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Threaded exhaust manifold

Wanted 
1K views 11 replies 7 participants last post by  Richard2 
#1 ·
As below
 

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#2 ·
I'm curious

Dr. G,
I'm curious as to the purpose of the threaded exhaust? I have a set with the studs holes manufactured closed. There are no bolts where your picture shows them.
just thought I'd ask,,
Greg
 
#5 ·
they thread holes are for a tap for a CO2 machine. Alfa actually had a special tool to go in the hole to check the co on each cylinder.
 
#6 ·
You may have problems there. It will not deliver EGR temperatures quickly enough to prevent ongoing detonation from causing damage. I'm avoiding this discussion but exhaust PORT temperature is "better", and still may be too slow to avoid damage. Lets not ask how I know.
Please contact Jim Steck for more information. You will need electronic fuel injection, programable, to avoid detonation.
From my experience.
 
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#8 ·
Some do, forged less than cast. I've seen broken top (conventional, not TotalSeal) top rings with no piston damage from detonation. I personally blew a hole through the crown of #4 cast piston with the other 3 showing no issues whatever, mixtures, plugs etc. all the same. this was an outside air temperature drop in a pure race engine. Why ONLY #4? I don't know.
Sometimes you will see a damaged ceramic tip insulator with detonation. I suppose it has to do with the specific area of flame front collision.
BTW, I've also run engines that rattled, with OBVIOUS detonation, yet show NO DAMAGE, and others just suddenly drop one cylinder. It's always that SUDDENLY part that is bothersome. Remember, maximum power always appears just as mixture goes to TOO LEAN.
 
#10 ·
Detonation

I wouldn`t bother with trying to measure exhaust gasses for temp. Instal a wide band O2 meter so you can set fuel/air mixes properly and avoid the potential for detonation. However you can screw the pooch with an incorrect ignition advance curve easily.
 
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