Hey all,
I am just about to start on the rebuild of my new engine, and have purchased a Come stroker kit for it. The kit comes with the Keith Black pistons.
The guy at the machine shop said that he has heard of these pistons losing the tops of them and beind problematic.
My questions is has anyone ever used Keith Black pistons before and if they have, have you had any problems with them?
Any feedback is welcomed.
Stroker Kits - Problems?
Started by
_BCR42Y_
, Feb 08 2006 08:22 AM
25 replies to this topic
#2
Tiny
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Posted 08 February 2006 - 04:13 PM
DONT USE KB PISTONS.
Theyre actually a cast poston and they collapse!
Use SRP forges slugs.. Good quality reasonablypriced and you can get the same pin height etc.
LXCHEV is going through this problem now.. his 383 stoker had the KB slugs.. no good! My engine builder will NOT use them.. has had dramas!
Best of luck!
Theyre actually a cast poston and they collapse!
Use SRP forges slugs.. Good quality reasonablypriced and you can get the same pin height etc.
LXCHEV is going through this problem now.. his 383 stoker had the KB slugs.. no good! My engine builder will NOT use them.. has had dramas!
Best of luck!
#3
_BCR42Y_
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Posted 08 February 2006 - 06:52 PM
There the hyperuectic pistons, not cast ones aparently there good for 9:1 comp?
I wouldnt dare use standard cast iron pistons, how much are the pistons you are referring too?
I wouldnt dare use standard cast iron pistons, how much are the pistons you are referring too?
#4
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Posted 08 February 2006 - 07:00 PM
Where can you get them? And what is a "reasonable" price?Use SRP forges slugs.. Good quality reasonablypriced and you can get the same pin height etc.
#5
Racehatch
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Posted 08 February 2006 - 07:19 PM
I bought a set of SRP forged pistons for my chev from my local speedshop (outlaw) $900
#6
Tiny
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Posted 08 February 2006 - 08:32 PM
Bout the $900 mark is what ive seen them for.. Theyre a full forged piston.
Personally i wouldnt use any other piston these days.. the price difference between the hyper or cast and forged pistons these days just isnt very much!
Cheers.
Personally i wouldnt use any other piston these days.. the price difference between the hyper or cast and forged pistons these days just isnt very much!
Cheers.
#7
dattoman
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Posted 08 February 2006 - 08:41 PM
I'm going with Speed Pro coated skirt Hypers with chrome rings
Cause I don't need forgies
Cause I don't need forgies
#8
_82911_
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Posted 08 February 2006 - 10:04 PM
Hyperutectic pistons are cast pistons....There the hyperuectic pistons, not cast ones aparently there good for 9:1 comp?
Just better quality material with more silica in the mix.
SRP, Ross, Aries or Venolia are all I woud ever use.
SRP on a budget,
Venolia or Ross on a "good" engine.
If you are going to use KB's or any Hyper piston keep your RPM under 7000 if you have a long rod 5.7" or longer. Or if you have a short rod..308 etc... keep the RPM under 6500.
Cheers Greg..
#9
LXCHEV
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Posted 08 February 2006 - 10:28 PM
What incredible timing to ask this question! As Tiny has already mentioned, my 383 Chev stroker was built approx 3 or 4 years ago with the Keith Black Hypereutectic pistons, (10:1 comp, 6" rods) and guess what, I have struck drama's!!! The KB's have shown no signs of breaking or anything, however I do have ring problems & big oil consumption etc. My new engine builder doesn't like the KB's and will not use them in his engines. Since hearing this, I have now heard the same thing from a few other reputable sources too! If only I knew 3 years ago!!!
However, I also found out today that my bores are not quite perfect, possibly due to a dodgy hone. So this could also be the main source of my ring problem, and not the actual pistons....
Either way..... We are going to replace them with the SRP pistons I believe. My engine was pulled down today, so we're currently in discussions as we speak. It's all certainly a learning curve. Even if the KB's aren't the cause of my problems, I am replacing them anyway for piece of mind, and also the better pistons will take NOS a lot easier when the time comes <insert very evil laugh here>
However, I also found out today that my bores are not quite perfect, possibly due to a dodgy hone. So this could also be the main source of my ring problem, and not the actual pistons....
Either way..... We are going to replace them with the SRP pistons I believe. My engine was pulled down today, so we're currently in discussions as we speak. It's all certainly a learning curve. Even if the KB's aren't the cause of my problems, I am replacing them anyway for piece of mind, and also the better pistons will take NOS a lot easier when the time comes <insert very evil laugh here>
#10
Struggler
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Posted 09 February 2006 - 06:55 AM
The KB is indeed a cast/hyper piston however it is a very good quality item.
