Valve guide wear - how to measure?

[brider]

When the day comes that I pull the heads on my Cal 2, is there a way to measure the condition of the valve guides? Radial throwout of the valve stem? Visual?

[pete roper]

Micrometer on the stem. Compare to book spec. Internal micrometer or Plug guage for guide itself.

In reality though just slip the stem into the guide and wiggle it about. If there is really any detectable slop it's time for new valve and k-lines.

A Cali II is now nearly 40 years old. Unless it's done nothing except sit in a hermetically sealed room for all that time it's almost certain to need valves and K-lines. Unless the guides are loose in the heads there is no need to re-guide.

Pete

[brider]

Thanks, Pete, I figured a seasoned hand would be able to determine excessive wear by the slop in the fit.

But my issue "stems" (ha!) from the excessive smoke I've been experiencing on start-up, leading me to believe it IS guide wear. Are you suggesting that the valve stems or valves themselves are likely worn by now? If slop is evident, isn't it more likely that the guide is worn, not the hardened valve stem? I am ashamed to ask what you mean by "k-lines".

I'm open to anything needing replacement, but I'm kind of baffled that a 45k-mile engine needs guides so soon. But indications are pointing to that, I just wanted to understand the standard checks for guide wear.

Didn't know they made an internal micrometer that small.

[pete roper]

Not a mic but you can get tiny bore guages.

Smoke on start up is almost certainly guide wear. If the poor thing has only done 45,000 miles in 40 years it must of sat for long periods of time un started. Condensation will cause surface corrosion on things like valve stems and when re-started this, along with lack of lubrication in the sintered metal of the guide is bound to produce wear.

Check the valves. If the stems measure up and they have sufficient margin? Put them back in. Really at this age why not just give it a birthday? Throw a new set at it.

As for K-Lines? Interrupted scroll liners for the guides inserted into the worn bores of the parent guide and reamed to size. They are actually superior to the parent material and keep the valve concentric with the seat meaning less cutting is required. Unless the guide is loose in the head they are by far the best option for repairing a worn guide.

Pete

[Don G]

I'm open to anything needing replacement, but I'm kind of baffled that a 45k-mile engine needs guides so soon.
 
If it were an old Triumph it would have likely be on its second or third top end overhaul by now!   DonG

[Chuck in Indiana]

Didn't know they made an internal micrometer that small.

Telescope and small hole gauges. There is some "feel" to using them with micrometers. Standard stuff.

[voncrump]

Dial gauge on the head of the valves in line with the rocker with the valve held open about 10mm or 3/8 of an inch. Then check against specs. The trouble with measuring is that you will get a different reading of the guide almost every time you check it. It will be worn in an hourglass shape. Experience can give you the answer without measurement.
Cheers, voncrump

[rodekyll]

I let the valve down about 1/3 and try moving it side-to-side.  If there's slop, compare it to the other guide and compare it to a new valve.  If it's still sloppy it at least bears further scrutiny from a sensitized hand if not an instrument.  It helps to know what a fresh guide feels like . . .

[PeteS]

I use a set of these along with a micrometer. With a little practice you can make an accurate measurement. Wiggling the valve around in the guide won't tell you much as wear will differ at different points along the valve and guide.

[brider]

I use a set of these along with a micrometer. With a little practice you can make an accurate measurement. Wiggling the valve around in the guide won't tell you much as wear will differ at different points along the valve and guide.

I remember now, I've used those before; snug it up (but not too tight) where you want to measure, then mic the spread.

Thanks, I'll report back when I pull the heads.

[Don G]

The best way is to strip the heads and take the valves and heads to a competent automotive machine shop, also take your shop manual or spec sheet, and have an expert assess the condition.  DonG

[brider]

Engines with pivoted rocker arms generally wear the guides more inline with the rocker travel.
If you have noticeable wiggle that way compared to inline with the pivot shaft they are worn.

That makes tons of sense, thanks!