tutzone

I have a carb hp 500 with 250 hours on it.I wanted to get the heads redone as recommened by many people with this motor.To my surprise i was told that there is some scoring on each cylinder wall.I have not seen it yet but i am wondering how this could of happen.The motor was running great.Also what will need to be done?Can i just get the springs done and use it this season or should this be taken care of now?

getrdunn

iTrader: (7)

Many engines will have scoring to the cylinder walls even shortly after fresh rebuilds. As long as they are not real deep don't worry about it now. Update/grade your heads as planned and pull the engine in the fall. At that time either bore or hone and go about your new reguild. Small scoring is not uncommon and you will not notice much if any performance loss.

Keep your oil changed regularly also.

blue thunder

You'll have to see it to know for sure, but I'd guess they are wanting to do a full rebuild and therefore will tell you the scoring is bad. Unless you can seriously catch a finger nail on the scoring, you will be fine doing the top end and running it.

getrdunn

iTrader: (7)

Good point...

I was going to say the same thing but didn't know the particulars. Regardless take a look at it yourself and when rubbing your finger nail across the scoring, if it hangs up big time then you might have some issues but I doubt it. Once again small scoring is very common. Many engines I've torn down to rebuild for WHAT EVER reason there is scoring on the cylinder walls. The only time I would worry about it much is if the scratches are completely horizontal (not likely). In that case a ring could possibly hang up on it or them and cause problems. Snap a picture of the worst cylinder and post it here.

stevesxm

its an easy answer to know. while the heads are off you make a small "cover" for the cylinder that you can screw a leak down fitting into. seal it with an o ring or a gasket and bolt it on and leak the cylider down. anything less than 10 % is fine, anything more than 20% needs work. anything in the middle requires a judgement on your part. the fingernail test isn't going to give you any information that means anything at all.

getrdunn

iTrader: (7)

Ya and while your at it be sure and rotate your crank every couple of degrees so your rings hit every position thoughout the stroke.... This will help determine if your rings are seated and not damaged. You might as well carve your intials in the bore while your at it. As long as the piston is at BDC everything should look great.

acaruso

If it over heated may be a problem the stock pistions & rings are verry soft the rings crack the ring grouves chip (heat will kill an engian)

Pesky Varmint

I've re done the heads on my 2001 575SCi's at 430 hours.

Both engines still had the crosshatching in the cylinder walls (looked
like they'd just been honed). They've never used oil.

I always use Mobil 1 for what its worth.

Go look for yourself. The 500 block is cut from the same cloth
as the 575SCi.

Pesky Varmint

tutzone

I am going tomorrow to have a look.I will take pictures and post them.Thanks for the responses!

stevesxm

i'm sorry. i made the foolish assumption that you knew what you were talking about. if you're not smart enough to block the rotation such that the rings are in the suspect area then you aren't smart enough to be doing the work. but then again if your precision measuring tools are your thumb and your fingernal then i should have realized how obvious that was from the beginning.

silly me.