Stupid K&B 3.5 question

[Kevin Burns]

I never owned a gold head K&B so may I ask if these engine require head shims or is it normal to be without a head shim?

1st engine)
Original SS #8935 w/black section M/pipe (I just put the red carb on it) 18,000 squish with no shims. I assume with the old school "Turbo" style head, 18,000 would be correct for 18 plus the old school "turbo button" style head reliefs would be similar to the volume of a 20,000th
But no shims? What gives?

I'm worried about the engine's sleeve/button being sealed and not so much the squish. I just thought it was odd seeing no head shim/s.

But yes, I use solder and calipers to check.

 

[Geraghty]

Don't worry....Head shims and cylinder sealing are the very least of your problems.....
Make sure you have your retrieve boat up to snuff.....You are going to be spending some time in it when using the Red carb and air-cooled head........

 

[Kevin Burns]

ohhhhhhh... I ran the red carbs on every past 3.5 with no issues (Water cooled).
Someone told me the other day the gold carb would be better that the red carb needle would be very sensitive, red carb needles were touchy but doable on the older engines. I didn't know why he said that. But I'm starting to link it together now.
Your saying the same thing except throwing the air cooled head in.
What would make the needle more difficult with this engine compared to the water cooled earlier versions of the engine?
May I ask why, or what goes on that the red card would be so difficult, I believe you, I believe him (Understand would be a better word) too now that I see what he was trying to say?

Could it have something to do with the hotter temp that the engine runs at being air cooled and going lean, having to run the needle over rich to compensate for that ending up having a low end spitting and sputtering trying to reach high rpm, dead in the water boat, perhaps?
Maybe drilling out the small aux air hole under the carb will help by increasing the air flow to keep up with the richer setting during the lower rpm band? IDK maybe.

If that's the case that the red carb just wont work then it will go on a water cooled 3.5 and the gold carb put back on this engine.
To be honest I really don't like this engine maybe because I'm so used the water cooled versions.

I have this engine at 18,000th and another water cooled engine that has no shim also and is at 16 tipping to 17,000th
Those are some pretty good tolerances without shims being the engines are designed for 18,000th. Checked with solder pinched, did it a few times to make sure my readings were accurate.

But at any rate, the shim, is one really needed? I can't for the life of me remember, ever not seeing a shim.
"I'm Getting old"

I had a few super thin 1000th shims but cant find them, mecoa don't have that thin either. (if a shim is required that is.) It will have to be a super thin shim. Ugggg I have 5,000 and 10,000 shims and that's all I have. I don't have access to a lath to turn the button either. SMH

 

[Grimracer]

I would get the motor as close as you can to the way it came out of the package and run it.. mine was a MONSTER.. VERY VERY fast little hot rod.

I have NO IDEA how many times (back in the day) I would get threatened with a claim.. LOL (back when we had that option) funny.. no body ever got off there wallets to do it.. LOL.. motor was out of the package and not even taken apart to clean the K+B installed filings out of the motor..LOL

Grim

 

[Kevin Burns]

Oh yah, the engine is all stock except I just put the red carb on it. I have the gold carb it came with.

I'm having trouble understanding your 2nd paragraph.

I know it's like K&B put manufacturing flash in the cases on purpose, lol.

I don't usually mess with timing and such. I just do case matching (Exhaust port to header) just a slight taper to let the fuel/air pass easier, and roughen up the sleeves boost areas to lessen internal fuel drag across the brass is all (I don't grind away brass or enlarge the boost areas, just roughen them up. Does that really lessen internal fuel drag across the brass...I don't think so but I do it anyways.
I also don't round the bottom of the sleeve like they do to buggy engines, in my mind it creates fuel drag, I kind of like the bluntness down there to "blume out the fuel" for lack of better words.

LOL But the shims, are they really needed or is it fine without a shim? I just can't remember, no joke.
Shoot, Ima gonna run it anyways with or with out lol. I just hope I don't hear SCREAM and BOOM!

 

[Terry Keeley]

I would try to run at least one shim, or lightly lap the head to the top of the sleeve to make sure it seals.

 

[Kevin Burns]

I would try to run at least one shim, or lightly lap the head to the top of the sleeve to make sure it seals.

Wow Mr. Keeley how have you been?
I didn't think of lapping, good idea.

I really don't like this head so I might just start looking for the original head that this gold head was copied from.
I'm always looking for a turbo head. Just playing, I think you sent me the last one you had a few years back.

Thanks for the lapping idea, I have done many old school valve jobs in the past, and still have the stuff to do it with, freaking awesome idea. My shims are just to thick or I would just shim it.

 

[Terry Keeley]

Wow Mr. Keeley how have you been?
I didn't think of lapping, good idea.

I really don't like this head so I might just start looking for the original head that this gold head was copied from.
I'm always looking for a turbo head. Just playing, I think you sent me the last one you had a few years back.

Thanks for the lapping idea, I have done many old school valve jobs in the past, and still have the stuff to do it with, freaking awesome idea. My shims are just to thick or I would just shim it.

Mr. Keeley, now I really feel old, lol!

Ya, we sold a shitload of those heads back in the day, they really woke that motor up. So much so that K&B decided to copy it...

 

[Kevin Burns]

Mr. Keeley, now I really feel old, lol!

Ya, we sold a shitload of those heads back in the day, they really woke that motor up. So much so that K&B decided to copy it...

I know man. With the popularity of the K&B's today. Crazy how many ppl still enjoy the K&B engines, quite a following. Would be nice to get em produced again. I know, I know, the tooling is probably an insane investment, I take it.

But really man thanks for the idea. I will do it, as I have everything to do it with too.

I am looking for a paper thin 1000th shim, If I can't find a set ill lap it.

Take care!! good talking.