Rocker Spindle Gasket Failure

Lovel · Oct 8, 2022

Looking for some advise on my 850 mk3 which suffered a gasket failure at the rocker spindle drive side leading to the loss of engine oil. From the photos attached it can be seen that the rocker shaft was basically flush with the gasket. When assembled about 1,500miles ago the rocker spindle was below the depth of the gasket which lead to an oil tight joint until the gasket shimmied out dumping a lot of oil. The bolts were tight when checked and had no signs of leaking. I am suspicious that because I revved the engine to high revs when it was cold perhaps the oil pressure was too high exacerbating the issue. The rear gasket rocker cover was also in the early stages of failing. I positioned the spindles back into the head again and fitted the new gaskets. Durin use it looks like the spindles have moved out slightly until they can’t move anymore, and perhaps the tension created bows the cover slightly although bolts tight, any thoughts?

Torontonian · Oct 8, 2022

Lovel said:
Looking for some advise on my 850 mk3 which suffered a gasket failure at the rocker spindle drive side leading to the loss of engine oil. From the photos attached it can be seen that the rocker shaft was basically flush with the gasket. When assembled about 1,500miles ago the rocker spindle was below the depth of the gasket which lead to an oil tight joint until the gasket shimmied out dumping a lot of oil. The bolts were tight when checked and had no signs of leaking. I am suspicious that because I revved the engine to high revs when it was cold perhaps the oil pressure was too high exacerbating the issue. The rear gasket rocker cover was also in the early stages of failing. I positioned the spindles back into the head again and fitted the new gaskets. Durin use it looks like the spindles have moved out slightly until they can’t move anymore, and perhaps the tension created bows the cover slightly although bolts tight, any thoughts?

Great opportunity to buy 4 one piece spindle covers.
Yes the plates can warp if overtightened.
You could put your heat gun to the spindle areas and then tap them in a little bit too.

L.A.B. · Oct 8, 2022

Lovel said:
Looking for some advise on my 850 mk3 which suffered a gasket failure at the rocker spindle drive side leading to the loss of engine oil. From the photos attached it can be seen that the rocker shaft was basically flush with the gasket.

That's how I would normally fit the rocker spindles because...

Lovel said:
I positioned the spindles back into the head again and fitted the new gaskets.

If the spindles are pressed right into the head then the inner plate location tabs don't always locate in the spindle slots.

Tornado · Oct 8, 2022

I have one spindle that doesn't stay firmly in position in head, rotates away from slots being horizontal. I have the one piece cover plates which have deeper tabs to better engage the spindle slots, still allow the loose spindle to rotate some. The three others stay where I place them. Thing this is from previous owners not heating head enough prior to pulling/inserting the spindle. Next time I have these out will use some locktite product for bushes/bearings on them.

I also use the reinforced, reusable silicone gaskets sets from JS Engineering on these and my rocker covers. Never had and signs of failure.

marshg246 · Oct 8, 2022

Lovel said:
Looking for some advise on my 850 mk3 which suffered a gasket failure at the rocker spindle drive side leading to the loss of engine oil. From the photos attached it can be seen that the rocker shaft was basically flush with the gasket. When assembled about 1,500miles ago the rocker spindle was below the depth of the gasket which lead to an oil tight joint until the gasket shimmied out dumping a lot of oil. The bolts were tight when checked and had no signs of leaking. I am suspicious that because I revved the engine to high revs when it was cold perhaps the oil pressure was too high exacerbating the issue. The rear gasket rocker cover was also in the early stages of failing. I positioned the spindles back into the head again and fitted the new gaskets. Durin use it looks like the spindles have moved out slightly until they can’t move anymore, and perhaps the tension created bows the cover slightly although bolts tight, any thoughts?

If may be that angle of the picture, but it looks to me that the spindle is slightly clockwise from correct. Also, the marks on the gasket make me think that inner plate is bent/over tightened., At any rate, it would seem that the pressure is not even across the inner gasket, or it would not blow out like that.

