D17 power crater pistons

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   I'm wondering about the difference in the shape of the power crater on different engine kits.  MikeB (SD) posted a nice chart of several different compression heights a while back which I saved for reference.  I have two D17 engines here one is a 1958 series one, the other is a 1964 series three.
Here is the series one - could be original: 

Here is the series three - some overhaul kit I think:

What shape are the craters on new kits today and is one better than the other?  My engines are both stuck and sitting with PB Blaster waiting for warmer weather.  I'm curious as to what compression height pistons are in them.  Thanks.  Tom

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TomMN Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 13 Sep 2009 Location: Elbow Lake, MN Points: 858	Post Options Post Reply Quote TomMN Report Post Thanks(0) Quote Reply Topic: D17 power crater pistons Posted: 28 Feb 2010 at 11:09am
	I'm wondering about the difference in the shape of the power crater on different engine kits. MikeB (SD) posted a nice chart of several different compression heights a while back which I saved for reference. I have two D17 engines here one is a 1958 series one, the other is a 1964 series three. Here is the series one - could be original: Here is the series three - some overhaul kit I think: What shape are the craters on new kits today and is one better than the other? My engines are both stuck and sitting with PB Blaster waiting for warmer weather. I'm curious as to what compression height pistons are in them. Thanks. Tom

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DanD Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 11 Sep 2009 Location: WI Points: 856	Post Options Post Reply Quote DanD Report Post Thanks(0) Quote Reply Posted: 28 Feb 2010 at 12:49pm
	Looks to me like the pistons in the second engine are aftermarket 4.25" pistons. Looks like the sleeve is thinner in the second picture. The pistons in the first engine look like original AC design.

mlpankey Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 13 Sep 2009 Location: Vols country Points: 4580	Post Options Post Reply Quote mlpankey Report Post Thanks(0) Quote Reply Posted: 28 Feb 2010 at 2:09pm
	are any of the pistons in the pics at tdc it looks as if 2@ 3 might be. still along ways away from zero deck height . i cant see why anybody would want that over a flat top. jmho

TomMN Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 13 Sep 2009 Location: Elbow Lake, MN Points: 858	Post Options Post Reply Quote TomMN Report Post Thanks(0) Quote Reply Posted: 28 Feb 2010 at 3:46pm
	No none of these are at tdc. I went out and measured the bores and the top picture is 4" and the bottom is 4 1/8". I don't plan on doing any pulling with the industrial D17 so I am thinking of trying on making the engine close to original, but of course price of engine kits will make a difference too. With so many different pistons that Allis used in the 226 I don't want to end up with only the compression of a WD45.

Dans 7080 Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 05 Feb 2010 Points: 1146	Post Options Post Reply Quote Dans 7080 Report Post Thanks(0) Quote Reply Posted: 28 Feb 2010 at 3:54pm
	I put a set of high compression 4" pistons in my D-17. I got the kit from the local agco dealer. If i remember right it took the compression ratio from 7.50 to 1 to 8.25 to 1.

mlpankey Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 13 Sep 2009 Location: Vols country Points: 4580	Post Options Post Reply Quote mlpankey Report Post Thanks(0) Quote Reply Posted: 28 Feb 2010 at 4:45pm
	if you arent gonna use any of those sleeves i sure would like to have them if you dont crack them removing them. those 4.125 would be good to bore 4.188 and the four inch i could use my 4 1/8 pistons that have alot of runs on them and have shrank a bit undersize