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Author Topic:   KB pistons
Dirt Roller

Total posts: 23
posted January 29, 2001 10:43 PM
Is their any thing I should know about building with and running them.What about the new light weight pins are they really worth the 60 or so grams in reduction

Dirt Full Roller

Total posts: 59
posted January 30, 2001 07:57 PM
Pay attention to the timing specs. Some KB's don't like alot of timing....

Dirt Full Roller

Total posts: 52
posted January 31, 2001 01:04 AM
Been running KB's three seasons now. Working ok for us. as was mentioned they do not like too much timing and will melt.

Also be sure to run around 20 thousandths end gap on the ring gap when installing them any less and KB's have been known to gauld up from heat.

Dirt Forum Racer

Total posts: 96
posted January 31, 2001 09:30 AM
Keith Black pistons use .008 x bore size to calculate ring end gap.

Dirt Roller

Total posts: 9
posted February 03, 2001 08:21 AM
I have a new set of SIL KB195. How much is to much timing? Using a Davis Unified Ignition-suggested plug gap of .050"-.055". Thanks Bob

Racer 111
Dirt Forum Racer

Total posts: 92
posted February 03, 2001 06:19 PM
Had them in a engine for 3 years.No problems.Engine builder use's them alot.Good pistons.The lighter pins will help you rev faster.It only takes a few grams of weight to make a big difference.

Dirt Freak

Total posts: 251
posted February 03, 2001 08:07 PM
I always run 38 degrees, total advance. I rev the engine up to about 4000 rpm and check it. If you can't run that much timing, I wouldnt spend my money on them. It probably depends how much compression your planning on running. Also, I wouldn't recommend running anything over .035 spark plug gap. On any kind of ignition. Use jetting and plug heat ranges, to get maximum power...AND TO KEEP FROM HAVING A MELTDOWN......

Dirt Roller

Total posts: 9
posted February 04, 2001 10:55 AM
THANKS Mod RAcer #93 Told the compression would be about 13.25:1, 55cc Combustion chambers. Starting with 51 sparkplugs. Thanks again

Dirt Full Roller

Total posts: 37
posted February 07, 2001 09:27 PM
The #1 thing to remember when using these pistons is that the high silicon content of the hypereutectic alloy will cause more than usual amount of heat to remain on top of piston, thus larger ring end gaps are required on the top two rings or the heat will cause them to **** together and cause alot of nasty damage. A top engine builder on the west coast told us .030 on top and .020 on second rings in a 355 ci street stock motor turning 6700 rpm. These type of pistons have a bad reputation with some folks, but it's only because they don't understand their characteristics and are unwilling to deviate from conventional engine-building practices. We use them, and we like them.

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