4 mil stroker

[RBD]

I am a little confused about stroker cranks and have a question;

 

I have been building good strong Banshee motors for my customers for many years now, carb work, head work, ignitions and porting. Now I have a customer that I have built the engine, ported (28 mm exhaust and big intakes), cool head, welded crank and carbs.

 

He now wants a 4 mil stroker (115 mm rods) and my question is; Do I use a spacer plate and 795 pistons or do I go with the stroker domes for the cool head and 795 pistons? I have heard of people doing it both ways.

 

Do I need to do any re-porting? I am a little confused on this issue, if I keep with the 28 mm exhaust timing (using the spacer plate) what gains will the motor see? In my way of thinking is, it would be a wash as the effective power stroke would be the same as a non stroker (with ported 28 mm exh) and the piston still has to travel an additional 4 mm.

 

If I use the stroker domes, that will in effect put the exhaust timing back to a stock stroke timing of about 30 mm.....

 

So I guess I am confused, where are the power benefits in a stroker crank?

 

Thank you,

Ron

[RILS]

I am a little confused about stroker cranks and have a question;

 

I have been building good strong Banshee motors for my customers for many years now, carb work, head work, ignitions and porting. Now I have a customer that I have built the engine, ported (28 mm exhaust and big intakes), cool head, welded crank and carbs.

 

He now wants a 4 mil stroker (115 mm rods) and my question is; Do I use a spacer plate and 795 pistons or do I go with the stroker domes for the cool head and 795 pistons? I have heard of people doing it both ways.

 

Do I need to do any re-porting? I am a little confused on this issue, if I keep with the 28 mm exhaust timing (using the spacer plate) what gains will the motor see? In my way of thinking is, it would be a wash as the effective power stroke would be the same as a non stroker (with ported 28 mm exh) and the piston still has to travel an additional 4 mm.

 

If I use the stroker domes, that will in effect put the exhaust timing back to a stock stroke timing of about 30 mm.....

 

So I guess I am confused, where are the power benefits in a stroker crank?

 

Thank you,

Ron

You will gain torque from the stroker and some hp as well.If your exhaust is at 28mm now and you put the 2mm spacer you will be around 196 duration.Most people have the domes cut and not use the spacer.If you cut the domes you can just drop the transfer floors to the top of the piston@bdc. Since you already have the coolhead you can simply just pick up a set of domes from david noss or about any builder a&s,fast,redline and passion are a few and drop the floors and be good to go.