Timing belt SNAPPED. Piston question.

[Sobo]

Hey all,

I figured instead of searching I'd post this so that way I can increase my post count. Sorry.

Well, I just picked up a wonderful 1g to supplement my evo x as a winter vehicle. Previous owner told me about how the t-belt snapped, they replaced it, and the car still didn't run.

So yeah, I assumed bent valves and what not and upon disassembling I did discover bent valves.

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However what I did not take into account was the fact that the pistons would have marks like these.

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So my question to you is:
Do I need to replace these pistons? All the damage is on the intake side.

If so, can I replace them buy just buying a set of used 1g pistons and taking the oil pan off while the motor is still in the car?

-Alex

 

[Calan]

Yes, and not easily.

I HIGHLY suggest you change the car in your profile to almost anything other than "Honda CRX"...or you will get flamed to no end.

 

[Sobo]

Mehhhhh. Is that better?

And just to clarify, you are saying: Yes, I should replace zee pistons?

And: No, you can't replace the pistons/rods while leaving the block in the car.

Because there looks like there is an awful amount of room to get that oil pan off...

 

[DSM_PWR]

Hey all,

I figured instead of searching I'd post this so that way I can increase my post count. Sorry.

Not always the best way to start off in any forum...

Yes i would replace the pistons, along with bearings, gaskets, etc... you might as well have the block/head cleaned and decked... why not just do things right from the beginning instead of having to redo later...

But thats just me... i dont like to half a$$ anything

 

[Sobo]

Not always the best way to start off in any forum...

No care. I'm here for the market.

 

[MidShipCivic]

I say if that not a huge piston dent off to the left in 2nd piston piston you can just polish those piston marks up and use them again it's just a winter time daily....

I don't consider this a ''flaming forum'' regardless of car in profile.

 

[Sobo]

I say if that not a huge piston dent off to the left in 2nd piston piston you can just polish those piston marks up and use them again it's just a winter time daily....

I don't consider this a ''flaming forum'' regardless of car in profile.

Is is not a huge dent. The only marks are on the intake side of things.

-Alex

 

[LiquidX]

No care. I'm here for the market.

Good luck with that


On a side note, replacing the pistons is the best option, however, depending on how bad the denting is you may be able to just grind down the high spots to prevent heat spots.

 

[jmartinez1228]

Pull the motor and just rebuild it. Can you slap on another head, tbelt and stuff? Yup but will it run right? Maybe or maybe not. Nobody can really give you the right answer. The best answer it to pull it and rebuild. If you are on a budget then put another head on because that head could most likely be toast, you dont know if the valve guides got damaged unless if you know how to check for that. So If you want to be cheap then throw another head on along with the needed parts and see. If it still runs crappy then you know you will probably need to yank the motor and rebuild.
Me personally I would have already pulled that motor and looked for another used motor online and call it a day but then you may end up in the same boat again so HAH!!!

 

[Sobo]

Pull the motor and just rebuild it. Can you slap on another head, tbelt and stuff? Yup but will it run right? Maybe or maybe not. Nobody can really give you the right answer. The best answer it to pull it and rebuild. If you are on a budget then put another head on because that head could most likely be toast, you dont know if the valve guides got damaged unless if you know how to check for that. So If you want to be cheap then throw another head on along with the needed parts and see. If it still runs crappy then you know you will probably need to yank the motor and rebuild.
Me personally I would have already pulled that motor and looked for another used motor online and call it a day but then you may end up in the same boat again so HAH!!!

1. I have a new cylinder head en-route with a new head gasket and cylinder head bolts
2. The PO put a new timing belt on the car prior to realizing the head was toast

3. I'm debating buying new (Used) 6 bolt rods and pistons. I just found a pretty good set for $80 shipped. I'd probably just drop the pan, remove the old pistons and slap the new ones in with new bearings.

Why? Because it's a winter car and I'm not pulling the motor to have it machined. The car is only worth probably $2000 all said and done. I'm sure used pistons and rods with new bearings would be dandy (No honing or machinework)

But I'm also pretty sure that the pistons would be fine in the car as it sits. I feel bad being as far into the car as I am to just leave it like that though. I mean I just need to pull the t-case and oil pan and it's all right there.

 

[DSM_PWR]

Seems like you already had your mind made up from the beginning and were just trying to see if anyone would agree with going the cheap route

 

[92AWDHX40]

You could do it right and make sure your winter car stays that way depending on what you do or dont do, im not doing things half but like i said it depends on what you decide to do. Winter i hate being stuck somewhere because i skipped somewhere but thats just me. The pistons might be fine might not.

Good point dsmboy, not getting into any arguments here its not worth it.

 

[jmartinez1228]

You could do that, throw in new bearings on an unturned crank could only do what? hmm i dunnno maybe end up trashing the bearings if a measurement is off? You really want to go through all that hassle?
used pistons ? sure if the bore is the same but why different rods? i dont see how the rods could be damaged so yea you could get away with a set of pistons from dsmgraveyard or something like that.
I guess the only question is have you built a bottom end before? If you have then you probably know the process if not then your setting yourself up for a bigger headache if any of your measurements are off. Everyone thinks it's so simple to just throw in new bearings and assume it will be ok. That's easy for anyone to say. Me I say try the head and see from there. Why? Because I've had your exact same situation happen a few months on my old car, pistons looked like crap like yours but i just threw on another head, headgasket and the other crap to go with it and the car ran fine. just saying. good luck

 

[Sobo]

I really don't know to be honest.

I was under the assumption that if you did not need to bore a cylinder out or machine anything that stock specced stuff is just a bolt up affair.

Why pistons and rods? So I don't have to have the pistons put onto the rods. $80 is cheap.