The problem with the tops coming off is related to people not reading the instructions correctly. As KB pistons have the top ring placed quite high (close to the top of the crown) the top ring gets hotter than it would on a normal piston. KB are aware of this and recommend wider than normal ring end gaps. Some people weren't reading the instructions, fitted the rings without checking the gap, thrashed their rig, the rings expanded, butted up and ripped the top off the piston. For a nat.asp. combo they are a great piston, but you must read the instructions.
I have used a few sets of the SRP pistons lately. Yes they are about $900 a set and use expensive thin rings but they are a work of art, almost too good to put in a motor !!! There is a 383 SRP piston with I think a 18cc dish, perfect for N2O use.
The problem with the tops coming off is related to people not reading the instructions correctly. As KB pistons have the top ring placed quite high (close to the top of the crown) the top ring gets hotter than it would on a normal piston. KB are aware of this and recommend wider than normal ring end gaps. Some people weren't reading the instructions, fitted the rings without checking the gap, thrashed their rig, the rings expanded, butted up and ripped the top off the piston. For a nat.asp. combo they are a great piston, but you must read the instructions.
I have used a few sets of the SRP pistons lately. Yes they are about $900 a set and use expensive thin rings but they are a work of art, almost too good to put in a motor !!! There is a 383 SRP piston with I think a 18cc dish, perfect for N2O use.
#11
_BCR42Y_
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Posted 09 February 2006 - 09:16 AM
I have those instructions here in front of me and it has a picture of a piston losing its top, and explaining what you have just said struggler.
It going to be a N/A motor and i wont be fitting nos to it, it runs highly ported vn heads, crow can and a 750dp.
The same top end on my old bottom end (344 stroker) made about 380hp on the engine dyno, so its not a hugely wild setup but enough to get me into alot of trouble and keep a smile on my face!
I definetely wont be revving it past 6500rpm, the details on the crank alone say not to rev it that high anyway as they are a strocker.
LXChev when you say massive oil consumption, how many litres would you say in 5000km's as i do an oil change on all my motors every 5k anyway.
It going to be a N/A motor and i wont be fitting nos to it, it runs highly ported vn heads, crow can and a 750dp.
The same top end on my old bottom end (344 stroker) made about 380hp on the engine dyno, so its not a hugely wild setup but enough to get me into alot of trouble and keep a smile on my face!
I definetely wont be revving it past 6500rpm, the details on the crank alone say not to rev it that high anyway as they are a strocker.
LXChev when you say massive oil consumption, how many litres would you say in 5000km's as i do an oil change on all my motors every 5k anyway.
#12
LXCHEV
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Posted 09 February 2006 - 10:56 AM
I drove my car to the Springnats recently - approx 3 hours of driving, and it used close to 1 litre of oil. But then other times it doesn't use anywhere near that much. If I've been generally driving the car around (to work, to mates places etc, just local), if I check the oil after a couple of weeks it will always need topping up.
However, I don't believe the blame lies with the KB pistons, but more on my bores (or a combo of both). Spoke to the engine builder today, and my bores are actually tapered (not perfectly circular), they are up to 4.5 thou out of whack which is certainly not ideal. We are now taking the block from 0.030" up to 0.040" up from standard. Combined with the brand new SRP pots and rings, my bottom end should be brand new!
If you use the KB pistons, just make sure you get those ring gaps EXACT as per the instructions and you should be fine. If in doubt though, you could go for different pistons, but I can see in your situation you've already paid the cash for them, so just make sure they get setup right.
Keep us updated!
PS. I had never heard those things before about the KB ring gaps - thanks for the info Struggler. Just out of curiosity, do you know what kind of ring gaps KB recommend? And what kind of gap would you run on something like the SRP's?
However, I don't believe the blame lies with the KB pistons, but more on my bores (or a combo of both). Spoke to the engine builder today, and my bores are actually tapered (not perfectly circular), they are up to 4.5 thou out of whack which is certainly not ideal. We are now taking the block from 0.030" up to 0.040" up from standard. Combined with the brand new SRP pots and rings, my bottom end should be brand new!
If you use the KB pistons, just make sure you get those ring gaps EXACT as per the instructions and you should be fine. If in doubt though, you could go for different pistons, but I can see in your situation you've already paid the cash for them, so just make sure they get setup right.
Keep us updated!
PS. I had never heard those things before about the KB ring gaps - thanks for the info Struggler. Just out of curiosity, do you know what kind of ring gaps KB recommend? And what kind of gap would you run on something like the SRP's?
#13
_[BOTTLEDUP]_
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Posted 09 February 2006 - 02:53 PM
For KB pistons in a 4.00" bore you use around 0.024-0.028 ring gap for the top rings... The second ring gap remains std.
