piston notching?

90lxwhite · Dec 7, 2012

Do the pistons have to be removed to have them notched?

95Vert383AOD · Dec 7, 2012

No Isky sells a tool to do it in the block

srtthis · Dec 7, 2012

no but they should be since youll have material going everywhere.

ratio411 · Dec 7, 2012

I'm sure you could do it in the block, but you'll never get all the metal out of your engine if you do.

95Vert383AOD · Dec 7, 2012

Putting a towel in the lifter valley and using a vacuum/ compressed air to get crap out the combustion chamber. Maybe even a spare piston or tape to cover the gap between the piston and the cyl wall. Wiping down the combustion chamber and piston with thinner may also help remove any oil residue that may cause shavings to stick.

Just some ideas. I contemplated doing this myself if i upgrade trickflow twisted heads.

xracer22 · Dec 7, 2012

I have edelbrock rpm heads with 2.02 valves had to notch my pitons jus a little bit. I had my motor on a stand though and did mine with a dremel tool and worked out ok for me. But like i said i just turned the block over and when i was done sprayed the cylinders down with brake cleaner. I would think that if you did it one at a time you should be ok. Take each piston to the top do it and then take your piston back down and most of the shavings are going to be stuck to the walls of the cylinder. Blow out the shavings and wipe the cylinders clean. Keep everything else covered except for the piton your doing and just change your oil every 500 miles for like twice and you should be good

ratio411 · Dec 7, 2012

Wow!
You guys are braver than I am.

I would never take that chance.
There would be no way I could think of to keep at least some from getting between the piston and cylinder bore, down on top of the rings, and those have gaps as well as grooves and lands they sit on. Way too many crevices in a very critical area.

If the engine was out, and on a stand, inverted on that stand, and I had no other option, I might try it, and then only if I didn't care too much for that engine.

Gotta watch out for the harsh chemicals too when you talk about cleaning out the rings/pistons/cylinder walls.
You can unseat rings that have seated, or prevent new rings from seating properly, without proper lube, or exposure to harsh chemicals.
Just not worth the risk IMO.

jrichker · Dec 7, 2012

No one thought about the material being removed from the pistons affecting the engine balance?

When an engine is balanced, all the pistons are weighed and then machined to have the same weight within a very narrow range. Machining notches in pistons in place leaves you with no match for balancing and no way to know if you removed too much metal.

srtthis · Dec 7, 2012

jrichker said:
No one thought about the material being removed from the pistons affecting the engine balance?

When an engine is balanced, all the pistons are weighed and then machined to have the same weight within a very narrow range. Machining notches in pistons in place leaves you with no match for balancing and no way to know if you removed too much metal.

to a point your right but the little bit thats removed isnt going to affect the balance. we have had to notch pistons and even rods in the race car and have have worried about the balance. and we spin the bitch to 9200

gearheadboy · Dec 7, 2012

Balance was my first thought and if you get one little sliver of metal that falls between the top ring and top of piston that doesn't come out with compressed air, you can burn a valve quick. Keep in mind they balance engines in grams. An M&M is a gram.

jrichker · Dec 8, 2012

gearheadboy said:
Balance was my first thought and if you get one little sliver of metal that falls between the top ring and top of piston that doesn't come out with compressed air, you can burn a valve quick. Keep in mind they balance engines in grams. An M&M is a gram.

Google says: 49 grains of rice to a gram.

That makes it easy to relate to the amount of shavings you would need to generate when machining valve reliefs. It mounts up pretty quickly if you have to cut very much of the piston.

srtthis · Dec 8, 2012

You'd seriously screw up a piston if you had to take that much off.

65ShelbyClone · Dec 8, 2012

You have to take the head off to use the notching tool, right? Tape off everything but the area of the piston crown you're working on. That will keep chips from getting between the piston and cylinder or anywhere else.

2000xp8 · Dec 9, 2012

I did this with the isky tool for my extruded honed twisted wedges and custom cam.
I would NOT do it again.
It's time consuming and these guys are right about getting metal in the engine.

My suggestion, come up with a different solution.

7991LXnSHO · Dec 9, 2012

I remember when all the magazines that did this with pistons in the car and I wondered about the shavings. I would have filled the piston to cylinder gap with grease or duct tape (if it would stick after a cleanning) with all the other saftety steps I could think of. But scratches from shavings seem inevitable. I will specify bigger piston notches in my eventual rebuild.

NIKwoaC · Dec 10, 2012

I've talked to a few engine builders about this, and it's my understanding that the FACTORY balance tolerances are looser than you could ever get by just cutting valve notches. So the balance thing is not really a concern for the average grassroots hot rodder.

The method below If the one I'll use if I ever get into a situation where it would be necessary. It's time consuming for sure, but cheap and the masking tape is pretty fool-proof about not getting shavings into the engine.

http://www.fordmuscleforums.com/engine-articles/484906-another-technique-piston-notching.html

65ShelbyClone · Dec 10, 2012

NIKwoaC said:
http://www.fordmuscleforums.com/engine-articles/484906-another-technique-piston-notching.html

What they did with the masking tape going across all the bores is exactly what I was talking about. Not sure why everyone is afraid of this.

srtthis · Dec 10, 2012

65ShelbyClone said:
What they did with the masking tape going across all the bores is exactly what I was talking about. Not sure why everyone is afraid of this.

when i just painted my block i wiped my deck down with acetone and still couldnt get masking tape to stick to it. i had to tape up old head gaskets and lay them down to keep paint off the deck. so getting stuck to stick is an issue

65ShelbyClone · Dec 10, 2012

Acetone is a polar solvent like alcohol and doesn't cut petroleum oil very well. Nastier nonpolar solvents like MEK and toluene work far better. Even white gas would probably be suitable. I usually use brake parts cleaner if it's handy (which is often a mix of acetone, methanol, heptane, toluene, etc).

When I notched my pistons, I didn't put much tape on the block; I used a trash bag to cover everything, cut a hole in it to access the reliefs, and taped it mostly to the crown.

xracer22 · Dec 10, 2012

I understand the balance thing but didn't bother me enough to not do it. Plus i have seen pistons with so much carbon on them that there's got to be at least a gram of weight right there and it never hurt anything, maybe a Lil bit of performance but never killed a motor.

Idk but it worked for me and i put about two bottles of nitrous through my motor before i sold the kit and still runs strong! Also keep in mind that I was using a stock 88 block with stock forged slugs and the pistons had valve reliefs in them and all i did was took a little bit off the corner of the stock relief and didn't really go any deeper on the reliefs. Too each his own but there have been alot of other people who have did this as well with good results!!

piston notching?

90lxwhite

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