61 replies to this topic

[Mike Collins]

3.273 pass 3.274 fails Scca has a zero tolerance approach too there rules

 

For SCCA Tech you get .5+/- off of the smallest measurement UNLESS what is being measures has an ABSOLUTE maximum/minimum....  So being out of round in cylinder bore is .006, you actually could be .011 and still be legal....  Nobody is cheating like that....  No gain...in fact you would have piston slap and poor fitting rings.  If I measured this bore, I would take multiple measurements looking for variance....  I might even measure multiple bores to see if you have a terrible machinist or a really old motor...

[Mike Collins]

I may have asked this before..

 

Has anyone writen/video, a manual of sorts for tech inspection for the volunteers ??

J~

Yes, the SMAC did an entire book with instructions and photos during the old compliance fee tech....  All of it is still relevant.  

[Bench Racer]

While watching them perform the test (With a contraption I am not familiar with), it became apparent to me that there were some suspect accuracy issues because of unsteady hands. I asked for another person to perform the test and WALLA! I was at 83MM? Or whatever was the exact spec.  The previous readings taken when I was at the drivers meeting were 85 and 86 (With some decimals

Mike, Sean, Jim and others made reference to this or another sort of through the spark plug hole cylinder bore measuring tool.

Can we improve on a given tool or concept a better tool. First we need to ask ourselves, what are we going to do with the measurement taken with this tool? I would suspect, it's a red or green flag tool. Red flag, the head comes off, green flag your good to go.

Within this address https://www.hyperrac...?product=80-700  you'll find a through the spark plug hole cylinder bore measuring tool. This tool maximum capability is 70 mm or 2 3/4 inch diameter approx. We need a 3 1/4 inch diameter tool which may be out there that I haven't found. As you can see the tool has a cost. Also found a similar tool with longer stems, don't know the diameter capacity. This tool is $100.00 more than the first tool.

Mike Collins, you seem to have had experience using a similar tool. Care to elaborate, manufacture name, good, bad,??? 

Tool use?

Improvements?

[Mike Collins]

They make a bigger version of that tool.  The problem is "tech" inspectors think that by using this tool they can actually measure bore....you can't....I can tell you with this tool if you have a standard bore, .010 over or more.  I cannot tell you with any certainty if you are slightly over....  I can use it to decide standard or over bore and I can set up the whistler to tell me all I really need to know...

[Bench Racer]

I can tell you with this tool if you have a standard bore, .010 over or more.  

 

I cannot tell you with any certainty if you are slightly over....

 

 I can use it to decide standard or over bore and I can set up the whistler to tell me all I really need to know...

Mike, from experience are you saying, this tool with a clutch micrometer you can not measure accurately to less than .010? If true what are the weakness of the bore tool, users capability?

Do we manufacture special pistons for this 10 over bore?

I'll bite on the Whisler telling you all you really need to know. Are you using the Wihstler backasswards by knowing that a measured to the edge engine will make "specific" volume/audiable sound that the Whistler will convert to a accecptable compression ratio number for a given engine? When the volume/audiable is up or down from that "specific" the compression ratio will be more or less. Have you ever DQ'ed anyone for bore over size based on a Whistler results? Has anyone ever been DQ"ed for over bore based on a Whistler results. Or is the Whistler bore results a red or green flag with reference to head off for further measurement or head on and go home.

Learning is good, correct.  

[Mike Collins]

The bore tool does not actually measure anything.  Its like opening an umbrella until it stops in the bore...closing it, taking back out through the spark plug hole, open it up the same amount and measure that....

 

Yes you can use the whistler as a go/no-go....if somebody were to overbore a motor and you whistled it at what it is supposed to be the reading would be way low...

[Bench Racer]

Mike or anyone, I suspect the measurement would have more accuracy if the measurement were made with the umbrella opened within in cylinder bore. Thoughts??? 

[Mike Collins]

Mike or anyone, I suspect the measurement would have more accuracy if the measurement were made with the umbrella opened within in cylinder bore. Thoughts??? 

tool doesn't work that way.  This particular tool has tons of variance.. you have to hold it PERFECTLY straight.  Just let the tool touch the edges of the bore...dont press them against the edge or the when you measure it, it will be larger...

[Bench Racer]

No one else wants to play.

