Wussup fellas I bought a b18a sleeved block brand new not even honed.....well I have a slight issue iv never owned a sleaved block so here's my problem. I'm stock 81mm piston won't fit the cylinder but when I put the piston skirt facing up the piston goes in half way then stops.... Is this because it needs to be bored out? Also it has the copper o rings installed already........ So I dunno how big I can go?

 

Normally the sleeve is about 84mm so if an 81 mm piston is getting stuck in there, something is off. Take it to a shop that knows what they're doing and have them check your block and answer your questions so you don't end up doing something you'll regret.

 

Thanks imma send it out tomorrow

 

Send the pistons WITH IT..

 

I sure will when order them..... I was under the assumption that the sleeves were slightly bigger than 81mm which is a stock piston size....just in case someone want to use 81mm pistons in a sleeved block...

 

I know Darton sells sleeves for 81mm and up and 84mm and up for the B series motors. When they install the sleeves, they are pressed in and in the process, they may not be 100% perfectly, absolutely, positively straight. Also, the block can warp a small amount from being heated and having sleeves forced in. So, they leave the sleeves a little smaller than necessary so that they can be bored and honed out, as well as decked, so that everything can be perfect.

 

i'd think they bore it to slightly less than 81mm so when you hone you can achieve whatever ptw tolerance you wish even with 81mm pistons. a dial bore gauge will help you determine your current bore. either way, its not even honed so it doesnt matter what it is currently being that its tighter than 81mm.


TheShodan said it best, send the pistons and the manufacturer's spec sheet with the block to the machine shop. if you are really going to make a ton of power 500,600+ then i'd consider looking into larger ptw. do some research on what seems to be best

 

Thanks blackeg and everyone else....I dial bore gauged it and it's at 80mm.. When I send it out I'm going to leave it at 81mm I think ...thanks guys

 

Just to add. The sleeves are left smaller so that you can determine the correct piston to wall clearance for you pistons per the instruction of the manufacture. Typically the piston manufacture will give a list of options for what you will be using the motor for such as drag racing or scca or just street use with the occasional track use. Be sure to supply the machine shop with the correct piston to wall clearance or you may end up with a junk motor like a buddy on mine did.

 

I'll make sure I do that the guy who I bought the block from is a friend of mine and he also owns a speed shop with in-house maching so I'll purchase the pistons and the rest of my internals from him just so there's no issue....I'll give it all to him to do....good thing he's only 5 mins away from me.......

 

Have the shop do the final hone with piston wall clearance appropriate for your engines use.
N/A, Turbo or Serious Boost 1000+. There are different clearances that should be used. Clearances need to be taken into consideration due to thermal expansion of the pistons.
PM us here at G.E. any time for all your build questions any time. You can hit us up on facebook too. Good luck with your build and have a great day.

 

Thanks for the info I'll let u know if I need any advice.....