My thought is that a dowel pin has no other function than matching the parts
together. The pin is not a press fit in most cases.
This means, if the dowel pin get rotational forces, then all is too late and
the car has to be parked.
The rotational force get transferred by the clamping force and the resulting
friction between fly wheel an crank only.
Cheers
Chris
Gesendet von meinem Windows 10 Phone
Von: Steve Yott via Fot
Gesendet: Donnerstag, 22. Juni 2017 12:55
An: 'Scott Janzen'; 'Barr, Scott'
Cc: 'FOT'
Betreff: Re: [Fot] TR4 ARP Flywheel Bolts Question
Properly made and installed that would be an good solution.? Issue is that if
they are not sized properly and they should have a t-shape and be counter sunk
they can cause even worse failure.
The right bolt used with the proper washer has a very large surface area and
the bolt itself is shouldered resulting in a pretty strong install.
The next best thing to do IMHO is to install a second dowel pin.? The real
purpose of the bolt is to hold the flywheel onto the crank but the main
strength is the counter sunk flywheel over the face of the crankshaft and the
dowels holding the rotation forces.? This way if the bolts should break you
have two dowels which will prevent the flywheel from flying in an egg shape and
destroying everything in its path.
Now the absolute best thing is to not use an aluminum flywheel!? There is a
reason they are not allowed in Europe?..? Buy a steel flywheel and ?use 6 to 8
bolts then most of the issues are gone.?
IMHO
Steve Yott
From: Scott Janzen [mailto:sjanzen at me.com]
Sent: Monday, June 05, 2017 3:28 PM
To: Barr, Scott <sbarr at McCarty-Law.com>
Cc: timmmurphh at gmail.com; Steve Yott <tr4 at wi.rr.com>; STEPHEN BOROWSKI
<biznzman at pacbell.net>; FOT <fot at autox.team.net>
Subject: Re: [Fot] TR4 ARP Flywheel Bolts Question
Don't you guys use steel inserts in those flywheel holes?
Sent from my iPhone
On Jun 5, 2017, at 7:55 AM, Barr, Scott via Fot <fot at autox.team.net> wrote:
This is what it looks like if you forget to chamfer the flywheel holes to clear
the radius under the head.
?
<image001.jpg>
?
From: Fot [mailto:fot-bounces at autox.team.net] On Behalf Of timmmurphh--- via
Fot
Sent: Sunday, June 04, 2017 5:53 PM
To: 'Steve Yott' <tr4 at wi.rr.com>; 'STEPHEN BOROWSKI' <biznzman at
pacbell.net>; fot at autox.team.net
Subject: Re: [Fot] TR4 ARP Flywheel Bolts Question
?
Thanks for the clarification Steve, that makes sense.
?
Tim
?
?
From: Steve Yott [mailto:tr4 at wi.rr.com]
Sent: Sunday, June 4, 2017 4:56 PM
To: timmmurphh at gmail.com; 'STEPHEN BOROWSKI' <biznzman at pacbell.net>
Subject: RE: [Fot] TR4 ARP Flywheel Bolts Question
?
The reason they state to not use washers is they are afraid that the washers
used will (1) not be hard enough and will compress under the bolt head and (2)
all ARP bolts have very liberal radii between the head and shank.? If there is
a tight fitting washer this would be strain on this radius and could break the
head.
?
The 7/16? ARP bolts used on Chevy flywheels is what I fit to TR?6, late
Spitfires and modified TR4 cranks.? These bolts come with the special washers
to use with them.? I have used a proper washer under the 3/8? ARP bolts many
times with no problems using a correct washer.? You can also use an ARP crown
wheel bolt for the same purpose and these come with proper washers.
?
Steve Yott?
?
From: Fot [mailto:fot-bounces at autox.team.net] On Behalf Of timmmurphh--- via
Fot
Sent: Sunday, June 04, 2017 1:59 PM
To: 'STEPHEN BOROWSKI' <biznzman at pacbell.net>; fot at autox.team.net
Subject: Re: [Fot] TR4 ARP Flywheel Bolts Question
?
FWIW
?
I just got a set of ARP 206-2802 flywheel bolts from Pegasus for the TR4.? They
are for ?BMC A series?.? The instruction specifically says, ?DO NOT USE ANY
WAHERS?, yes, all in caps for emphasis!? They further state that ARP will not
be responsible for failures is washers are used.? The instructions also say,
?Make sure there is an adequate chamfer under the bolt holes on the flywheel to
clear the radius under the head of the bolt.?? Torque is 55 Ft-Lb with
specified lubricants on the threads.
?
I?ve never had that much good luck grinding the ends of bolts and still having
it square so as not to start it cocked and runing the female threads.? Maybe
it?s just me?
?
Tim
?
?
From: Fot [mailto:fot-bounces at autox.team.net] On Behalf Of STEPHEN BOROWSKI
via Fot
Sent: Friday, June 2, 2017 3:28 PM
To: FOT List <fot at autox.team.net>
Subject: [Fot] TR4 ARP Flywheel Bolts Question
?
Does anyone have experience using the ARP flywheel bolts sold by Moss and
others?
I understand that you may have to shorten the bolt or it breaks the rear seal???
Are they supposed to have a washer or not?
?
Thxs. Steve
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