Valve to cylinder wall clearance,Shrouding Question?

[blwilliams]

Curtis, what happened to your tech page on your web site?
I guess I should have cut and pasted it a while back for easy reference

[e-tach]

What are the effects on static compression ratio when desrouding the valve via releiving the bores, as in the pics Wolfplace posted?

I like to work Wolfplace did in those photos, but with the removal of metal from that area of the block, should one use a sonic tester to verify you still have enough thickness?

[cboggs]

Curtis, what happened to your tech page on your web site?
I guess I should have cut and pasted it a while back for easy reference

Web guys, .. ;-(

Plus I haven't had time to write any new tech articles, .. I'd really like to though. Too busy running a shop and porting.

I want to do one on the design process for a cnc program, from casting
changes, hand models, computer models, CFD modeling, ..etc.
I think people would be surprised what goes into some designs, ..
not just throwing a hand port on the digitizer and making chips and a quick buck.

I also want to do a follow up to that story that ran in the Engine builder magazine, mostly about airspeed in engines and one that would compliment or accompany some of Darin M's writings.

What would you like to see on that page??

Curtis

[LilRacr]

Curtis,
How about a tech page to show all the tricks to needed velocities on different heads!

I hate figuring out the tricks on porting a different casting..... Curtis you and some others on here make it look asy at times!

-Bobby-

[mike123]

Curtis, I only found them for small blocks. Do they have them for BBC. thanks

[cboggs]

Curtis, I only found them for small blocks. Do they have them for BBC. thanks

Sorry it's Moroso, .. my bad,, .. part # 37900

Curtis

[mike123]

I know you are busy. Thanks for taking time to reply. Mike

[cboggs]

I know you are busy. Thanks for taking time to reply. Mike

glad to help, .. just sitting here programing the cnc, ..

Curtis

[Wolfplace]

What are the effects on static compression ratio when desrouding the valve via releiving the bores, as in the pics Wolfplace posted?

I like to work Wolfplace did in those photos, but with the removal of metal from that area of the block, should one use a sonic tester to verify you still have enough thickness?

=
It goes down
From memory the notch is in the 2-3cc range but I have not measured one for a long time so I could be wrong here
Pretty easy to check, just fill the notch with clay, remove the clay & drop it in a known amout of liquid

No you do not have to sonic check the notches, the block is solid at the deck

[e-tach]

What are the effects on static compression ratio when desrouding the valve via releiving the bores, as in the pics Wolfplace posted?

I like to work Wolfplace did in those photos, but with the removal of metal from that area of the block, should one use a sonic tester to verify you still have enough thickness?

=
It goes down
From memory the notch is in the 2-3cc range but I have not measured one for a long time so I could be wrong here
Pretty easy to check, just fill the notch with clay, remove the clay & drop it in a known amout of liquid

No you do not have to sonic check the notches, the block is solid at the deck

Thanks Wolfplace! I am also curious how you were able to make each notch close to the same - what did you use as a template - a head gasket located off the dowels?

[Wolfplace]

You are welcome

Correct, just put the gasket on & mark the deck, don't get in a hurry & it is pretty easy
They are not out to the gasket, I use the gasket to get the shape right
If you mark it with a fairly wide marking pen & leave the mark this is about the way I like them.

Only hard part is keeping the angle into the bore about the same but if you are careful they will come out pretty decent
I use a carbide burr & finish with a sanding roll

[Dodge Freak]

I recall a dye that can mark the metal. The type I seen was blue and you brush it all over the metal and once dry in a few mins, you could take a scribe and draw a line at the edge of the area you don't want to grind. You could make a templet or like use a coin for cylinder walls.

It was at a tool and die shop that I was at for a while before the jobs were lost to Mexico and overseas

The marker sounds good too but the dye would not come off until you washed it off with acohol, paint thinner, etc. You could wipe the metal with dry rag and the dye would stay put.

[Ron E]

I recall a dye that can mark the metal. The type I seen was blue and you brush it all over the metal and once dry in a few mins, you could take a scribe and draw a line at the edge of the area you don't want to grind. You could make a templet or like use a coin for cylinder walls.

It was at a tool and die shop that I was at for a while before the jobs were lost to Mexico and overseas

The marker sounds good too but the dye would not come off until you washed it off with acohol, paint thinner, etc. You could wipe the metal with dry rag and the dye would stay put.

Are you taling about machinist blue? A popular brand is Dyykem. Works just like you described.

[kirkwoodken]

While you are at the 'Dykem store", buy some of the Dykem marking pens in your favorite colors. That stuff will stay on forever. I have some pens that must be 20 years old, and still usable. Great product.

I've been buying my tooling related stuff here for 40 years:

http://www.scottspecialtools.com/

They also carry CMD#3 extreme pressure lube that I used to use for Chevy rocker arm break-in. Works good and no moly. Good on pushrod ends.

Good people to work with.

[Lazy JW]

Is there a clearance value beyond which the "eyebrow" in the cylinder would be of zero benefit? Or would it always be of some benefit? Seems like such an easy/cheap thing to do even if the gain is small.
Joe