Custom COnnecting Rod for small 2 cycle engine

[turboglenn]

Here's a few snaps of some stuff i do on 1/5th scale RC car engines (basically highly modded weed eater engines)

THis is a +3 mm longer connecting rod to of course, change the rod ratio and allow the engine to make more power and rev out freely up top.. The common ones i do are +3 and +5 but there's not much use for the +5 IMO unless you have one of the custom machined reed case induction cases (like the one i have ) or ou are using nitrous to force feed the engine.. I am cutting these rods from 2 materials depending on requirements.. This one is 4140 Chro-Moly, and sometimes i'll make them from 440C SS (but that stuff EATS end mills even in anealed state)

I've made some aluminum ones for these4 engines but turning 21k + RPM at peak revs puts some major wear them pretty fast, thebearing holes will oval out since you can't leave enough material to prevent it given the size constraints yuou have to work within

Anyway, though tyou guys might get a kick out of this.. I still neet to thin out the middle, add oiling ports for the bearings and micropolish the last .0005" from each bearing journal to complete this..

In case you're wondering the price to do this is about 285 bucks to 300 if you ship me a complete engine and i tear it down and rebuild and port it for the longer rods.. it's really a lot of work since you have to split the crank, then re-pin ad align it (about 2 hours to do that alone) but man these engine RIP once you've got reed case induction and a loger rod.. eventhe piston port models now being offered commercially with long rods are making just about 7hp ( a tad over) on a 30.5cc engine.... (and mods since htis isn't even DSM related let me knwo if i still should mention the price) but i'm not here trying to sell these

The "finished" looking one is a factory rod that is 50mm from journal center to journal center.. this one i'm making is 53m at the same measurement

 

[BLINKY619]

looks good... i had a smaller rc and it dipped..

 

[Lofty]

Wow!

That's exceptionally impressive!

You must have a whole damn metal shop in your garage, CNC mills and all.


Oh, 3 axis, not 2.

 

[1990AWD]

Wow 7 hp from 30cc!

I'd love to see pics of a split crank; sounds interesting.

 

[turboglenn]

Wow!

That's exceptionally impressive!

You must have a whole damn metal shop in your garage, CNC mills and all.


Oh, 3 axis, not 2.

Thanks, I'll post up some pics of the completed engines, lightened and relieved pistons and everything else ere in a bit as well since people sound interested in seeing it.. And you're right i do have a metal shop (this is my daily grind and how i pay the bills, and it only took me till 28 years old to figure out it was what i wanted to do for a living and not just a hobby. I'll do anything from RC, to 4g63, motorcycle and any other type of engine or metal working anyone wants done.. the only down fall is i love doiung it so much i often find i've been in the shop 15 hours once it's too late to clean up to do anything else

I dont have any CNC (well I have the kit to bolt on to my mill but untill i get a 2nd one i'd prefer to keep my main one manual operated for now)

I get pretty into these engines.. I tried making a "simple porting video" and due to the attention to detail is was over 3 hours edited

Wow 7 hp from 30cc!

I'd love to see pics of a split crank; sounds interesting.

Thanks! ANd i'll post pics of this crank and the jig i use to re-align the lobes after i pin it back together.. I didn't know people here would be this interested or i'd have been showing ya'll this stuff for a couple years now

 

[Lofty]

Glen, I need a cage, some chassis welding, a full port and polish, and a shaved engine bay.

My car will show up to your house tommorrow on a trailer.

Oh yeah, I need a bracket for my sparco!


THANKS DUDE!




I wanna see this shop you've got going on sir!

 

[turboglenn]

Lofty... just make sure to drop the keys in the small opening in the driver window of my eclipse, she'll be ready in about 2 maybe 3 weeks

The shop isn't much right now. I had to leave my retail space after the divorce cause she got 51% of everything i had cause that's how much of the bubiuness was in her name. RIght now it's all stuffed in storage and my garage, but i'm good with what ihave.. and have conserved sapce well., My mill is a benchtop model and under it with tarps over top of them i have my MIG, TIG, Plasma cutter, then the lathe is on the right of the mill on i'ts own stand wher ei've also got grinders, buffing wheels, oxy/acetaline torch etc.. i'll get ya some pics here in a bit.. I'm still running back and forth machinhing and posting

 

[Lofty]

I'm still running back and forth machinhing and posting

If you looked up MAN, this would be an example.

 

[turboglenn]

here's variouse pics.. feel free to browse the thousands of pics on my photobucket account as well..there's only one private folder becuause they contain instructions on installing and tuning a custom 1-2 autshift transmission i make for these cars too and i'm working to keep the china clone-a-part guys out of my pocket

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drag bike i've built and sponsor with labor/parts

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car tire adaptwd to it here

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here;'s a finished rod prior to knife edging it i run in one of my engines (27.2 cc)

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assembled with long rod and lightened and windowed piston to match the 2 new transfer ports i machine into the cylinders

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here's the first one i made before the rod was finished, shows a seperated crank

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some shop pics

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]
here's an engine i cut the top off of and made a removable head that looks like a revolver cylinder

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cylinder that's been modded to use on a case reed inducted set of cases..see the 2 new transfers (this one is old my work is MUCH cleaner now

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the cars these go in// i made the expansion chamber by hand forming 18 gauge sheet metal

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[turboglenn]

bracket for lighting my camcorder

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long rod engine assembled

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I even made this vice from scratch

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Lofty, just caught yoru last post.. ,,,thanks!

