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Run this piston or replace?
https://slantsix.org/forum/viewtopic.php?t=45908
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Author:  JR [ Wed Aug 10, 2011 6:49 pm ]
Post subject:  Run this piston or replace?

Going through a 225 that has been shoved in the corner for a while. I pulled it out of my truck because it had a knock in the bottom end on a recent rebuild. My guess is that the previous owner did not own a torque wrench or lube up the bearings enough because all the main bearings are toast and the caps didn't feel as tight as they should be. The top end looks great, the motor ran great and didn't smoke it just knocked around 2300rpm.

I am going to get the crank turned with all new main and rod bearings then slap it all back together. When I pulled the oil pan I found a small piece of the #6 piston in the pan. All the cylinders are in great condition with no marring at all (very recent rebuild before I bought the truck). The pistons are all in good condition (with the one exception) and 40 over. I have pulled worse looking pistons out of perfectly running V8s before and this isn't going to be a high reving go fast motor.
So would you not worry about it or replace the piston? It is a no name, flat top piston with a small hole in the center and the only number I can find is on the inside of the rear skirt and says B-200.

Image

Author:  ceej [ Wed Aug 10, 2011 6:56 pm ]
Post subject: 

What do taper and bore size measure?

If they fat fisted something as simple as torque on the mains and rods, I'd be meticulous about checking everything out.

CJ

Author:  JR [ Wed Aug 10, 2011 6:59 pm ]
Post subject: 

I haven't pulled the rest of the pistons yet, just this one so far. I will be taking the block to my machinist and have it checked out along with having the crank turned sometime this week. So far everything with the exception of the mains LOOKS good. The motor had a new head along with a Clifford 268 cam that is in great shape along with the lifters, a set of shorty Clifford headers(yeah I know Clifford sucks and they are a$$holes) and a super six intake with a new carb.

Author:  ceej [ Wed Aug 10, 2011 7:03 pm ]
Post subject: 

I would not run the damaged piston.

CJ

Author:  JR [ Wed Aug 10, 2011 7:07 pm ]
Post subject: 

That's kinda what I'm leaning towards too. Do you have any idea how to find out where they got it from so I can get a new one that matches the other 5? So far searches for "slant six B-200 piston" haven't come up with anything.

Author:  ceej [ Wed Aug 10, 2011 7:13 pm ]
Post subject: 

If they are OEM, just search for 3.7L (225) Dodge. Your machinist may be able to help you. I don't think I have any 40's. All my 60's are either in an engine, or the recycle bin. :lol:

If they are not OEM, your machine shop should be able to help. Should the bores need to go over, the point is moot. Just get a set of .060 over pistons for a slant. If your doing a performance build, which I wouldn't think you would be on a 3/4 ton, there are aftermarket solutions.

Get balance of the reciprocating assembly checked too. The crank balances to itself, but the pistons and rods need to be weighed and balanced to each other.

CJ

Author:  CNC-Dude [ Wed Aug 10, 2011 7:15 pm ]
Post subject: 

A set of cast pistons wont hurt your pocketbook too bad, I would go ahead and replace the whole set. You might end up with that one piston being a lot heavier or lighter than the other 5, and make it impossible to get balanced to match.

Author:  JR [ Wed Aug 10, 2011 7:25 pm ]
Post subject: 

Yeah, I just checked and I can get them from the local O'Reilly for $25 each. Napa wants $54 each!

Author:  ceej [ Wed Aug 10, 2011 7:34 pm ]
Post subject: 

Or perhaps this.

2¢

CJ

Author:  kielbasa [ Wed Aug 10, 2011 7:57 pm ]
Post subject: 

I bought my sealed power pistons .060 over from summit for 21 a piece and they were all with in 1 gram from eachother straight out of the box. So I didn't even have to pull out the die grinder also got sealed power rings from them as well.

Author:  JR [ Wed Aug 10, 2011 8:15 pm ]
Post subject: 

Anyone ever deal with this guy, Dustin M Guest? One state away from me, KB Silvolite pistons with rings, buy it now, and shipped for $161

http://cgi.ebay.com/ebaymotors/1961-198 ... 3805wt_897

Summit won't ship until the 22nd and they only have 5 in stock so one would be back ordered.

Author:  DusterIdiot [ Wed Aug 10, 2011 8:27 pm ]
Post subject:  Buy a full set and replace...

You want to buy a full set...last time I bought a few new pistons to replace and they were the same brand as the previous ones but they were much heavier and could not be lightened enough to match the existing ones, I then bought a matched set of 6 from same brand and they all matched...but were a different alloy than the other "singles" I bought previously...

Some days you can't win...

-D.Idiot

Author:  kielbasa [ Wed Aug 10, 2011 9:10 pm ]
Post subject: 

That's still a cast piston. In my mind your paying for the name Keith black that's not even the real company just a sister company. But it is still a good deal.
Quote:
Anyone ever deal with this guy, Dustin M Guest? One state away from me, KB Silvolite pistons with rings, buy it now, and shipped for $161

http://cgi.ebay.com/ebaymotors/1961-198 ... 3805wt_897

Summit won't ship until the 22nd and they only have 5 in stock so one would be back ordered.

Author:  Doc [ Thu Aug 11, 2011 9:12 am ]
Post subject: 

Take a closer look at that number... my bet is that it is really "P"-200.
If so, that is a Badger piston.
Also check the inside walls to see if the piston has steel expansion struts casted into the piston, around the pin bosses.
Many of the replacement Badger pistons I have seen for the SL6 do not have the expansion struts, the Silvolite cast replacements are the same way. (KB does not show a piston for the SL6)

Over the years, I have seen many SL6 engines with broken Badger pistons... yours is another one.

The "better" cast pistons ( if there is such a thing) I see these days are "branded" Enginetech, Sealed Power and Federal-Mogel. (sp)
DD

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