Thread: Technical Repository

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Hello Bill,
I was reading your "respect" sticky and have a suggestion.
I think sometimes that the regular fellows on this or any other forum get a little tired and disgusted with answering the same questions over and over. I understand that the newbies don't know much, just like ALL of us didn't know much at one time, but it does get old with the same questions over and over. On another forum, there is a....let's call it a "Technical Repository" that gets referred to quite often. We don't have such an animal here on CHR, but I feel that we should. When a fellow asks how to adjust the valves on a SBC, I just go to the repository, copy and paste the answer on the thread and we're done. Over there, I have posted or edited 260 articles. I have gone to that particular repository and posted answers on THIS forum. Whether or not I should have isn't the pivotal question in my mind. The question is, was the newbies question answered properly and in depth so that he/she could understand it, or did I just ignore it because I shouldn't use stuff from another forum? What say you? Start a Technical Repository or no?

Tech, what if they dont pay attention and ask the question again or ignore your advice....can we send them a "technical suppository"? Some appear to not know how to use Google or how to dial their component's tech line.

mike in tucson

HE! HE! HE! I know what your saying Tech; It does get annoying some times.
But to be perfectly honest I have forgotten stuff and had to go back and ask again because I could not remember the post or how exactly to to do something.
And just about everything I learn has been hammered in there at one time or another, so me reading it over a couple of times helps with the old memory.
I would not mind if you called it memory dump, as long as it is there for me to access or be able to read again.
Thats why some times I still post some of the easier stuff, in case there is someone on here that does not know how to do it.
I know all of the old timmers know the stuff but we have been getting alot of new young members on here.
I still like learning some old tricks the old timmers may have seen in the past that we may never learn because that particular car is pretty much extinct now.
Call it what ever you want, I'll still be here Tech. HE! HE! HE!

ok tech could you go over this one more time .well i will tell you i will not post on here much any more .some other engine guy can pick up the slack ... no big deal... there allways some guy waiting in the wings

Tech,

Sent a link to this thread over to Brent as he is the "man behind the curtain" when it comes to things like this.


Bill S

Originally Posted by robot

can we send them a "technical suppository"?

Thanks for the laugh Mike, but you're absolutely right, some of them don't have sense enough to come in out of the rain, as my Mom used to say.

Originally Posted by pat mccarthy

ok tech could you go over this one more time

OK Pat, but this time, pay attention.

This is an easy thing to do. Send me links to the posts or the threads which you want to refer to and I'll add them to the "supository".

Seriously though, just give me the links or otherwise write new ones and send them to me and we can build the database of tech articles.

Sounds Like a good Idea!!! Easy access works for me.
Kurt

Originally Posted by Brent Mills

This is an easy thing to do. Send me links to the posts or the threads which you want to refer to and I'll add them to the "supository".

Seriously though, just give me the links or otherwise write new ones and send them to me and we can build the database of tech articles.

Most of techinspector1's posts or even pat mccarthy post's are examples. Just look at those that are in the Engine Talk area.

Originally Posted by Brent Mills

just give me the links or otherwise write new ones and send them to me and we can build the database of tech articles.

Send to you how? Is there still a 1000 character limit on PM?

How about just post them here.

OK, the way I see it, each technical entry will have to be cross-referenced with all words that are in the heading. Otherwise, you'll end up with hundreds or thousands of technical articles and no way to find the one you're looking for. This has always made me nuts with indexes, they only index one word of the title and it may not be a word that you would normally think of, so you miss the whole thing and have to spend time searching through all the pages to find whatever it is that you're looking for. Here is a for-instance. I wrote and article for a poster explaining how to determine static compression ratio using domed pistons. To my way of thinking, this article should be referenced.....

Compression ratio, static, using domed pistons, see static compression ratio, domed pistons (this reference should be under "C", alpahbetically)
Ratio, static compression, using domed pistons, see static compression ratio, domed pistons (this reference should be under "R", alphabetically)
Domed pistons, static compression ratio, see static compression ratio, domed pistons (this reference should be under "D", alphabetically)
Pistons, domed, static compression ratio, see static compression ratio, domed pistons (this reference should be under "P", alphabetically)

...................starting here with the article.....................

Static compression ratio, domed pistons, how to figure the math.
We'll use a 454 Big Block Chevy for this explanation. Let's say we're using the stock bore and stroke of 4.250" and 4.000" and production cast iron heads with 122cc chambers. The pistons are down in the bore 0.025" (piston deck height) and have a dome volume of 28.7 cc's (get this info from the piston mfg or figure the dome volume yourself: See Determining Piston Dome Volume). To figure static compression ratio, you need 5 different values...

1. cylinder volume in cc's
2. combustion chamber volume in cc's
3. piston crown volume in cc's (+ or - or flat with eyebrows)
4. piston deck height volume in cc's (volume above the piston crown up to level with the block deck with the piston at TDC)
5. head gasket volume in cc's

Let's take these one by one so that you and others will know how to figure SCR with a domed piston....

1. We know that the bore is 4.250" and the stroke is 4.000", so we multiply (.7854 times 4.250" times 4.250" times 4.000" times 16.387) and find that there are 929.88 cc's in the cylinder.

2. Anyone building a motor should use a burette and colored alcohol to "pour" the chambers and determine the exact volume in each and every chamber (yes, they differ one to the other, but can be equalized prior to assembly), but I doubt that many of you fellows do that. These heads are advertised at around 119cc's, but production heads will usually pour a little bigger, so let's call them 122 for this exercise.

3. OK, we'll do a little play acting here. We will visualize taking a sharp instrument and slicing the dome off the piston, leaving only a flat plane crown with no eyebrows. So, here we are holding a lump of aluminum that displaces 28.7 cc's. We are now going to jam that lump up into the combustion chamber to reduce the chamber volume to 93.3 cc's. This will result in a piston crown value of zero.

4. We have no idea what the piston deck height is on this motor, but let's just use a theoretical value of 0.025". So, we have a bore of 4.250" and the piston is 0.025" in the hole at TDC. Remember, the piston is now a flat-top, so we will simply multiply (.7854 X 4.250" X 4.250" X 0.025" X 16.387) and find 5.81 cc's.

5. I'm going to assume that the decks of the block and heads are flat enough to use a Mr. Gasket shim head gasket, #1131, 4.370" X 0.020". This will put our squish at 0.045". Again, figuring cc's just like anything else that's round and has a thickness......(.7854 X 4.370" X 4.370" X 0.020" X 16.387) and find 4.92 cc's in the head gasket.

Now, we add all our values together....
929.88 + 93.3 + 0 + 5.81 + 4.92 and find a total volume of 1033.91 cc's.

Now, we will drop out the cylinder volume and add the other 4 values together....
93.3 + 0 + 5.81 + 4.92 and find a compressed volume of 104.03 cc's.

Now, we will divide the larger volume by the smaller volume (1033.91 / 104.03) and find 9.94:1 static compression ratio.

Nice! Here's the link. http://www.clubhotrod.com/content/se...l-library.html You'll see a link to the CHR Technical Library on the front page.