Measure the GRP rod. Post the wrist pin diameter, crank pin diameter and the length of the rod. For rod length, measure it with the inside forks on the caliper in the holes. So you will have the length from the top end of the rod bushings inside diameter to the bottom of the crank bushings inside diameter. Then if you want center to center, just subtract half of the diameter of both bushings.

Once everyone knows these measurements, people with other motors and lots of old parts laying around (like me :D) can compare.

I wish KMW was still in business. Steve Kellum (Pops),
who is retired now, is one of best machinest there is.
He made and sold the first sets of super big bore shocks
and offered silicon impregnated hardened brass shock shaft
bushings. I know that he can re-bush a con rod or build an
entire new rod. Great machinest like him are getting to be
hard to find now days. I'm sure someone will offer up a
rod or rod repair soon.

I'll see what I can do.
There is so many people in need of this replacement con-rod.

i have a few grps and parts im gonna recycle. they went bust. damn shame. one of the first engines i started to buy exclusively for rebuilds etc... you ask me the old ninja case with new grp internals is one sweet machine. some super fine craftsmanship. all factorys have bugs but grp had too many apparently. i just dont see that its worth the hassle. replacement machined rods might be good for a production year but there after sleeves and other parts are gonna be toast. kind of like theres nothing like a good old movarossi or os and i hate to say that

There's nothing like a big bore,short stroke engine.

grp 21 0ff road motor NO PARTS TO BE GOT
 

l am so mad l just got 2 grp motors and now no new parts to be got can any one help me plz

Join the club.

Glow Plugs GRP
 

What other Glow Plugs will work with the GRP .21.

O.S. Seem to fit. O'donnell fits ok but not well.

What has everyone been running.

OSP6 for me. Ultra hot.

OS P4 has been good to me.
So.... will an nova R7 rod work or not?:confused:

No it won't work. Seems a certain engine modder
told alot of us that it would. I say if I can't trust
him for some advice I can't trust his work either.

i concur.

odo99t. the os plug has a different taper! sure it works but isnt correct taper. i ran all my grps with a odo99t and they ran at 190 degrees with perfect power. i sold all my grp stuff and moved on. this whole rod thing that grp left us with wasnt cool.

THIS IS WRONG INFORMATION.....

geo-y-rock did the measurements and found the taper to be the same......i have used os plugs since day one with these motors....they work great....the only plg i had problems with was the od plug....they would leak...thr the plug, you had to kung fu grip em to seal them...

i will find the post by geo...

here is the post in this thread

http://www.rctech.net/forum/4398158-post186.html