I recently installed a set of stainless covers where the little tabs that fit into the spindle were too wide. I didn't realize that because they seemed to seat into the spindle. When tightened the inner plates were bowed. When I started the bike there was oil everywhere.

Lovel · Oct 9, 2022

L.A.B. said:
That's how I would normally fit the rocker spindles because...

If the spindles are pressed right into the head then the inner plate location tabs don't always locate in the spindle slots.

To clarify, I moved the spindle in about .010” deeper than the gasket material concerned that the lugs of the plate would not engage. I’m satisfied that the lugs are engaging With the end of the shaft.

Lovel · Oct 9, 2022

Torontonian said:
Great opportunity to buy 4 one piece spindle covers.
Yes the plates can warp if overtightened.
You could put your heat gun to the spindle areas and then tap them in a little bit too.

Yes I have found them and they look the part, but they appear to be emblazoned with go faster logos which I’m not too excited about.

Lovel · Oct 9, 2022

marshg246 said:
If may be that angle of the picture, but it looks to me that the spindle is slightly clockwise from correct. Also, the marks on the gasket make me think that inner plate is bent/over tightened., At any rate, it would seem that the pressure is not even across the inner gasket, or it would not blow out like that.

I recently installed a set of stainless covers where the little tabs that fit into the spindle were too wide. I didn't realize that because they seemed to seat into the spindle. When tightened the inner plates were bowed. When I started the bike there was oil everywhere.

Was surprised just how quickly the oil came out, lots of what ifs came to mind, doesn’t bear thinking about. In my haste yesterday just to get her home after a sort of pit stop temporary repair I never checked the end plate for flatness, but now home safely I will investigate.

Lovel · Oct 9, 2022

Tornado said:
I have one spindle that doesn't stay firmly in position in head, rotates away from slots being horizontal. I have the one piece cover plates which have deeper tabs to better engage the spindle slots, still allow the loose spindle to rotate some. The three others stay where I place them. Thing this is from previous owners not heating head enough prior to pulling/inserting the spindle. Next time I have these out will use some locktite product for bushes/bearings on them.

I also use the reinforced, reusable silicone gaskets sets from JS Engineering on these and my rocker covers. Never had and signs of failure.

Never tried silicon gaskets, I somehow thought they would be all squidgy and easier to extrude? the gaskets I had originally fitted were AN supply, I don’t fault the gasket material. It must be down to the oil pressure being sufficient enough to shimmy the gasket out due to too much clearance between cap and head surface. I still think I gave the engine too much revs early on after starting could have been the cause on a perhaps marginal joint that is distorted , just can’t stand young whipersnappers passing me.

L.A.B. · Oct 9, 2022

Lovel said:
I still think I gave the engine too much revs early on after starting

The OPRV seems able to cope with higher revs when the oil is cold (at least it does on the 850 Mk3 where oil from the OPRV isn't being directed back to the feed inlet) even SAE 50 monograde as I've checked this with an oil pressure test gauge so maybe the OPRV is sticking closed.

Also, perhaps check the OPRV hasn't been overpacked with shims in an effort to increase oil pressure.

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Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Genuine Factory Spare Parts for Norton motorcycles built before 2002.

andover-norton.co.uk

Lovel · Oct 9, 2022

I have removed the timing cover in the past for a close inspection but found nothing untoward tbh. I changed the crankseal as a matter of course. Everything seemed to be untouched so put it all back together and obtained an oil pressure gauge which gave readings comfortably in the expected range. Im using 20/50 GTX classic.

L.A.B. · Oct 9, 2022

Lovel said:
I have removed the timing cover in the past for a close inspection but found nothing untoward tbh.

Ok, although the OPRV assembly is only accessible from outside the timing cover (seen here with the cap, spring and piston removed):

marshg246 · Oct 9, 2022

L.A.B. said:
The OPRV seems able to cope with higher revs when the oil is cold (at least it does on the 850 Mk3 where oil from the OPRV isn't being directed back to the feed inlet) even SAE 50 monograde as I've checked this with an oil pressure test gauge so maybe the OPRV is sticking closed.

