Brodhead Pietenpol Association

Original Posted By: dpilot
Model A Guys,I pulled the heads off of the pair of A's that I bought. One is +.080 and theother is +.100bore wise. What is the largest overbore that you can go and is it considered safefor aircraft use.I've dealt with thin cylinder walls on VW engines before and I don't want to getinto that. One carguy told me that when they get to .080 he has them sleeved, has anyone gone thisroute or is itnecessary? I had an airplane guy tell me that this wasn't necessary due to thefact that youcan overbore to 3/16", I had heard .125 but not 3/16".I'll most likely pull them down and have the cranks and rods magnafluxed and blockshot tankedand checked for cracks and then set them aside till later on this winter. Alsoneed to come up witha set of head studs as one didn't have any.Meeting with a guy this week about doing my Menasco bearings, will hit him up forthese also.Al Latham________________________________________________________________________________Date: Wed, 3 Sep 2003 18:48:36 -0700 (PDT)

Original Posted By: Isablcorky(at)aol.com
Subject: Re: Pietenpol-List: Model A questionsIn a message dated 9/3/03 5:42:05 PM Central Daylight Time, geebeed(at)grm.net writes:>The place that did the babbit on mine, told me a Model A engine can be bored .125" over. I think that is pretty extreme, but you can get aftermarket pistons that size. Mine was .060" over. I would suggest you use forged pistons,instead of the cast alum pistons, and drill the crank and go with a pressure oiling system. These stock engines have to opporate at 80% power, or more, justto maintain level flight.Chuck G.________________________________________________________________________________

Original Posted By: "Gadd, Skip"
There are pistons available for the Model A up to 0.125 oversize, although Iremember hearing somewhere that it may not be the best idea. As I recall,the rule of thumb was after 0.080, it was a good idea to have them sleeved.Regardless, I haven't heard anything negative about sleeves, actuallysleeves were always discussed to me in a positive manner. It just seems itwould require additional machine work. I've always turned to Mac's orSnyders catalogs for help with these questions, but don't have one in frontof me at this time.Obviously, all my information is not from personal experience orexperimentation, so to a scientist, it wouldn't be worth much.Robert HainesDu Quoin, IllinoisP.S. - I do have a spare Model A engine I considered redoing for a SuperAce, but I have since dropped that project. The block is in acceptablecondition (at 0.020 or 0.040 over, can't remember) but one cylinder issleeved due to some nasty event unknown to me. The engine is available.________________________________________________________________________________

Original Posted By: helspersew(at)aol.com

Original Posted By: "taildrags"
Fantastic John! Steve...let me check the correct way to spell cheque...Scotty--------Tamworth, AustraliaBuilding a Corvair Powered Pietenpol Air Camperwww.scottyspietenpol.comFuslage now on its undercarriage! About to start wing spars...Corvair engine atRoy's Garage waiting to be modified.Read this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: Model A questions

Original Posted By: John Weber
Water temp and bearing clearance deficiency don't necessarily correlate. I hada early 40's Allis B tractor that used to seize due to NO oil flow all the time...Embarrassingly it took me a couple years to figure that out! To make a long story short, due to NO oil flow, it would heat up, bearing clearancewould disappear and it would seize. When it cooled down, started and rangood. After two years of this, I figured it out, removed the clog and it hasrun good since, apparently no real damage. it's about a 20 hp 4 cylinder overheadvalve gas burning engine. During that entire time, the operable and observed water temp gauge NEVER showeda problem. After all, it's a water temp gauge, not a bearing temp gauge. Nevershowed obvious signs of overheating (smoking block, radiator blowing it'stop, knocking, water loss, anything), it would suddenly lose power and quit. Wouldn't restart. I kept assuming it was the fault of a bad ground and the usualproblems with a six volt system. Obtaining proper bearing clearance isn't trival. I had an engine rebuilt by the(then) editor of Hot Rod magazine. He sent the engine out to his normal engineshop. If there's ANYONE you'd think he'd do a good job for, it would be thecurrent editor of a national car enthusiast magazine. However, it was Jeff'spractice to double check clearance by putting in the inserts, torquing thecaps down and simply measuring with good tools. He sent the block back TWICEbefore it was correct. He said this was pretty normal. The clearances were good enough that the engine would have run well, but wouldn'thave had the longevity it should have had...The point is, even though a reputable builder built the engine, it's possible yousimply have clearance issues that need to be double checked. The other possibilityis a clogged oil passage (I'm not familiar with the entire oil systemof a model a... am now pretty familiar with the venerable Allis model B!). I'dcheck those issues for sure. Would love to know what you find out!Read this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Re: Pietenpol-List: Re: Model A questions

Original Posted By: Douwe Blumberg
Thank you, Oscar. JohnSent from my iPhone> On Jun 8, 2014, at 11:45 PM, "taildrags" wrote:> > > John;> > I'm sure you'll get some feedback from the good people on this list, but in the meantime, you can really get some good information on what you're asking by looking at some of the engine pictures on www.westcoastpiet.com .> > A couple of good ones come to mind: Larry Williams, Dan Helsper, Howard Henderson,and one of the real experts, Ken Perkins. Looking at the engine picturesof those guys' airplanes, you can see a lot of detail on how they did theircarb heat. And looking at the cockpit and control panel shots of those airplanes,I don't see a manual choke control in the cockpits but there may be one righton the carb. I don't know Fords well enough to tell you.> > --------> Oscar Zuniga> Medford, OR> Air Camper NX41CC "Scout"> A75 power> > > > > Read this topic online here:> > http://forums.matronics.com/viewtopic.p ... 528#424528> > > > > > > > > > ________________________________________________________________________________Date: Mon, 9 Jun 2014 08:25:10 -0400 (GMT-04:00)

Original Posted By: John Weber
Been somewhat on the fence about bringing up the Piet, but have decided to do it.Will be starting from 9A5, Lafayette GA. Probably overnighting near Sullivan IN,then getting in the next day. Prob take off Wed, get in Thurs noonish.Will likely have a ground chaser coming along. Anyone wanting to fly along ormeet along the way is more than welcome. May be a couple more planes coming fromthe Atlanta area, no confirmations yet. Will also be taking her up to the convention on Sun morning for the week.Read this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Re: Pietenpol-List: Re: Model A questions