which cyl get the hottest?

BOATN70 · Apr 13, 2006

in a 502, i understand that two cyl get hotter than the others. i heard it was #2 and #7 for a carb application, but....
is the 502 mag mpi the same? i heard those get hot on #5 and #7, is this true?

i ask because we're adding pyros to the two different setups and need to make sure we choose the correct cyls.

thanks

Rock Steady · Apr 13, 2006

What is a Pyro?

speter4205 · Apr 13, 2006

pyrometer. Checks exhaust gas temp.

C team · Apr 13, 2006

Rock Steady said:
What is a Pyro?

Somebody who likes to burn! :hothead: :laugher:

BOATN70 · Apr 13, 2006

exhaust gas from the boat motor!! not from my exhaust!!

anyone know about this? the hottest cyls, that is???

chevy57 · Apr 13, 2006

I would check it with an infrared heat gun to make sure which ones are hottest before installing the pyros. You can buy the guns for about $100.00

chevy57

BOATN70 · Apr 17, 2006

so nobody knows what the most commonly "hot"cylinder is on either of these motors?

Ok, so who has burned these things down and which cylinder was the most damaged?

chevy57 · Apr 17, 2006

My guess would be #1 or #8. The real answer is whichever cyl. is running the leanest will be the hottest. If everything is working correctly the torque on the engine will cause it to rotate toward the port side leaving the starboard engine banks higher than the port. These (starboard) cylinders will be leanest. If you have twin engines I suspect your boat is tail heavy making the front starboard cylinder the leanest.

chevy57

Turboboater · Apr 17, 2006

Typically the hottest cylinders on a BBC are #3 and #6.

Mudball · Apr 18, 2006

Well, on my motor, #1 and #2 are the richest running! I assume these are the coldest.

But, on this otherwise stock HP500 carb (800 Holley with a Dart intake), I am running a crossover with a 140 thermostat, without the magic CFM and Sting water crossover on the intake, but I'm not sure how that might matter....

At least these plugs read the fattest.

Going back from there, they get a little leaner progressively...

The #1 and #2 plugs for instance is usually pretty black. The #7 and #8 plugs are still fairly dark, but not black.
In between they are shades darker from front to back...

According to my micro-knowledge of reading plugs, the rear plugs are still a little fat. The front ones are too rich....

I thought this was strange...

I'm thinking about dropping a jet size (two?) in the carb...
Kent

which cyl get the hottest?

BOATN70

Rock Steady

speter4205

C team

BOATN70

chevy57

BOATN70

chevy57

Turboboater

Mudball

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