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Post by 69hcode on Apr 16, 2017 16:20:27 GMT
I have my car tuned up pretty good. I set the idle @ 750 in neutral. When I put it in drive it drops to around 500rpm's. It's low enough that my voltage slowly drops and now that the temps are rising, my car is getting hot at idle. It will creep up to 99C pretty quick. When I start going again it will drop to about 90C in a quarter mile or so. Which is where my thermostat is. It runs nice and cool while cruising.
I'm running a SPI converter right now. I don't know if it should drop the rpm's that much. This is on my original 1981 998 lump. I'm planning to rebuild a SPI 1275 to put in the car. It will be carbed with twin hs2's. Waiting on a head and cam from Martin. I also have a 1989 998 auto lump that is supposed to run good. They guy is putting a Honda motor in his car. I'm not sure which converter I should run when I do the bigger engine. I have 3 to choose from the 81 998, 89 998, and the SPI.
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Post by limby2000 on Apr 17, 2017 7:40:23 GMT
Yeah dont know the differences between the alternatives other than there different stall speeds. My tuned 1098 ive kept the original mini 30 998 t/c but i,m running it via a gearbox from a late 1275 sprite running the tall 2.76 diff. Hoping the increase in torque from the long stroke should suffice. As for your idle speed, looking through some of my old auto manuals, i see that it list the austin 1100 auto (ado16) as 650 rpm. Getting hot in idle should be checked out, have you flushed recently?,blocked rad?. Theres always the option of the smaller fan pulley,will give you more cooling at the cost of a bit more fan noise at higher rev,s. I have the smaller fan pulley on mine too but for other reason,s.
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Post by notamini on Apr 17, 2017 12:41:02 GMT
Go to this site Austin America USAGo to the Technical Advice tab and chose Cooling System. Follow his advice there. It will work for you. Should you have any overheating problems after that, it's because of something else, i.e. timing, mix, pump (unless you have his recommended pump) |
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Post by 69hcode on Apr 18, 2017 2:21:09 GMT
I have newer large water pump. A smaller pulley and a 6 blade export fan. And a aluminum radiator. I think my engine block is getting plugged up. It doesn't drain out the back of the block. I tried different flushes last summer. I'm running about 25-30% coolant to water. I'm going to add a heater matrix behind the grill. I know there won't be much air flow at idle but a little more capacity will help.
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Post by notamini on Apr 18, 2017 15:56:45 GMT
That shouldn't be necessary. A 3-core rad and a hi flow thermostat combined with the 10 blade plastic hi o/p fan is all our cars need, ever!
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Post by 69hcode on Apr 19, 2017 0:47:52 GMT
Where I live is over 5,000 feet with very low humidity. That and hot 37 degree summers is taxing on a lot of cooling systems.
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Post by limby2000 on Apr 21, 2017 16:28:40 GMT
When i had machining work done at a reputable engine shop i had the block oilway plugs removed and the block chemically cleaned, i,d previously removed the water jacket coreplugs. When i got it back, i could still see crusty rust inside the block jacket. I spent a hour with a long thin screwdriver scraping it out, enough to easily fill a jam jar. Beware what lurks inside your water jacket.
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Post by 69hcode on Apr 22, 2017 3:25:20 GMT
I fitted a heater matrix for a 90 Bronco. Runs nice and cool now but I know it's just a band aid. Not a hot day though. Just trying to keep it on the road until I can build the other motor.
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