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Author Topic:   pistons
YAZ
Member
posted February 05, 2004 08:32 PM
anyone use keith black silv-o-lite pistons.
I been hering good things and bad.


Wallydog9g
Member
posted February 05, 2004 08:46 PM
there a good piston up to about 550 hpand 7500 rpm... like any racing part properly clearanced to the cylinder and taken care of it'll last a long time


Raz_900
Member
posted February 06, 2004 07:44 AM
The can handle quite a bit for the price. Just make sure the builder/machinist knows how to set them up. They take a much tighter piston-bore clearance spec than most forged pistons and the top rings need special attention. A typical street 350 needs about .026" top ring gap and a racer about .032".

Very important to read the phamphlet in the box.

dan ferry
Member
posted February 06, 2004 07:32 PM
yep, good pistons just misunderstood u could say... i run them no probs. my long lost buddy was just complaining about his pistons coming apart and messing things up and i asked what pistons and he told me and i asked first who put pistons in and he said i did, did you have to file the rings ?nope i just checked end gap on a few and they were ok.. well theres the problem the top ring is higher and requires special attention read directions.. he looked at me like i just stole his wife.. any ways i think thats the biggest reason for the bad talk spme of us cant read or ask questions or research. also reccomed letting machinist bore the block for those pistons and requirements i always have mine bored for each piston in its perspective hole ans thats were they stay. some say needless and may be but it madkes sence to me..


Okie11m
Member
posted February 06, 2004 09:34 PM
Just like Dan said, ring gap is the key. The KB hold more heat & if the ring gaps are too close they will expand & touch. Off comes the top of the piston & you have an instant boat anchor!! If you buy a set, it has all the details in the instuctions.


77k
Member
posted February 07, 2004 03:17 AM
got some 5.7 rod/383 pistons on x-rods,fully balanced.


stockcar5
Member
posted February 07, 2004 08:45 AM
you'd be better off getting a set of speed pros.
they cost less and dont have the ring end gap problems like the kbs do. plus those kbs have that stupid notch on the edges of the piston near the valve reliefs and above the top ring...whos bright idea was that anyway

luke

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UNVRNO
Member
posted February 07, 2004 09:26 AM
10-4 easier to just throw them in and not worry about anything like less rotating mass or compression it takes too long to do it right the first time always enough time to do it again later. by the way i dont think all the kbs got the "notch" i like the kbs


stockcar5
Member
posted February 07, 2004 08:45 PM
if your worried about rotating mass and doing it right the first time then i wouldnt buy speed pros or kbs. i'd buy wisecos or cp's. i figured he was running a claimer so good pistons were out of the question.
(maybe thats why hes interested in kbs)

luke

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YAZ
Member
posted February 08, 2004 09:15 AM
thanks guys.
no claimer rule, was just looking at the price. kb are half the price, but there
about 100 grams lighter.


Raz_900
Member
posted February 08, 2004 06:06 PM
If you have to run flat tops, KB231 (5.7" rod) or KB260 (6.0" rod) are the way to go. They're approx. the same weight as JE 'standard' forged pieces (a few grams lighter actually and come with pins that are 30 grams lighter) and cost about half the price. Of course JE/Ross etc LW forged pieces would be lighter, but they're really ridiculoud price wise.

You'll save at least 100 grams per piston (about 2 lbs total wieght) going with the LW Keith Blacks. That's a huge savings in rotating weight.

Most of the people that bad mouth KB's put them in wrong and blew the motor up. About the same as the crankshaft thread. It's not the part's fault the builder didn't install them right.

stockcar5
Member
posted February 08, 2004 08:05 PM
i guess im one of the lucky ones...i've never run kbs. just watched people i race with that run them start to slow..then a little smoke..then i can finally pass them!! lol.

seriously though...they are a junk design. look into wiseco pro trues. you can get fts on ebay new for 359 (i believe) with rings. and they'll last a ton longer. if you do get the lw kbs your gonna spend 269 or so plus about 45 for a cheap set of rings and your already closing in on 359.

i wont even get into when you gotta buy the second set of kbs in june.....

luke

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Raz_900
Member
posted February 09, 2004 10:00 AM
quote:
Originally posted by stockcar5:

seriously though...they are a junk design.....

i wont even get into when you gotta buy the second set of kbs in june.....

luke


I respectfully disagree. I've run the same set for 3 years. So not sure about the 2nd set in June. I also machined a 347 with a 8 psi blower and 250 HP nitrous kit that made over 800RWHP on the gas with KBs.

