Pistons

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Dan the man

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I've noticed that when somebody builds a 360 that they seem to always use KB-107 pistons. The ring end gaps have to set according to what kb says. Now, I don't know this as a fact or from personal experience but I have read and talk to people who have used them and they have said that kb pistons are known for breaking in the top ring area because they don't handle detonation very well. I haven't heard or read this about the speed pro hypereutectic pistons but again I don't know any of this as fact. Speed Pro pistons don't need any specific ring end gaps as they reccomended the piston ring manufacturer's gap. Also the speed pro pistons have friction coated skirts. The compression height between the two is like 0.015". I thought that I would ask the guys who build engines from anywhere from mild to race, what are the advantages of the kb pistons over the speed pro pistons? All that I've said is only from reading and talking to different people who have built engines. I'm not saying that anything that I've said is true or not. Just asking.
 
feed any hypereutectic a whole bunch of detonation and it won't matter a good gat-dang what your ring gap is.
 
273 said:
What's with these questions ?
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he's gonna johnny cash up his magical fantastical warmed over 318.

monday was intake and a carb, today pistons, on friday he'll sneak out the transmission and block in his buddy's mobile home. one piece at a time. a 318 worth at least 100 grand!
 
junkyardhero said:
he's gonna johnny cash up his magical fantastical warmed over 318.

monday was intake and a carb, today pistons, on friday he'll sneak out the transmission and block in his buddy's mobile home. one piece at a time. a 318 worth at least 100 grand!
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I don't what it is, something seem off about his question, it's like he asked one of those chat A.I's for some possible questions to ask us.

No offense Dan, keep asking away just something seems weird.
 
I don't know a hell of a lot but I have a set in my 340. I've heard, lol that the lighter piston makes your motor wind up a little quicker and breaking top shelf is mostly a result of improper ring gap. Go easy on me guys lol
 
Kendog 170 said:
I don't know a hell of a lot but I have a set in my 340. I've heard, lol that the lighter piston makes your motor wind up a little quicker and breaking top shelf is mostly a result of improper ring gap. Go easy on me guys lol
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Pins are lighter too
 
It’s been a little while but the KBs have a higher compression height and they are lighter iirc. So similar cost but more return on investment at least in my opinion.
The ring gap recommendation on KBs is because of the alloy they use which I’m pretty sure is different from Speed Pro. All hypereutectic pistons are light, strong, and thermally stable, but they are like tool steel: brittle. Plus in KBs case they seem to tend to hold the heat in the crown and top ring. So you have to account for that heat in the top ring gap, or the ring ends can butt and the ring warps in the groove and snaps the edge off. It’s not detonation. It’s heat. Detonation if its bad enough to cause catastrophic failure looks very different and the piston basically shatters.
 
Dan the man said:
I've noticed that when somebody builds a 360 that they seem to always use KB-107 pistons. The ring end gaps have to set according to what kb says. Now, I don't know this as a fact or from personal experience but I have read and talk to people who have used them and they have said that kb pistons are known for breaking in the top ring area because they don't handle detonation very well. I haven't heard or read this about the speed pro hypereutectic pistons but again I don't know any of this as fact. Speed Pro pistons don't need any specific ring end gaps as they reccomended the piston ring manufacturer's gap. Also the speed pro pistons have friction coated skirts. The compression height between the two is like 0.015". I thought that I would ask the guys who build engines from anywhere from mild to race, what are the advantages of the kb pistons over the speed pro pistons? All that I've said is only from reading and talking to different people who have built engines. I'm not saying that anything that I've said is true or not. Just asking.
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Hey Dan. I’ve built several 360’s using the KB-107. I have also used the SpeedPro pistons. They also need a specific ring end gap and following the KB instructions will suite any hyper piston.

If the gap isn’t enough, the rings touch and press against each other applying pressure to the piston. The top is the weak point of the piston. Enough pressure from the rings, the top will pop.

Bad ignition timing will wreck any piston.

