Balance Shaft + NHRA Rule Book

[DELTA_Rotary]

I just had a question regarding the balance shaft removal. I pretty sure I read in the NHRA rule book that the cars had to run the balance shafts. I had planned on taking mine out when I rebuilt the engine but I dont want to make my car illegal for competition. Does anyone have any insight on this?

 

[98TsiAWD]

How would they ever know they are gone..

 

[Windowpicker]

If they don't ask, you don't tell. It's probably for the best you never mention all of your mods to people so down the road it doesn't come back to haunt you.

 

[GRNDSM]

Are you sure that they are talking about balance shaft (unique to 4 cylinder engines) and not "SFI approved harmonic balancer".

Most NHRA people are so 4 banger illiterate, that it would surprise me if they would know a balance shaft if one hits them across the head . Never mind making a rule regarding it.

LeoN
RR

 

[zac83]

FYI: chevy vortec motors and quite a few other v blocks have ballance shafts... for some reason they forgot to include all the siezing problems like DSMs have

you could ask someone who runs a vortec in the class if they know of any rules...

 

[UndergroundR32]

Originally posted by GRNDSM
Are you sure that they are talking about balance shaft (unique to 4 cylinder engines) and not "SFI approved harmonic balancer".

What's the danger of not having a harmonic balancer on your crankshaft?

 

[InferiorWang]

Originally posted by UndergroundR32


What's the danger of not having a harmonic balancer on your crankshaft?

been discussed several times before. [yoda]Answers will a search reveal[/yoda]

 

[GRNDSM]

Originally posted by zac83
FYI: chevy vortec motors and quite a few other v blocks have ballance shafts... for some reason they forgot to include all the siezing problems like DSMs have

you could ask someone who runs a vortec in the class if they know of any rules...

Well, I stopped keeping track US V engines years ago, so I am surprised to be wrong on this one, but is seems strange that they would use balance shafts on them.

One reason why DSM shafts are prone to seizing is the combination of high engine rpms (3500-4000 highway/7500rmp redline) and doubling of balance shaft rpms. So a shaft spinning at 15000rpm on bearings usually used on 7k rpms applications, is not going to be the most durable combination.

Leon
RR