Piston to head clearance

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Re: Piston to head clearance

05 Jan 2009 08:32
#256257
Detonation occurs after TDC ,and detonation can cause pre ignition, witch occurs before TDC.
Detonation is the collision of more than 1 flame front, cased by excessive heat and pressure in the combustion chamber cause the air/fuel mixture to auto ignite. Often too much compression.
Pre ignition is spontaneous or uncontrolled combustion at the incorrect time. Usually caused by a hot spot . Glowing hot carbon, sharp edges (remember to smooth all sharp edges on those new pistons) , Thin valve edge margins, lean fuel mix, detonation can create hot spots and thus pre ignition.
76 KZ, frame gusset work,1200CC.Ported by Larry Cavanaugh, 1.5mm.over intakes, Carron Pipe, ZRX12 rear end, and seat,96zx9 front end.
01 CBR600F4i Track bike.
Cobourg, Ont. Can.

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Re: Piston to head clearance

05 Jan 2009 09:04
#256260
PLUMMEN wrote:
id stick with the .050,i pushed the limits years ago and it cost me a brandnew motor with less than 50 miles on it,i did manage to save the 73 z1 engine cases but crank ,pistons and head were destroyed in the process!:S :blink: :unsure: :ohmy: :huh: :dry: :( the motor was built for a hot streetbike but i somehow got talked into putting it into a dwarfcar that needed a motor.it would of been fine in a motorcycle but sitting sideways in that dwarf car with little airflow to #s 1 2&3 brought out expansion issues and took it out hard!but it was smoking every car on the track for like 9 laps before it let go!:woohoo:remember dragbikes that only run a 1/4 mile at a time and get cooled off can get away with a lot more than a streetbike ridden all day in traffic B)

Do u know what the squish clearance was on that motor?

It is said that the best tunners stand beside the largest pile of scrap motors.U just have to keep reducing clearances untill the motor tells u it cant take anymore.:woohoo: B)
76 KZ, frame gusset work,1200CC.Ported by Larry Cavanaugh, 1.5mm.over intakes, Carron Pipe, ZRX12 rear end, and seat,96zx9 front end.
01 CBR600F4i Track bike.
Cobourg, Ont. Can.

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Re: Piston to head clearance

05 Jan 2009 15:21 - 05 Jan 2009 15:22
#256303
i dont remember the clearances on that motor it was back around 1990,its safe to say it wasnt enough to allow for the extra heat in those back cylinders with little airflow as things started to expand though!:laugh: that would of been a killer street/dragbike motor!:woohoo:i think that was actually the first and last 1075 motor i ever built!;)
Still recovering,some days are better than others.
Last edit: 05 Jan 2009 15:22 by PLUMMEN.

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Re: Piston to head clearance

05 Jan 2009 17:14
#256333
Thats too bad . It would have been a good # to have. I hope i never have a story like that to tell.
76 KZ, frame gusset work,1200CC.Ported by Larry Cavanaugh, 1.5mm.over intakes, Carron Pipe, ZRX12 rear end, and seat,96zx9 front end.
01 CBR600F4i Track bike.
Cobourg, Ont. Can.

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Re: Piston to head clearance

05 Jan 2009 17:22
#256335
that was the most short lived bike motor i ever had,i built a 427 chevy one time for an old vette and glassbeaded the stock aluminum manifold and ran it through the dishwasher 3-4 times thinking i was safe,should of ground the rivets off holding heat shield on bottem of it.some glass beads worked their way out from behind it and smoked the motor in about 50 miles!:angry: :angry: :angry: :angry: :angry: a brandnew steel crank and a new set of bearings later it was running but 1st i ground off the damn rivets and cleaned out that shield,put it back on with safety wired allen head bolts!yeah its been an expensive learning curve over the years on more than one occasion!:laugh: i couldnt outrun that vette with my 1170,i tried really hard!B)
Still recovering,some days are better than others.

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Re: Piston to head clearance

05 Jan 2009 19:14
#256350
I talked to Paul Gast today. My block and pistons will go in the mail tomorrow.
I havent got my motor out of the bike yet. I did get the bike down to the basement though.
I have to insulate my basement before i tare into this rebuild.
Allways lots to do.;)
76 KZ, frame gusset work,1200CC.Ported by Larry Cavanaugh, 1.5mm.over intakes, Carron Pipe, ZRX12 rear end, and seat,96zx9 front end.
01 CBR600F4i Track bike.
Cobourg, Ont. Can.

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Re: Piston to head clearance

08 Jan 2009 11:34
#256725
Any 2V Kaw head - MINIMUM .050" intake and .080" exhaust
(more on the exh because of the heat)
1978 KZ650B2 w 1197cc Z1 engine
1977 KZ650B1 w 750cc Spectre engine
1979 KZ650C3 w 831cc Hot Rod engine
1978 KZ650C2 w 762cc DFI project
1977 KZ650C1 stock restoration project
1978 KZ650B2 modified project
1978 KZ650B2 Injected Drag 831cc
1980 Z1 Custom Frame Drag 1327cc
1981 Z50R Honda tow bike

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Re: Piston to head clearance

08 Jan 2009 15:22
#256760
Injected wrote:
Any 2V Kaw head - MINIMUM .050" intake and .080" exhaust
(more on the exh because of the heat)

Not piston to valve but piston to head.
Thanks anyways.
76 KZ, frame gusset work,1200CC.Ported by Larry Cavanaugh, 1.5mm.over intakes, Carron Pipe, ZRX12 rear end, and seat,96zx9 front end.
01 CBR600F4i Track bike.
Cobourg, Ont. Can.

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Re: Piston to head clearance

16 Jan 2009 07:40
#258219
I've been away for a while and I am catching up on the threads.
Does any one know the compressed thickness of the head gasket, for graphite and shim. As this will play a role in quench area?

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Re: Piston to head clearance

19 Jan 2009 11:05 - 19 Jan 2009 11:09
#258776
.043" is the compressed thickness.
I heard back from a guy who succesfully ran the piston flush with the deck and had a .043" compressed head gasket.
= .043" squish.
This was on a street riden KZ.
76 KZ, frame gusset work,1200CC.Ported by Larry Cavanaugh, 1.5mm.over intakes, Carron Pipe, ZRX12 rear end, and seat,96zx9 front end.
01 CBR600F4i Track bike.
Cobourg, Ont. Can.

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Last edit: 19 Jan 2009 11:09 by mark1122.

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Re: Piston to head clearance

19 Jan 2009 16:12
#258855
Is that for graphite or three layer gasket?

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Re: Piston to head clearance

19 Jan 2009 17:26
#258865
Hello Everyone!
This is my 1st. post on this site.

I was told a number of years ago by a man, let's call him B.H. He told me that when you run zero deck height (pistons flush with the top of the cylinder)It increases bottom end and mid range. Your top end MPH will be hurt greatly. He said these bikes had good torque from the factory but fell short in the MPH area. He told me the answer was to have a .035" deck height to increase my MPH. I tried it, and it made the differance between night & day. On all of my bikes I shim or mill the cylinder until I reach my .035" deck height. Chevy's seem to like zero deck height but not Kawasaki's. Maybe next time you build an engine you might just give it a try!

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