flyrotary@lancaironline.net Mailing List Archive

Kelly, I’ll await responses from others but I doubt that mixing bolt sizes is an issue; the bolts were most likely beefed-up for the very reason I had to replace this one.

The necked-down bolts were prone to breaking … My take is that the bolts are simply a multi-point clamp and any resonance/harmonics they produce was an oversight on the part of Mazda engineers.

Lynn, what’s your take on this?

Jeff

From:	Kelly Troyer <keltro@att.net>
Subject:	Tension Bolt Extracted ... what a relief!
Date:	Tue, 1 Feb 2011 13:09:41 -0800 (PST)
To:	Rotary motors in aircraft <flyrotary@lancaironline.net>

Jeff,

If I understand you previous reply correctly you have replaced your broken tension bolt with a later

model larger diameter bolt..........If I remember correctly my 86-88 13B tension bolts are necked down

(smaller) in the shank area than the later 89-91 (and probably up to 95) bolts.............I question mixing

different size bolts in the same engine (weird harmonics ??)...............Perhaps our Rotary "Guru" Lynn

Hanover will weigh in here with some real world advice in this matter...................May be of no concern

but better safe than sorry !!...................

Kelly Troyer
"DYKE DELTA JD2" (Eventually)

"13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil Manifold

"TURBONETICS"_TO4E50 Turbo

From: Jeff Whaley
Sent: Tuesday, February 01, 2011 3:22 PM
To: 'Rotary motors in aircraft'
Subject: Re: Tension Bolt Extracted ... what a relief!

Hmmm … that’s a scary thought, as there are 15 other bolts in question. Either this one was lighter coated, lighter tensioned than the rest or the others are also in jeopardy.

I put a heavier spiral on the replacement bolt, which is also larger in diameter.

Jeff

From:

Tracy <tracy@rotaryaviation.com>

Sender:

rwstracy@gmail.com

Subject:

Re: [FlyRotary] Tension Bolt Extracted ... what a relief!

Date:

Tue, 1 Feb 2011 12:47:16 -0500

To:

Rotary motors in aircraft <flyrotary@lancaironline.net>

Looks like you needed to be much more generous with the RTV when installing. It should look a LOT messier than what yours looked like. There needs to be enough to smear off on the housings when installing.

Tracy

On Mon, Jan 31, 2011 at 12:26 PM, Jeff Whaley <jwhaley@datacast.com> wrote:

We were minutes away from an engine tear-down, when we tried one more time to extract the broken tension bolt. The bore scope allowed us to see exactly where the pilot hole was drilled into the broken piece; the left-hand drill bits would not grab on and extract the part but did help in enlarging the hole and perhaps loosening the threads a little. Ultimately I was able to start an easy-out with light tapping and it grabbed on – the result is in the attached photo. The easy-out is welded to the end of the original broken bolt and you can see that a spiral of RTV was applied to the length of the bolt between the threads and the bolt head.

Jeff

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