I don't particularly like KB's, they're an old school design strong but very heavy. The extra ring gap is necessary because of the material the piston is made out of, not because of the distance to from the crown to the top ring.
SRP's are a good budget Forging, good for 550-600hp n/a and able to cope with a 150-200 shot of gas.
For our race engines we use CP pistons not cheap but probably the best quality on the market at the moment (within a reasonable price anyways).
I don't particularly like KB's, they're an old school design strong but very heavy. The extra ring gap is necessary because of the material the piston is made out of, not because of the distance to from the crown to the top ring.
SRP's are a good budget Forging, good for 550-600hp n/a and able to cope with a 150-200 shot of gas.
For our race engines we use CP pistons not cheap but probably the best quality on the market at the moment (within a reasonable price anyways).
Edited by [BOTTLEDUP], 09 February 2006 - 02:54 PM.
#14
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Posted 13 February 2006 - 04:03 PM
If you are going to use KB's or any Hyper piston keep your RPM under 7000 if you have a long rod 5.7" or longer. Or if you have a short rod..308 etc... keep the RPM under 6500.
When there is talk of keeping it under 6500 etc are we talking about extended periods of time like a burnout, or is it runs all day taking it over 6500 or never going over 6500 at all?
I have hypers in my 333 stroker in which my cam is rated from 3200-7000 and I'm wanting to know if I'm needing to take any action or not. I'm assuming that the amount of times I'm going to take it up to 7000 is not going to have a huge impact upon the reliability or longevity of the pistons.
Peace,
#15
_BCR42Y_
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Posted 19 February 2006 - 04:04 PM
Hey All,
Wasnt sure if i said thank you before for the advise!
The machine shop still has the block, cant believe how long it takes to acid dip, bore and torque plate a block!
I dont want them to rush it though as, if i do and something goes wrong there more than likely to say it was my fault for rushing them.
Just one question with the block preperation, do you think it is good to tunnel bore the block? it think thats what it is called? or would you settle if they check and see that it is okay?
Wasnt sure if i said thank you before for the advise!
The machine shop still has the block, cant believe how long it takes to acid dip, bore and torque plate a block!
I dont want them to rush it though as, if i do and something goes wrong there more than likely to say it was my fault for rushing them.
Just one question with the block preperation, do you think it is good to tunnel bore the block? it think thats what it is called? or would you settle if they check and see that it is okay?
#16
_Bomber Watson_
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Posted 19 February 2006 - 05:00 PM
it's usualy recomended to make sure it's all strait. if you already have your mains bearings, give them to the machine shop and tell them you want max bearing crush. this will help prevent spun bearings.
#17
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Posted 19 February 2006 - 05:28 PM
So out of curiosity, what's a reasonable price for a set of them?,Feb 9 2006, 04:53 PM] For our race engines we use CP pistons not cheap but probably the best quality on the market at the moment (within a reasonable price anyways).
#18
LXdamo
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Posted 20 February 2006 - 07:52 PM
#19
_Bomber Watson_
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Posted 20 February 2006 - 08:11 PM
BAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA
dude i nearly cryed from laughing at that one....
out of curiosity, whats it out of??? i'm guessing large deisel mining majigga...but i've seen pison/rod combo's out of them and they look diferent????
dude i nearly cryed from laughing at that one....
out of curiosity, whats it out of??? i'm guessing large deisel mining majigga...but i've seen pison/rod combo's out of them and they look diferent????
#20
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Posted 20 February 2006 - 08:13 PM
When my youngerbrother did work experience at M.A.N. in Germany, he said you could stand inside the engine whilst working on it. So that piston isn't really that big in comparison. It would make a fair sized ashtray.
#21
_Bomber Watson_
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Posted 20 February 2006 - 08:25 PM
yes i agree i to have seen bigger, but that is still rather large....
#22
_CHOPPER_
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Posted 20 February 2006 - 08:27 PM
If it's the biggest he had lying around, I suppose he can be forgiven.
#23
LXdamo
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Posted 20 February 2006 - 08:29 PM
V 16 diesel
645 cubic inches per cylinder
turbo-supercharged
3000hp at 907 rpm
Thats what holds my shed door open!!!
Out of a railway engine
Just thought it looked good on there hehe
Damo
645 cubic inches per cylinder
turbo-supercharged
3000hp at 907 rpm
Thats what holds my shed door open!!!
Out of a railway engine
Just thought it looked good on there hehe
Damo
#24
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Posted 20 February 2006 - 08:36 PM
Nearly 170 litres of displacement. Gets about 40 yards to the gallon?
#25
LXdamo
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Posted 20 February 2006 - 08:40 PM
not the most efficient little beasties
Still keeps my arms black with engine oil up to the elbows!
Still keeps my arms black with engine oil up to the elbows!
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