Performance Forums > V6 or Straight 6 Engines

exhaust manifolds

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Cranman:
When timing is retarded the gas doesn't get a chance to do a total job in the cylinder and the late ignition in the exhaust causes a red hot manifold. Apparently some guys have got away with as much as 14 deg but I don't know if you could get away with that much without too much pinging. I've changed the counter weights on the distributor of GM's to get more. If a timing light is used there is sometimes confusion as to the timing marks on the 300 Ford. There is apparently two marks and the one you chaulk is the smaller one?? On the Chrysler six I don't use timing light, I just keep advancing until I start to get pinging under load in high gear. Driving in 8 inches of new snow is ideal. It's ok to hear some pinging at peak load but I try to find the point it just goes away. I find this gives the most power and gives best gas mileage. I've heard a clogged catylitic converter can cause this also but not to worry about this in bombardiers. On the other hand,our bombardiers don't have any back pressure unless we put baffles in so this may be a concern. In my hotrodding days when we made our own staight headers they ran red hot too. It may be a combination of factors at play here.

bluetoque:
Timing change makes little difference...the next time someone is out at nite check your exaust manifold and ex pipe on your 300..tell me if its red hot!!

chopperguy:
I run a 300 six in my narrow gauge and I know my timing isn't spot on but I never notice my exhaust getting that hot that it glows....wow I'll have to check next time I'm out.

Averyman:
bluetoque
If timing changes make no difference then I would still suggest that your valve clearances are too tight...ie: burning exhaust gases are  escaping from the cylinders through  exhaust valves which are not completely closing. .  I am told that engine has adjustable tappets and hydraulic lifters. You could remove the valve cover and back off each exhaust valve  adjuster one turn and see what happens. Can't hurt to try... Clarence

bluetoque:
The jury is still out but I think it may be as a result of a faulty clutch fan....I dont think there is enough air movement with a thermosatic controled fan to disapate the heat created in the engine compartment. We installed an exhaust fan simmilar to Skenmans and it does help for sure. We are going to change it to a direct drive fan and try that .

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