Piston question

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dartfreak75

dartfreak75

Restore it, Dont part it!
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Any of yall that follow my build thread already know that I have ran into a speed bump with my engine build my block didnt clean up and. 03 or .04 so I'm having to go .060 the problem is I cannot find any speed pro h116cp+.060 pistons in stock summit says they wont be available till September but when I called them they said they dont know if they will have them then either. I have checked alot of places all are out of stock my machinest even called sealed power and we can't get them thru them either. So I'm kinda thinking of going with the kb107 pistons I would like the small bump in compression it will give me but my machinest doesnt like them he said you have to run more ring gap because they expand more or something like that. He told me he would rather run a low compression height factory replacement piston than the kb107s but it was up to me. Have you guys had any trouble with the kbs any body running them now? Let me know what you thing good and bad. Thanks guys
 
Your machine is just doesn't want anything coming back on him. That's shouldn't be in the mind of a confident machinist.
They're fine, run the top ring @.034 gap, 2nd you can leave alone, but...if you're like some here and are the extra cautious type..you can add a little to theb2nd ring gap as well, like another .010

I've run the 243 version numerous times with the ootb 2nd ring gap around .020-.022
I like to run the skirt clearance around .0025-.003 but no less than .0025 and no more than .004 . Too tight and it runs a lil hotter and and you can scuff the wall/skirt.. too loose and the rings aren't as stable imo and again, scuff come back to play.

Seems to me there was a set on ebay @.060 of the 116cp.
 
kb work fine
the rings expand more but close up to same when running- thy are supposed to do that
factory rebuilder pistons may be "copensated" = compression height lowered to make up ccs gained from the bore-
which in .060 would be significent
plus many are budget built
BVVC
remind me what heads, what ccs, bore and stroke etc
cheers
ps disclaimer
I helped design the quench dome kb pistons- so highly recommended for open chamber heads- IMHO only way to get the most out of them (except racing)
 
MOPAROFFICIAL said:
Your machine is just doesn't want anything coming back on him. That's shouldn't be in the mind of a confident machinist.
They're fine, run the top ring @.034 gap, 2nd you can leave alone, but...if you're like some here and are the extra cautious type..you can add a little to theb2nd ring gap as well, like another .010

I've run the 243 version numerous times with the ootb 2nd ring gap around .020-.022
I like to run the skirt clearance around .0025-.003 but no less than .0025 and no more than .004 . Too tight and it runs a lil hotter and and you can scuff the wall/skirt.. too loose and the rings aren't as stable imo and again, scuff come back to play.

Seems to me there was a set on ebay @.060 of the 116cp.
Click to expand...
Thanks man. That's pretty much what he explained to me too. I think he said .026 on the top ring gap tho I will have to recommend him go .034 if i go with that piston. I have looked on Ebay I didn't see any in stock I actually found a set and ordered them but they refunded my money this morning and emailed me saying they couldn't get them. I will look on Ebay again. Thanks bud I appreciate it
 
Wyrmrider said:
kb work fine
the rings expand more but close up to same when running- thy are supposed to do that
factory rebuilder pistons may be "copensated" = compression height lowered to make up ccs gained from the bore-
which in .060 would be significent
plus many are budget built
BVVC
remind me what heads, what ccs, bore and stroke etc
cheers
ps disclaimer
I helped design the quench dome kb pistons- so highly recommended for open chamber heads- IMHO only way to get the most out of them (except racing)
Click to expand...
It's a 3.58 stroke 360 with factory heads I had the heads milled .030 they will be close to 65 cc if I cced them correctly before they was cut. With a felpro gasket and the h116 I will be at 9.7 with the speed pros and 10:1 with the kbs
 
dartfreak75 said:
Thanks man. That's pretty much what he explained to me too. I think he said .026 on the top ring gap tho I will have to recommend him go .034 if i go with that piston. I have looked on Ebay I didn't see any in stock I actually found a set and ordered them but they refunded my money this morning and emailed me saying they couldn't get them. I will look on Ebay again. Thanks bud I appreciate it
Click to expand...
For what I do, I use the 4.06 x .0085=.034 formula in the directions, but at normal street .0075 it's actually .030.
I like a lil more than that for those here and there days I abuse it off n on wot.
 
As stated, KB107s are fine if you run the right gap. I ran a set daily and Hard for 6 years. My oldest son used those exact same pistons for over 7 years until his recent roller lifter failure.

He built that motor when he was 18, so I doubt he took it easy on it. 2 years ago he swapped to the solid roller.

Because of the cam trash that went through the motor, he ordered a new set of the 107s.

Now the IMPORTANT part! His new set had one piston .0072 too small, would have had .009+ clearance at 4.03 bore. That was a setback time wise. So, I recommend measuring them, as soon as you get them!
 
The wider gaps are no problem AS LONG AS you run them. Some may disagree, but when I use the KB pistons, I always use the nitrous ring gap specs just to be on the safe side. They are a little wider. Won't hurt a thing.
 