 

[MidShipCivic]

Realistically, the valves just touched the reliefs on the pistons if the engine rotates smoothly
and, it ran before then I don't see no problem with getting some abrasive compound after cleaning the piston tops then buffing them clean.

Everyone talks with their friends thinking about what they should do or not with their cars whats the difference, no need to jump on him for coming on here and talking about it.

Putting bearings on a crank without micro polishing will not cause an engine failure, ''turning'' is resizing the crankshafts journals unless my terminology is skewed.

 

[92AWDHX40]

Im redoing mine now near everything taking no chances, spend the money get it right its not a tire or starter its the engine.

 

[Sobo]

I just don't get the point in all this machine talk.

My crank is fine.

My cylinders are fine.

It's not like I had a catastrophic failure, I simply have some marks in my pistons.

Someone explain to me why I can't get away bolting stock pistons with new stock size bearings to a stock crank.

I understand there may be some "Warpage" which could lead to increased wear on the pistons. But the car will likely not see another 20,000 miles so who cares.

Any other reasons?

 

[Calan]

What is stuck to the valves in the first pic, and what is that in the second pic that looks like a big gouge out of the piston? Is that just HG material?

If that is HG material on the valves, how did that happen? Did you just yank the head off and the valves got into the HG or something?

 

[92AWDHX40]

Im not gonna sit here you and try to explain to why this and that its your engine throw it together the way you want and be done with it. I dont think were jumping on him at all from reading above more of trying to help and guide. Trying to give you suggestions from those who have been there, i skimped on some things never again because i have to redo stuff i learned i really hate doing things over ahhh, oh well.

 

[Sobo]

What is stuck to the valves in the first pic, and what is that in the second pic that looks like a big gouge out of the piston? Is that just HG material?

Just carbon and debris. There is only damage to the intake side of the piston crown as pictured. The reason it looks like that was because I forgot to take the fuel return line off after I was picking the head/intake manifold off at one and had to set it down to remove it.

Im not gonna sit here you and try to explain to why this and that its your engine throw it together the way you want and be done with it. I dont think were jumping on him at all from reading above more of trying to help and guide. Trying to give you suggestions from those who have been there, i skimped on some things never again because i have to redo stuff i learned i really hate doing things over ahhh, oh well.

I'm not gonna sit here and listen to you tell me anything because it's obvious you have no first hand experience with this at all. How about that?

Provide me with a technical reason WHY. Not because you heard or read, or because you think it's "skimping" over something.

 

[MidShipCivic]

I just don't get the point in all this machine talk.

My crank is fine.

My cylinders are fine.

It's not like I had a catastrophic failure, I simply have some marks in my pistons.

Someone explain to me why I can't get away bolting stock pistons with new stock size bearings to a stock crank.

I understand there may be some "Warpage" which could lead to increased wear on the pistons. But the car will likely not see another 20,000 miles so who cares.

Any other reasons?

How do you know the cylinders are fine with the piston in the way? At such mileage they could very be out of round. Do not drop other used pistons in there without knowing! It'll have to be machined for that and from those pics man those bores look worn out those blocks aren't perfect from factory back then even decks were distorted on normal engines never modded.

I've taken many 4g63 to my machinist for work/refreshing a honing could fix that lil prob for $60 + 20 for block cleaning. I've found out many lil odd things about older 4g63 blocks as many others have.

 

[Sobo]

Im not gonna sit here you and try to explain to why this and that its your engine throw it together the way you want and be done with it. I dont think were jumping on him at all from reading above more of trying to help and guide. Trying to give you suggestions from those who have been there, i skimped on some things never again because i have to redo stuff i learned i really hate doing things over ahhh, oh well.

How do you know the cylinders are fine with the piston in the way? At such mileage they could very be out of round. Do not drop other used pistons in there without knowing! It'll have to be machined for that and from those pics man those bores look worn out those blocks aren't perfect from factory back then even decks were distorted on normal engines never modded.

I've taken many 4g63 to my machinist for work/refreshing a honing could fix that lil prob for $60 + 20 for block cleaning. I've found out many lil odd things about older 4g63 blocks as many others have.

Thank you.

I don't know that the cylinders are fine, but physically I do not see any gouges or extreme damage.

I'm not too concerned with the tightness of this motor though. As long as it actually works and keeps working for a while.

This car is bone stock. Right down to the exhaust. I don't think that this car will be making anything more than 200 chp anytime soon.

Do you see my point of view? I do want this done correctly, but only so as much as to keep the car running. It's a beat 1g. The body is toast. Also, for me to take the motor to a machine shop and have it sit there means more downtime before the white stuff starts flying. And man, I do hate working in cold weather.

So let me know your verdict.

Keep the pistons in there and smooth them

or

Put a good set of used stock pistons/rods with new clevite stock size bearings

 

[Calan]

But the car will likely not see another 20,000 miles so who cares.

Why not?

 

[redyute1]

Realistically, the valves just touched the reliefs on the pistons if the engine rotates smoothly
and, it ran before then I don't see no problem with getting some abrasive compound after cleaning the piston tops then buffing them clean.

Everyone talks with their friends thinking about what they should do or not with their cars whats the difference, no need to jump on him for coming on here and talking about it.

Putting bearings on a crank without micro polishing will not cause an engine failure, ''turning'' is resizing the crankshafts journals unless my terminology is skewed.

Agreed clean it up slap a new head and gasket and boom winter beater

 

[Sobo]

Why not?

Buffalo winters = salty. Salt = sad mitsubishi's.

The car is just rusty. The subframe is rusty, the oilpan is rusty, the body has some rot.

The interior is nice though. 6 bolt, 5 speed, awd w/ lsd rear. 75k miles. It was a good deal for the amount of car.