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Post by pushnfords on Oct 13, 2013 18:38:25 GMT -5
I've got 320 miles on the GTII now and it runs good. The oil temp sender is in the remote filter mount attached to the side of the engine compartment. At 70mph or slower it'll stay under 210 degrees. But...if I run up to 75-80mph it promptly starts to overheat. I'm wondering if the cut out in the engine cover is simply not drawing in enough air?
Specs:
Rebuilt 1679 with dual carbs & Pertronix distributor. All OEM tin with new oil cooler, Hoover bit, and the velocity ring that Awesome Powercoating sells. Total timing is 32 BTDC.
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Post by Dan MacMillan on Oct 13, 2013 22:01:07 GMT -5
Have you separated the hot and cold sides of the engine? At high speeds the turbulence in the engine bay can severely affect the airflow to the fan inlet. Do you have a stock fan shroud and pulleys? Are your thermostat flaps installed? Is the bellows working? Are the lower cyl tins in place as well as the sled tins that bolt to the sides of the oil pan/engine block? Is airflow still connected to the heat exchangers? {J tubes increase heat by not helping to cool off the heads the way heat exchangers do.} The location of your temp sender will give a cooler reading than normal. The velocity ring was never intended to be used on a 1600 based engine. What temp are you reading at high speed? Can you check the oil without getting burnt after a high speed run?
Post some pics of your engine bay.
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Post by pushnfords on Oct 14, 2013 2:02:12 GMT -5
Have you separated the hot and cold sides of the engine? At high speeds the turbulence in the engine bay can severely affect the airflow to the fan inlet. Do you have a stock fan shroud and pulleys? Are your thermostat flaps installed? Is the bellows working? Are the lower cyl tins in place as well as the sled tins that bolt to the sides of the oil pan/engine block? Is airflow still connected to the heat exchangers? {J tubes increase heat by not helping to cool off the heads the way heat exchangers do.} The location of your temp sender will give a cooler reading than normal. The velocity ring was never intended to be used on a 1600 based engine. What temp are you reading at high speed? Can you check the oil without getting burnt after a high speed run? Post some pics of your engine bay. I have the original Bradley shelf in place to separate the hot/cold sides. I have all of the factory tin in place although the crank pulley is aftermarket. The thermostat & flaps are installed but looks like the thermostat has failed. I did check the linkage travel though and the flaps are stuck open. The lower tin is all in place. I'm running 210 degrees at 70mph or slower. If I got to 75 or 80mph it'll start heating up pretty quickly...I've pulled over or slowed down when it does but it has been to 240. This is the Venturi Ring I put on...why do you say it isn't intended for 1600 engines? I've taken an IR temp gun with me the last couple of times & temps at the sending unit on the filter housing and on the block seem to be consistent with each other. I don't think the filter housing is any cooler than the block. The engine... |
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Post by larry9j on Oct 14, 2013 11:44:55 GMT -5
I am interested in what you call a Bradley heat/cold seperator. Was this a factory option from Bradley or one that you made? Is it possible for you to give me the measurements of this unit,also could you tell me what material this unit is made of.
My gtll did not have this unit and therefore my request.
Thanks
larry9j
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Post by pushnfords on Oct 14, 2013 15:14:59 GMT -5
I am interested in what you call a Bradley heat/cold seperator. Was this a factory option from Bradley or one that you made? Is it possible for you to give me the measurements of this unit,also could you tell me what material this unit is made of. My gtll did not have this unit and therefore my request. Thanks larry9j Take a look at this picture: The engine...It is a fiberglass panel approx 1/8" thick. I found some rubber at a wholesale store that I cut & riveted to the edge where a similar original seal had decayed and fallen off. It attaches with three factory holes in the engine tin & the rear just hangs. The one I'm working on had to be clearanced to make room for the oil filter hoses to run through and it also had to be cut in half to be able to be installed. |
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Post by Dan MacMillan on Oct 14, 2013 19:13:46 GMT -5
Have you separated the hot and cold sides of the engine? At high speeds the turbulence in the engine bay can severely affect the airflow to the fan inlet. Do you have a stock fan shroud and pulleys? Are your thermostat flaps installed? Is the bellows working? Are the lower cyl tins in place as well as the sled tins that bolt to the sides of the oil pan/engine block? Is airflow still connected to the heat exchangers? {J tubes increase heat by not helping to cool off the heads the way heat exchangers do.} The location of your temp sender will give a cooler reading than normal. The velocity ring was never intended to be used on a 1600 based engine. What temp are you reading at high speed? Can you check the oil without getting burnt after a high speed run? Post some pics of your engine bay. I have the original Bradley shelf in place to separate the hot/cold sides. I have all of the factory tin in place although the crank pulley is aftermarket. The thermostat & flaps are installed but looks like the thermostat has failed. I did check the linkage travel though and the flaps are stuck open. The lower tin is all in place. I'm running 210 degrees at 70mph or slower. If I got to 75 or 80mph it'll start heating up pretty quickly...I've pulled over or slowed down when it does but it has been to 240. This is the Venturi Ring I put on...why do you say it isn't intended for 1600 engines? I've taken an IR temp gun with me the last couple of times & temps at the sending unit on the filter housing and on the block seem to be consistent with each other. I don't think the filter housing is any cooler than the block. The engine... Thermostats generally fail in the cold engine position causing hi temps. Is the crank pulley stock diameter or is it a power pulley? The increased air speed at lower pressure into the fan does not translate into more air volume out. . Could be the dual carbs. In Beetles the engine cover is opened at the top as dual carbs steal too much of the available cooling air. |
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Post by pushnfords on Oct 15, 2013 16:50:16 GMT -5
Thermostats generally fail in the cold engine position causing hi temps. Is the crank pulley stock diameter or is it a power pulley? The increased air speed at lower pressure into the fan does not translate into more air volume out. . Could be the dual carbs. In Beetles the engine cover is opened at the top as dual carbs steal too much of the available cooling air. The thermostat was bad but the flaps were mostly open. I adjusted the bracket all the way up to jam the flaps open and no difference in the temps. The crank pulley is stock diameter I believe. I don't have the original crank pulley here to measure...do you know the size and I'll double check? Really the only place for the fan to draw in air is around the carbs or from under the car. The shroud almost touches the body at the top. |
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Post by Gary Hammond on Oct 15, 2013 19:55:52 GMT -5
Hi pushnfords,  Are you sure your carbs are not leaning out at high RPM? This can also cause overheating. Gary Hammond,   |
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Post by jspbtown on Oct 16, 2013 8:33:12 GMT -5
Gary thats my thought as well. Leaning out at higher RPMs. Might be worth a jet change. How do the plugs look?
