Why the Spacer Plate??

[boosta1395]

I have built plenty of KZ 1000 turbo engines back in the 70's and 80's and never had to deal with a spacer plate at the bottom of the juggs.Just toss in a set of turbo pistions wield up the crank and go with 35 pounds of boost and nitrous to boot. Now I see you can't do this with a Busa engine,why is that? Now ya got use a base plate, redegree the cams and fight them on to the cam chain. What would happen if you just skip the .80 base plate and just installed the turbo pistions (and studs focourse)?

 

[cdhoroho]

the pistons would stick out the hole .08
the deck height of the pistons is taller then the stock piston (pin to top of piston)
that is why the spacer plate is required

 

[jspin]

i've never build a busa motor before, but my guess is that the lenth of the rod/stroke/deck doesn't give the piston maker enough room to put the pin where they want inside the piston. they can obviously make whatever kind of piston they want right? however if they can't make it strong enough, they aren't going to put there name on it. a spacer just gives you a taller deck height, same idea as a "deck plate" motor that you see with big v8's. i guess you could get around the problem with a shorter rod or crank, but the simpler route would be a spacer.

i like the idea of a destroked turbo motor myself, but not it's not completely desirable in a drag racing engine i suppose. perhaps in a land speed or road racing type application where piston speed has a dramatic effect on reliability.

 

[boosta1395]

WELL THAT EXPLAINS IT. THANKS GUYS.

 

[smithabusa]

you can also move the lower timing chain sprocket 5 teeth and get back very close to stock cam timing.

 

[gixxerfast1x]

wow

 

[gixxerfast1x]

wow thats true

 

[03BUSABOY]

not required. just helps lower compression, no spacer here and running 8lbs from richard!

 

[Mr Bogus]

I have built plenty of KZ 1000 turbo engines back in the 70's and 80's and never had to deal with a spacer plate at the bottom of the juggs.Just toss in a set of turbo pistions wield up the crank and go with 35 pounds of boost and nitrous to boot. Now I see you can't do this with a Busa engine,why is that? Now ya got use a base plate, redegree the cams and fight them on to the cam chain. What would happen if you just skip the .80 base plate and just installed the turbo pistions (and studs focourse)?

I asked the same thing, if I am buying a low comp turbo piston, why should I have to also put in a spacer plate..

Answer I finally got was:

there simply is not enough meat on the top side of the slug after the compression is dropped and the wrist pin hole bored..


( I think we need a "tall deck" )