The advantage of the Speed Pro piston is the coated sides.
At one point in time, the pistons and ring package by Speed Pro was cheaper than the KB. Price check is always the order of the day on parts and even more so since these two pistons are really nice street parts with differences being extremely small.
 
Are you talking 360 or 318 pistons? The KBs tend to have the top ring closer to the crown so it gets a lot more heat hence the need for a larger gap. Hypereutectic alloys are lighter but more brittle and will fail faster than a typical cast or forged slug if you have detonation issues. The speed pros have the top ring land lower on the piston so the end gaps are less critical but you should still run a larger gap.
junkyardhero said:
feed any hypereutectic a whole bunch of detonation and it won't matter a good gat-dang what your ring gap is.
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True, however I run speed pro hypers in my hemi six and at 180psi cranking PSI with an iron head i had detonation issues in top gear around 2500rpm for a good while and they handled it pretty damn well until I had it sorted out.
Pretty sure I have a spare 318 kb167 & a speed pro piston kicking around at home somewhere, when I'm back from overseas I can try to find them and post a pic showing the difference in top ring placement.
 
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KB pistons have coated skirt now, i ran them in my 360 for 10 years with a .030 top ring gap, i drove it on the street, and then it became just a race engine.
 
340six said:
I think the kids in the dorm have a bowl or something of things to ask. They pull a subject. Then come here and ask.
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Was the comment about running out of questions about the 318 directed to me? I surely hope not
 
I used those KB107s in my 367. I used the KB ring-gap spec. I had overheat issues that I could not solve. The engine would also lock up every time I shut it off, for 10 to 15 minutes.
I took the engine apart and opened up the gaps to the next spec, and ran the hone thru her a couple of passes, and with no other changes, (except new file-fit rings) just like that, the overheat and the lock-up were solved.
Then I increased the minimum running temperature to 207*, and it still didn't overheat. Then I retarded the timing, still no overheat. Then I put a clutch on my fan, still no overheat. That was ~2002, Engine now has over 100,000 miles on it. With still the same sparkplugs. It used to be my DD.

Those hyper-eutectics are lightweight, strong enough for a 4-speed on the street, and mine revs to 7200 in a heartbeat, time and time again. I got nothing bad to say about the KB107s.

And yes, I would buy them again.
 
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mygasser said:
unfortunately........ yes :poke: :lol:
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I was only asking what you guys thought about speed pro pistons vs kb. I asked this simply because when somebody builds a 360 they use kb pistons. It had nothing to do with running out of questions on the 318. I don't mean to sound rude but I do get tired of some of the comments that get directed to me. Believe this or not but people learn by asking questions.
 
Dan the man said:
I was only asking what you guys thought about speed pro pistons vs kb. I asked this simply because when somebody builds a 360 they use kb pistons. It had nothing to do with running out of questions on the 318. I don't mean to sound rude but I do get tired of some of the comments that get directed to me. Believe this or not but people learn by asking questions.
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Yes and you could of answered most of your questions with just a Google search, (like most of us do) and your asking a very particular question about an engine your don't have or seem to have any interest in and even if you did doesn't seem like you plan on doing a rebuild and you had answer in your question.

It don't overly seem like you want to learn, it just seem like you look for possible trivia questions to post, just for whatever reasons you have but learning doesn't seem like one of them.
 
273 said:
Yes and you could of answered most of your questions with just a Google search, (like most of us do) and your asking a very particular question about an engine your don't have or seem to have any interest in and even if you did doesn't seem like you plan on doing a rebuild and you had answer in your question.

