Long overdue update

[Bonz]

How the heck do you turn the cams, at the same time or even just one, while the head is on a bench? I mean, I know you CAN but it ain't the easiest thing to turn them and work the valve springs open without a lot of leverage, no?

[sethhope]

The engine is turning with the starter. I can see the pistons moving properly. I did a leakdown test using a very simple air compressor nozzle and seal. Seems to be failing in the exhaust valves. The cams WERE on it when I received the head, but I packaged it in soft towels/tshirts for transport, and then promptly removed the cams when I got it home while it was still in towels. I doubt that would bend ALL the exhaust valves.

[3Phase]

Use the hex flats cast into both of the camshafts next to the timing gear ears. A wrench or water pump pliers work great. You can use them with a quick jig to hold both cams and keep them from turning while you install the gears and chain.

Cinching the bearing caps down with the cam lobes in the 'wrong' position will put a valve into the benchtop or another open valve too, no turning necessary.

[Bonz]

Removing the cams would let all the valves sit flush up in the head no harm done there.

[3Phase]

Seth, if it's all Exhaust valves it's possible the Exhaust cam got turned before you got it or something on the way to your house. Machinists use dye to check the valve face-to-seat fit when they do valve work and it takes very little force to bend the little bitty valve stems in a motorcycle engine enough to cause a leak even if it looks good by Mark I Eyeball.

Removing the cams would let all the valves sit flush up in the head no harm done there.

Yep, that's how you're supposed to store and install the heads: no camshafts at all or just resting in place with the bearing caps loose so no valves are opened.

If you get really, really, unlucky you can bend even a seated valve with the cylinder studs as you put the head on the engine. All it has to do is drop too hard on the threaded ends of the studs or catch the lips on the valve faces and, "Presto! You need new valves!"

[Bonz]

Store heads that way... what is the purpose? To keep valves from being damaged?

Like Seth said, how do you damage all 4 exhaust valves? It was packaged properly, just like I'd do it wrapped in towels, etc.

I look forward to the final word on what is wrong.

[3Phase]

Store heads that way... what is the purpose? To keep valves from being damaged?

Well, yeah. It helps keep the valves from getting accidental damage and none of the springs are under more than normal closing pressure. You're less likely to get tweaked springs from leaving the head on the shelf with a couple of valves held open or partially open for a couple of years/decades.

Like Seth said, how do you damage all 4 exhaust valves? It was packaged properly, just like I'd do it wrapped in towels, etc.

I look forward to the final word on what is wrong.

I want to find out what happened too, I'm just guessing.

I don't know that it happened in this instance but I know that you can mess up four or more valves at once by turning a camshaft when the head's off the engine; rags or no rags, sitting in your lap or wherever, the valves are fragile.

Dropping the head on or hanging it by the cylinder studs can do it too. The studs are almost ideally spaced to be able to hit all four of the combustion chambers at the same time. That was something that I never really thought about until a few months ago when I ganked my hand on one of the stud ends as I was putting the head back on Columbo.

I didn't bother torquing the head. I pulled it out, checked the valves and three of them were messed up from when I dropped it on the studs. They all looked fine but they weren't and I need to do some valve work that I keep putting off to ride my XJ.

[Ranger_xs1100]

I did a leakdown test using a very simple air compressor nozzle and seal. Seems to be failing in the exhaust valves.

At this point, would a valve gap check be useful?
Could there be no clearance gap due to the wrong size shims causing the valves to be held open?

[3Phase]

A gap check would be useful, no clearance at all would do it but wouldn't give the initial feeling of compression on the kicker that went away and now the engine just spins, apparently with no pesky compression to slow it down.

[Ranger_xs1100]

gap

A gap check would be useful, no clearance at all would do it but wouldn't give the initial feeling of compression on the kicker that went away and now the engine just spins, apparently with no pesky compression to slow it down.

And If I am thinking about this correctly...
If the valves are bent and stuck open,
I think you then would see an unusually large clearance gap that never closes.

[IanDMacDonald]

I think it'd be best to pull that head back off, and assume the exhaust valves are bent. Something happened, and it happens to the best of them.

Look for another head with intact valves, or put some new one's in. New seals, etc.

It got to the point where I can pull a head in less than 30 minutes, and that includes pulling the exhaust, etc.

Good luck!

[MPittma100]

Cylinder Head Install

Some of the things you may not SEE that can cause you to fail when installing the head are:

Position of crankshaft (piston to valve interference)) when reinstalling the head.
Valves can interfere with each other in the cylinder head.
Using starter to rotate engine will bend valves.

Before installing head:

Make sure crankshaft position is correct.
Make sure there is not interference while installing head to block.
Do NOT turn engine until cams are in time and chain is on the sprockets with tensioner installed.
Camshafts can be installed temporarily prior to head install to adjust valve lash (off of the engine).

After head is installed,

When rotating engine, do it manually with wrench on the square lug on the end of the crankshaft behind the pick-up coil (left) cover. Feel for any interference. STOP if you feel a problem. DO NOT USE THE STARTER!. You are smart to disconnect the battery. Find a written procedure and copy it. Keep it at the bike while working on it. Cylinder head removal/install is DIFFICULT. Pay attention to what you are doing. Valves are becoming scarce and are expensive.

Good Luck.

[sethhope]

Some of the things you may not SEE that can cause you to fail when installing the head are:

Position of crankshaft (piston to valve interference)) when reinstalling the head.
Valves can interfere with each other in the cylinder head.
Using starter to rotate engine will bend valves.

Before installing head:

Make sure crankshaft position is correct.
Make sure there is not interference while installing head to block.
Do NOT turn engine until cams are in time and chain is on the sprockets with tensioner installed.
Camshafts can be installed temporarily prior to head install to adjust valve lash (off of the engine).

After head is installed,

When rotating engine, do it manually with wrench on the square lug on the end of the crankshaft behind the pick-up coil (left) cover. Feel for any interference. STOP if you feel a problem. DO NOT USE THE STARTER!. You are smart to disconnect the battery. Find a written procedure and copy it. Keep it at the bike while working on it. Cylinder head removal/install is DIFFICULT. Pay attention to what you are doing. Valves are becoming scarce and are expensive.

Good Luck.

I was very scared that id bend valves when installing. I was very aware of the risks. I have a clymer manual and I followed the install proceedure to the letter. I even practiced it once with the known bad head (didnt torque anything down, but put everything in place). I really am at a loss as to HOW it happened, but at this point, bent valves are my only thought.
As for clearences, i did a crude check to make sure that they werent being pushed open by the cams, and the exhauzt valves all have decently large clearences. Maybe a sign?

[Ranger_xs1100]

I was very scared that id bend valves when installing. I was very aware of the risks. I have a clymer manual and I followed the install proceedure to the letter. I even practiced it once with the known bad head (didnt torque anything down, but put everything in place). I really am at a loss as to HOW it happened, but at this point, bent valves are my only thought.
As for clearences, i did a crude check to make sure that they werent being pushed open by the cams, and the exhauzt valves all have decently large clearences. Maybe a sign?

Sounds Like you're gonna need Bonz's recommended valve spring compression tool after all!

[IanDMacDonald]

Maybe a sign?

Yes, a sign of bent valves.