Stroker crank
Thread Starter
Racer
Joined: Aug 2011
Posts: 343
Likes: 10
Stroker crank
I have been talking with the mechanic at my job and he is telling me that with a 3.80 stroke on a stroker crank you dont have to deck the block like on a 3.75 stroker crank. If this is true why wouldnt you just buy the 3.80 crank and be done with it spend that money somewhere else? Experts please dime in. Something does not sound right.
Racer
Joined: Jan 2014
Posts: 324
Likes: 7
From: Littleton Colorado
He needs to recheck his math. Many rebuilder pistons put the crown .025" "down in the hole" to allow for decking to true the block surface if necessary. 3.800" minus 3.750" = 0.050" - the piston will stick out of the hole if you don't use pistons for the 3.800" stroke.
Thread Starter
Racer
Joined: Aug 2011
Posts: 343
Likes: 10
The mechanic didnt mention using different pistons. I should have said ok and walked away from him.
Racer
Joined: Jan 2014
Posts: 324
Likes: 7
From: Littleton Colorado
His whole (hole??) premise is faulty. So, yeah, you probably should have just walked away.
Le Mans Master
Joined: Feb 2005
Posts: 6,479
Likes: 565
From: Clearwater Florida
..... The .050 change in stroke gets divided in half ... .025 up ... and .025 down ... effectively providing a Zero deck on an untouched block ... however , the most important part of decking a block is to make sure that the cylinder head surface is flat and square to the crankshaft centerline in both planes ... fore and aft ... side to side ... how much material that is removed from the deck is sometimes determined by how far off square it was to begin with ........... so , technically , yes you can use a 3.80 stroke crank to zero deck your block ... but that is only true if the deck is known to be square ... I would not recommend this approach ......... Take the block to the machine shop and pay the man ..........
Racer
Joined: Jan 2014
Posts: 324
Likes: 7
From: Littleton Colorado
You're right! I should recheck my own math! 
however , the most important part of decking a block is to make sure that the cylinder head surface is flat and square to the crankshaft centerline in both planes ... fore and aft ... side to side ... how much material that is removed from the deck is sometimes determined by how far off square it was to begin with ........... so , technically , yes you can use a 3.80 stroke crank to zero deck your block ... but that is only true if the deck is known to be square ... I would not recommend this approach ......... Take the block to the machine shop and pay the man ..........
(And I'd better shut up now...
)
Last edited by five7kid; Jan 22, 2014 at 07:25 PM.
