Author Topic: exhaust rocker spindle line up  (Read 124 times)

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easterndriver

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exhaust rocker spindle line up
« on: 28 October, 2020, 11:11:46 »
does anyone know if there is an easier way to line up the exhaust rocker spindle with the shims and thrust washers. have been trying for an hour and it just seems impossible to line up the washers with the spindle.

wardy

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Re: exhaust rocker spindle line up
« Reply #1 on: 28 October, 2020, 11:40:29 »
Not sure if there's an easy way, I just fitted the rockers, plain and sprung washers, lined it up by eye and tapped the spindle through progressively. May be possible to see though the hole "end to end" as it were. In addition to 4 plain and 2 sprung washers there is a plain washer that goes outside the RH carrier (between the carrier and the nut) which is of smaller internal diameter which the large diameter of the rocker shaft won't go through.

Editor

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Re: exhaust rocker spindle line up
« Reply #2 on: 28 October, 2020, 11:55:59 »
I have done this assembly many, many times without any problems at all. Until the last time on the A50. Took me over 2 hours and I was spitting blood by the time I'd finally succeeded.

I use the method explained by Wardy, but this last time the thackery washers were just flying out at will. I think a previous owner (aka bodger) had the same problem and left out the plain washers that sit between the thackeries and the alloy post on the head. Result- the thackeries wore the ally away and I had to have them built up by laser welding. 

Persevere, it will come good in the end!

Chris

easterndriver

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Re: exhaust rocker spindle line up
« Reply #3 on: 28 October, 2020, 12:15:34 »
thanks to you both, just managed to do it after a few choice words!  surely when being manufactured there must have been a special BSA tool for it. trouble is now after a few hundred miles I have to take it all apart again to check the two head bolts and re torque them or do people bother to do that?

wardy

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Re: exhaust rocker spindle line up
« Reply #4 on: 28 October, 2020, 13:11:41 »
It is a bit of a fag. The bolts are fairly robust so I suppose one might slightly overtorque them (say 30 lb ft) and trust to luck. You can always check the torque on the accessible bolts in due course, see if anything has changed, and take a view I guess. It's a far cry from the torque on an AJ133 Jag engine crank damper bolt (450 NM)...

DAVE BRADY

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Re: exhaust rocker spindle line up
« Reply #5 on: 28 October, 2020, 13:25:42 »
Hi,

I would re-torque the head.  Look upon the removal and refitting of the rockers as practice for the next time.
I do not think that initial over torquing will work as I believe that the idea of re-torquing is to ensure that the gasket is compressed sufficiently.  Surely over doing it will compress the gasket more but as/if it beds in and settles the torque will be relaxed and need re-doing?

Dave.

wardy

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Re: exhaust rocker spindle line up
« Reply #6 on: 28 October, 2020, 14:11:10 »
Maybe Dave. I guess the obvious thing is to check the accessible bolts and see if they're slackened off, if not you may be OK I guess. If they're noticeably slacker than it would probably be best to do it all again

DAVE BRADY

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Re: exhaust rocker spindle line up
« Reply #7 on: 28 October, 2020, 15:18:27 »
Hi,

I suppose each has to decide for themselves but I wonder how many A65s have had a leak between cylinders or in to the pushrods tunnel with no visible outward signs.   I used to have a stack of used head gaskets and there were as many with signs of internal leakage as external. 
Either way the rocker shaft will have to removed to re-torque after a few hundred miles or at some later stage when the gasket may need to be replaced.

Dave.

wardy

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Re: exhaust rocker spindle line up
« Reply #8 on: 28 October, 2020, 16:01:14 »
Wrong brand I know Dave but T140's often leak between the bores. Increasing capacity from 650 to 724 and then 750 while shortening the stroke makes for big bores and a small joint surface between them. So they softened the cams to stop the engine blowing the lid off. More meat on the A65!
 

Mike Farmer

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Re: exhaust rocker spindle line up
« Reply #9 on: 28 October, 2020, 16:45:33 »
 :) :) :)

My method for what it may be worth. Put a stack of grease on the castings and the washers, then with luck once you have them lined up the first time they'll stay in place which helps to get around having to try to jiggle (lovely word) more than one place/washers at a time.

Mike 8) 8) 8)

DAVE BRADY

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Re: exhaust rocker spindle line up
« Reply #10 on: 28 October, 2020, 16:50:49 »
Yes.  Definitely more of a problem with big bores.  The big bore 750 barrels are similar in that the limits are being pushed.  I think the big bore barrels had special head bolts that reduced in size to allow a bit more meat between the cylinders.  Even so some people took them out even more.  Performance vs reliability - it depends on what you want from your BSA.

Dave.
 

easterndriver

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Re: exhaust rocker spindle line up
« Reply #11 on: 29 October, 2020, 17:05:58 »
thanks everyone for your replies, much appreciated.