my dads 95 talon AT has a spun rod bearing. it was driven like this for a while too. i took it apart and the #4 cyl rod was the one. we got new bearings for it but i think it needs a new rod to. because the rod can move sideways a good amount. about 1/8th inch.. so what does that mean? is the block no good any more or is just the rod grinded away from being driven like that? ?

New bearings are not going to do him any good. Have a machine shop inspect the parts and do the necessary repairs. But if there is actually 1/8 inch of slack between the side of the rod and the crank, both will probably need to be replaced.

so if i replace the crank and just put 4 new(used) rods and pistons in with new crank and rod bearings am i guarenteed to be ok ?

Needs rebuild


Block and head need to be cleaned of all metal shavings from bearing

Crank is to be grinded down and polished

Oversized bearings will need to be purchased

Rod will have to be replaced


Good idea to replace all gaskets, orings, belts, ect...

Rebuild and clean oil pump or just buy a new one


and since you have the mootor apart, its not a bad idea to replace the rings, water pump, belt tensioner, valvestem seals...ect.



I spun a bearing in mine @ 60k miles and i did a complete overhual.

id rather just buy a used crank from someone and used rods too cause i think the crank it has is kinda shot.

you can do that too.

I was luckey, as soon as my car started clackin away, i pulled over and called AAA and had them tow it to my house.

depends how bad the crank journals are scarred. If it looks pretty bad like gashes and stuff you'll probably need to get it machined. If its not bad you could try cleaning up the oil pan REALLY well and put a new bearing in just that one.

Your best bet is to just get another engine that runs. My MR2 had a spun rod and we just swapped the engine out on it. Thought 420A are harder to find than old MR2 engines I think O_o...

This happened to me. Just take the rods & crank to a machine shop. They'll check the rods to see if they need to be resurfaced. They'll check the crank & probably need to turn it. Then they tell you what size bearings to get, it's that simple. It'll cost maybe around $150. If you buy a used crank and throw it in there, it may be mildly out of round, which you cannot tell by looking at it or feeling it. In which case, it will spin the bearing again. Same case with the rod.

Easiest way is to take the rods & crank to a machine shop and let them tell you what needs to be done, no guess work.

You have to replace the rod, because when the bearing spun, it will have enlarged the big end of the rod. If you put a new bearing it, it will be loose and spin again.

You will need to have the crank cut to the first undersize to remove the groves, and make sure the clearances are correct.

Originally posted by AFX_Manufacturing
You have to replace the rod

No you don't.

Originally posted by cougar694u

Originally posted by AFX_Manufacturing You have to replace the rod

No you don't.

Depending on how bad it is, yes, you may have to. If the bearing becomes too thin by wear, it can actually move around in the saddles. This can score and enlarge the rod end, and also the rod cap end. This is exactly the case with a 420A i'm building up for a friend now..One badly spun bearing, and rod/cap are not re-usable.

Originally posted by XtremeRS
Depending on how bad it is, yes, you may have to. If the bearing becomes too thin by wear, it can actually move around in the saddles. This can score and enlarge the rod end, and also the rod cap end. This is exactly the case with a 420A i'm building up for a friend now..One badly spun bearing, and rod/cap are not re-usable.

Same thing happened with my car. The bearing was worn all the way down to almost a flake. Rod end was scored and crank was scored beyond any degree of reusing. I ended up overhauling the motor though for future boosting.

I ended up having to replace my crank because a piston skirt snapped off and ended up scoring one of the journals. You may want to inspect the crank or have a machine shop do that for ya as well.


http://www.dsmregistry.com/detail.php?carid=1030

Originally posted by cougar694u

Originally posted by AFX_Manufacturing You have to replace the rod

No you don't.

LOL. I know your joking and most of the guys that have built motors know your joking, but there are alot of younger guys on here that might take you seriously. Need to put a "j/k" after statements like that so they know.

Originally posted by AFX_Manufacturing

Originally posted by cougar694u

Originally posted by AFX_Manufacturing You have to replace the rod

No you don't.

LOL. I know your joking and most of the guys that have built motors know your joking, but there are alot of younger guys on here that might take you seriously. Need to put a "j/k" after statements like that so they know.

I wasn't joking, but not 100% serious either, it was in reference to the fact that you said you have to replace it, meaning that it's mandatory, no matter what. That's why I told him to take the rods & the crank to the machine shop and let them tell him if it needs to be replaced, resurfaced, or if it's fine. I spun a rod bearing while racing in San Antonio on the bottle, and kept racing, realizing later that I had a rod knock. I drove the car back to Houston to tear it apart, and my rod was fine.

There's no way to tell unless the machine shop inspects it. They'll tell you what needs to be done.

The factory rods are fracture rods, and once egg shaped from a spun rod bearing they cannot be resized.