What's some things to look for when buying a 'used' engine or transmission?

 

well if u are buying a LB that is out of car take a comp gauge, and a battery powered impact drill and what ever size socket for crank pulley and use impact to "turn" motor over and do like any other comp test

if the head is off then pull the pan if dark brown and skinks stay away bad maintenance done to it

tranny's look for gear oil in it take inner cv joint to stick in tranny and make sure they stay locked in and no bad bearings when u spin inner cv in the tranny

but best policy is to buy one u can test drive and be pulled in front u that day

hope it helps

 

I don't see how doing a compression test on a motor out of a car is even possible. Sitting there with an impact wrench on the crank pulley bolt is not the correct way to spin the motor over. Its just going to snap the bolt or strip the head if you use a very powerfull one. Trying to turn a motor over with a impact sorta defeats the impacts purpose.

Even if you did, the motor would turn so slow your compression reading would be crap.

Leak down test is a different story, would much rather recomend that.

If you buy something and cant see it run, plan on rebuilding it. Its not that much to have a machine shop do a little work, and new NPR pistons, bearings, and rings can be had for pretty cheap. Lots of stuff can be reused one reconditioned or inspected at a engine shop.

 

ok if u say so i have done it many many times with the race car and i said BATTERY they dont beat as hard as a air one and a GOOD battery one will spin plenty fast enough

 

Okay. Thanks for that wisdom.

Anything else I should look for regarding tranny's? Kinda hard to ask a guy to crack the tranny open on the spot.

 

well u can grab the shift lever in back and make sure it goes in and out i think 3 postions but dont quote me on that

if u are looking at a tranny deff take some inner cv parts with spline parts to insert into tranny and spin like i said and make sure axle dont just pop out seen that many times

pull vss and look in it, look in diff for rust, and so on pull drain plug put ur pinky in the hole and get some fluid out if u can, gear oil=bad things most of the time

 

I have a sticky note taped to my computer, it reads:
When you need a transmission
1. Dont buy from any site with racing in the name
2. When you do ANYWAY dont cry when you drain the Syncromesh out and realize the synchro's cost more than you paid for the whole tranny

 

With the transmission, try to wiggle the input shaft and see if there is any play. If there is you are looking at a worn bearing which will most likely make noise once installed. Also, put a screw driver in where the shift linkage attaches with the bitch pin and slowly shift into each gear. Feel for lock outs and if it shifts smoothly. This is about all you can really do without driving it.

As for the motor, remove the valve cover and see what color it is under there. If it is like a golden color the motor was most likely taken care of. If it is dark or more brownish the motor is probably old (high mileage) or not well taken care of. Check to see if everything spins freely while turning over by hand (while valve cover is off) and check for correct cam timing. Check for wear marks on the cams. Check for "leaking" around the head gasket. If possible, pull the exhaust manifold off and see if there is equal carbon deposits in all four runners. Do a leak down test to check for condition of rings or if rings are even in there (had a friend buy a motor once off TR that was missing rings).

 

Buying a used tranny is a guessing game. Yeah you can try to shift through gears as stated before, BUT that don't mean it wont grind or pop out etc etc.

As far as the motor is concerned their is a few things you can do as custom240sx said, but as far as the other guy saying turn it over with an impact that just makes me smile. When you rotate the motor it is counter clock wise and it can loosen the bolt, if the impact is strong enough, BUT an impact by design will HAMMER once it see's resistance. When it hammers it will not rotate the motor and IF you get a drill strong enough to rotate the motor fast enough I would not want to be the one holding it because once it rotates and hits the compression stroke it will break your wrist.
Do what custom240sx said and also when oil pan is off also grab each rod and check for play or just pull all the main caps and rod caps and look at bearings.