My intent is to fab a similar/different tool without the knobs. The large diameter outside piece will have a pilot (no threads) fit in the threaded plug hole/bottoms out on plug mount surface and will have a soft rubber bushing that fits inside the recess in the valve cover to pilot the large outside diameter piece. Also the large diameter outside piece will protrude enough above the valve/head cover so there is length for finger slots 180* apart for extending and retracting the umbrella center rod. The top end of the large outside diameter piece's end will be flat/square with the world. The top end of the umbrella center rod will also be flat/square with the world. When the umbrella is open the umbrella center rod top end will be below the top end of the large diameter outside piece. Take a depth micrometer and measure from the top end of the large diameter outside piece to the top end of the umbrella center piece. One will calibrate this dimension end to end for a specific bore diameter and recalibrate as required through use of this tool. During debug/proving process, the umbrella levers will be improved as required to eliminate issues. Fabing a umbrella tool to this measuring process IMHJ will eliminate several current issues.

Your thoughts???  

[Johnny D]

No one else wants to play.

My intent is to fab a similar/different tool without the knobs. The large diameter outside piece will have a pilot (no threads) fit in the threaded plug hole/bottoms out on plug mount surface and will have a soft rubber bushing that fits inside the recess in the valve cover to pilot the large outside diameter piece. Also the large diameter outside piece will protrude enough above the valve/head cover so there is length for finger slots 180* apart for extending and retracting the umbrella center rod. The top end of the large outside diameter piece's end will be flat/square with the world. The top end of the umbrella center rod will also be flat/square with the world. When the umbrella is open the umbrella center rod top end will be below the top end of the large diameter outside piece. Take a depth micrometer and measure from the top end of the large diameter outside piece to the top end of the umbrella center piece. One will calibrate this dimension end to end for a specific bore diameter and recalibrate as required through use of this tool. During debug/proving process, the umbrella levers will be improved as required to eliminate issues. Fabing a umbrella tool to this measuring process IMHJ will eliminate several current issues.

Your thoughts???  

 

If I had my choice and the end result was the same, I'd go noninvasive with the whistler than the measurement route that appears to be sketchy.

J~

[Bench Racer]

If I had my choice and the end result was the same, I'd go noninvasive with the whistler than the measurement route that appears to be sketchy.

J~

The Whistler is also a go/no-go gauge, not an end result dimensional measurement. How many regions you know that have Whistlers at $2,300.00 per???

 

[Johnny D]

I've been whistled

 

Just saying if at all possible, work smart. Not hard, expensive, time consuming or complicated, especially with volunteers.

J~

[Chris70]

S.A.C. racing  bought one last year and it was more like 2.5 k. Our cam doctor plus was almost twice that.

And they are both just measuring tools.

And we wonder why the price of racing keeps going up.

Ademir

[davew]

Back in the "compliance team" days, part of our money was used to purchase tools (including a whistler) for every division. I have had cars whistled at Blackhawk, Road America, Sebring, Atlanta and NOLA in the last couple years.

 

Dave

[Johnny D]

SCCA's going on 70 years. Do they wind up in somebodies toolbox taken home?

Just asking.

J~

[Bench Racer]

Back in the "compliance team" days, part of our money was used to purchase tools (including a whistler) for every division. I have had cars whistled at Blackhawk, Road America, Sebring, Atlanta and NOLA in the last couple years.

 

Dave

And if one were to show above the compression ratio, what's the next step???

 

 

Johnny, I stated region, Dave stated division. While your adding to the thread do you have any valuable input to improving the bore measuring tool through the plug hole.

[Johnny D]

Bench, no, but that never stopped me from posting.

 

IMO, Bench, you're focusing on a tool to measure, (god bless) but maybe not looking at the whole picture or there's more than one way to skin a cat.

J~

[Bench Racer]

Bench, no, but that never stopped me from posting.

 

IMO, Bench, you're focusing on a tool to measure, (god bless) but maybe not looking at the whole picture or there's more than one way to skin a cat.

J~

My profile title kind of says the same thing as Different Ways to Skin a Cat, Different Strokes for Different Folks. If your engine ever blows a higher ratio than allowed, what's you next move???

On my engine, anything other than head off to measure is a go, no-go gauge. No-go and the head comes off.

[Johnny D]

 

Yes you can use the whistler as a go/no-go....if somebody were to overbore a motor and you whistled it at what it is supposed to be the reading would be way low...

 

Have you read this??

J~

[Bench Racer]

If your engine ever blows a higher ratio than allowed, what's you next move???

If you read this ^, you never answered.

Nuff of your  for me.