 

[Lofty]

Wow. Incredible!

Do you make any 4g63 specific parts?

 

[turboglenn]

Yea, i make FWD lowered battery trays, saturn alternator brackets, and a bunch of stuff that is univeral for cars, there's things like hood prop latches and so much more that i can't even think of i've done, but i haven't done any "production runs" of much stuff at all for the mitsubishi.. Looking at my car's engine bay, you can see that i've done everything in it as well.. basiclaly if you can think it up and it's within my machinieroes capabilities i'll do it and make some nice parts

A few of my other "tools"

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and here'smy "shop" as a whole (compressor is single stage 220v 60 gallon unit behind where im taking picture from,

 

[1gcrazy]

Wow. Call me Hulk, I'm envious...

 

[turboglenn]

WELl, i was gonna throw some video up of the long rod engine i hav compared to the same engine witha standard rod ratio. BUT carb issues stopped me from filming my current LR engine.. But when i get mycarb sorted i'll toss some up, the workd record sand top speed is like 73+ mph and the car pulled a wheely in it's very top RPM at the point of like 68mph according to the radar gun being filmed

i'll get some more up on this current build when i finish shaping the rod (it's about 85% done now)

 

[phunny]

Wow. More pls

 

[turboglenn]

well, i will get some more up very soon, the rod is finished and i'm spending a lot of time trueing the crankshaft to with in .0002" (each lobe in relation to each other/center) since the crank is a pressed affair, having the lobes out of alignment will kill bearings which cause case seals to leak and on a 2 smoker that's about one of the worst things you have have happen becuuse those seals are what makes sure the intake and transfer proceses are done in the most efficient manner

Here's a couple update pics of the rod in this latest build attached to the machined out piston (lightened inside and relieved at the top to prevent lean siezing on an aircooled engine )


the notches in the bearing journals of the rod are for oiling access, this is the way the OEM rods are oied and i've stuck with it eventhough i would like to do some holes on one here soon.. (i just decided to give another aluminum alloy a go and do limited life aluminum long rods )

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more to fgollow this weekend

 

[floader]

Do you RC guys weld the pins on the cranks? On the 2 and 3 cylinder sled motors we build we have problems with crank picking up runout after a while.

 

[turboglenn]

Do you RC guys weld the pins on the cranks? On the 2 and 3 cylinder sled motors we build we have problems with crank picking up runout after a while.

ON really high compression engines it's common for them to come out of alignment during pull starting, also really high HP ones can twist on their own from on-off-on throttle situations on good traction.. I wil usually take the TIG and jopin the pin to the outter lobes once i'm happy with the cranks trueness and assembly al arround.. of course keeping it inline to the .0002 while welding it is a B(*&h but ya lear how to counteract one warp with antoher after a while

 

[Ravenous]

Would you mind sharing the models of you lathe and mill? I have a big garage but I need to keep space consolidation in mind and the scale of your tools are perfect.

 

[turboglenn]

The mill is a Grizzly G0463 (a.k.a the Sieg X3 mill) Which is a very capable mill for it's size and i love it, along witha decent array of tooling i couldn't really ask for much more in my space limitations.

And the lathe is just an old harbor frieght 3-in-1 multi tool that is so limited in milling it's nothing more than a lathe with a drill press, the tick marks on the the dials suck as they aren't to any standard measurement so other than it's size of being a 14 x 21 material handling it's somethiong that about any decent lathe could match up to or outperform.

The mill on the other hand is very nice for an import model, and has a very nice rotary table (yausa 8") and all tick marks are graduated to .001 on the x and y and to .0005 on the Z and the backlash is very controlable with an average of about .003 (i cna make it tighter but at the cost of increased wear o0n the acme screws)

Mainly what it comes down to is the ability to tune the machines, keep them in tolorance and user skill.. the mill is a common model for CNC conversion but most times you lose all manual operation on CNC conversions and i like hand milling. Being disabled these machines are my living (most won't guess me to be disabled but really i can't stand for much more than 30 minutes without agonizing pain and live on pain killers awaiting the many siurgeries i've had and still have to come - had my left leg operated on 3 times to be able to use it and need 3 operations on my back yet and one on my right knee in order to be "able" but i will still technically be disabled by medical standards.. but these machines keep me going to where i don't draw any money off the tax payers and make my bills pretty much on time every month, so i love em no matter how some may look at them )

 

[Ravenous]

Thanks for sharing the info, it is very much appreciated. I have looked at the Sieg mill a few times now and will eventually figure out a way to talk the little lady into it or have a big enough month that the extra money won't be missed (perk of commission based job, as long as the bills are payed and the honey dos are done then I get to do with the extra as I wish.) I keep waiting for an atlas lathe that needs restoration to come across craigslist to take care of my turning needs but until then I will keep watching these threads, I love to see what people do with a little ingenuity.

 

[turboglenn]

Yea, an Atlas is a classic piece of tooling that performs awesome. For as old as they are some people that don't know any better sell them cheap at estate sales and such and you can often pick them up for 4-600 bucks with tooling and all.

Other than that i've learned that grizzly tools does carry a good line of equipment, and with the bill me later option through paypal or whatever you can get it for no payments and no interest for 6 months. Thatt's how i got mine, then used it to pay it's self off. Bein in my situation my tools are my living and the mill has been one of the most valuable in my collection, along with the TIG i bought back when i was still working construction I never have a shortage of things to do, and honestly have to turn quite a bit of crap work away now days