More power with profilometer

[67RS502]

What kind of power are you guys seeing from using a profilometer and
the correct hone? A friend who builds sprint car motors has been using
one and tells me they have seen 15-20hp more with the better bore finish.
Anyone have any dyno or track testing to speak of?

From what I understand you can have a bore finish with the peaks removed,
while leaving the valleys, which hold oil and keep the cylinders lubed, thus
making a bit more power. Sounds like less friction and better seal, good
deal all around.

Thanks
Rafel

[Alan1966]

I'm sure everyone has a hundred different opinions on this, but what I see is that you want a plateau finish smooth enough to where the rings receive very little wear in not having to knock off the peaks. Also you don't want to have the valleys too deep because this could create leak paths for combustion gasses to pass the rings.
An excellant rule of thumb for racing applications is:
RPK 5-15
RK 15-30
RVK 15-30
Ra is just an average and any small imperfection or scratch will skew the number, and make you think it's rougher than it really is. The RK numbers are most important.

[Wolfplace]

Hi Rafel,

This has been pretty standard fare for a number of years now.
What we do is finish to size with 280 & hit it a few strokes with 400 to "knock off the hi spots,,,"
The RA numbers are normally in the low teens but as was mentioned RA is an average so if you get a goofy number that doesn't make sense you want to check a few other places.
If you hit any kind of pocket or scratch it skews them.
The true RA finish in my opinion is normally the lower numbers you find.

[bill jones]

-since the price of profilometers are something like $1500 to $1800 most small shops like myself are pretty reluctant to buy one.
-But I'm still wanting to improve certain areas like the head and deck surfaces specifically making them smoother for the multi layer steel gaskets.
-So I decided to try something a little different, relatively cheap---under $200---and it turned out fairly interesting.
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-I have several dial indicators that read out in ten thousandths of an inch so I made up a simple teflon block about 3/4" thick out of a piece of 2" diameter round bar stock and reamed a hole to allow a slight press fit of the dial indicator stem into the teflon to where the indicator stem just barely protrudes out the bottom about .010".
-I can slide this across the machined lines (90 degrees) of a milled surface and you can SEE the needle vibrate.
-then when you run the along the length of the machined lines the needle is way more steady.
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-So I have been able to make adjustments in my milling procedures that I can witness the differences in needle vibration and this easily shows me when I'm finding the smooth surfaces.
-It only takes running this tool across a few surfaces to be able to SEE the real differences of the needle jitters.
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-I came across this idea when checking a set of NEW Edelbrock FE Ford valves that had come in an assembled set of heads.
-I use this ten thou reading indicator on my valve face run out gauge and I was seeing the needle jitter like I'd never seen before---but the runout of the valve face was actually less than .0040" total indicated runout.
-So I lightly ground the face of the valve and double checked the face again and the indicator needle jitters were 100% gone.
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-I took one the jittery valves before I refaced it and lightly lapped it to a seat in the head and you could SEE the marks that were making the needle jitter---yet refacing the valve face just .0004" totally removed the jittery surface.
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-Cost of tenth reading indicators is between about $140 and $190 and the slide block could be made from a piece of wood or plastic or aluminum or whatever as long as the bottom is flat sanded smooth.
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-It would be neat to have one of you guys with a profilometer do this idea and tell us how the jitters relate to "R" numbers.

[OldSStroker]

Bill,

Check out the page linked here: Try P/N 06558019.

http://www1.mscdirect.com/CGI/NNPDFF?PM ... T4TP=*LTIP

It might be just what you are looking for. There are a number of other comparator plates llisted for specific propcesses.

Also if you have sample surfaces you want checked, I'll do it with our Pocket Surf. PM me.