum at the ported line at idle.
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461 Cu. In. Pure Pontiac Power: 1969 Pontiac GTO - Back On Top - Popular Hot Rodding Magazine |
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