[Stogierob]

She’s running again.  New piston rings, gaskets, valves & springs, and decompression valve.  Pardon the wiring mess.  I’m in the process of removing everything it doesn’t need, which happens to be most of the lights and switches.

I think the tappets are too tight.  Opinions?  —> https://youtu.be/3Wb9fgzskgI

Thanks
Rob

[ace.cafe]

If they are too tight, you won't be able to spin the pushrods easily with your fingers at TDC.

[Stogierob]

If they are too tight, you won't be able to spin the pushrods easily with your fingers at TDC.

i'll check that tomorrow. 

Thanks
Rob

[cyrusb]

Too tight would be inclined to make them quieter.  You are asking if they are too loud so maybe they are too loose.

[cyrusb]

When you assembled the head did it have lash caps atop the valves?

[Stogierob]

Don’t know what a lash cap is.  I’ll have to say no.  And now I’m going to go look that up on the parts diagram...

And LOOSE would be the correct diagnosis.  There was at least 1/4” play on the intake and maybe 3/8” play on the exhaust side.  Testing will occur tomorrow afternoon.

Rob

[mrunderhill1975a]

Yep, that is loose......I think Pete Snidal said that at TDC on compression stroke the push rods should be "thumb free" meaning you should just be able to rotate the rods using your thumb and fingers when the engine is cold.  One quarter inch at TDC is way too much and I am surprised the engine would run with that much lash.

[Paul W]

I’m surprised that the pushrods haven’t jumped out of their seats! Is there really that much adjustment?

Maybe the lash caps have been missed out or have disintegrated.

[Bilgemaster]

After a rebuild those pushrods will probably want to settle in a bit, so you might want to keep a close eye and also ear  on them--check them every couple hundred miles or so for a awhile or if you sense an audible change in their tippity-tapping. Once you get used to their "normal" racket, you should quickly become attuned to any changes.

At some point, just for a gag, you might try adding just an ounce or two of a goop called Lucas TB-Zinc Plus Break-In Oil Additive to whatever engine oil you're using. I saw this stuff being recommended by Ace for Iron Barrels quite a while back, started using it, and since then haven't had to adjust my tappets in nearly 10,000 miles. I check 'em, sure, but they're always just fine. Basically the Lucas goop just adds a dash of extra zinc to bring it up to those "oldtimey" pre-90s SAE grade levels of 1,500 ppm or higher that our flat tappets seem to enjoy. I'm running a cocktail of it and Mobil1 15W-50 full synthetic, which has about 1,300 ppm zinc just on its own. You can pick up the Lucas TB-Zinc at Walmart (online only for store pickup or delivery) or Amazon. Both currently charge $15.96 for 16 oz., enough for maybe 8 to 10 oil changes.

[Stogierob]

Valve stem caps...  i think that’s the reason for so much play after the rebuild.  I found two bits on the work table after the rebuild and now I think i know what they are.  Completely missed them in the diagrams during the rebuild.  At least it’s just the rocker covers and rockers that have to come off. 

Well, looks like i have something to do tomorrow after work...

Rob

[tooseevee]

Valve stem caps...  i think that’s the reason for so much play after the rebuild.  I found two bits on the work table after the rebuild and now I think i know what they are.  Completely missed them in the diagrams during the rebuild.  At least it’s just the rocker covers and rockers that have to come off. 

Well, looks like i have something to do tomorrow after work...

Rob

           Dontcha' just love those "Aha!" moments when it finally comes clear?  I had many of those in the early years of the saga of this '08 AVL of mine, it being my first "Britbike" since 1959.

            You've been through some real trials with yours and I wish you more good luck.

[Paul W]

Hopefully you have found the problem lying on the bench! 🔩

Why lash caps are part of the design in the first place (rather than the alternative of just making the valve stems slightly longer and hardening them) is open to discussion. I suspect this is more tradition than actual engineering requirement! I was surprised to find them on my 350; I’ve worked on many different engines over fifty years and this was a first for me.

[cyrusb]

Maybe they could be needed if the valve is made out of stainless which is limited in heat treatment. It is almost like the shim and bucket method without the shim. But hardly needed on an engine that would be right at home mounted to a rototiller. The caps, wiggling piston oil pumps, cork and quill bolt are all straight out of the British model engineering culture. I have been a big fan of it for 40 years and while these details work perfectly in modeling, in full scale sometimes, not so desirable...

[Paul W]

Maybe they could be needed if the valve is made out of stainless which is limited in heat treatment. It is almost like the shim and bucket method without the shim. But hardly needed on an engine that would be right at home mounted to a rototiller. The caps, wiggling piston oil pumps, cork and quill bolt are all straight out of the British model engineering culture. I have been a big fan of it for 40 years and while these details work perfectly in modeling, in full scale sometimes, not so desirable...

Yes, but stainless tends to be harder in any case. The original exhaust valve on my 350 iron barrel wasn't stainless (probably why it lasted only about 3,000 miles or less). There's absolutely no need for shims and buckets on an Enfield because there are tappet adjusters instead. Which are a lot easier to deal with in practice - as long as you haven't got any bits left over when you put the engine back together. 

[cyrusb]

No, stainless with its nickel content tends to be softer. How long does a stainless knife stay sharp? Even the hardest grade can't hold a candle to carbon steel. Yes, there is no need for shim and bucket, as I said. The reasons your original exhaust valve failed could be numerous. Valves not of stainless can and do last for very long service lives.