And what field of engineering and/or metalurgy is your degree in? Or did you just look at them and decide they are a junk design? Just curious....


Ego Racing
Member
posted February 09, 2004 11:19 AM
I agree with RAZ. We ran a 358ci Chevy at over 12 to 1 with KB's I didn't build the motor and I even expected it to blow up. We were the fastest car at USA international Speedway (5/8 mile asphault). Just kept the Rpm under 7500 and finished in the top 5 on a 50 lap race. We ran the motor 6 more times that year and about 14 times the next and when rebuilt it was just a hone and ring job.
We even screwed up on a motor and put our small chamber heads on it and ran them 20 laps at over 14 to one and it did not blow, it more than likely would have if we left it that way though.
If I was going to build a cheap motor or a clamer I would run them.


stockcar5
Member
posted February 09, 2004 11:26 AM
i am a "field product tester" for all brands of racing parts....i buy em and "test" em....lol.

at first i didnt likke the kb cause of the larger top ring gaps...seemed fishy to me. then when i called to ask about it they really turned me off. their excuse was that the way the pistons are designed they hold more heat in the top of the piston. if this is true thats fine...but why would yo want that??? maybe if you were in a detonation contest???
im sure they work just fine like you said....i just dont see spending that much on hypers when forged arent much more.


luke

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Ego Racing
Member
posted February 09, 2004 01:21 PM
You are right the forged are not much more but the cheap forged are heavier that the hyp's also I was part of a detonation study. It found that the silica cast pistons, due to the amount of silicon in the castings survived more detonation cycles than a regular cheap forged piston due to the flexability.


Raz_900
Member
posted February 09, 2004 02:25 PM
From KB's site...

"Ideal piston temperatures in an operating engine would suggest refrigeration during the intake and compression stroke, and incandescence during the combustion and exhaust stroke. The advantage of a hot piston on the power stroke is that less combustion energy is going to be absorbed by the piston. So far, it is not practical to heat and refrigerate a piston 6000 times a minute. However, if the incoming air is not heated by the piston and the piston reflects the heat of combustion, you start to approach ideal conditions.

A polished hypereutectic piston will reflect combustion heat back into the combustion process. This reflection, combined with the insulating qualities of the hypereutectic alloy, keeps the heat in the cylinder during the power stroke. A smooth polished piston runs cooler than a non-polished piston, even after combustion deposits have turned both pistons black. A cool, smooth piston will transmit a minimum of heat to the incoming fuel air mix."
http://kb-silvolite.com/article.php?action=read&A_id=4 http://kb-silvolite.com/article.php

They have quite a bit of info on their site if you read it all.

Until I reach the limits of them (Not sure I'll ever hit that in a stock, mod or limited late) I'll keep using 'em. The extra large ring gap is to allow expansion from the high ring placement. Heat goes through the piston, into the ring then into the block. The faster you can do this, the better the chamber eff. If the piston is heavy (can hold alot of heat) and doesn't tranfer the heat quickly, it's hurting you both in weight and efficiency.

stockcar5
Member
posted February 09, 2004 04:16 PM
you'd be suprised at the weights ego..

the 6 inch rod 383 pistons from kb are 435 grams and a set of wiseco pro trues are 395. this is a flat top piston without pins.
luke


Dixon
Member
posted February 09, 2004 04:32 PM
I haven't seen anyone mention SRP pistons, which are JE's without the name. They are cheaper, and really nice pieces.


Ego Racing
Member
posted February 09, 2004 07:34 PM
Stockcar5 I know that the Weisco, SRP's, Manley's, JE's, Aria's, Ross's and MANY others are lighter. BUT someone looking for a cheap piston for a low $ motor and is compairing Keith Black pistons at $150-$250 a set is NOT looking at a $350-700 set of pistons they are going to be looking at Speed Pro/TRW at $180-$250. I run some that are 358 grams and we can get it to about 350 with a good polish and debur but they run about $650. If I am looking at a motor to put $650 pistons in it I wont be thinking about KB's, But if I am going to build an engine I might loose for $350 There is NO WAY I am going to put $780 worth of pistons and rings in it.
The first reply you brought up Speed Pros check the weight between them and KB's.


