when hopping up a flathead, what makes it sound nice and loopey? (like a long stroke engine in a norton or harley, etc.) you know the sound. is it the 4 inch crank from a mercury? or a combination of that and adding more carbs, etc? i want to hop up a 51 running ford flathead i scored and build it the way the kids did back in the 50's.
Man there was a thread like this not too long ago and I still dont fucking know what everyone means by sounding 'Loopey'
yeah, i was trying to find that post now that i need it. loopey sounding, means like the timing is real slow or the engine has an extremely long stroke. have you ever heard a norton? like the engine is going to cut off before it bangs again.... the opposite of a damn rice burner.... (short stroke) i guess retarding the timing is one way, then using exhaust you can (amplify) the effect. all kinds of factors. did you hear jimmy white's hemi?
oh sorry, i can't spell. guess my masters in history from FSU does not help in hot rod spelling. my bad guys, LOL
My broke ass friends used to lean out the mixture screws until their flatheads would barely run at idle. The plan was to make a stocker sound like it had a full-race cam. Sounded bad and might have occasionally fooled somebody.
alright, easy tricks, just what i wanted...... so putting in the 4 inch mercury cranks just adds a few horse power, right? is it really a big deal? does it add any durability to the flathead compared to normal cranks?
From the other thread on this, I think it came down to valve overlap and valve size?? Im sure someone will correct me cause my memory aint that good.
I will Preface this by saying: I'm not a flathead expert. but.... The principle is the same for all fourstroke gas motors: Big valve lift and lots of overlap (when the intake valve opens before the exhaust valve is completely closed) give a motor that "lopey" sound. The trouble is, that sort of combo is great for high RPMs but usually lacks low end power, and idle vacume which makes for less fun (relatively speaking) in a street drivin car. You also have to think about how much fuel is being dumped into the motor which is not only expensive, but also can cause ring wash, and oil contamination when idling or running at low RPMs. Don't get me wrong, I like lots of lift and duration (as well as high compression for that really crisp cackling idle), but be prepared for a compromising in other aspects. my $.02 -Nate
A cam with a narrow lobe seperation angle(108ish) will have more lope than a long one(114ish) because you have more valve overlap. You can run moderate lift and moderate duration with a narrow LSA, have lots of lope, and still be reasonable streetable. Finding an off the shelf cam like that may be a trick though.
You'll find most guys over on Fordbarn will tell you the HP/$$ isn't worth the 4" crank - they use the stock numbers to back themselves up with -15HP If you're building a hot Flatty, there's no replacement for displacement & the 4" crank buys you a bit more torque - which is very useful for a low-revving engine like the flatty. As for lopey idle - go for one size bigger cam than you need & idle it down low...
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