It don't overly seem like you want to learn, it just seem like you look for possible trivia questions to post, just for whatever reasons you have but learning doesn't seem like one of them.
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I have done Google Search and sometimes I don't find what I'm looking for and I thought that asking the one's who have the experience was the best thing to do. For example, I asked why most on here have used KB pistons instead of using Speed Pro pistons. I entered that on the Google search bar and believe it or not For A bodies only came up. As far as having a interest, well of course I do if not why would I be asking questions. I did find out about the ring end gaps needed for both pistons ( believe it or not but I found that on my own ). KB pistons require the rings to be gapped according to what kb requires and the Speed Pro pistons can be ran with the ring gaps reccomended by the ring manufacturer. The KB pistons are more prone to the top of the piston breaking due to the top ring location, apparently the kb's are more sensitive to detonation than the Speed Pro pistons are. Now I'm sure that your wondering where / how I came across this information, I Google it, is it correct? I don't know. This is why I asked about the differences between the two pistons, it had nothing to do with having a interest in a particular engine or even rebuilding one, it's all about learning,learning from the one's who have the experience with these sort of things. Is Google helpful? Sure it is but it always doesn't have the answers that one maybe looking for and there's no replacement for one's experiences. Have a good day.
 
Dan the man said:
I have done Google Search and sometimes I don't find what I'm looking for and I thought that asking the one's who have the experience was the best thing to do. For example, I asked why most on here have used KB pistons instead of using Speed Pro pistons. I entered that on the Google search bar and believe it or not For A bodies only came up. As far as having a interest, well of course I do if not why would I be asking questions. I did find out about the ring end gaps needed for both pistons ( believe it or not but I found that on my own ). KB pistons require the rings to be gapped according to what kb requires and the Speed Pro pistons can be ran with the ring gaps reccomended by the ring manufacturer. The KB pistons are more prone to the top of the piston breaking due to the top ring location, apparently the kb's are more sensitive to detonation than the Speed Pro pistons are. Now I'm sure that your wondering where / how I came across this information, I Google it, is it correct? I don't know. This is why I asked about the differences between the two pistons, it had nothing to do with having a interest in a particular engine or even rebuilding one, it's all about learning,learning from the one's who have the experience with these sort of things. Is Google helpful? Sure it is but it always doesn't have the answers that one maybe looking for and there's no replacement for one's experiences. Have a good day.
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I’ll tell you Dan, the biggest issue I have with any KB piston is the garbage 5/64 ring pack.

I can’t think of a single scenario where those thick tractor rings would be better and I can’t think of one.

In my world any piston made today would have no thicker ring than .043 and it could be made even more simple if they just used a 1 mm ring.

Other than it’s about all you can get IMO a 1/16 ring pack is obsolete as well.

Thick rings eat power, cause more heat and don’t seal worth a crap.
 
Newbomb Turk said:
I’ll tell you Dan, the biggest issue I have with any KB piston is the garbage 5/64 ring pack.

I can’t think of a single scenario where those thick tractor rings would be better and I can’t think of one.

In my world any piston made today would have no thicker ring than .043 and it could be made even more simple if they just used a 1 mm ring.

Other than it’s about all you can get IMO a 1/16 ring pack is obsolete as well.

Thick rings eat power, cause more heat and don’t seal worth a crap.
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Thanks for sharing this with me, I learned something new and that's awesome
 
Newbomb Turk said:
I’ll tell you Dan, the biggest issue I have with any KB piston is the garbage 5/64 ring pack.

I can’t think of a single scenario where those thick tractor rings would be better and I can’t think of one.

In my world any piston made today would have no thicker ring than .043 and it could be made even more simple if they just used a 1 mm ring.

Other than it’s about all you can get IMO a 1/16 ring pack is obsolete as well.

Thick rings eat power, cause more heat and don’t seal worth a crap.
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I just looked up speed pro pistons and they have a 5/64 ring as well. Guess it would take a high dollar piston to get away from the 5/64 ring
 
Dan the man said:
I was only asking what you guys thought about speed pro pistons vs kb. I asked this simply because when somebody builds a 360 they use kb pistons. It had nothing to do with running out of questions on the 318. I don't mean to sound rude but I do get tired of some of the comments that get directed to me. Believe this or not but people learn by asking questions.
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you haven't learnt how to buy a car yet though...... :BangHead: :rofl:
 
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