SStroked 410

I have some score marks in a few cylinders and wanted to clean it up some. I have the Lunati stroker kit which comes with a 4.000 crank and 4.030 bore in my iron short block. I don’t have the money for new pistons so I need to keep them. Whats the most I can hone this block and still be able to keep the same size pistons? Can I go more then 2 thou's?

My motor is at a machine shop and I told them I would like to have it honed only 0.001 or at the most 0.002. They said it might not take out some of the marks?

I asked this on the other board and got 0 replys

BLK02WS6

iTrader: (2)

I would say it depends on what your wall clearance is now. I believe Lunati recommends .003 to .005 wall clearance on their pistons - so if you are at .003, then you can get .002 more and stay in spec. Question is will it get all the marks off.

If you go outside the spec, your gonna get a ton of slap, and possibly oil or ring problems. I'm replacing my engine right now because a machine shop screwed me and took the walls out to far - it slaps like you wouldn't believe - trust me you don't want that!

For an engine like that, I would say do it right, or you'll be doing it again soon!
Maybe a new block would be a reasonable way to go. You can get one for $400 and your already doing some amount of machine work, so it wouldn't be that much more to bore/hone.

Just my 2 cents, but it doesn't seem worth it to shortcut and have to turn around and pull the motor again soon.

SStroked 410

Yeah I know what you mean, if I am going to do this I might as well do it right the first time!

I got this shortblock with 1,500 miles on it. I found out later that the reason for the score marks is from Piston slap? I would just replace the block but its already been o-ringed and ARP head studs so I would like to try to keep it. The next thing that comes to mind is going with a 4.035 size piston from Diamond maybe. The guy I got the motor from says he doesnt like Lunati pistons? Does piston slap happen to a lot of Lunati pistons?

strokedls1

iTrader: (1)

If you go with larger pistons then bore out to 4.040 and rebalance the rotating assembly. I have never heard of problems with the lunati parts. Everything I have bought from them has been top notch quality. Maybe your machine shop messed up and over bored from the get go and the piston slap scored the walls. Either way you are looking at spending over a grand.

BLK02WS6

iTrader: (2)

If it were me, I would compare a new block (you can reuse the studs, don't know if o-ring is really needed??) with getting 4.040 pistons from Diamond, bore your current block and balance the rotating assembly.

I think it would almost be a wash.

SStroked 410

I should find out tomarrow how much honing will be needed to get rid of these score marks. Damn!
I was really hoping that I could just hone it a few thou's and put it back together.

Pro Stock John

iTrader: (34)

Find out what the current bore is and go from there.

Can you coat the pistons, is that like +.001 per piston?

SStroked 410

I will find out soon.

"Can you coat the pistons, is that like +.001 per piston?"
what do you mean?

Keith

I think PSJ means to put an anti-friction coating on the skirts of the pistons.

SStroked 410

Well I just talked to the guy at the machine shop and this is what he told me
My bore is 4.030 but 1 cylinder is 4.031 and 2 of them are 4.032?
He also said a few pistons were different sizing
a few being 4.0225 and 4.02575?
I told him the motor only has 1,500 miles on it and it was also had a 200 shot sprayed a few times. He said that this possibly happen from too much heat with the nitrous and detonation. So he is going to call Lunati and get some info from them and the guy I bought this motor from. Looks like I might have to go with 4.040. This is starting to cost more then I expected

BLK02WS6

iTrader: (2)

It always does!!

Sounds like you really ought to go to 4.040 and get new pistons to get the whole thing right! I know it hurts the finances and it sucks to get screwed over by not getting what you thought you were getting (I know that pain all too well), but in the long run, you'll be better off doing it right rather than trying to throw it back together.

I would look at Diamond pistons - their service is great, and their prices on custom pistons are good too. And get the rotating assy balanced!

Make sure your machine shop has a really good track record with Gen III engines - talk to some of their previous customers if at all possible.

Keep us posted on how things work out for you - I wish you the best!

SStroked 410

yeah I think thats what I am going to do. The guy I got the motor from is a really cool guy but I wish he went more into detail about this motor so I knew what I was going to be dealing with. I think it would be fair for him to atleast maybe help me out with part of the cost of the pistons. I think He thinks this motor isnt as bad as I am saying
We'll see what happens,

2001 Pewter WS6

iTrader: (43)

Did you use run the motor at all? What issues did it have? Any pics of the cylinder walls before the hone?

SStroked 410

Never ran the motor, had a few people look at it first and they said it wouldnt be a good idea to run it as is cause there could be more damage that cant be seen since it was assembled. The score marks are pretty deep you can actually feel with your finger nail. I later found out from the guy I bought the motor from that the score marks are from piston slap. So if I were to just hone it 1-2 thous it would most likely get worse. Today I found out that the pistons are not all the same size so looks like keeping the same pstons is out of the question
I wish I had a digital camera to take a few pics but I dont