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Author Topic:   loss of rpm
dirtracr
Dirt Maniac

Total posts: 199
posted July 31, 2005 08:31 PM  
went from running 7200 to 7500 to 6700 to 7000...changed valve springs, distributer..no help..timing is 36, car doesn't flutter, pop, crack or miss in anyway just flat as he!!...i've went from a 5.14 to 5.67 trying to get more umff..any thoughts would be appreciated..

CUSTOMPERFORMANCE
Dirt Forum Champ
Total posts: 1172
posted August 01, 2005 05:06 AM  
Cam going flat or are you hooked up a bit tighter than before?

dirtracr
Dirt Maniac

Total posts: 199
posted August 01, 2005 06:06 AM  
i guess it's possible could be the cam..we also heard to try unhooking the tach and put about a 7500 chip in and see if it will hit it....on the hooked up part, i couldn't say 100% sure, it seems like going from the 14 to 67 really hasn't seemed to change anything...thanks for the input.

Dman
Dirt Freak

Total posts: 270
posted August 01, 2005 08:25 AM  
Fuel filter dirty? Pinched or collapsed hose?
We run a fuel shut-off and our driver was shutting the fuel off before the engine. This caused the line between the shut-off and the fuel pump to delaminate and collapse internally especially under high draw (high rpm).Fuel hose is not rated for vacuum (we found out).You could actually see the hose collapse as we revved the engine.This may be the problem.Have you notice a temp. increase? Good Luck!

dirtracr
Dirt Maniac

Total posts: 199
posted August 01, 2005 09:33 AM  
temp's been good, 180-200 on gas, we changed the fuel filter after heat race saturday...plugs look great...another reason we're scratching our heads...any thoughts about unhooking the tach?? thanks for the input

J Swords
Dirt Roller

Total posts: 7
posted August 01, 2005 02:28 PM  
quote:
Originally posted by dirtracr:
temp's been good, 180-200 on gas, we changed the fuel filter after heat race saturday...plugs look great...another reason we're scratching our heads...any thoughts about unhooking the tach?? thanks for the input

when is the last time you changed or replaced your air filter

dirtracr
Dirt Maniac

Total posts: 199
posted August 02, 2005 06:33 AM  
we've ran a k & n forever, always keep it clean and oiled....but...we changed it saturday too just to see if there was a difference, no difference

rpm20
Dirt Freak

Total posts: 338
posted August 02, 2005 06:57 AM  
i went through something similar and i noticed that a few weeks ago i had lowered my throttle arm down on the pedal lever and it was not allowing me to get full range of motion on my carb linkage.
have you made a similar change recently??

check your throttle stop also.

dirtracr
Dirt Maniac

Total posts: 199
posted August 02, 2005 08:08 AM  
LOL, that was next...i'm goin to do a compression check on it tonight also just to eliminate that...any thoughts on unhooking the tach, ever had a bad tach do that??

rpm20
Dirt Freak

Total posts: 338
posted August 02, 2005 08:16 AM  
never had a tch do that, and never heard or that.

quote:
Originally posted by dirtracr:
LOL, that was next...i'm goin to do a compression check on it tonight also just to eliminate that...any thoughts on unhooking the tach, ever had a bad tach do that??


Sweeney21
Dirt Roller

Total posts: 5
posted August 02, 2005 06:08 PM  
We had a tach that was making the moter run real flat and poped a few times. So i would try un hooking the tach and see what that does.

locknload
Dirt Roller

Total posts: 13
posted August 02, 2005 06:41 PM  
Did any of your rocker arms look a little on the dry side, I had a cam bearing spin in a late model and it went from running a consistent 7000 to 6100-6200. It took about 4 weeks and lots of $ to find the problem.

dirtracr
Dirt Maniac

Total posts: 199
posted August 02, 2005 06:43 PM  
tonight i did a compression check and may have found the problem, here's what i got, what do you think.
1- 205 2- 190
3-200 4- 175
5 205 6 180
7 205 8 205

pumped oil in low cylinders and they came up to 200 so i think i got ring problems, agree? thanks for replies

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