1967brutus

Finally saw the vid with sound (my workstation doesn't have speakers and subtitles don't help much ) and I have to say, that engine runs like a champ!

Raleighcopter

they do.

1967brutus

I tried telling everyone... I really tried...

John_M_

So now you know what to do, make a generic carb throttle body available, with venturi and thermal insulator inserts for the various displacement engines... who knows the hobby engine industry maybe watching

1967brutus

Still too many variables in carb attachments to the engine and such for me to make that viable.
Maybe if I had my own CNC equipment and a CAD/CAM library containing every engine coming on my path, but even then....

Raleighcopter

Just start with a suitable ft160 tbi carb and go from there. 😁😁😁

cmulder

There is no absolute requirement that a carburator body has to be made from metal.
The perry carburators for example have a plastic body (nylon?)
It should be possble to 3d print a body with the hole for the barrel undersized and then drill that for the correct clearance of the barrel.
No cnc router needed just a drill press.

Glowgeek

I've only had one engine with a Perry carb. As I recall it had a plastic carb body with a brass liner.

Cat 1

My Feedback: (1)

Some of us listened - And some of us have "saved" so many we wonder if we have an addiction problem!!! I have tried to keep all of mine piled together on one shelf as a visual reminder to stop this madness, but more keep mysteriously arriving..

Stand By!!!

I agree - unfortunately I don't have the right Machine or process for this - Thinking a resin printer with a carefully selected material would be in order - Might try Delrin for the body of the next "machined one" though.

I have a few Perry's here and I don't think any have a brass liner (will check) - I do recall this though.

Cat 1

My Feedback: (1)

Sooooo... Remember that engine problem I mentioned earlier - A quick search turned up 5 Perry's... Here is the skinny on two comparable ones. One is off a "converted" OS 61FSR (smaller bore) and one off a K&B 61 Pumped (larger bore) - both are correct for the engines they were on.

The smaller bore carb appears newer and differs in an aluminum outlet tube and an aluminium (vs brass) metering disk. I think the aluminum neck is "molded" in as the body is formed. The plastic is hard - very much like Acetal or Delrin. - could be nylon but a very hard version. The barrels are brass but run straight in the plastic bore on all I have here. Its a neat and simple design but I haven't run one for years so I can't comment on how well they run or adjust as I don't have much time with one. Some guys swore by them.

Here is a neat finding - Both bodies are the same size - but the bore in one is +9mm and the other one is 7mm - they take care of this by a simple chamfer which makes the bore transition oval and it does not really match up with the body bore - I avoided doing this with my bore reduction as I thought it might cause issues but seeing how it works, I don think it would. On mine I pressed a bore reducer in and then spent time hand carving the transition with an x-acto to make the matchup work as I knew a "camfer bit" would make an oval...






Think I am going to try plastic on the next body -

1967brutus

Interesting development!

Glowgeek

No brass liner in a Perry carb. Thanks.

My memory serves me poorly, more so as time passes.

Cat 1

My Feedback: (1)

i have seen the plastic with a liner arrangement. But I can’t remember where. Maybe it wasn’t a perry as there were a few copies of the “plastic carb” floating around

Glowgeek

Thanks Chris, I feel vindicated........kind of.

Back to the shop to work on my current project.


Saito 200TI

Low time engine but arrived with a stripped out glow plug and improperly timed cams. The Timesert 1/4-32 thread repair kit arrived yesterday, $$$$$. Pretty excited about moving forward with this engine. Eventually I'll attempt to make custom exhaust from thin wall brass tubing. The Rcexl twin ignition arrived as well, just waiting for delivery of the sensor bracket and magnet ring from CH Ignitions to compete the gas conversion.

John_M_

I believe the metal sleeved plastic carbs were on some of the buggy slide carbs... I remember seeing posted somewhere a plastic carb with a sleeved throttle barrel bore... Perry claims their carb bodies are injection molded black reinforced nylon, and with proper clearances between the brass throttle barrel and plastic bore, should not show any wear, not with the oil content in the fuel.

Raleighcopter

new printer arrived and I got it assembled. Filament arrives tomorrow and the new extruder and bed leveling kit are in customs. Hope to be printing by the weekend.

Glowgeek

Nice Dave! Where is the green with envy emoticon?

Glowgeek

My 200TI glow plug thread repair did not go as planned. The hole had been previously repaired with a Timesert, or so I thought, but the Timesert 1/4-32 glow plug inserts I bought are too small in OD. The OD of the broken threads I removed from the hole are .312 OD, the Timeserts I purchased are .286 OD.

Timesert does make an insert called a "Bigsert" however they are not available online for 1/4-32. Not listed on the Timesert webpage either.

Is there another brand of insert that looks like, and locks in place just like a Timesert?

1967brutus

Bummer!

John_M_

So you choose the filament type, probably will be more versatile in the long run... looks like a decent printer.

John_M_

Make your own threaded insert from some brass rod...Drill and tap the 1/4-32 ID, then cut the OD threads with the appropriate thread Die... the only issue you'll be faced with is crowding the valve seats, but you can bias the oversize plug away from the valve seats... then just use red loc-tite on the brass threaded insert... you won't need it to be swaged in place like the time-serts.

John_M_

Looks like Big-Sert only makes a 1/4-28 oversized insert... Why they don't make a 1/4-32 is puzzling.

Glowgeek

Had thought of that John. The threads in the cylinder are already cut for 5/16-32. No dies available for that. The bore for that threading is already the max before valve seat interference/heat transfer becomes an issue. What I need at this point is to find the insert manufacturer the hole was drilled and tapped for, or have someone machine a custom insert. I don't have a metal lathe at my disposal.

As far as I've been able to research, Timesert is the only insert manufacturer that uses opposing matched threading for ID and OD. I.e. the same thread pitch for internal and external threads. Going to give them a call today. Maybe there is a Bigsert kit (1/4-32) that they can provide but don't advertise. Worth a try.

cmulder

Try www.prusa3d.com/page/prusaslicer_424/

Its is free and most likely already has the presets "profile" for your printer included.
Also
Depending on the type of filament best keep it in a sealed (ziplock) bag when you are not using it to keep it from absorbing humidety.
A glue stick like "pritt" is usefull as a base coat on your print bed in case the print does not stick well and also a protecting layer if it stick too well.
It cleans with water and soap if it build up to much.

This model is designed to confirm if your printer is working well or shows where adjustments are needed.
Benchy the boat

Enjoy

Raleighcopter

i've installed Cura slicer since that's what Cat1 is using and he's been helping/answering questions for me. i've got a roll of PLA and a roll of ASA coming today and should be printing a benchmark model today. i need to tighten the build platform because it has some play in it and the CR touch for bed leveling and direct extruder I ordered will be here in a few days hopefully.

it's a well built piece of kit and i'm trying to resist printing all sorts of upgrades for it like cable chains and whatnot.

i have a couple friends who also 3d print and they've been pointing me towards resources and giving advice, especially the advice to keep filament dry.