tri-z bottom end rebuild

[Killabee]

Hi
Im building an 85 tri-z motor with a sprock 310 topend kit. I want to put a new or rebuilt crank and rod in it. I've never gotten in a bottomend before (although Ive built a couple 350 chevy's). would anybody recommend me doing the work or should I farm it out? I don't have a machine shop. so i would farm the machining out. I also have a blown motor I can practice on and 2 good runners plus some empty cases I will use for the build. I really want to learn how to rebuild the bottom myself. Anyways any links, threads, pictures, suggestions any help at all would be great!

[chris200x]

I believe the crank bearings have to be pressed in.

[Bryan Raffa]

you guys are killin me .. I wanna go to bed!


heat the case up with a torch, hot..(around the bearing area) and tap the cold bearings in with a punch on the outer race in a circle motion ..untill seated ..Also a seal driver works great for installing... it will make a hollow sound when completely seated..

then let cool ... then take the left side case and heat the center race until hot..incert the crank (stator side) and tap in with a lead or rubber mallet..I like the lead as it nice and soft..But heavy.. the crank may stop before all the way in ... just heat the race up hot again and tap it in..

put the tranny together

use some yamabond or 1104 coat the seam throughly I like to use a small paint brush ..like a kids paint brush .. and do both sides of the case

heat the inner race on the other side HOT and mate the cases together .. have your bolts ready..same thing ,, you may need to heat the inner race again..to tap it completely together

Make shure the crank spins freely!!!!!!
If not you have to heat both races and tap it around one way or the other,, till it's perfect!

cool down..take a break... come back and apply grease to the bearings ,, like when you took them out of the wrapper.. install seals, retainers... shift fork ect..top end...zing zing..thats how I learned

REMEMBER SEALS LAST..

[Bryan Raffa]

I should have took pic's of the torch steps..I have been meaning to do that..and I use MAPP GAS

[Bryan Raffa]

and yes practice disassembly on a old motor first ..it will give you a idea how it go's together.. and you will save yourself a ton of money..

[Killabee]

thanks for the help I appreciate it!
Im gonna do it this weekend! I accually have a tri-z and a 89 kdx200 (I bought for $200 bucks from a father who was mad at his kid for ditching school to ride. BAD DADDY!) which ran but needed a top and bottom when I got in to it.
Thanks again for the help!

[chris200x]

you guys are killin me .. I wanna go to bed!


heat the case up with a torch, hot..(around the bearing area) and tap the cold bearings in with a punch on the outer race in a circle motion ..untill seated ..Also a seal driver works great for installing... it will make a hollow sound when completely seated..

then let cool ... then take the left side case and heat the center race until hot..incert the crank (stator side) and tap in with a lead or rubber mallet..I like the lead as it nice and soft..But heavy.. the crank may stop before all the way in ... just heat the race up hot again and tap it in..

put the tranny together

use some yamabond or 1104 coat the seam throughly I like to use a small paint brush ..like a kids paint brush .. and do both sides of the case

heat the inner race on the other side HOT and mate the cases together .. have your bolts ready..same thing ,, you may need to heat the inner race again..to tap it completely together

Make shure the crank spins freely!!!!!!
If not you have to heat both races and tap it around one way or the other,, till it's perfect!

cool down..take a break... come back and apply grease to the bearings ,, like when you took them out of the wrapper.. install seals, retainers... shift fork ect..top end...zing zing..thats how I learned

REMEMBER SEALS LAST..

So your telling me the bearings dont have to be pressed in at a shop? Seems like a risky job if you dont know what your doing.

Just outta curiousity what does a shop charge to have those bearings installed? I had my tri z motor compltelty rebuild but never asked how much that particulair job cost.

[Bryan Raffa]

at a shop you pay by the hour .. probley a 1 hr min.. and it takes a few min..

and yes you can use a press also,, whats the shop rate these days 60-70 a hr...

rod rebuilds I send out and cost around $50

[Bryan Raffa]

thanks for the help I appreciate it!
Im gonna do it this weekend! I accually have a tri-z and a 89 kdx200 (I bought for $200 bucks from a father who was mad at his kid for ditching school to ride. BAD DADDY!) which ran but needed a top and bottom when I got in to it.
Thanks again for the help!

No prob ....if ya quite dont understand anything just ask..

