mud99

iTrader: (6)

I've recently purchased a new piece of equipment for my milling machine which you can see below - it is an ER40 collet set, which appears to be the ideal piece of equipment to accurately pinch cylinder sleeves. The collets come in all different sizes, and were originally designed to hold milling bits with very high force.

This set up seems ideal for pinching, as it maintains the perfect round shape of the sleeve while being able to exert substantial pressure evenly around the sleeve. I've pinched three motors so far with no issues and very good compression/running characteristics afterwards.

I believe this is leaps and bounds better than a hose clamp or cheap sleeve resizer.

The only problem I have now, is that I don't have any engines that need to be pinched. I need more junk engines to practice on before I start working on high end engines.

So here's the deal. Mail me your old piston,sleeve, and connecting rod, along with $4 return shipping in a padded reusable envelope and i'll pinch it for you.

I can't guarantee the results, I don't know if your motor will run afterwards, I may turn your piston/sleeve into total junk, but chances are pretty high that you'll get back a pretty well resized sleeve. If you have a junk motor which you were going to toss anyway, might as well give it a shot.

The only thing I ask is that you don't send me a whole engine. Just the piston/sleeve/connecting rod. I don't want to have to take apart a bunch of engines for people.

It would also be helpful if you let me know how your engine runs afterwards, so I know i'm doing the right thing.

PM if you are interested and i'll send you over my address.

Mark

I have 10 sleeves on the way, so this offer is up! Everyone else will have to wait until I have completed this batch, I don't want to commit to too many at once!

egobuster1

iTrader: (5)

if i had a junk one id send it but i dont

shrabber

iTrader: (2)

Good idea keep up the good ideas your mind set is right for sucess

2fst2c

iTrader: (114)

Just curious, but wouldn't that pinch the entire sleeve instead of just the top part?

shrabber

iTrader: (2)

Top part would be your head I would assume and that would not matter.

pat7723

iTrader: (11)

i have a 4.6 thats beat.ill take it apart and send it to you.pm me your addy and everything

2fst2c

iTrader: (114)

The top part is usually the only part that gets pinched. Atleast that's what I've been told. Otherwise if you pinch the entire sleeve, it would be smaller around the port areas where they match the case.

mud99

iTrader: (6)

On every worn motor i've seen, the sleeve is already too worn starting from the top of the ports - hold the motor up to your ear with the glowplug in, and you can hear the blowby as soon as the piston passes the exhaust.

So I disagree, I believe you need to pinch more than just the top. After all, compression starts after all the ports close, and if you don't have a good fit until further up the sleeve, compression is going to be lost.

I'm not sure about the idea of the sleeve being 100% matched to the ports. The fit obviously has to be close, but I don't believe it would be affected by the small changes in compressing the sleeve. Also, since you can move piston/sleeve between engines, the fit can't be that precise, it isn't a matched set.

Mark

Davidka

iTrader: (86)

Modern sleeves are tapered. The taper begins (ideally) right above the ports and is tightest at the top. While sleeves may expand very slightly, the majority of compression loss comes from the aluminum piston wearing against the much harder chrome sleeve surface. The best possible pinch would re-size the taper.

Your tooling is the right thing for the job. I think another component would be slugs that are fitted a touch smaller than the inner diameter of the sleeve (these exist in a set, I forget their name) to guarantee that the sleeve is not over compressed.

K.Copeland

iTrader: (96)

You need to only pinch the top portion of the sleeve above the ports. Pinching the entire sleeve ( as these collets will do) will only cause it to fit loosely in the engine block ( and you need a tight fit there as well, I learned the hard way a few years back).

I made up some collars to fit various sleeves that when tightened within a collet ( I used a 5c in a manual Hardinge lathe) would only pinch the uppermost portion of the sleeve.

I also used gauge pins in different sizes to ensure that when I did pinch the sleeve, it would not get crushed. I mic'd the piston and got a + size gauge ( .0001 - . 0002 ) .


Have fun and good luck

mud99

iTrader: (6)

Davidka,
Since you seem to know a lot about this, how is the taper initially put into the sleeve? Is it milled out from the inside, or is it so slight that it is pinched in by the manufacturer? Is their an optimal taper on all engines, or is this secret engine voodoo?

I could mill a tapered plug but I don't think my tolerances would be good enough for it to be usable, i'm using a small sized mill with not too much weight to it. I'd also be worried about damaging the inside of the sleeve with a plug. It seems like if the plug is hard enough to prevent the sleeve from distorting it would be hard enough to damage the chrome coating.

I've noticed the er40 collets put somewhat more clamping force towards the tip, so i seem to have some flexibility with where I am applying the pinch, which is a nice coincidence. It's been a really simple set up to use. On the sleeve's i've done so far, I pinch the top until if starts to bind slightly, then move maybe 50% of the way to the top of the ports until I barely get to the point of not getting any blow-by.

It seems like the right process, and my engines seem to run like new, so I don't know what more to hope for.

Mark

2fst2c

iTrader: (114)

I hope it works out for you! I know there is a little science to it, but it sounds like you are on the right track. I was told what I said about pinching the top part above the ports only by my engine modder RB. Are you only looking for .21 sleeves or any size? I have a friend with a bunch of .18tz's that could all use some help. LMK and good luck with this.

Davidka

iTrader: (86)

Gauge pins are what I was thinking of. I really don't know how the pinch is established. I would have to assume that it's machined into the sleeve but that's a guess.

I would not worry about damaging the inside of the sleeve. It is hard chromed so if the process were to damage it then the pressure was way out of the ball park.

When you squeeze the sleeves you want to go just a little farther than the point where the compression comes back. There should be a little mechanical pinch at the top of the stroke. While the goal is to re-size it perfectly round, the piston might not be perfectly round anymore. Squeezing it so that it needs to be re-broken in helps to re-match the piston to the sleeve.

I'm not an expert on this but it sounds like you're on the right track.

mud99

iTrader: (6)

bump, I'll do four more, but then i'm going to be waiting to hear back results - this is a trial run.

Also, I can do any sized sleeve up to a 1" diameter, such as .15, .18, .21, .25 no problem.

I don't know if all .28 and .32 motors will fit, if the sleeve is too think and the bore is too wide, it's possible they may be too large for the tooling I have.

Make sure to include your return address inside the padded envelope.

Thanks,
Mark

mud99

iTrader: (6)

OFFER IS DONE, I HAVE 10 SLEEVES ON THE WAY.

No more will be accepted for now.

Thanks,
Mark