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#21
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Sanding pulleys decreases surface area, and can make them slip. Pulleys need a clean, smooth surface, and true so the belt 'sticks' to it.
You don't have to believe me, but call ram air resto and talk to tech, they can explain it much better. Some might get lucky when sanding them, but it's most likely due to there not being an issue to begin with. If you have an excessive load, and it only slips sometimes, sanding them will make it worse. Sometimes a pulley will look perfectly fine, but still slip. Most of the time you can't tell with the naked eye when a pulley(s) has/have been compromised. On 1st gen birds, an air dam helps considerably, but many refuse to install one for whatever reason(s). Even so, the air dam helps very little to none at a stop. I honestly believe that the trans cooler has very little to no effect, but I would still do an air gap on it. It might provide that slight margin that could make a difference. .
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. 1970 GTO Judge Tribute Pro-Tour Project 535 IA2 http://forums.maxperformanceinc.com/...d.php?t=760624 1971 Trans Am 463, 315cfm E-head Sniper XFlow EFI, TKO600 extreme, 9", GW suspension, Baer brakes, pro tour car https://forums.maxperformanceinc.com...ght=procharger Theme Song: http://www.youtube.com/watch?v=7zKAS...ature=youtu.be |
#22
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Much of this problem is Obvious. Wrong Fan shroud.
There is NO way there should be that huge gap at edges of the blade to the shroud. Just like Fluid dynamics and the water pump plate, the Aerodynamics of the fan shroud / blade is the same. I am 100% sure there is air turbulence affecting the draw of the fan. Are the temps verified with an IR gun? You can eliminate the radiator tank trans cooler and go straight out front if you like. A 160 T stat with give your cooling system a head start on cooling, and would be full open at a dynamic temp of around 180 on a normal working system when its hot out. But First., Get that shroud fixed. Pontiac had RA4 cars tested in the desert with automatics for heat and cooling. Lastly, Folks tend to use a "Recommended" A/F ratio for their injection systems. With the alcohol in fuel , Pontiacs anyway, need a richer Idle mixture to run right and stay within temp parameters.
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"The Future Belongs to those who are STILL Willing to get their Hands Dirty" .. my Grandfather |
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#23
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ok, thanks for the explanation. its not a matter of believing you or not, i just never heard of that being a problem before, or at least not for the average light sanding with finer paper to clean light surface rust/debris... light sanding wont reduce the surface area since no metal is really being removed.
now heavy sanding with 80grit to a heavily rusted or pitted pulley i can understand, but for all the factory pulleys i have sanded there has never been any problem. any serious slipping is usually audible & will show signs on the belt like being glassed over etc. |
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#24
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Quote:
thats what i noticed too... whether its the shroud not being right or the fan im not sure, but one or the other looks like the wrong size. |
#25
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I thought they only make 2 shrouds for 1st gens? One for the 2 core, and one for the 3 core. I don't recall if they ever had 4 cores for them?
I only see 1 shroud listed in Ames catalog? It was cooling properly before the addition of the A/C condenser, maybe it was borderline then? .
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. 1970 GTO Judge Tribute Pro-Tour Project 535 IA2 http://forums.maxperformanceinc.com/...d.php?t=760624 1971 Trans Am 463, 315cfm E-head Sniper XFlow EFI, TKO600 extreme, 9", GW suspension, Baer brakes, pro tour car https://forums.maxperformanceinc.com...ght=procharger Theme Song: http://www.youtube.com/watch?v=7zKAS...ature=youtu.be |
#26
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This is an interesting observation re: fan shroud. It is an OEM 69 Firebird shroud as far as I can tell and the fan is 19.5". The spacing is a little tighter on bottom and sides (1 inch) - and the top is not as bad as picture depicts but Ill get measurements. Also noted on the AFR...
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Will Rivera '69 Firebird 400/461, 290+ E D-Ports, HR 230/236, 4l80E, 8.5 Rear, 3.55 gears ‘66 Lemans, 455, KRE D-Ports, TH350, 12 bolt 3.90 gears '69 LeMans Vert, 350, #47 heads: work in progress |
#27
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What is the idle AFR set at? And your idle RPM?
.
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. 1970 GTO Judge Tribute Pro-Tour Project 535 IA2 http://forums.maxperformanceinc.com/...d.php?t=760624 1971 Trans Am 463, 315cfm E-head Sniper XFlow EFI, TKO600 extreme, 9", GW suspension, Baer brakes, pro tour car https://forums.maxperformanceinc.com...ght=procharger Theme Song: http://www.youtube.com/watch?v=7zKAS...ature=youtu.be |
#28
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Idle AFR is 14.2 and RPM is 850
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Will Rivera '69 Firebird 400/461, 290+ E D-Ports, HR 230/236, 4l80E, 8.5 Rear, 3.55 gears ‘66 Lemans, 455, KRE D-Ports, TH350, 12 bolt 3.90 gears '69 LeMans Vert, 350, #47 heads: work in progress |
#29
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That should be good, maybe throw 2 degrees in timing at idle at it. What's your timing at idle? 16-18 ?
.
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. 1970 GTO Judge Tribute Pro-Tour Project 535 IA2 http://forums.maxperformanceinc.com/...d.php?t=760624 1971 Trans Am 463, 315cfm E-head Sniper XFlow EFI, TKO600 extreme, 9", GW suspension, Baer brakes, pro tour car https://forums.maxperformanceinc.com...ght=procharger Theme Song: http://www.youtube.com/watch?v=7zKAS...ature=youtu.be |
#30
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Idle timing is 25. So I added spacers at trans cooler mounts and now have about 1.25” between it and the condenser.