Also, perhaps check the OPRV hasn't been overpacked with shims in an effort to increase oil pressure.

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Genuine Factory Spare Parts for Norton motorcycles built before 2002.

andover-norton.co.uk

A little off topic but I'm wondering if there is any info on the change in relief pressure with differing numbers of shims. Also, various parts manuals say five shims and AN says two - any idea about those? Did the factory actually install 5 (I've only seen 0, 1 and 2)?

Tornado · Oct 9, 2022

Lovel said:
Yes I have found them and they look the part, but they appear to be emblazoned with go faster logos which I’m not too excited about.

EuroJamb where I got mine, no emblazoning:

Norton Stainless Rocker Plate SET 750 850 Commando CUSTOM

Awesome custom parts. Perfect fit to OEM gaskets. This listing is for one complete set, as shown. These rocker plates are single-piece, only one gasket per piece required, and constructed of beautiful stainless steel. This kit should be suitable for ALL twin cylinder Norton.

www.eurojamb.com

L.A.B. · Oct 9, 2022

marshg246 said:
A little off topic but I'm wondering if there is any info on the change in relief pressure with differing numbers of shims.

I'd say each shim adds approximately 5 PSI to the cold oil blow-off pressure.

marshg246 said:
Also, various parts manuals say five shims and AN says two - any idea about those? Did the factory actually install 5 (I've only seen 0, 1 and 2)?

The shims used to be supplied in packs of five. The actual quantity would normally be 0 - 2 so the parts quantity should be 'AR'.

Lovel · Oct 9, 2022

Interesting findings today when I had more time to investigate the reason for failure. I found that the outer most of the covers was bowed slightly, but the inner cover with the key that engages with the spindle was still flat. Way back when the caps were fitted originally they were torqued up to 8ft/lbs.

htown16 · Oct 9, 2022

According Mick Hemmings video shim the spring until it just rattles when you shake it once assembled.

Larry S · Oct 9, 2022

Lovel said:
Interesting findings today when I had more time to investigate the reason for failure. I found that the outer most of the covers was bowed slightly, but the inner cover with the key that engages with the spindle was still flat. Way back when the caps were fitted originally they were torqued up to 8ft/lbs.

Sounds to me that your rocker spindle is too far clockwise (as previously stated) and is not flush with the head. That could cause the outer spindle cover to bow as you said resulting in gasket failure. I’ll bet if you heat your head, orient your spindles properly and tap them in until flush, you’ll have fixed the problem. I could be wrong, but it sounds right to me.

Fast Eddie · Oct 10, 2022

Tornado said:
EuroJamb where I got mine, no emblazoning:

View attachment 100041

Norton Stainless Rocker Plate SET 750 850 Commando CUSTOM

Awesome custom parts. Perfect fit to OEM gaskets. This listing is for one complete set, as shown. These rocker plates are single-piece, only one gasket per piece required, and constructed of beautiful stainless steel. This kit should be suitable for ALL twin cylinder Norton.

www.eurojamb.com

There was a thread about these recently saying the tangs need filing a little to fit.

JS ones are plain alloy, no ‘go faster’ logos and fit without filing.

YING · Oct 10, 2022

Lovel said:
Yes I have found them and they look the part, but they appear to be emblazoned with go faster logos which I’m not too excited about.

You can find one-piece plain spindle covers with no logo if you search.
Mike

Rocker Spindle Gasket Failure

Lovel

Torontonian

L.A.B.

Moderator

Tornado

marshg246

Lovel

Lovel

Lovel

Lovel

L.A.B.

Moderator

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Lovel

L.A.B.

Moderator

marshg246

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Tornado

Norton Stainless Rocker Plate SET 750 850 Commando CUSTOM

L.A.B.

Moderator

Lovel

htown16

Larry S

Fast Eddie

Norton Stainless Rocker Plate SET 750 850 Commando CUSTOM

YING

Pittsboro,NC

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