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JE Piston......stupid question / Broken Valve......dented head!

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After doing a complete rebuild to replace a crank bearing, I went out for a ride today and a valve snapped and dropped into the cylinder. Clean break about 1 cm from the tulip

 

I'm not sure if it was caused by me during the rebuild or the valve actually failed itself, either way, I wanna get to the bottom if it

 

The piston and the inside of the head are a bit chipped, but seems like a light grinding will bring them back. There is no evidence of cracking and the cylinder is fine

 

There is no visible marking on the piston face that give an impression that a collision between the valve and piston was not the cause of the broken............hmmmm

 

Also, this might sound a bit stupid, but when I re-installed the JE Piston during the rebuild, I assumed that the imprint in the surface was relevant/matched to the size of the valves above it. I mean the large indent should be below the intake, the small below the exhaust

 

Can any one clarify this for me and has anyone got any feedback as to a valve could fail or something I may have done wrong?

 

I've ordered a set of Ferrea valves. Does anyone know a way of replacing them without needing a valve clamp?

 

BTW Kibblewhite Black Diamond are nothing but trouble........700km!!!

 

 

 

IMG_2201.JPG

IMG_2204.JPG

Edited by dr-z465

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Kibblewhite valves have a poor rep here on TT.  Yes the top of the piston matches the valves.

 

I will assume quite a bit of motor modifications. You should do a trial assembly and check piston to valve clearance.  Cam timing, valve lift, deck height, piston maker, all affect piston to valve running clearance.

 

Yes there are ways to change the valves without a valve spring compressor.  Look for a Utube vid. Too hard to explain in words.  Or buy a compressor or have a local shop to it.

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Ok, so I removed the valves and found all 4 of them to be bent. I'm positive that there was valve piston collision causing this

I inspected the cams and found that the timing marks lined the lobes up as in the pics

 

Can someone put me right, because it doesn't look right to me as I was always under the impression that the lobes on the cams are meant to be at 2 and 10 o'clock, 'mirror image', pointing away from each other???

 

If I set them the timing to the marks on the cams, this would surely be the cause of the 2 exhaust valves to bend (assuming the timing marks are incorrect). Could the snapped valve bouncing around in the cylinder lead on to cause the 2 intake valves to bend?

 

How can I check for clearance once the top end has been re-installed?

IMG_2230.JPG

IMG_2231.JPG

Edited by dr-z465

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Wow - cam drive gears welded to the cams. Who and how was that done?  Strongly suspect the cam gears are not indexed correctly to the cams.  Plus I can tell you with certainty you can not weld the powder metallurgy cam gears to the cams with any degree of success.  Throw the cams away.

 

 


 Could the snapped valve bouncing around in the cylinder lead on to cause the 2 intake valves to bend?  -----Yes

 

How can I check for clearance once the top end has been re-installed?-------Much too detailed to go into here.  Talk to a local engine builder.  Often done with clay on the piston.  Can also be done with very weak valve springs so they can be pushed own with finger pressure and measure the movement with a dial indicator.

 
 

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Wow - cam drive gears welded to the cams. Who and how was that done?  Strongly suspect the cam gears are not indexed correctly to the cams.  Plus I can tell you with certainty you can not weld the powder metallurgy cam gears to the cams with any degree of success.  Throw the cams away.

 

 

 Could the snapped valve bouncing around in the cylinder lead on to cause the 2 intake valves to bend?  -----Yes

 

How can I check for clearance once the top end has been re-installed?-------Much too detailed to go into here.  Talk to a local engine builder.  Often done with clay on the piston.  Can also be done with very weak valve springs so they can be pushed own with finger pressure and measure the movement with a dial indicator.

 
 

 

The cams are Web-cams. Supplied with the BB/stroker kit I bought 2 years ago. Apparently Web have been welding their cams since 1945, so there must be a way of doing it:

http://www.power-barn.com/servlet/the-1639/Web-Camshafts-for-Kawasaki/Detail

 

I would like to know the TDC position of the lobes. Am I correct in assuming that 2 and 10 o'clock is correct?

I'm reluctant to throw them away if it just means finding the correct position

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Where did you source those cams.?

Whats the component set up specs with your engine..?