[sblt500r]

raffa and i have totally different ways of putting a bottom end together!

i use an arbor press to install the engine bearings. that way they go in flat and you don't cock the bearing on the way in. if you don't go in flat, the crank could be tight like raffa said and the crank won't turn. if you run it like that the mains wil burn up.

you should never bang a crankshaft. it can throw it out of wack. always pull them in from the flywheel side. the right case will just need a litttle tapping and will go on easy.

i always put the main seals in first, makes it so much easier with the crank not in the way. actualy i put all the seals in first, then assemble.

i never heat the bearings when i slide the crank in. it will burn off all the lubrication.

it costs me $30 to have a crank rebuilt, but i need to ship it out, so it costs $50 at the end.

put blue loctite on the main seals.

[Bryan Raffa]

raffa and i have totally different ways of putting a bottom end together!

i use an arbor press to install the engine bearings. that way they go in flat and you don't cock the bearing on the way in. if you don't go in flat, the crank could be tight like raffa said and the crank won't turn. if you run it like that the mains wil burn up.

you should never bang a crankshaft. it can throw it out of wack. always pull them in from the flywheel side. the right case will just need a Little tapping and will go on easy.

i always put the main seals in first, makes it so much easier with the crank not in the way. actually i put all the seals in first, then assemble.

i never heat the bearings when i slide the crank in. it will burn off all the lubrication.

it costs me $30 to have a crank rebuilt, but i need to ship it out, so it costs $50 at the end.

put blue loctite on the main seals.

yes its easer with a press ... but I find it just as easy with a alum seal driver..just use the correct size.

thats why I wait for the seals last so I can apply the grease that melted off ..Plus if it needs to be tapped around it don't melt the seals..when heats applied..

Never directly bang on the crank.. use a piece of wood with the nuts on the end of each.. I have done so many that ,,, I have got the touch i guess.. and use the right ... soft...

GOOD Deal tho!! Good talkin the little tricks to make it easy!

and yes I need a press..that comes with the garage...

[Dirtcrasher]

Lots of ways are probably fine, and if it doesn't launch or leak you must have done AOK

Here's mine....

I toss the bearings and the crank overnite in the freezer.

Then I press the mains into the cases with my 20 ton press using a old bearing or bushing that presses on the OD only.

Then I pop in the main seals with a coating of Permatex fast drying and setting sealant on there O.D. The seal ID gets a bit of grease smeared on it before the crank is slid in.

Then I coat both sides with Yamabond or similar with an acid brush and quickly assemble them.

To assemble them, I have a bunch of sleeves that I use with an ID a bit larger than the crank journal and an OD smaller than the seal inside area. I lightly tap the main bearings inner race over the crank journal with a plastic and begin closing the cases. I keep checking it for square and I make sure the gear and fork shafts and shift drum are all aligned until it's seated perfect.

I have only had a crank not feel right a couple of times, I used the plastic to tap either end of the crank just a bit until it was smooth. I've never had to whack it so hard that I could possibly throw the crank halves out of whack but I know what your saying SBLT....

- I don't use any heat but I have heard of plenty of people that heat the cases with MAPP or in an oven.

I save all old bearings and bushings and also have a lathe for turning my own drivers for different sizes.

[tecat-z]

The easiest and least brutal way i have found to drop in main bearings "all makes" is to lightly grease baaring saddle. Then have ice cold bearing in the freezer "the colder the better" still in plastic wrap. Heat in a circular motion with mapp gas the saddle and the surrounding area til hot to the touch. But not to the point of melting metal or causing distortion. It has to be even and thourough heat. Then as fast as possible just drop bearing into saddle. I've never had one that won't just drop in, or just need pushing with thumbs to seat. Installed in seconds. And no chance of running bearing in slightly off. Of course lots of this depends on how careful past people were, to take care of this critical area. Tolerances are so tight that when it cools together, they are locked. I am extremely careful during asssembly of any kind. It pays big dividends in the end. I guess we all have our little bag of tricks we have picked up over the years. And just because you take it to a shop, it doesnt mean they won't use a crude way of installing bearing either. I use these steps for all bearing races such as tranny as well.

[Killabee]

Thanks for all the ideas guys! Anybody else have an idea let me know thanks!

[Bryan Raffa]

that freezer method works good too .. also works Great on O ring seals.. shrinking them..we all know how fun them are.. Good Stuff keep it comeing!