Block question

**wick** · 02-15-2009, 08:30 PM

Allright. here it is. I bought a .030 over block a while back. It had pistons in it. I didnt take it apart until tonight. In number 6 cylinder there is a scratch about .010 wide and about 2 inches long. Its at the bottom of the cylinder. You can feel it with your finger. I ran the hone through it and still the same. My question is, think its still useable? I bought speedpro .030 pistons, rods and arp hardware already under the assumption that the block was still good. So basically, a bore is out of the question. If I did use it, what would possibly happen? The ring does come into it.

**Silverhatch** · 02-15-2009, 08:49 PM

#1 what do you think caused it? Did it happen above or below where the piston travels? Is it possible to reinstall the piston on the crank and see if the rings drops below the scratch? Not sure what would happen if it was in the piston travel. Possibly lower compression on that cylinder.

**wick** · 02-15-2009, 08:55 PM

Originally Posted by luxurysportscar

#1 what do you think caused it? Did it happen above or below where the piston travels? Is it possible to reinstall the piston on the crank and see if the rings drops below the scratch? Not sure what would happen if it was in the piston travel. Possibly lower compression on that cylinder.

Not sure what caused it. I looked at the #6 piston and there is nothing on it. It does drop below the scratch. Only for about 1/2" though. It might have been from before. Possibly the reason the engine was bored .030 in the first place. It just didnt clean out. I also need a crank. This one was cut .010 and there were std bearings in it. It needs cut again...

**HidalgoGT** · 02-15-2009, 09:14 PM

Hate to say it but sounds like either get another block or bore that one. I just can't see that scratch being a very good thing if the piston travels past it. Would surely cause premature wear on the rings.

**blizzard** · 02-15-2009, 09:29 PM

you didn't mention how deep except that you can feel it? sounds like maybe from rod during disassembly? i say take the hone to it again and do your best to polish it out, and run it. might come out okay, but if the cylinder lets go, oh well you knew it might've, while searching for another block.. can't hurt anything like runnin' the wrong size bearings

**wick** · 02-15-2009, 09:33 PM

If I had to guess I would have to say a couple thousandths deep. Not a chance of the rod hitting it. They didnt even touch the cylinders upon disassembly. I just tossed in one of the new speed pro's and used a sharpie. It is right at the top of the piston where it starts. Goes all the way down. This was something from an engine running that caused this. Not removal of a rod.

**wick** · 02-15-2009, 09:40 PM

Originally Posted by blizzard

can't hurt anything like runnin' the wrong size bearings

It wasnt my doings. Probably a simple mistake. Its how I got it. There are tiny hardly fingernail feelable scores on two journals of the crank. Those might be ok. Probably dirt from the original engine builder.

If I choose to run this crank, the correct .010 undersize will be going in.

**gmkillr** · 02-15-2009, 09:56 PM

Stock blocks are super cheap, I would pick up a new block for $100 or less and have it bored to match your pistons.
Or sell your pistons and buy a new assembled shortblock from a reputable builder.

**wick** · 02-15-2009, 10:15 PM

Then I am at $500 or more for something I assumed was a done deal. Its aggervating. Whats machining cost now?

**somethingclever** · 02-15-2009, 11:11 PM

Did you check to see if the bore job is good (out of round) or if the deck is square? If these are not in spec then you'll need machining anyway so might as well start fresh. if the above is good, then I would run some emery cloth over the scratch to make sure there are no high spots and run it.

heck i'd like you to run it and do a compression test so we all know how much it really does affect it. :)

**gmkillr** · 02-15-2009, 11:21 PM

Originally Posted by wick

Then I am at $500 or more for something I assumed was a done deal. Its aggervating. Whats machining cost now?

Thats the name of the game brother........:)

You have to pay to play...........

If its cheap, then it ain't good.

Sorry to hear of your find though.
Good luck on the project though.

**Silverhatch** · 02-16-2009, 12:01 AM

Sometimes you gotta cut your losses and move on. You know how I know (today). Guess you won't be buying any more blocks from that engine shop though.

**wick** · 02-16-2009, 12:04 AM

Originally Posted by somethingclever

Did you check to see if the bore job is good (out of round) or if the deck is square? If these are not in spec then you'll need machining anyway so might as well start fresh. if the above is good, then I would run some emery cloth over the scratch to make sure there are no high spots and run it.

heck i'd like you to run it and do a compression test so we all know how much it really does affect it. :)

This just may be what happens. I honestly dont see any affect this will have on the engine. During cylinder filling, the piston will be past the bad spot. The only thing that worries me is on deacceleration, such as engine braking down a hill, it might draw a tiny bit of oil up and get some smoke.

**wick** · 02-16-2009, 12:05 AM

Originally Posted by luxurysportscar

Sometimes you gotta cut your losses and move on. You know how I know (today). Guess you won't be buying any more blocks from that engine shop though.

HAHAHAH Yeah. Big Bob was telling me of the fun ride.

**wick** · 02-16-2009, 12:08 AM

Originally Posted by gmkillr

Thats the name of the game brother........:)

You have to pay to play...........

If its cheap, then it ain't good.

Sorry to hear of your find though.
Good luck on the project though.

HAHAH I know. Unseen set backs. It seems that for very step I take forward, I get sent back 10. It could be raining pussies and I would be the only one that gets hit with a dick.

**Balaska347** · 02-16-2009, 12:16 AM

By the sounds of what you are describing I can promise you that it is no big deal and that it will have no effect on the motor at all. You won't lose performance and it won't smoke.

My block had the same scratches in several cylinders when I took it apart after several years of racing and street miles. I was also worried about it and talked to several reputable engine builders which said it is common and no big deal. If I would have had it bored to get rid of them they would just come back. Some say its from dirt and others say it from the piston skirts hitting the cylinder wall.

Anyway I left it as is freshened the motor up and it has been perfect.

**2001GTTT** · 02-16-2009, 04:01 AM

Originally Posted by wick

HAHAH I know. Unseen set backs. It seems that for very step I take forward, I get sent back 10. It could be raining pussies and I would be the only one that gets hit with a dick.

oh my god

rofl

**wick** · 02-16-2009, 09:45 AM

Originally Posted by Balaska347

By the sounds of what you are describing I can promise you that it is no big deal and that it will have no effect on the motor at all. You won't lose performance and it won't smoke.

My block had the same scratches in several cylinders when I took it apart after several years of racing and street miles. I was also worried about it and talked to several reputable engine builders which said it is common and no big deal. If I would have had it bored to get rid of them they would just come back. Some say its from dirt and others say it from the piston skirts hitting the cylinder wall.

Anyway I left it as is freshened the motor up and it has been perfect.

This is the answer I dad looking for from a seasoned racer. Thanks man!