X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 23 May 2005 22:08:14 -0400 Message-ID: X-Original-Return-Path: Received: from imo-m14.mx.aol.com ([64.12.138.204] verified) by logan.com (CommuniGate Pro SMTP 4.3.2) with ESMTP id 961255 for lml@lancaironline.net; Mon, 23 May 2005 19:15:15 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.138.204; envelope-from=JIMRHER@aol.com Received: from JIMRHER@aol.com by imo-m14.mx.aol.com (mail_out_v38_r1.7.) id a.1de.3c25bd91 (4410); Mon, 23 May 2005 19:14:28 -0400 (EDT) From: JIMRHER@aol.com X-Original-Message-ID: <1de.3c25bd91.2fc3bdd4@aol.com> X-Original-Date: Mon, 23 May 2005 19:14:28 EDT Subject: Re: [LML] TSIO-550E Saga continues X-Original-To: noel@cginteractive.com, lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1116890068" X-Mailer: 9.0 SE for Windows sub 5011 -------------------------------1116890068 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en =20 In a message dated 5/23/2005 2:31:29 PM Pacific Daylight Time, =20 noel@cginteractive.com writes: Jim;=20 I think I can relate to your story. I HAVE 200 HRS ON MY TSIO 5550, live in= =20 hot and humid Puerto Rico and don=E2=80=99t fly the ivp much. Now my cylin= ders are=20 low on compression. I have been flying the engine one hour a day for 10 day= s=20 as a prescription from my mechanic before testing my compression again.=20 Charlie Kohler blames the problem on low flying time and humidity.=20 What were your readings in those three cylindrers?=20 Thanks in advance, Noel Hi Noel, I really don't think the humidity has much to do with it, even thought I =20 respect Charlie very much. This is why; The exhaust valves and the piston ri= ngs. =20 First the valves, I don't think that TCM does anything to insure that the =20 exhaust valve have a full wide seat. They just grind the seat and the valve=20= and =20 expect them to match. I had the new cylinders disassembled and Lapped the=20 valves and two of them wouldn't lap in and needed to be recut or ground. Wh= en I=20 looked at the old exhaust valve seat they weren't the same all around and t= o=20 my mind that is what caused them to start burning and that caused the low=20 compression. 2 at 44 and 1 at 38. This was using the calibrated orifice whi= ch=20 allows 11 cfm of air at 80 psi. What I found out about the piston rings is=20= that=20 in the mid 1990's, I was told 92, TCM changed the pistons from all Aluminum= =20 to a steel belted piston. This is where the rings sit into the ring lands.=20= On=20 the Alu. pistons they got a lot of ware and they required more choke in the= =20 cylinders because of expansion. Someone thought that the steel belted Pisto= ns=20 would ware better in the ring lands and have less expansion so they could g= o=20 down to about .003 in. of choke. As it happens the old pistons seal better=20 with the 80 psi test than the steel belted. So they came up with this spec.= to=20 control the cfm input and allow compression down to 40 psi. If below 40 you= =20 are grounded in the US. After installing the new cylinders with lapped valv= es=20 and ground running, the compression tested at 67/80 on all cylinders. This=20 is the best it gets with the new steel belted pistons. As a side note I als= o=20 have a Bonanza A36 1981 IO-520 with the original engine and 1600 hrs. It mu= st=20 have the old style pistons because it's compression is 68 to 74 over 80 on=20 all cylinders. It has sat around a lot and shows corrosion in all cylinders= at=20 the top but still has the compression and OK oil consumption. My view of the Humidity is that when it sits and a valve is open you can ge= t=20 the air movement and moisture in those cylinders but the Valve is stainless=20= =20 and very low corrosion prone where the cylinder barrel is Nitride Steel whic= h=20 is very hi corrosion prone. The valve seat is the only other steel of=20 interest and while it could corrode, somehow I haven't seen that much, so r= unning it=20 like you are now and taking another compression test may make a difference.= =20 Other wise you need to plug the exhaust pipe when you park it for extended=20 periods. I'll post this on the LML and others may have more input/corrections. Regards, =20 Jim Hergert N6XE (An Sexy) -------------------------------1116890068 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en
In a message dated 5/23/2005 2:31:29 PM Pacific Daylight Time,=20 noel@cginteractive.com writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000080 size= =3D2>

Jim;=

 

I think I can r= elate=20 to your story. I HAVE 200 HRS ON MY TSIO 5550, live in hot and humid=20 Puerto Rico and don=E2=80=99t fly the i= vp much. Now=20 my cylinders are low on compression. I have been flying the engine one hou= r a=20 day for 10 days as a prescription from my mechanic before testing my=20 compression again.

 

Charlie Kohler=20= blames=20 the problem on low flying time and humidity.

 

What were your=20 readings in those three cylindrers?

 

Thanks in advan= ce,=20 Noel

Hi Noel,
I really don't think the humidity has much to do with it, even thought=20= I=20 respect Charlie very much. This is why; The exhaust valves and the piston ri= ngs.=20 First the valves, I don't think that TCM does anything to insure that the=20 exhaust valve have a full wide seat. They just grind the seat and the valve=20= and=20 expect them to match. I had the new cylinders disassembled and Lapped the va= lves=20 and two of them wouldn't lap in and needed to be recut or ground. When I loo= ked=20 at the old exhaust valve seat they weren't the same all around and to my min= d=20 that is what caused them to start burning and that caused the low compressio= n. 2=20 at 44 and 1 at 38. This was using the calibrated orifice which allows 11 cfm= of=20 air at 80 psi. What I found out about the piston rings is that in the mid=20 1990's, I was told 92, TCM changed the pistons from all Aluminum to a steel=20 belted piston. This is where the rings sit into the ring lands. On the Alu.=20 pistons they got a lot of ware and they required more choke in the cylinders= =20 because of expansion. Someone thought that the steel belted Pistons would wa= re=20 better in the ring lands and have less expansion so they could go down to ab= out=20 .003 in. of choke. As it happens the old pistons seal better with the 80 psi= =20 test than the steel belted. So they came up with this spec. to control the c= fm=20 input and allow compression down to 40 psi. If below 40 you are grounde= d in=20 the US. After installing the new cylinders with lapped valves and ground=20 running, the compression tested at 67/80 on all cylinders. This is the best=20= it=20 gets with the new steel belted pistons. As a side note I also have a Bonanza= A36=20 1981 IO-520 with the original engine and 1600 hrs. It must have the old styl= e=20 pistons because it's compression is 68 to 74 over 80 on all cylinders. It ha= s=20 sat around a lot and shows corrosion in all cylinders at the top but still h= as=20 the compression and OK oil consumption.
My view of the Humidity is that when it sits and a valve is open you ca= n=20 get the air movement and moisture in those cylinders but the Valve is stainl= ess=20 and very low corrosion prone where the cylinder barrel is Nitride Steel whic= h is=20 very hi corrosion prone. The valve seat is the only other steel of interest=20= and=20 while it could corrode, somehow I haven't seen that much, so running it like= you=20 are now and taking another compression test may make a difference. Other wis= e=20 you need to plug the exhaust pipe when you park it for extended periods.
I'll post this on the LML and others may have more input/corrections.
Regards,=20
 
Jim Hergert
N6XE (An=20 Sexy)
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