keith black piston ring gap

[77warlock]

HELP!!!!!!!!!! I am building a 360 .04 over motor for my truck and have bought some k.b. hyperutectic pistons and I am getting confused abought how much ring gap I should have.The motor is bored .04 and has a edelbrock performer intake with edelbrock 600 carb,headers,cam grind is 218/228 at.05 and lift is.441/.441 and 114 centerline,crane hy.lifters,stock heads.can someone please help me out I want to know what ring gap should be and what kind of idel I can expect from this cam and if anyone has any Idea how much H.P. I will be making? thanks for helping out a newby! Shane: rolleyes:

[gmblows]

http://www.kb-silvolite.com/speclear.htm

That cam will be good in a 360. I have it in a
318 and it's a little weak down low, although it's
in a Cordoba, stock converter, and 2.73's.
The 114 LSA keeps the idle mellow, but not stock sounding.
Don't forget to gasket match the manifold and heads.

[77warlock]

so if I read this chart right I should have a top ring gap of aprox. .026 and the other rings stay at stock clearance?you said a mellow idel will it have any lope to it?

[dwc43]

We run KB's along with a friend of mine in our dirt track cars. Do not go over .018 gap on the top ring period. Mines in a .030 over 360 and my friend runs a 350 chebby. 018 is more than enough.
Cam aint much more than stock. I'd use a dual pattern 268* 272* cam. Forgot the lift. Great bottom to mid range. Healthy lope. Get you a Wieand action plus dual plane with a thermoquad. they are 800 cfm and much more suited for the 360. 600 too small. Remember lilte red exspress truck was stock 360 with a tq. and was the fastest production vehicle the year they came out.

[gmblows]

"so if I read this chart right I should have a top ring gap of aprox. .026 and the other rings stay at stock clearance?"

Yes, ring manufacturers specs for the others.

"you said a mellow idel will it have any lope to it?"

It's not a rumpity-rump cam, but you will know it has a cam.

If you are looking for a lopey cam you should reconsider your
build up, you have a good combination of parts that will work together.

[77warlock]

keep in mind on the cam numbers they are at .05. the advertised duration is 276/286 this still may be a puke cam.I do have a thermaquad carb but was reluctant to use it.the piston gap they recomend is .026 but that seemed like a ton of space .

[dwc43]

Originally posted by 77warlock
keep in mind on the cam numbers they are at .05. the advertised duration is 276/286 this still may be a puke cam.I do have a thermaquad carb but was reluctant to use it.the piston gap they recomend is .026 but that seemed like a ton of space .

Sorry about that, I wasn't typing what I was looking at. Put the wrong cam numbers down. Actually you have the one I was thinking of.
The .026 is way to much gap. The KB's need more gap to keep the rings from bustting the top ring land out of the piston, 'cause it is much closer to the top of the piston than most, but .026 is too much. It will have too much blow by.
If there's nothing wrong with your tq put it on there. You'll see a diffrence over the 600 and will like the torquey throttle response from it. We use a big block tq on one of our dirt track cars. It works great off the corners with no stumble what so ever.

[77warlock]

Like I ased the other guy.What do you think abought the idel lopy or not!any idea on hp Iwill get out of this thing?

[dwc43]

Originally posted by 77warlock
Like I ased the other guy.What do you think abought the idel lopy or not!any idea on hp Iwill get out of this thing?

I'd guess 325 - 350. Depends on the rest of what you got. We run a 10.7: 1 360 .030 around 400. Would be more, but we have to run cast manifold instead of aluminum. If you have headers on it, it will sound really lopey. Flowmasters would not hurt either.

[77warlock]

Thanks guys I couldnt find many people around my neck of the woods that even mess with Mopars they are all to busy building chevys and after a bad experiance with a local (so called speed shop) pistons pressed on rods backwards,rong cam installed in block,cam bearing holes completely rotated to where the oil holes didnt line up, bent one of my rods,put.02 over rings on pistons instead of .04,rod caps all mixed up,plug left out of lifter oiling gallery,they really scred me up!My father is a mechanic and I a machinist so we decided to teare all the way down and start from scratch.Dwc43 I see you are from Tenn. not that far away, I have some 440 stuff,block,heads,pistons,crank,and other BB items if you know anyone interested. Block needs a .04 bore to clean up. thanks again Shane

[dwc43]

Might be interested in those.

There's a shop aaround there that some friends use something like AR head service or Racing Heads service? Ring any bells? Used to see it in the mopar mags years ago. Cant quite remember the name. Seems some drag racer friends of mine spoke highly of it.

I've used Mikes speed shop for some of the stuff I need done. One in Murfreesboro and one in Nashville too.

[77warlock]

maybe R&R ? We will talk later on the BB items I have got to go to bed I dont want to start assembly of my motor tomorrow half asleep you can email me at thompson237@yahoo.com on the bb items that you might be interested in. Ill be fair on the stuff and will even consider trading for some sb items. the 440 was complete I dissasembled it and have everything its a 77 model out of a new yorker well thanks again for the info and for your time. Shane

[dwc43]

O.k. catch you latter. David

[Marvin S]

Did you not get instructions with the pistons.I just done this yesterday and according to the instructions it has a special notice on this.in short it says that the top ring runs much hotter on these pistons than others and and must be given extra end gap that will close up after piston reaches normal temp.If this is not done you can risk butting the rings and breaking the piston or worse.Street normally aspirated engines should be .0065 x bore dia.It goes up from there the harder you use the engine.I have the instructions if you need more.

[77warlock]

Yes I got instructions and if you follow them as I did last time.You will have blowby so bad it wont even be funny.I built this engine last year and followed the directions on the pistons and used a comp cam 252h and could not keep the oil dipstick in for the compression getting past the rings was pressurizing the oilpan.So I made a snap on dip stick top to prevent this and it started coming out everywhere it could find to escape.I used hasting rings and ground the gap to .0264 since I had a 4.04 bore.Now with that said I carried the block to the machine shop that build motors in my neck of the woods and I told them what I had gaped them at and they acted like I was crazy.They said they use KB pistons all of the time and never put over .016-.018 gap. how long before you have yours running? Let me know what the outcome is . Because if that wasnt my problem I sure would like to know what was! thanks Shane

[Marvin S]

My engine is completly apart yet but I have filed my rings according to directions.Maybee I will check into this more. I hate like hell to have problems like you mentioned.

[b-1ken]

Why don't you just use regular (non file fit) rings and the gap will come out all right without any thought process. I have run race engines with 4 3/8 bores with rings at .014" gap with no problem. I was told by one engine builder, that even THAT was too wide, that he set his at .012" (definitely scarey!). I've seen articles by prominant engine builders that say they run .025". In other words, stop worrying about it and just put stock rings in it. What you DON'T want to do is get cute and try to run them too tight (like .010"). For your engine, .018" - .020" is fine.

[Dart]

You had better follow the recommened end gap clearance with the KBs or you will go bang. Too many guys have done this and this is exactly why a number of people don't like the Hyperutectic pistons. Call KB to make sure you read the instructions correctly and follow thier specs.

[b-1ken]

Take Dart's advice on this one.