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170 flywheel

Posted: Thu Mar 13, 2008 3:07 am
by rosbullterier
Please would you confirm; is the 170 flywheel removed with a puller? The intention is to present the offensive end cap later today for perusal by the machinist.

Posted: Thu Mar 13, 2008 7:22 am
by Charles uk
Unless the flywheel has 3 number 2BA holes drilled & tapped into the steel center, remove in the normal Seagull manner.
If your having a phosphor bronze end cap made, don't worry about the balance factor, but expect to pay 2 ish hours machining time as well as a costly lump of bronze, whoever is doing the work will need a CNC mill.

The oil clearance on a 170 bigend bearing should be about 1.5 thou, 3/4 of a thou each side.

Charles in NZ

Posted: Thu Mar 13, 2008 11:23 am
by rosbullterier
What is the NZ time for 6.22 am British Time Charles?

170 big end caps

Posted: Thu Mar 13, 2008 1:02 pm
by John@sos
Just a little extra snippet, I have heard from Sweden, that their mehod of dealing with this is simple and it has proved to be effective.

They remove the conrod and cap, then make a close fitting metal, Steel, strap to fit snug against the end cap and be held with the two cap screws. the extra weight makes no difference to the balance and it provides the support for the ali!

Could this see the resurgence of interest in the 170?

Regards,
John
SOS

Posted: Fri Mar 14, 2008 6:04 am
by Charles uk
All the dying 170 rods that I've seen have the bearing surface of the end cap badly worn, bronze as a bearing surface will almost run dry, but aluminium drags badly & wears away quickly without sufficient oil to protect it, leaving too much room for the oil to lubricate properly.

So I can't really see what a steel band over the cap would achieve.

ali big end caps

Posted: Fri Mar 14, 2008 11:01 am
by John@sos
Hello Charles,

this was my thought too, but these Swedish lads have been using the 170's like this for some years, so maybe they up the oil as well, will have to find out more...

Have you ever found a bronze bearing on any of the caps?

Regards,
John
SOS

Posted: Fri Mar 14, 2008 7:37 pm
by Charles uk
No John, I have never seen a bronze bigend cap, I think the bronze bearing gossip originated in Sesgull's R&D dept.