Are my pistons still good? PIC >>

[turbotalonawd]

Ok well I finally took my head off to see what the hell all happened in my engine when my timing belt took a sh!t. The engine had 60k on it, and what ever happened to the timing belt happened at an idle. What im asking is. Take a look at the top of my pistons, with those little dings do you think I need to rebuild the lower end? there is no cracks just those dents. The cylinder walls look damn good also. Any input would be great.


All 4 of the pistons have almost the same amount of damage I just took the pic of two soo you could see better.

 

[Defiant]

Just smooth those down as best you can, to eliminate any rough or sharp spots. Make sure you work _away_ from the cylinder walls, so you don't dump any garbage down onto the ring.

 

[FastRthenU]

You can still re use them. But if I were you I would replace them. No matter what you do. They just arnt as strong as they should be.

 

[candela]

Looks like its time for some 2G pistons

 

[chaye]

off topic..........but what are the benefits of 95 pistons on a six bolt engine..or a 1st gen engine..
thanks guys

 

[Pennywise]

2g pistons have 8.5:1 compression as to the 1g pistons that have 7.8:1. the higher comp will let you spool faster.

 

[jfarber]

Yup,

Here's mine. Our cars must be related. Belt broke a few weeks ago. Bent 12 valves. I am still working out the bugs of getting it back together.

http://www.dsmtuners.com/forums/showthread.php?s=&threadid=46577

I blended in the marks as to not have any sharp edges. I used a buffing wheel on my dremel (looks kind of like a scotch pad, relatively forgiving). DON't use a grinding wheel! You will be fine. Yould also use the sandpaper as well, just takes a bit longer.

Oh, and don't forget to use the timing belt faq on www.vfaq.com. The Haynes manual kind of forgets to tell you to check the phase of the oil pump sprocket (rear balance shaft). At least mine did.

Good luck!

 

[turbotalonawd]

Ok if I do decide to go with the 2g pistons it would be ok to keep it stock bore right. Just drop the pistons and rod thru the bottom, take them to the machine shop have them put the 2g's on the 1g's, put new rings on and call it good?

 

[chaye]

ok so the higher compression and faster spool up is all?
i heard somewhere here in dsmtuners, i think, that it either reduces the chances of knock or increases themm...is this correct and which one is it thanks a bunch....

 

[DSM mechanix]

Originally posted by chaye
ok so the higher compression and faster spool up is all?
i heard somewhere here in dsmtuners, i think, that it either reduces the chances of knock or increases themm...is this correct and which one is it thanks a bunch....

it slightly increases the chances of knock, but not enogh to be matter. If u do the swap u should be very happy with the results...

 

[4pistons]

Just smooth those down as best you can, to eliminate any rough or sharp spots. Make sure you work _away_ from the cylinder walls, so you don't dump any garbage down onto the ring.

Like DEFIANT said just smooth down the rough edges but here's a tip. Crank the piston to top dead center and use strips of duct tape to seal off the gap between the cylinder and piston (the ring land) and all the water passage and oil drainback holes in the block. If you clean it up real good before removing the tape you won't get any debris in the engine.

Rick - '91 GSX

 

[Something Rudy]

IF the valves caused that much damage, then how are they looking?? Did they bend??

Poor

 

[thumper]

hey here's yet another in the same boat right now. I had a mechanic friend of mine look at it. mine looked just a shade less damage than yours. He told me to fix the head, and the pistons should still be good. I'm waiting for my head to get back i took it in yesterday to get it fixed. Only 4 of my valves looked bent though. I still had told them to check all of them just for good measure Ithink the people before me had the same problem cause the pistons all looked the same.

Hey I have one off topic question though. SInce i have a lot of stuff tore apart in the little rebuild i'm doing, would it be a good idea to change the water pump? I asked a mechanic and they said it should be ok. I have 106k on the car and as far as i know the only thing it had replaced was a radiator and head. just wondering if anyone with experience has an opinion. Thanks. p.s. i'll be posting pics soon of everything torn apart as soon as my comp gets fixed at home untill them i can't get pics up.

 

[4pistons]

would it be a good idea to change the water pump? I asked a mechanic and they said it should be ok. I have 106k on the car and as far as i know the only thing it had replaced was a radiator and head

HOLY CRAP!! You've got a water pump with 106k on it?? Seriously, change it. It's only like a $45 item and it's easy if everything else is apart. You wouldn't want to do all that head work and put everything back togethher and then the water pump fail, belch coolant all down your timing belt and have to re-do the head again would you???

Rick - '91 GSX

 

[jfarber]

Replace the pump! And all the pulleys associated with the timing belt. Do the math, the timing belt replacement makes you good for another ~30-60k miles before doing it again. What are the odds of that 106k mile H20 pump going bad before then. The last thing you want is water dripping all over your new hardware.

 

[NosLaser]

Yes, you could have the 2G pistons machined on to the rods, re-ring them, re-hone the cylinders and call it a day. If your rod bearings still look good I would simply clean them and re-use them. Ir you *could* deburr the tops of your current pistons and clean them up and re-use them. However, if you plan on making big power (400+) in the future, you may be chasing a hot spot that will drive you crazy. I will offer my perspective in saying that I like the 1G pistons a bit better than the 2G. Yes, there is a compression difference but you can always make that up with more boost. The 1G pistons however are stronger than the 2G, and have a larger upper ring land. You can go either way but that is my $.02. Oh, and good luck.

Regards,

 

[thumper]

for 300 hp they should still be good though right? I plan to clean em up get them to near level with the surroundings. I mean i don't think i'll try for more than 300 and if i do i can understand that new pisotns would be needed then. Thanks for the help.