Eljojo
Member
posted February 09, 2004 07:52 PM
Now you got me curious...what IS the weight difference between the speed pro's and the KB's?


Okie11m
Member
posted February 10, 2004 11:22 AM
Speedpro is lighter


stockcar5
Member
posted February 10, 2004 11:39 AM
thats what im trying to say ego!!

lw kbs 269+45 for CHEAP rings=314
wisecos 359 with rings

price differance 45$
quality differance A TON!

luke

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Ego Racing
Member
posted February 10, 2004 01:51 PM
Where Are you getting forged Wiseco's for undr $500? I haven't seen them that cheap. Most sets list for $550-$700 and do not come with the rings.
Speed pro part #2256 (350 forged flattop piston 5.7 rod 0.030 over bore) 610 grams without rings. about $250 a set
Keith Blacks part # KB231-030 ( 350 cast flattop piston 5.7 rod 0.030 overbore) 485 grams without rings. about $220 a set.
Total weight saved per cylinder 125 grams
125 grams X 8 cylinders = 1000 grams
Total weight saved in all cylinders 2.204629 pounds.
As a side note the 610 grams the Forged Speed Pros weigh. The only Keith Black Pistons that weigh over 600 are for a big block!
How can you say Speed Pros weigh less?


chomme
Member
posted February 10, 2004 03:00 PM
the same company that chomme is talking about is the one that sells the wisecos under 400 for FTs.

sometimes you gotta search to find the best bang for your buck.

chomme...how do those mahles look? i am planning on getting a set of FT 400 pistons fron them

luke

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Ego Racing
Member
posted February 11, 2004 09:20 PM
Thanks on the info on the pistons I will check them out. Why con I not find the weight of the wiseco's listed? They are not even on the wiseco web site.


chomme
Member
posted February 12, 2004 10:28 AM
ego...i got my weight from pistons that i had. they come marked with each pistons weight.

chomme...thanks for the info..

luke

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nolimit92
Member
posted February 17, 2004 09:07 PM
quote:
Originally posted by Ego Racing:
Where Are you getting forged Wiseco's for undr $500? I haven't seen them that cheap. Most sets list for $550-$700 and do not come with the rings.
Speed pro part #2256 (350 forged flattop piston 5.7 rod 0.030 over bore) 610 grams without rings. about $250 a set
Keith Blacks part # KB231-030 ( 350 cast flattop piston 5.7 rod 0.030 overbore) 485 grams without rings. about $220 a set.
Total weight saved per cylinder 125 grams
125 grams X 8 cylinders = 1000 grams
Total weight saved in all cylinders 2.204629 pounds.
As a side note the 610 grams the Forged Speed Pros weigh. The only Keith Black Pistons that weigh over 600 are for a big block!
How can you say Speed Pros weigh less?

I beleive if you check into that more some of the wieghts on the Speed Pros are with wrist pins. We just had a set balanced with our rotating assembly and they wieghed 437 grams they were for a 350 chevy 30 over.

Also just looking at the JR motorsports catalog both pistons look comparable in wieght. I have personally seen 3 engines in the last year pull the wrist pins out of the bottom of the KB pistons. We run Speed Pros in everything we build and have NEVER had a piston related problem (with a 355 with 255 pounds of compression).



Ego Racing
Member
posted February 18, 2004 07:27 AM
If they are pulling the pins out there clearences are not right or they are overheating the engine. We ran a 350 with 11.5 to 1 KB'b and were using a 58cc chamber (the pistons were rated with a 64 cc) and just kept the rpm under 7000 and ran a season with them on asphault. It did blow up when I got rearended going onto the corner and ended up KO'd with my foot on the gas and the rear tires about 18 inches off of the ground. The tack showed 9700 on the memory and it was a head gasket that blew from the side of the engine being slammed into the concrete wall and cracking the block and head.


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