Heat issues :(...

wine country ghia · Post by **wine country ghia** » Mon Jul 12, 2004 2:30 pm

Hello all,

Well I'm not sure where to look now. I recently refreashed a 1500 single port a friend gave me to a 1600 sp. Here are my engine stats

1500cc sp updated to 1600 sp using CB flat top pistons 85.5
Heads two year old new sp heads stock
compression ratio 7.7:1
Head cc 50-51cc
Deck .040
carb pic 30/31 new with 127.5 main jet
Oil 20/50 Castrol
Have all engine tin installed and engine bay gasket
Using 87 grade fuel

Any ideas why she's getting hot oil sender says 240F after driving 70mph for 20min continuously with ambient temps aprox 76-80F

-Eric

Oil temp sender placement T fitting that goes where oil presser sender goesb

Post by **Marc** » Mon Jul 12, 2004 2:48 pm

What distributor/timing?
If that's a stock cam I'd try better fuel, 7.6 is really pushing your luck.

Guest · Post by **Guest** » Mon Jul 12, 2004 4:16 pm

Hey Marc,

Dizzy is a 009
Timing is 32deg advance
Stock cam
Stock crank

Ok will bump the fuel oct up what do you think 89 or should I go straight to 92?

Thanks,
-Eric

Also I have oil relief sending unit on order I think I may be getting heat soak from the case since I'm using the T fitting so my reading are invalid I think

-E

wine country ghia · Post by **wine country ghia** » Mon Jul 12, 2004 4:19 pm

Sorry forgot to sign in also I'm using petronics instead of points. When I was at half a tank I did fill the other half with 92 it seemed to help but still getting hot was that ok to do?

-Eric

Guest · Post by **Guest** » Mon Jul 12, 2004 5:57 pm

I figure that at about 8/1 comp. What cooler are you using? Is
it a dog house or the old in shroud cooler, that can make a big
differance

wine country ghia · Post by **wine country ghia** » Tue Jul 13, 2004 1:45 am

Hey there,

Yeah I'm running the old style in the in shroud oil cooler. I rechecked my calculations using the aircooled.net compression calculator it says with my measurments it should be around 7.7:1 compression that should be ok right for 89 fuel or should I bump up to 92?

Thanks,
-Eric

Max Welton · Post by **Max Welton** » Tue Jul 13, 2004 6:15 am

wine country ghia wrote:Hey there,

Yeah I'm running the old style in the in shroud oil cooler. I rechecked my calculations using the aircooled.net compression calculator it says with my measurments it should be around 7.7:1 compression that should be ok right for 89 fuel or should I bump up to 92?

Thanks,
-Eric

Well ... an .040" deck with a 50cc chamber is 8.1:1. That's the problem. You need low 7s to get by with a stock cam non-doghouse motor at sea level.

Higher octane gas will make detonation (pinging) less likely, but it will probably not run any cooler.

Max

Guest · Post by **Guest** » Tue Jul 13, 2004 9:37 am

Hey Max,

Well I guess I must be using the compression calculator wrong then it keeps telling me my compression is 7.7:1? Ok I will increase my deck height to say .060 I'll re shim it.

Thanks,
-Eric

Max Welton · Post by **Max Welton** » Tue Jul 13, 2004 10:13 am

The results I get from John's calculator page match my manual calculations (rounded to the nearest tenth). Check your units?

A deck of .060" , 85.5 bore and 50cc chambers works out to 7.7:1. IMO this is still too high for your engine at your altitude.

I just built a stocker for my winter driver at 7.7:1 (.065" deck and 50cc chambers). But that engine is for operation in an altitude range of 6000'-7500' and has a doghouse shroud. At your altitude, I would expect problems.

Max

wine country ghia · Post by **wine country ghia** » Tue Jul 13, 2004 2:11 pm

Hey Max,

Yep rechecked my math your correct it's really 8.0:1! Wow I messed up no wonder it's getting hot LOL. Ok so I'm shiming her to .080 deck
by my calcs makes it 7.4:1 I think I should be ok at that compression.

Thanks!,
-Eric

Searoy · Post by **Searoy** » Tue Jul 13, 2004 5:41 pm

Your gas milage will get worse and you might get even hotter by shimming.

You would be better off taking a little out of the chamber, then polish it nice. Get your chamber up to 55 ccs. Take it out of the slopes, but don't touch the edges of the quench pads. The preferable spot would be next to the spark plug on the exhaust port side. A very minor amount of quench pad removal on this side would be acceptable, up to the spark plug hole.

Another option, perhaps preferable, would be to have your pistons dished 5cc. Cheap at your local machinist. Keep the diameter of the dish to 60mm or less, and for 5cc that's a .070" cut, safe. Still polish the chamber.

Guest · Post by **Guest** » Tue Jul 13, 2004 5:47 pm

Hey Searoy,

Well all I can say is when I first tore this engine apart I found that it had barrel shims and the pistons were dished it ran at 150F all day long I updated it only because it was consuming allot of oil. Ok I'll look into having the pistons dished that might make more sense.

Cheers,
-Eric