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Kirkham Motorsports

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  #21 (permalink)  
Old 05-16-2016, 08:47 AM
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Quote:
Originally Posted by Aussie Mike View Post
Glad you got it sorted Michael. Is the piston OK?

Cheers
I think so - I stared at it for ages and it held together

It looked to me like I was very fortunate with the timing of the valve drop and it appeared that the valve had just knocked the carbon off the piston.

... stand by for my future thread on a broken piston and conrod through the block



LB
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  #22 (permalink)  
Old 05-16-2016, 05:50 PM
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Good stuff LB.
Have you measured the old pushrods to see what length they are?
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  #23 (permalink)  
Old 05-16-2016, 06:20 PM
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Originally Posted by boxhead View Post
Good stuff LB.
Have you measured the old pushrods to see what length they are?
Going from memory 6.250" - which I think is standard length

ta
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  #24 (permalink)  
Old 05-16-2016, 07:36 PM
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Just to clarify, is it not the valve head that has snapped off, which happens from piston contact.

The valve stem has snapped just under the valve collets from side loading, from the rocker arm pushing the retainer at early valve lift.

That would be a rare failure, but it shows the strength of your collets and retainer.

I would hope all of the valves were inspected for this condition.

Now this time, with the light spring fitted, every clearance needs to be checked, valve to piston clearance, retainer to rocker, rocker to stud etc, throughout the full 4 stroke cycle of the engine.

Gary
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Old 05-16-2016, 07:43 PM
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I just hope you can find all those pesky little metal parts that went somewhere when it broke!
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  #26 (permalink)  
Old 05-17-2016, 04:10 AM
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Originally Posted by Aussie Mike View Post
You've thrown the burley all over yourself. It's a Ford Windsor motor LOL
Faaarrk It's really hard to talk with a mouthful of crow feathers...........should have looked harder
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  #27 (permalink)  
Old 05-17-2016, 05:24 AM
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I've had another look for some time, and the lifter for this valve failure also looks different in your photo compared to the other 7.

The pushrod seat in the lifter looks different.

Pushrod seat has come out?

Gary
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  #28 (permalink)  
Old 05-17-2016, 06:24 AM
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Originally Posted by Gaz64 View Post
I've had another look for some time, and the lifter for this valve failure also looks different in your photo compared to the other 7.

The pushrod seat in the lifter looks different.

Pushrod seat has come out?

Gary
Wow - good eyes - and thank-you for taking the time to look for more clues

I have uploaded a better picture (below - you can zoom in by holding down Ctrl and scrolling up with your mouse)

The lifter looks different because it is not covered in oil - I suspect I wiped it as part of the general inspection - if you zoom in you will be able to make out the various parts of the lifter (as visible from that angle) and those parts will just be cleaner than the ones around it.

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  #29 (permalink)  
Old 05-17-2016, 07:02 AM
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Quote:
Originally Posted by Gaz64 View Post
Just to clarify...
..I would hope all of the valves were inspected for this condition.

Now this time, with the light spring fitted, every clearance needs to be checked, valve to piston clearance, retainer to rocker, rocker to stud etc, throughout the full 4 stroke cycle of the engine.

Gary
All the valves are new now - I was just looking for the itemised receipt - If I can find it soon I'll post a copy

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Originally Posted by Bernica View Post
I just hope you can find all those pesky little metal parts that went somewhere when it broke!
...what harm could they do...?

Quote:
Originally Posted by Rog246 View Post
Faaarrk It's really hard to talk with a mouthful of crow feathers...........should have looked harder
Don't beat yourself up too much Rog - it shows why the LS is perfect for a replica cobra - because it is a replica windsor
(and like replica cobras - has 40 years worth of updates )
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  #30 (permalink)  
Old 05-17-2016, 07:28 AM
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On with the show

here is the recovered valve


Gaz - and some of the less eagle eyed amongst you - will notice a harmonic balancer sitting on the bench behind the ex-valves.

And you may notice that in Post #28 there is a ratchet attached to the crank bolt. Its a very convenient way of turning over the engine as you check all sorts of stuff and as you re-assemble the engine and set stuff up.

And after 4 months it may transpire that you finally have all the bits and pieces you need and can (and do) re-assemble your engine and fire it up.

Stopping to recharge the battery because it seems to have difficulty turning over...

Only to look down at the front of the engine when you're trying to set the idle and notice your ratchet is now hard up against the chassis and appears to have wisps of smoke coming off it
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  #31 (permalink)  
Old 05-17-2016, 08:21 PM
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Wow, look at the bend in the valve stem.

Sheared off straight under the valve collets.

Thank god the piston is ok.

Can you see what I mentioned about the lifter for that valve in one of your early photos?

Or is what I see an illusion?

Gary
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  #32 (permalink)  
Old 05-17-2016, 08:46 PM
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Again, did you find the rest of it somewhere in the engine?
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  #33 (permalink)  
Old 05-17-2016, 11:47 PM
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Can't believe the silly string valve pic! Holy moly.
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  #34 (permalink)  
Old 05-18-2016, 01:55 AM
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Quote:
Originally Posted by LoBelly View Post
All the valves are new now - I was just looking for the itemised receipt - If I can find it soon I'll post a copy



...what harm could they do...?



Don't beat yourself up too much Rog - it shows why the LS is perfect for a replica cobra - because it is a replica windsor
(and like replica cobras - has 40 years worth of updates )
Well most of the DOHC ENGINES are made at the Windsor even though most people don't call them that........but hey.............'what's a pushrod ?" LOL
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  #35 (permalink)  
Old 05-18-2016, 02:37 AM
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I should have mentioned this earlier.

Have you thought about going to beehive springs?

The technology is out there now with a lot of spring manufacturers.

Lighter springs, combined with a lighter retainer.

Would also give a little more clearance with the rocker arm.

Gary
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  #36 (permalink)  
Old 05-18-2016, 04:26 AM
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Quote:
Originally Posted by Gaz64 View Post
Wow, look at the bend in the valve stem.
Sheared off straight under the valve collets.
Thank god the piston is ok.
Can you see what I mentioned about the lifter for that valve in one of your early photos?
Or is what I see an illusion?

Gary
Hi Gaz
I think it might be an illusion - I just cleaned that lifter to get a good look at it to see if I could find anything wrong

Quote:
Originally Posted by Bernica View Post
Again, did you find the rest of it somewhere in the engine?
Hi Bernie -
As Gaz says the valve tip just sheared off so the 'rest of it' was retained by the collets in the top of the spring. Its in one of the earlier photos

Quote:
Originally Posted by Gaz64 View Post
I should have mentioned this earlier.
Have you thought about going to beehive springs?
The technology is out there now with a lot of spring manufacturers.
Lighter springs, combined with a lighter retainer.
Would also give a little more clearance with the rocker arm.

Gary
That would have been a good idea - but the top-end is back together now and I have issues elsewhere to attend to...

ta
LoBelly
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