I guess I missed your thread, just found it and wow, over 40 pages! That will give me something to read with my morning coffee the next few days!
 
dartfreak75 said:
He told me he would rather run a low compression height factory replacement piston than the kb107s
Click to expand...
find a new machinist.
I like Wyrmriders thinking.
If you have an open chamber head, IMO, it is well worth it to a streeter, to get the Q into the zone of .034 to .044; if that means you gotta get a raised Q-pad then that is what I'd do.
Compression Ratio by itself is not your engine's enemy.
The wrong Q can be, and so can a high cylinder pressure. But the cam you choose, needs to
be co-ordinated to the Scr to keep the pressure low enough to stay out of detonation with the gas you intend to use.... but high enough to make a sharp, fun,engine.

Just wondering;
If you already have the pistons, wouldn't it be cheaper/easier/better to just get another block?
 
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you should be looking at kb 373 232 362 depending on head and head ccs and cr you want
you can't get any quench with a FT piston and open chamber heads
 
Wyrmrider said:
you should be looking at kb 373 232 362 depending on head and head ccs and cr you want
you can't get any quench with a FT piston and open chamber heads
Click to expand...
I'm not try to get quench. 9.5-10 Is fine for me I'm not building a race car
 
AJ/FormS said:
find a new machinist.
I like Wyrmriders thinking.
If you have an open chamber head, IMO, it is well worth it to a streeter, to get the Q into the zone of .034 to .044; if that means you gotta get a raised Q-pad then that is what I'd do.
Compression Ratio by itself is not your engine's enemy.
The wrong Q can be, and so can a high cylinder pressure. But the cam you choose, needs to
be co-ordinated to the Scr to keep the pressure low enough to stay out of detonation with the gas you intend to use.... but high enough to make a sharp, fun,engine.

Just wondering;
If you already have the pistons, wouldn't it be cheaper/easier/better to just get another block?
Click to expand...
Why would I find a new machinest it isnt his fault my block didnt clean up and its not his fault that pistons I want are no where to be found. These guys have done a phenomenal job imo they have took the time to help me and teach me I read all the horror stories about machinist taking forever and stealing parts and all that stuff. This places has kept me updated and communicate has been excellent. He goes over everything with me gives me the pros and cons. Iv spent alot of time there in the last 3 months he has let me watch the whole process and taught me as it has come along. I spent 4 hours there the other day and watch him cut the valve seats and start the boring process he explained all that to me and how it works. He explained all the seat angles and everything and took the time to show me cam degreeing and actually degreed one right there in front of me. I don't think there is to many machinest that are gonna teach their trade like that for free!
As far as the block goes no it wouldnt be cheaper or easier. 360 blocks are hard to come by in these parts and when you do find one they are not cheap. Plus I have to pay for the machine work already done on the block I have plus start over on a new one. The pistons I bought I'm sending back I already got my money back so I'm not spending any extra money than I would have I just gotta find the pistons.
 
Because
#1 he recommended low compression.
#2 because he is willing to go .060, and did I miss that he sonic-checked it? LAs are "lightweight A engines" for a reason, not all will successfully take .060..
#3 Machine work already done to the block?
the "bore-ability" should have been the first thing to be checked, and no machine work started until it was known that whatever size decided on, would work. Now, you are stuck between a rock and a hard place. I mean I really hope it works out for you, But from where I'm standing right now, I would be very uncomfortable.
#4
dartfreak75 said:
Let me know what you thing good and bad. Thanks guys
Click to expand...
 
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dartfreak75 said:
I'm not try to get quench. 9.5-10 Is fine for me I'm not building a race car
Click to expand...
I think you have the wrong idea about Quench. Every engine benefits from a tight-Q design..... especially a street engine.
Your engine will be; not might be, will be; more fuel-efficient, more responsive, happier, and be able to run at a higher pressure or on a lower octane fuel.
If you take advantage of it, your engine should make more power at smaller throttle openings, with less ignition timing, and less propensity towards detonation, at what some would call hi-compression.
If you don't take advantage of it;
You will have to reduce your cylinder pressure, likely at least 5psi, and increase your Q to more than ~.080 to stay out of detonation at full timing.
At or near 800ft, a 10/1 Scr with iron heads is already iffy, it will take a pretty good sized cam to drop the pressure into the zone for best pump gas.....
But I'm sure your machinist would have mentioned all this, and you probably just forgot.... in which case, sorry I brought it up.
Look; I really am a nice guy, and I really wish you all the best success.

