NO! NO! NO!

Any stock crankshaft has the same stroke!!! Installing a long-rod with an 86 piston DOES NOT increase stroke!!

To have a "stroked" motor you need a stroker crankshaft. The crank has to move the rod up/down further than stock to be a stroker.

Look, you can install a 86 piston on an 87-89 crank, install a spacer plate at the bottom of the jug and run it.

A shop here that rebuilds cranks will install either style rod on your crank for you. You just need to tell them what you want.

Another arguement to throw in here, many people believe the 86 revs faster than the other years. Hmmmm. Who knows?

 

i believe the 86 has a better R/S ratio because that simple fact. but i would like to know why it wears the cylinder walls more compared to a long rod like previously stated.

 

Because at the bottom of the stroke a longer rod won't try and push the piston sideways as much a a long rod does. A long stroke puts a lot of side load on the piston also. Thats why Jap car engines last so long, most don't have much of a stroke to speak of. Thats why big stroke engines such as the Olds 455 wear so fast.

 

i know that. These Japanese motor run very nice R/S ratios like the famouns B16a. The short rod 250r also has a near perfect R/S ratio, better than that of the long rod. the question is, i want to know why the short rod creates more wear than the long rod like previously stated from member dan250race. this would not make sense in the sense that the better R/S (short rod = 1.74 and 1.75 being ideal for minimal sidewall loading) would cause more cylinder wall wear. im not saying its not true, just asking for why this would be.

 

Think about it. Picture a short rod and long rod motor next to each other running, and the rods going up and down. Now sence the top of the short rod is 5mm lower when its all the way down then the long rod its going to have more of an angle to it. The short rod is therefor "thrashing" against the cylinder walls harder than the longer rod. (because of the angles) Make sence?

 

Thanks dragracer789, you said it way better than I did.

 

you guys, the rod to stroke ratio (sidewall loading) is on the short rods side, not the long rod. 1.75 is generally ideal and the short rod is 1.74. the long rod is undoubtingly further from this figure. the question stands.