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Old 10-03-2011, 01:23 PM   #31
wmax351 OP
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Quote:
Originally Posted by supershaft View Post
I was thinking rod bearing and valve spring too but it is east to push/pull on the rod and look at the springs to see if one is broke.
They are fresh rod bearing shells, and I pulled on them to check for excessive play. There is no significant play either direction. I do wonder a bit about the small end though.
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Old 10-03-2011, 01:34 PM   #32
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Have you had the flywheel off. Just wonderin if it's been alighned back proper?
Had it off. Had endfloat adjusted, bearings inspected, and Rear Main Seal installed by Dave Gardner.
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Old 10-03-2011, 01:45 PM   #33
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What bearings inspected?
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Old 10-03-2011, 01:49 PM   #34
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What bearings inspected?
Main Bearings (which were perfect), as well as thrust washers (which were damaged and replaced).
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Old 10-03-2011, 01:54 PM   #35
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You can't inspect the mains without removing the crankshaft. Was it taken out?
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Old 10-03-2011, 04:33 PM   #36
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Had it off. Had endfloat adjusted, bearings inspected, and Rear Main Seal installed by Dave Gardner.
It may have been put back 360 degrees out, therefore you're valve's are opening/shutting on one side when it should be the other side.

Have you checked TDC (OT) with piston position?
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Old 10-03-2011, 04:53 PM   #37
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If it's 360 out, that would bring it right back in line.

Right?

That, and if the timing marks are lined up when the chain is installed, how could it be wrong?

And finally, what difference does it make if the valves are operating for the left cylinder when they should be taking care of the right side instead?

If the valves are working 180 degrees out, I see no reason why it wouldn't run since the piston goes up and down twice for each power stroke (no difference between strokes as far as the piston is concerned) - why would it matter which stroke is the power stroke since the two pistons will always be in synch?

The carburetors don't care, the exhaust doesn't care and the timing doesn't care. If there's fuel, air, compression and spark at the right time, she'll run.


As for the valves kissing the pistons - you've certainly got my attention! I really want to know what's at the bottom of this one.
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Old 10-03-2011, 04:59 PM   #38
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If it's 360 out, that would bring it right back in line.

Right?

That, and if the timing marks are lined up when the chain is installed, how could it be wrong?

And finally, what difference does it make if the valves are operating for the left cylinder when they should be taking care of the right side instead?

The carburetors don't care, the exhaust doesn't care and the timing doesn't care. If there's fuel, air, compression and spark at the right time, she'll run.


As for the valves kissing the pistons - you've certainly got my attention! I really want to know what's at the bottom of this one.
Dont be silly, why do you turn the crank 360 to do the valve lash on the opposeing side
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Old 10-03-2011, 05:04 PM   #39
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There is no putting the flywheel on 360* off. That would be the place where it started. I think you mean 180*. That is also not possible because there are 5 flywheel bolts so there are only 5 positions the fltwheel can be installed in. The flywheel can be installed 72* off, 144* off, 216* off or 278* off. You may notice there are 4 incorrect positions the flywheel can be in and only one that is correct. This does not seem to be the problem from where I'm sitting but I don't claim to have this figured out yet. I'm sure that I will see it when it is explained after they find the problem. Just like everybody else will then be saying, "Oh yeah. I was thinking a bout that." Right.

I think we are waiting for the autopsy of the timing chest area to see if the cam chain was correctly placed. It is likely that the problem is here I think but if so then why one side worse than the other and both intakes and exhausts?

The last explanation was about lifters not moving in their bores so they got stuck? Debris maybe? I think you have the head (s) off so should pull the cylinder(s) and inspect the lifter bores.

Is it also possible that new valve guides were installed and not properly reamed? The valves could then be seizing in the guides?

I don't suspect small end rod bearings. These get very little oil because they need very little. And they are only splash oiled.
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Old 10-03-2011, 05:10 PM   #40
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There is no putting the flywheel on 360* off. That would be the place where it started. I think you mean 180*. That is also not possible because there are 5 flywheel bolts so there are only 5 positions the fltwheel can be installed in. The flywheel can be installed 72* off, 144* off, 216* off or 278* off. You may notice there are 4 incorrect positions the flywheel can be in and only one that is correct. This does not seem to be the problem from where I'm sitting but I don't claim to have this figured out yet. I'm sure that I will see it when it is explained after they find the problem. Just like everybody else will then be saying, "Oh yeah. I was thinking a bout that." Right.

I think we are waiting for the autopsy of the timing chest area to see if the cam chain was correctly placed. It is likely that the problem is here I think but if so then why one side worse than the other and both intakes and exhausts?

The last explanation was about lifters not moving in their bores so they got stuck? Debris maybe? I think you have the head (s) off so should pull the cylinder(s) and inspect the lifter bores.

Is it also possible that new valve guides were installed and not properly reamed? The valves could then be seizing in the guides?

I don't suspect small end rod bearings. These get very little oil because they need very little. And they are only splash oiled.
You're right on the flywheel, my mistake. But I still think the Flywheel's been put on wrong and I'll go for that.
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Old 10-03-2011, 05:16 PM   #41
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Dont be silly, why do you turn the crank 360 to do the valve lash on the opposeing side
Because you are turning the cam shaft 180* to bring the other side to TDC.

The timing chain can be installed 180* off and everything will be happy. It can be advanced or retarded on most engines a couple of degrees. But the timing chain has a limit how far off it can be before the valves start hitting. But if this is the case then it would be the intakes or the exhausts. Not both.

I don't think the problem is in the timing chest. But it does have to be checked at this point.
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Old 10-03-2011, 05:24 PM   #42
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Am I right in thinking that if the flywheel has been put on wrongly to what ever degree and you set the valve lash to OT mark on flywheel, then a some point you're going to get unwanted contact twix piston and valve's (being 4 stroke)?
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Old 10-03-2011, 05:28 PM   #43
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I am so use to seeing guides set up on the loose side I didn't think that they might be set up too tight. It's easy to tell if you have a valve spring compressor.

Ream? Do not use a ream when you could use a Sunnen valve guide hone. A ream is comparatively like using a chisel.
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Old 10-03-2011, 05:38 PM   #44
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Maybe but maybe not, I think. If you are setting valves you do this at TDC and the object is to put some space in the valve clearance. Too much space and you won't be getting closer to the pistons. Set them at zero and I don't think they will hit. If the piston is in any other position other than TDC then the valves will be opening or closing and if you set the valves in this position then you will only be getting gigantic valve clearances. there actually will be a point that the adjustment screw will run out of threads and the spring will still be holding the valve open.......So don't be silly.

If the flywheel is incorrectly placed the ignition can not be set.

If the timing chain marks in the timing chest are incorrect then you have valve problems.

But the timing chain marks are controlled by the keys in the crank and the cam shafts. They have nothing to do with where you put the flywheel.

I hope this helps. It's not rocket science...OK it's worse than rocket science. But when you see it it will click. Try not to think too hard.
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Old 10-03-2011, 06:05 PM   #45
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One consideration from Ted Porter,

Quote:

I would have a lot of questions about this assembly. Those look like the special high compression 750 pistons, is that true? Is the cam stock? I would also want to look at the depth of the valves in the head. Obviously you need some clearance somewhere. ;)
Do those look like stock pistons? I'm not sure. They're .5 over, 82.465 mm. That puts them .5 over on a R75/7, but still not 100%.
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