BTW
In my 367, I run the KB107s loose, with large top gaps, like RRR, and others say using the nitrous/towing spec. I had to take my engine apart to make it so, because it would lock-up on me every time I shut it off. I installed Plasma-moly file-fit rings, custom fit ,in as near to perfectly round bores as it gets, and the result was a freshly installed LD rate almost immeasurable. And I was able to increase my minimum coolant temp from 180 to 205. Lemmee tell ya, that engine pulls real nice. The only successful run of four tries, it went 93 and change, in the Eighth, at 3457 pounds, 930ft elevation,with 3.55s and BFG Drag-Radials. The sixty foot was over 2.4 seconds, so you know the track was crap... or my suspension was,lol, but she still did the deed in 7.92 seconds, spinning most of the way. And it did it all with a 230@.050 cam, a manual trans, and Q=.034.
 
dartfreak75 said:
Why would I find a new machinest it isnt his fault my block didnt clean up and its not his fault that pistons I want are no where to be found. These guys have done a phenomenal job imo they have took the time to help me and teach me I read all the horror stories about machinist taking forever and stealing parts and all that stuff. This places has kept me updated and communicate has been excellent. He goes over everything with me gives me the pros and cons. Iv spent alot of time there in the last 3 months he has let me watch the whole process and taught me as it has come along. I spent 4 hours there the other day and watch him cut the valve seats and start the boring process he explained all that to me and how it works. He explained all the seat angles and everything and took the time to show me cam degreeing and actually degreed one right there in front of me. I don't think there is to many machinest that are gonna teach their trade like that for free!
As far as the block goes no it wouldnt be cheaper or easier. 360 blocks are hard to come by in these parts and when you do find one they are not cheap. Plus I have to pay for the machine work already done on the block I have plus start over on a new one. The pistons I bought I'm sending back I already got my money back so I'm not spending any extra money than I would have I just gotta find the pistons.
Click to expand...

Got any pictures of the top of the cylinders that did not clean up ?

Lets see what they look like at .040
 
George Jets said:
Got any pictures of the top of the cylinders that did not clean up ?

Lets see what they look like at .040
Click to expand...
I didnt take any it was a section about an inch long and just enough to catch a nail on right at the the top where the ring ridge always is. It came out on all but 2 cylinders. He said it would probably be fine to run but I didnt want to chance it
 
dartfreak75 said:
I'm not try to get quench. 9.5-10 Is fine for me I'm not building a race car
Click to expand...

Thing about it, if you're running the stock type open chamber head, you're never gonna see quench even with the KB107 at zero deck height. What's the chamber depth? Something like .095"? That plus the head gasket. LOL

If I were you, I'd stick with finding the pistons you had but in .060, just like you started out doing. Even if it means waiting. Have you got a deadline other than just wanting it done? Maybe move onto something else until you get the pistons. Just a thought.
 
RustyRatRod said:
Thing about it, if you're running the stock type open chamber head, you're never gonna see quench even with the KB107 at zero deck height. What's the chamber depth? Something like .095"? That plus the head gasket. LOL

If I were you, I'd stick with finding the pistons you had but in .060, just like you started out doing. Even if it means waiting. Have you got a deadline other than just wanting it done? Maybe move onto something else until you get the pistons. Just a thought.
Click to expand...
I would rather have the speed pros just because that is what I planned and did the most research on. I dont have a problem with the kb107s I would run them I was just hesitant on buying them because my guy dont like them he said they are junk. He said he has seen more than one engine locked up blew up messed up because of kb pistons. He cracked me up he is old guy it's a family operation him his son and grandson all run the place his grandson is like 25 and he said I would run the kb they will be fine the old guy spoke up and said I have seen so many tops come off kbs I wouldnt put one in a lawn mower. Haha
The only difference I see between the two is the kb has a slightly higher compression height @ 1.675 vs 1.660. And the the speed pros have coated skirts which I like better. And the kbs are slightly lighter which is why I stayed away from them in the first place
 
dartfreak75 said:
I would rather have the speed pros just because that is what I planned and did the most research on. I dont have a problem with the kb107s I would run them I was just hesitant on buying them because my guy dont like them he said they are junk. He said he has seen more than one engine locked up blew up messed up because of kb pistons. He cracked me up he is old guy it's a family operation him his son and grandson all run the place his grandson is like 25 and he said I would run the kb they will be fine the old guy spoke up and said I have seen so many tops come off kbs I wouldnt put one in a lawn mower. Haha
Click to expand...

I am sure he's right too. Not that they're junk because they're not. But I'm sure he's seen them do exactly as he described, but through the error of those who set the ring gaps......I would be hesitant to use him if that was him. More likely, it was his machine customer setting them up themselves and not following KB's recommendation. I've seen it all too much with Chevy guys especially. They will even read the instructions and somehow in some grand moment think they know more than KB and just set the rings to the stock spec.

Plus, the Speed Pros require none of that special ring gap stuff anyway, so you don't have to worry with it.
 
Tims 66 Cuda said:
Try Northern Auto Parts in Iowa. They carry them.


Tim
Click to expand...
I just places an order thru them. I guess we will see if they are in stock or not!
It's really funny because I found them on there before I read your post and literally just ordered them 2 mins ago and then found your post recommending them
 
AJ/FormS said:
I think I read heads cut to 65cc; I think the math on that is .030/.035 or so. So still no Q with flat tops. But the ugly zone is fast approaching.
Click to expand...
What is the ugly zone you talk about?
Ok so let's talk quench. What piston would I need to obtain a quench with open chamber heads?
 
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