Components:

JE piston 94mm

Cylinder Works cylinder

+4mm Hot-Rods stroker crank

Web cams

Previously, Kibblewhite Black Diamond +1 mm valves and Ti spring kit

 

Specs?

Edited by dr-z465

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Yeah , my RHC ( Web) cams supplied by Eddie have welded drive gears .

My Kibble white valves on my Stroker also failed ( I replaced them before they flew apart ) .

Next time you have the top end cover off, take a snap of the lobes at TDC and send it to me :thumbsup:

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Your head is looking a bit mullered there, something funny with the directions of the lobes in that picture if that is how it was timed, how did it run before it blew?

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Ok, so I removed the valves and found all 4 of them to be bent. I'm positive that there was valve piston collision causing this

I inspected the cams and found that the timing marks lined the lobes up as in the pics

 

Can someone put me right, because it doesn't look right to me as I was always under the impression that the lobes on the cams are meant to be at 2 and 10 o'clock, 'mirror image', pointing away from each other???

 

If I set them the timing to the marks on the cams, this would surely be the cause of the 2 exhaust valves to bend (assuming the timing marks are incorrect). Could the snapped valve bouncing around in the cylinder lead on to cause the 2 intake valves to bend?

 

How can I check for clearance once the top end has been re-installed?

 

 

it's hard to see from your picture if the arrows on the cogs are lined up with the face of the head- are they ? 

 

the cams look close to timed there, but possible 2 teeth off on the intake, or exhaust, (the relationship between the cams). 

 

 

 

have you checked the connecting rod yet ? i bet it's bent/damanged. 

 

who supplied the springs, and who assembled the head/engine parts ? 

 

did the timing chain break too  ?

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Ok, so I removed the valves and found all 4 of them to be bent. I'm positive that there was valve piston collision causing this

I inspected the cams and found that the timing marks lined the lobes up as in the pics

 

Can someone put me right, because it doesn't look right to me as I was always under the impression that the lobes on the cams are meant to be at 2 and 10 o'clock, 'mirror image', pointing away from each other???

 

If I set them the timing to the marks on the cams, this would surely be the cause of the 2 exhaust valves to bend (assuming the timing marks are incorrect). Could the snapped valve bouncing around in the cylinder lead on to cause the 2 intake valves to bend?

 

How can I check for clearance once the top end has been re-installed?

The valves could have bent after the broken valve dropped in the cylinder. I personally would not re use that head or piston. Re using that stuff even after a clean up could cause detonation issues. The head may be repairable by a professional but defiantly needs new valve seats.

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Your head is looking a bit mullered there, something funny with the directions of the lobes in that picture if that is how it was timed, how did it run before it blew?

actually, it ran fine with no rattling or tapping at all before it blew.

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it's hard to see from your picture if the arrows on the cogs are lined up with the face of the head- are they ?

the cams look close to timed there, but possible 2 teeth off on the intake, or exhaust, (the relationship between the cams).

have you checked the connecting rod yet ? i bet it's bent/damanged.

who supplied the springs, and who assembled the head/engine parts ?

did the timing chain break too ?

The lines on the cog are not inline with the face of the head

 

Springs supplied with the valve kit, I assembled the head and engine parts

Con rod is fine, no bend or distortion is noticeable

Cam chain didn't snap either

Edited by dr-z465

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The valves could have bent after the broken valve dropped in the cylinder. I personally would not re use that head or piston. Re using that stuff even after a clean up could cause detonation issues. The head may be repairable by a professional but defiantly needs new valve seats.

Yeah, in the ideal world, I would love to be able to chuck out this head and piston and the rest of the worn parts on my bike and buy it all new, but unfortunately in the real world, I've got to make do with the limited budget and time I have to get this back into a usable state

Edited by dr-z465

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have the head rebuilt and a new piston.

 

the other valve have bent because the broken valve have been between them and the piston.

 

kibblewhite for the DRZ: People still buy those?

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have the head rebuilt and a new piston.

 

the other valve have bent because the broken valve have been between them and the piston.

 

kibblewhite for the DRZ: People still buy those?

Yep, only idiots like me, but never again

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Yep, only idiots like me, but never again

 

 

we share the knowledge, we all learn a thing or two. no idiots involved in learning :)

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