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Post by pushnfords on Oct 16, 2013 9:44:40 GMT -5
When I bought the rebuilt engine from Chico Performance I also got the dual carb kit from him so they would be matched to the engine. I know that doesn't always mean that much...especially since we had to add a balance tube to get it to idle on more than two cylinders. I checked the plugs after running the engine at 4K rpm and they looked good. Tan insulator with a little soot on the metal. No signs of leaning out.
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Post by Gary Hammond on Oct 16, 2013 10:09:21 GMT -5
Hi pushinfords, Try backing the total ingition advance off to the recommended 30 deg. You my be getting a little inaudible detonation at 32 deg which can cause performance loss, overheating, and extra stress on internal engine parts. This only shows up at higher throttle opening and high rpm. Gary Hammond, |
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Post by pushnfords on Oct 18, 2013 14:19:21 GMT -5
Hi pushinfords, Try backing the total ingition advance off to the recommended 30 deg. You my be getting a little inaudible detonation at 32 deg which can cause performance loss, overheating, and extra stress on internal engine parts. This only shows up at higher throttle opening and high rpm. Gary Hammond, I backed it off to 28 degrees last week with no change in operating temperatures. Will your Bradleys run at 3500rpm for extended periods without overheating? |
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Post by Gary Hammond on Oct 18, 2013 15:56:55 GMT -5
Hi pushinfords, On a hot summer day at sustained 70+ mph and 3500+ rpm mine runs warmer than I like. Oil temp will climb to 230-240 deg F and cyl head temp will climb to 325-340 deg F range. At 65 mph and below it stabilizes at 190-200 deg F oil temp and 275-300 deg F cyl head temp. This is at sustained running in hot weather. Outside air temp does seem to affect it some, especially at higher speeds. I'm running 15W40 Valvoline racing oil in a totally different engine and vehicle than yours. It has dry sump oiling, external (only) oil cooler, power pulley, center mount fan, super cooling tin, no thermostat, homemade exhaust that is heat wrapped, 9 to 1 compression, after market dash tuneable fuel injection, MSD 6A ignition box, cold plugs gapped at .060", in a GT - not a GTII. The engine compartment is all open, no good way to divide the hot side from the cold side. It also has an air scoop on the top of the rear deck to bring in more outside air for both the fan inlet and the oil cooler. Gary Hammond, |
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Post by leonardabell on Oct 19, 2013 9:05:40 GMT -5
I have no heat gages, so don't know what my temperatures were, but on a long drive back from Carlisle Pa, I experienced low oil pressure, so I stopped and changed oil from 10-30 to straight Valvoline Racing 50. Kind of hard to find, but the oil pressure was much better.
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Post by gitrdun on Oct 20, 2013 10:13:45 GMT -5
All i can say is the first and only time i took my GT1 out on the highway at 70mph i locked up the motor in 4 miles. I check the oil level everytime before i take it out. Rebuilt an older engine and put it in and i havent been back on the highway since. 60mph all day long is no problem, but to high sustained RPM for highway speeds for me. A highway tranny to reduce the RPM in final gear is in my future when i can afford one.
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Post by horen2tas on Oct 20, 2013 15:43:11 GMT -5
I've mentioned it before but I'll do it again: BRAD PENN 40 weight RACING OIL Order it on the internet by the case (about $6.50 a quart ) It's worth it's weight in gold - - does not break down under extreme heat - - I have first hand experience! Manufactured in Pennsylvania it's actually green in color Recommended by a lot of experienced old school VW builders & racers. www.mrxmotors.com/index_files/brad_penn.htm |
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Post by centralvalleygter on Oct 24, 2013 14:26:07 GMT -5
Horen2tas is right. I now use Brad Penn 40. It is recommended by Pat Downs of CB Performance and definitely reduces engine wear, thereby prolonging engine life.
Best Regards,
Steven
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Post by pushnfords on Nov 1, 2013 10:24:51 GMT -5
[/quote]On a hot summer day at sustained 70+ mph and 3500+ rpm mine runs warmer than I like. Oil temp will climb to 230-240 deg F and cyl head temp will climb to 325-340 deg F range. At 65 mph and below it stabilizes at 190-200 deg F oil temp and 275-300 deg F cyl head temp. This is at sustained running in hot weather. Outside air temp does seem to affect it some, especially at higher speeds.[/quote]
That's about what I'm running into. At 65mph or below it was running 200-210 degrees. Once I hit 75mph or faster temps started climbing. The oil temp gauge only went to 250 but I was pulling over or slowing down to cool it off once I hit 240. Don't have a cyl head temp gauge. Outside temps were high 60s to low 70s.
The same RPM's that cause overheating also start to blow oil out of the breather tube.
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Post by Dan MacMillan on Nov 1, 2013 19:22:53 GMT -5
 Which pulley dia do you have? Is the fan correct width for the shroud? |
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