Box Stock

predator hemi rpm issue

G

GillRacing57

Member
Recently having problems the last 2 races with a completely stock hemi with 5500 stand rule.

throttle screw the whole way out, will not turn over 5000-5100 on stand
-tried zip tieing the govenor linkage like others posted before and no higher rpm, still 5100 max on stand.

Motor is a slug on the track compaired to before with other motors.

any ideas?

Thanks
 
If its a sudden loss of rpm . Might be the rod getting tight .
How about when you run the trottle by hand . The actual butterfly on the carb .
99.00 time to try another one .
 
Give it a try tonight, actually had 2 that we bought for this year with same issue, throttle screw the whole way out and zip tie on govenor spring and only turn 5000-5100 on stand. I did notice there is tension on the govenor arm, pulling it back the whole time. engine from last year has some free play until you pull throttle.

It seems to be more of a linkage problem but I don't know what else to change.

flattop one I will check it tonight at the butterfly

Thanks all!
 
I haven't messed with a predator in 2 years but are you able to zip tie or some other way hold the governor open and try revving it to kinda confirm you are having a linkage problem and not internal problems?
 
I have been called three times on this so far. I tell everyone to adjust the arm on the shaft that goes down through the block. No one has gotten back to me regarding if it solved the problem
 
DynoDon said:
I have been called three times on this so far. I tell everyone to adjust the arm on the shaft that goes down through the block. No one has gotten back to me regarding if it solved the problem
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i was going to say the same thing . was unsure if it was round or half moon .
the only govener i adjust is on the lawn equipment .
no feedback could go either way . no news is good news .
 
DynoDon said:
I have been called three times on this so far. I tell everyone to adjust the arm on the shaft that goes down through the block. No one has gotten back to me regarding if it solved the problem
Click to expand...
I was thinking along those lines as well, seems to be a linkage problem more than a mechanical problem I'm guessing. With these being new motors and guessing something was out of wack. Hard to hit 5000 on track if it barely will free wheeling on stand.

I'll let you know what I find. Thanks Don!
 
It has been discovered that the springs in the new engines are weak and will not allow the engine to achieve 5500. Replacing the springs with the 10.8 springs will fix the problem. Although it is considered altering the engine it really isn’t. Many of the yesterday engines I have inspected had springs that were identical to the 10.8
 
our local track has found this as well as carb differences and has since allowed the blueprinted carb and 10.8 springs.
 
OVALTECH1 said:
our local track has found this as well as carb differences and has since allowed the blueprinted carb and 10.8 springs.
Click to expand...
So it appears the stock motor, in the stock class, is now at a disadvantage. If you can do it yourself, that's all right you, but if you can't you, you're in for some more expenses.
 
yeah I just went to an event this past weekend like that. Stock engine with a drum clutch against “stock” engines with bully clutches
 
I still need to do some research to see if moving the arm helps. We tried zip tieing the spring like the rules and our tech guy said too. 3 out of our 4 motors only turn 51-5200 on stand with screw the whole way out. It has to be govenor linkage issue or week springs like don said.
 
DynoDon said:
It has been discovered that the springs in the new engines are weak and will not allow the engine to achieve 5500. Replacing the springs with the 10.8 springs will fix the problem. Although it is considered altering the engine it really isn’t. Many of the yesterday engines I have inspected had springs that were identical to the 10.8
Click to expand...

I agree. The springs are the variable. I like the engine rules keeping everything stock like they are in PA, keeping the price down and equality but I wouldn't mind if the rules stay the same and tech becomes springs must pass 10.8 rule down the road. Might keep people from thinking they have a dud and more even playing field than stock.
 
mine is untouched aside from governor removal and oil sensor removal.... it hits a brick wall right at about 4960 it lays over and sounds like it’s coming apart. Geared 15/57-60 on an 1/8 miler. I don’t like to test Chinese rod bolts but I doubt it would free rev on a stand much past 5,000...
 
flattop1 said:
GillRacing57
Did you hold the throttle wide open and same result ?
Does it even go wide open ?
Click to expand...

Yes wide open at butterfly at 51-5200 screw all the way out with stock engine. Last years engine would of been closer to 6000 like that always ahad screw in about 1/4'' to stay at 5500.
 
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