Pop Top Tom's Rebuild Thread <updated 10-17

[Westy78]

But the valve geometry has me worried a tad!

You've read this yeah?

http://forums.aircooledtechnology.com/s ... d.php?t=25

[Amskeptic]

Is there an advantage to using the feeler blade, in this application, over the dial indicator?

I am not talking about the feeler blade and all that junk bolted up to the outside of the case.

I am talking about the method where you set the end-play while the case is still apart using a feeler blade between the crankshaft and the #1 main bearing. This method guarantees you that any imperceptable movement of the bearing in the saddle does not inadvertently become part of your reading. It is a method I prefer when putting together an old engine . . . like my old one.
Colin

[poptop tom]

But the valve geometry has me worried a tad!

You've read this yeah?

http://forums.aircooledtechnology.com/s ... d.php?t=25

I have it printed out right here! Certainly a help!

I am not talking about the feeler blade and all that junk bolted up to the outside of the case.

I am talking about the method where you set the end-play while the case is still apart using a feeler blade between the crankshaft and the #1 main bearing. This method guarantees you that any imperceptable movement of the bearing in the saddle does not inadvertently become part of your reading. It is a method I prefer when putting together an old engine . . . like my old one.
Colin

Colin,

I did not do the feeler blade.

[Amskeptic]

I have it printed out right here! Certainly a help!

Geeze, I think I can make it a little easier than that.

Your rocker arms describe an arc as they open a valve. Let's say at the beginning of the opening event that the adjusting screw is pushing "up" sideways on the valve stem. Midway, the screw is directly pushing the valve stem. At the later stage of opening the valve, the adjusting screw is pushing "down" sideways against the valve stem. This causes wear of the valve guide. We want the arc to be at the middle to divide the "up" wear and the "down" wear of the valve guide equally. Improper geometry will cause rapid wear primarily against one of the two possibilities above, shortening the lifespan of the guide.

Directions To Come . . .

[poptop tom]

I have it printed out right here! Certainly a help!

Geeze, I think I can make it a little easier than that.

Your rocker arms describe an arc as they open a valve. Let's say at the beginning of the opening event that the adjusting screw is pushing "up" sideways on the valve stem. Midway, the screw is directly pushing the valve stem. At the later stage of opening the valve, the adjusting screw is pushing "down" sideways against the valve stem. This causes wear of the valve guide. We want the arc to be at the middle to divide the "up" wear and the "down" wear of the valve guide equally. Improper geometry will cause rapid wear primarily against one of the two possibilities above, shortening the lifespan of the guide.

Directions To Come . . .

Easier than that would be wonderful, Colin! Some it still seems foreign to me.

Minor setback this a.m. Need to order some .040" cylinder shims to get my deck height around .050". I only have .020" and .090" shims on hand. That sucks. Was hoping to have the P & C's, and cylinders toqued on today so I could start valve geometry first thing next monday.

[poptop tom]

Well, another setback.

You would think SOMEONE out there would sell cylinder shims.

And no, to think these right here, that I had 2nd day aired to me and arrived last night, might be the ones........of course not. They are shims for between the head and cylinder, not cylinder and case.
http://www.cbperformance.com/catalog.asp?ProductID=126

I badly need .040" shims to get my deck height to .055". All the resources I've tried have NOTHING.

Any help out there?

I feel like throwing a wrench.

[dtrumbo]

Does this help?

http://www.aircooled.net/new-bin/viewpr ... 19&cartid=

John specifically says these go between the cylinder and case for adjusting deck height (he even offers some tips and tricks in the part description). The price if for a full set of four which seems even cheaper than CB. I've had good experiences with them. They'll probably take them back and refund your purchase price, but you'll likely be on the hook for shipping both ways.

Soldier-on, Tom!

[poptop tom]

That may be the ticket, Dick! Thanks! I remember seeing those, but the info in the description had me nervous - burrs, different sizes, etc. Then I found what I thought I needed at cb perf. ........and well, you know how that worked out.

I'll call John this morning and see if he can help me out.

Tom

[spiffy]

I believe Rocky Jennings here in Walla2 could help you out as well. He can probably machine any size you want if he doens't have them on hand.

[poptop tom]

I believe Rocky Jennings here in Walla2 could help you out as well. He can probably machine any size you want if he doens't have them on hand.

Thanks spiff! I have a call in to John at ac.net. He should be in shortly!

[Oregon72]

This may have been mentioned already, Tom.
You've made sure your barrel fins don't interfere with the head. Right???This is important... Everybody says to not use head gaskets, but there are circumstances which allow you no other choice but to use em' (at least without the trouble of expensive machine work to your barrels). In order to determine whether or not you can elimate them, you need to make sure your heads weren't flycut too deep. There should be a little bit of space between the cylinder and the head so you know the barrel sealing surface is the part that is contacting the head for proper sealing not the fins. If you don't have a gap, you are then forced to use the cylinder to head gasket otherwise you will have a horrible compression leak. If your heads were not flycut too deep, you are in luck and can then eliminate the cylinder to head gasket and go to work solely with your base shims (case to barrel) to get your proper deck ht.

That's probably not a great explanation, but hopefully it makes sense.

[poptop tom]

This may have been mentioned already, Tom.
You've made sure your barrel fins don't interfere with the head. Right???This is important... Everybody says to not use head gaskets, but there are circumstances which allow you no other choice but to use em' (at least without the trouble of expensive machine work to your barrels). In order to determine whether or not you can elimate them, you need to make sure your heads weren't flycut too deep. There should be a little bit of space between the cylinder and the head so you know the barrel sealing surface is the part that is contacting the head for proper sealing not the fins. If you don't have a gap, you are then forced to use the cylinder to head gasket otherwise you will have a horrible compression leak. If your heads were not flycut too deep, you are in luck and can then eliminate the cylinder to head gasket and go to work solely with your base shims (case to barrel) to get your proper deck ht.

That's probably not a great explanation, but hopefully it makes sense.

That's a great explanation, and something I hadn't totally checked out. I will tomorrow. I did finally find the base shims from Cip1. Two-three day air delivery should get them to me soon. In the meantime, I slap my .020" shims on, P & C's on one side, and will mock up the cylinder head on there and check the clearance. Adrian, at Headflowmasters, did the heads, and the P & C's are Mahle 94 mm. Height measurements are all equal on the cylinders.
Thanks for the heads up!

[Oregon72]

You should be able to check your clearance on the bench. Just set your cylinder down in the head and look for the gap. Mine had no gap, so I was forced to use the headgaskets

[poptop tom]

I gotta tell ya, this soooooo damn frustrating.

Order from CIP1, what I was told by the guy on the phone, the correct .040" shims (EMPI) for my deck height. 94 mm.

Get them yesterday afternoon (another 2-3 day express shipping deal).
Open the package, and they look like the ones I special ordered from CB Performance. They have the same four indentations for the studs.

I didnt think the deck height shims should have these. The .020" ones I originally bought from Jake weren't like this.

So....I have my heads at home with me (bus is at work) to clean them up with hot soap and water. Open the new shim package, try to fit a shim at the cylinder head base, and it won't fit!

I'm thinking....this is good news. Although I'm leery about those indents.

Go to fit a shim over my cylinder base a few minutes ago, so I can recheck deck height again, and they don't even fit over the damn barrel of the cylinder!

WTF?

I'm calling Jake's place. And if no luck with them, I'll call HeadflowMasters.

This sucks.

[Ryno]

Hey Tom!....FWIW....I got my shims from rimco, I think they make them right there. Great outfit to deal with.

http://rimcovw.com/services/