K&B HEAD CLEARANCE

[waterbug]

K&B HEAD CLEARANCE

Hey everyone !!!

I just got through checking my head clearance on my K&B 3.5 #8907. I took the shim out and did the solder test . It measured .024 after taking the .010 shim out does this sound right ???

I have not run the engine but that sure sounds like alot to me . Talk about poor performance !!! All I had was large solder so I mashed the end with flat jaw pliers to get the size down so I could get the engine to turn over. .012-.010 is what i'm shooting for.

Any comments ??

 

[GTR]

Re:K&B HEAD CLEARANCE

Hi Waterbug,

Without a shim at all it should be 18thou as advertised by K&B. I re-checked a bunch of 3.5's the other day and they were all pretty much spot on 18thou. They are however all now between 8&12thou. I expect to see consistent performance at this deck height.

Why does your engine have a shim at all?

Take it out. Try running regularly checking the plug. Are you running a pipe or exhaust through the leg?

Let us know how you go.

GT 8)

 

[waterbug]

Re:K&B HEAD CLEARANCE

GTR

I'm running a copper header and a silverbullet pipe. Haven't had it but two weeks, I have never run it. I polished the case passages and opened the top of the ports to match the sleeve and cut the sleeve ports to bottom of the sleeve,exept exhaust. Thats .024 without the.010 shim !!!!! I'll go over it again to make sure of my measurements . Yep !! it's .024 . I cut it down measuring the top flange and I took off from .0835 to .0605-.0610.

I put the head on and tried to turn it before I tightened the bolts and OOOPPSS!!! I put the .010 shim back in and now it is .0085-.009. I will run it like this and see how she does .

 

[mark james]

Re:K&B HEAD CLEARANCE

hey bug.

just to let you know, bill Mcgraw (speedmaster prod.) has a nice dial guage called the accu-check for measureing head clearance.well worth the $30.00

My k&b 3.5 is running at .012

mark

 

[waterbug]

Re:K&B HEAD CLEARANCE

Yea I saw the gauge . I have the dial indicators but not the aluminum piece . Went out yesterday and got a drill press and a 4" cross slide vice to make my own little milling machine. $ 80.00 Harbor Freight has some nice little laths, milling machines at very good prices they had a miniture lath for 299.00 and a good mill for 299.00 but were sold out of the mill. they had a larger one for 399.00. And combo laths/milling machines in the 400.00-600.00 range.

If you are really in to racing boats of different types, you could pay for the machine in three sets of running hardware !!