So I was installing my header today on my 79 truck. Everything was going well when i noticed the engine 'tag' stamped on the block. It says 21R. I have heard very little about these engines except people say to get rid of them.
The header installed no problem, everything lined up. So what other parts from a 20R are compatible with this 21R? I have a new weber 32/36 and adapter for a 20R sitting in my shop waiting to install. Why does everyone say these motors are junk?
I am at least the third owner of this truck and have had it for about 9 months, i have thousands of dollars of parts waiting to install, springs, gears, lockers, steering, tcase 4.7, all kinds of stuff. Now I'm a bit concerned about the 21R.
Last week i discovered my newly acquired W56 was full of rusty water, now this... :pat:
oh well, i guess I'll run it till it dies then look for a 20 or 22R.
sorry about the long post, just kinda frustrated right now...

Brian

 

doh! The dreaded 21-RU Jap crate engine. Junk. Its a 1.9L engine, with no power. Good luck finding parts for those engines.

I'd say leave it in until it blows up, then put the correct engine back in it.

 

so does anyone know if a cam and rockers for a 20R would fit the 21R? I was going to get a cam when i thought I had a 20R, if it would work on both I'd still get a cam and swap it to a 20R when the 21R dies.
Thanks!
brian

 

top end is still the same as a 20R/22R. cam and rockers will fit just fine.

the only real difference between a 20R and 21R is that the 21R has a smaller bore. all the other parts are pretty much interchangeable. not a bad engine, just gutless.

 

Well you got better luck than I, I had all the motor rebuild then after all I spend I learned about it and believe me it was frustrated to know about the motor:

http://www.cardomain.com/id/semork99

I was very frustrated when I learned about it here that this motor was from a fork lift and all those things you have heard but well until I tried out I is pretty strong I have gone to 80m/h In the freeway 70 easily 80 behind a big truck so if you plan to rebuild it I'm shure you wont get disapointed.