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Will Rivera '69 Firebird 400/461, 290+ E D-Ports, HR 230/236, 4l80E, 8.5 Rear, 3.55 gears ‘66 Lemans, 455, KRE D-Ports, TH350, 12 bolt 3.90 gears '69 LeMans Vert, 350, #47 heads: work in progress |
#31
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Quote:
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Will Rivera '69 Firebird 400/461, 290+ E D-Ports, HR 230/236, 4l80E, 8.5 Rear, 3.55 gears ‘66 Lemans, 455, KRE D-Ports, TH350, 12 bolt 3.90 gears '69 LeMans Vert, 350, #47 heads: work in progress |
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#32
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The RPO K02 fan has a slightly smaller diameter than the 5 blade. That said, it MUST be centered in the shroud and just barely inside it.
I would try to get a diameter on a factory shroud and compare to this repop. I would make sure the top plate is on tight and sealed, and make sure the radiator is sealed on the sides to the core support. I didnt really see it in pics, you do have the top plate? Even with AL heads, I would run a 160 T stat if you have AC and run alcohol in the fuel. IF, you are one of the OLD OIL, OLD School folks that feel the need for their "Oil to Boil" You could try a 170 T stat. I think Stant makes these.
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"The Future Belongs to those who are STILL Willing to get their Hands Dirty" .. my Grandfather Last edited by Formulabruce; 08-28-2021 at 01:30 PM. |
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#33
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Quote:
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Will Rivera '69 Firebird 400/461, 290+ E D-Ports, HR 230/236, 4l80E, 8.5 Rear, 3.55 gears ‘66 Lemans, 455, KRE D-Ports, TH350, 12 bolt 3.90 gears '69 LeMans Vert, 350, #47 heads: work in progress |
#34
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Quote:
The shroud looks much smoother on the top than a factory unit. May have to make sure the core support is not bent and radiator sits in correct spot. We just fixed a 400 heating issue by tweaking the core so the shroud sit evenly and lined up to the fan. A/F closer to 14.0 may help as well. Good luck, youll get it ! Has been a hot summer.
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"The Future Belongs to those who are STILL Willing to get their Hands Dirty" .. my Grandfather |
#35
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I measured the clearance between the fan and the shroud. At the top it’s about 1.5” , sides and bottom 5/8”.
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Will Rivera '69 Firebird 400/461, 290+ E D-Ports, HR 230/236, 4l80E, 8.5 Rear, 3.55 gears ‘66 Lemans, 455, KRE D-Ports, TH350, 12 bolt 3.90 gears '69 LeMans Vert, 350, #47 heads: work in progress |
#36
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Everyone has their own comfort levels, but if you are seeing 195-200F water temp during extended idling in 95F ambient weather, I personally would not be worried about a thing here.
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1966 Pontiac GTO (restoration thread) 1998 BMW 328is (track rat) 2023 Subaru Crosstrek Limited (daily) View my photos: Caught in the Wild |
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#37
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Quote:
Thanks - I hear you - I'm trying to get it in better shape for when AC is operational as the extra load and heat in condenser will make it run even hotter.
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Will Rivera '69 Firebird 400/461, 290+ E D-Ports, HR 230/236, 4l80E, 8.5 Rear, 3.55 gears ‘66 Lemans, 455, KRE D-Ports, TH350, 12 bolt 3.90 gears '69 LeMans Vert, 350, #47 heads: work in progress Last edited by grivera; 08-29-2021 at 01:42 PM. Reason: Added pic |
#38
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The path of least resistance.
IF the fan can suck air from under the hood, vs Through 2-3 "heat exchangers" , it always will. Adding a exchanger, in use or not, is more load and restriction on the path of the air. I am not versed in the bracketry of this radiator, vs stock, BUT I think you could try some window closed cell foam insulation in this area as a temporary measure to force the fan to suck though the radiator. This will help tell you if you need to do more besides a T stat. IIRC the HD fan ( 7 blade) is only 17.5 across, vs the 19.5 on a stock 5 blade?? This could be why it looked odd to me.
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"The Future Belongs to those who are STILL Willing to get their Hands Dirty" .. my Grandfather Last edited by Formulabruce; 08-29-2021 at 09:05 PM. |
#39
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Based on the Parts catalog, Pontiac only used 1 V-8 Shroud, regardless of the fact that the HD 7 blade fan is smaller Diameter.
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"The Future Belongs to those who are STILL Willing to get their Hands Dirty" .. my Grandfather |
#40
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Thanks. The seven blade on this car is 19.5". That is an older pic I have on phone to illustrate top plates - and at the time it had a Summit brand direct-fit radiator. The current Cold Case radiator doesn't fit much differently. That being said, those gaps were there with the prior desert cooler radiator as well - I was just looking at them yesterday - may try backer rod in appropriate size. The 1st gen cars have a crude interface between radiator and radiator support - the gap around perimeter of hole in the radiator support that corresponds with the radiator core is much smaller.
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Will Rivera '69 Firebird 400/461, 290+ E D-Ports, HR 230/236, 4l80E, 8.5 Rear, 3.55 gears ‘66 Lemans, 455, KRE D-Ports, TH350, 12 bolt 3.90 gears '69 LeMans Vert, 350, #47 heads: work in progress Last edited by grivera; 08-30-2021 at 07:59 AM. |
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