Notched my first piston "pics"

dmc919 · Jan 14, 2009

did it with a dremel and went as far down as the dished part to be safe. had .040 clearance and it's about .040 deep on the dished section. Haven't had a chance to clay it again, will do that tomorrow. I had the rest of the motor covered with a towel, metal shavings went everywhere. I'm going to oil the bit on the next piston to help with the shavings from flying everywhere. hopefully 1 down and 7 to go

View attachment 277763

bentley429 · Jan 14, 2009

2000xp8 · Jan 14, 2009

Why not use the notching tool?

Bullitt347 · Jan 14, 2009

While notching the piston the way you are will work...it will be impossible to make all of the pistons exactly the same. As a result you will end up with some different compression #'s from cylinder to cylinder, and not just because the static compression will vary slightly, but because you are going to change how the air flows past the intake valve when it opens. Without the above mentioned notching tool, flow #'s from port to port will be all over the place and compression will vary as well. Again while it will work, and maybe for your application it really does not matter, it is not optimal for achieving the best engine performance for the parts being used.

lang williams · Jan 14, 2009

i had to widen the relief cuts on mine for the shaved gtp heads an their larger intake valve. I did it the same way. i just marked them all the same an cut them with a carbon bit. i took a cartridge roll to smooth any high spots.

NIKwoaC · Jan 15, 2009

Bullitt347 said:
While notching the piston the way you are will work...it will be impossible to make all of the pistons exactly the same. As a result you will end up with some different compression #'s from cylinder to cylinder, and not just because the static compression will vary slightly, but because you are going to change how the air flows past the intake valve when it opens. Without the above mentioned notching tool, flow #'s from port to port will be all over the place and compression will vary as well. Again while it will work, and maybe for your application it really does not matter, it is not optimal for achieving the best engine performance for the parts being used.

I avoided flaming this idea last night, as it was my first reaction, but I was thinking about it this morning, and I had a thought.

First off, people hand-port intake manifolds and cylinder heads all the time. I would think that if there were a concern about inconsistent intake flow cylinder-to-cylinder, hand ported runners would have a more dramatic effect than would a valve clearance notch.

Second, I've seen professional engine builders smooth down sharp corners after notching a piston by hand with a Dremel or other rotary tool. I've also seen professional engine builders hog out the combustion chamber by hand to reduce the compression ratio for forced induction applications.

Is it the preferred process? Probably not. Will it work on a mildly built street motor? Probably. Actually, I imagine if you were careful to take out the same volume of material on each piston (by claying it), its probably a viable idea.

saleen9973 · Jan 15, 2009

I dont think we are talking about a race motor here guys. This will probably be fine for the street, all in all not optimal, but should work. Just make sure you smooth it good as not to get hot spots. Even try to use some water in the spot the material was in order to get each as close to the same as possible? I think buying the right tool would have been the best way but good luck and lewt us know how it works out for you.

Saleen8786 · Jan 15, 2009

damn,you got some brass ones doing that i'd be scared of messing up my pistons and have to build the whole damn block.

ls1beater4eva · Jan 15, 2009

doing this is not as bad as some people lead on to be , its actually rather easy you just have to have a little bit of paitence , i have done this a few times now and yes the tool makes it easier but hell not everybody has one.

capri debris · Jan 15, 2009

Have you considered that doing this by hand with the pistons in the engine may cause a balance issue? Aren't the pistons supposed to be all the same weight with an acceptable difference of like only 7 grams or something. 7 grams isn't much and doing the notching by hand and having no way of wieghing the pistons to see how much material is being removed doesn't seem like the best approach to me. I mean a small weight on a rotating tire and wheel assembly makes a big difference... now think about how fast the pistons are moving at 6000 rpm. A small unbalance between the pistons may set up a vibration that could crack the block at high rpms.

Brian@PAR · Jan 15, 2009

This is what you get when using the tool. This took about 45 minutes per bank once I got all set up.

white 89 GT · Jan 16, 2009

You know I have a set of stock 91 forged pistons still mounted on the rods you could have for the price shipping and $10. I would never try to do this by hand.

2000xp8 · Jan 16, 2009

Stop now, buy the tool.
When you are done, re-sell it.
This would appear to be the equivalent of me (electrician) using scissors instead of wire cutters.
Ya, it can be done, and it may work, but that still don't mean it's a good idea.

5spd GT · Jan 16, 2009

2000xp8 said:
Stop now, buy the tool.
When you are done, re-sell it.
This would appear to be the equivalent of me (electrician) using scissors instead of wire cutters.
Ya, it can be done, and it may work, but that still don't mean it's a good idea.

vadim · Jan 16, 2009

2000xp8 said:
Stop now, buy the tool.
When you are done, re-sell it.
This would appear to be the equivalent of me (electrician) using scissors instead of wire cutters.
Ya, it can be done, and it may work, but that still don't mean it's a good idea.

i'd take the guy up on the offer that has the pistons already with valve relieves. i wouldn't run that they way it is, even if it was a lawn mower. do it right the first time, saves having to do it right the second time and alot of grief. just my .02

Modular2v · Jan 16, 2009

Buy the 87-92 pistons, new rings, bearings and save yourself a headache.

88mouse · Jan 16, 2009

Me and ls1beater did the motor thats in my sig over two years ago. And have never had a problem. I Have solid mounts in the car with no vib's. at any speed or rpm.

dmc919 · Jan 16, 2009

got one set of pistons done and the head bolted down. should have it all put back together by sunday evening. the hardest part or the most "time comsuming" part is covering up the motor and making sure the metal shaving dont get in the piston rings. other than that it takes about 5min to notch with cutter tool and smooth out with stone. i'll let yall know if it works out good or bad.

1987stangman · Jan 17, 2009

Modular2v said:
Buy the 87-92 pistons, new rings, bearings and save yourself a headache.

I totally agree. But I don't know if I would used a set of used pistons from another motor in a different block even with new rings. Although I have built a couple motors with great success I'm not a master engine builder but it makes sense that the pistons (even the hard to kill forged slugs) have worn to the cyl they were in, esp. in high mileage Mustangs. It would almost be like putting the stamped number 2 rod and piston in the no. 6 cyl. by mistake when doing a basic overhaul. Just a though and if someone has done this please let me know the outcome because I have an old vic motor and a set of old forged slugs I could build for my sons LX 4 hitter.

Based on those pistons that looks like a non-HO motor. I am guessing he is nothing them to use a bigger cam?

dmc919 · Jan 17, 2009

you have to notch them to use e7 heads. the cam is a stock ho cam out of a 94 stang

Notched my first piston "pics"

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