Maryak 10

[steamer]

Looking like a nice piston.

I assume you are going to go for the lap fit....?

cool

avagoodweekend yourself!....hope the choppers are better?

Dave

 

[Maryak]

Hi Dave,

Thanks for your concern about my chompers. I think it's going to be a long and involved saga.

Yes I am going for a lap fit. After the gudgeon is finished I intend to mate the piston and cylinder.

After a bit of thought I am now opting for a semi floating gudgeon with the pin locked to the conrod. It should save trying to machine circlip grooves in the piston and I need not have bushed the gudgeon end but hey this is experimental so why not ???

Best Regards
Bob

 

[Philjoe5]

Thanks again for keeping us updated on your progress Bob. Thm: I, like many others, find this build and your documentation enlightening.

Cheers,
Phil

 

[Maryak]

Phil,

Thanks for the kind words and continued support. :bow:

Best Regards
Bob

 

[Maryak]

Yesterday was a public holiday here for the Adelaide Cup so nothing on the model front.

Below is today's effort.

Parting off the gudgeon pin.

Tapping the conrod for the gudgeon pin locking screw.

The gudgeon pin in the locked position.

A mandrel to hold the piston for lapping

Bronze for the piston lap.

Lapping the piston.

A trial assembly.

 

[stevehuckss396]

Seeing the engine chucked in the vise next to the paint can made me realize how big this build is. This is no Cox .049.

Looking good!

 

[deere_x475guy]

Good eye Steve I didn't even notice that. Looking great Maryak and thats for the pics...

 

[kvom]

Newbie question on gudgeon (wrist) pins in general. Since you have a lock screw it is evident that as the piston moves the pin must oscillate in the side walls of the piston. Should I assume that the bronze of the piston acts as bushings?

On my smaller CO2 engine, the plan has the piston rods moving over a stationary gudgeon. I am wondering if there will be a problem with the piston rod walking sideways. If so, I imagine I could make some brass bushings to keep it in the center. Thoughts? FWIW the diameter of the pistons is 3/4". The wrist pin is 1/8" diameter rod (could be drill rod or brass).

 

[steamer]

Yes Steve makes a great point.......WHEN it starts Bob ;D.....make sure we don't end up calling you "fingers", as I assume your putting a prop on the front of that beast?

Knowing something of your past endevors....I have every reason to believe that won't happen....you've been around big stuff far to long to be careless now!

Dave

 

[Maryak]

Steve and the other Bob,

Thanks guys for your continued interest and support. :bow: :bow: Yep, bigger than Ben Hur. ;D

Newbie question on gudgeon (wrist) pins in general. Since you have a lock screw it is evident that as the piston moves the pin must oscillate in the side walls of the piston. Should I assume that the bronze of the piston acts as bushings?

On my smaller CO2 engine, the plan has the piston rods moving over a stationary gudgeon. I am wondering if there will be a problem with the piston rod walking sideways. If so, I imagine I could make some brass bushings to keep it in the center. Thoughts? FWIW the diameter of the pistons is 3/4". The wrist pin is 1/8" diameter rod (could be drill rod or brass).

Kvom,

1 Above, yes the gudgeon/wrist pin oscillates in the piston. In this case 316SS against t200 cast iron. I was originally aiming for a fully floating setup with circlips to prevent sideways movement of the pin. I settled for the above as being far easier to machine and secure. I need not have placed a bronze bush in the gudgeon/wrist pin end of the conrod with the method I ended up with.

2 Above, your mechanism is the 3rd option of those used for conrod oscillation. Maybe you could lock the pin with a screw from the underside of the piston. Maybe you could shorten the pin a little and fill the ends with soft solder. Last but not least, if your piston has rings one of the latest innovations, (12":1ft), is to put aluminium end caps on the pin which if it moves pushes the aluminium against the cylinder wall. Can't say I'm all that thrilled about the idea but it's out there working so there must be something to it.

And..... thanks for your support and Interest. :bow:

Yes Steve makes a great point.......WHEN it starts Bob ;D.....make sure we don't end up calling you "fingers", as I assume your putting a prop on the front of that beast?

Knowing something of your past endevors....I have every reason to believe that won't happen....you've been around big stuff far to long to be careless now!

Thanks Dave, :bow: I've broken a few on the way by dropping boiler doors on them, (just as well I'm not a concert violinist :), but I've managed to keep all my digits, (all 21 of them).

I think attempting to run this thing will be an outside job with a substantial mounting block and a couple of bloody great clamps.

Below is today's effort.

Some Aluminium for the cylinder head.

Reaming the centre hole for the compression screw plug.

Drilling for the head bolts.

Set up for machining the cooling fins.

Last but not least, I finally received my Xmas present from my daughter, (its' been on back order).

Now I will have to expend extra energy and impose self discipline to finish M10 before delving into gas engines and electrics.

 

[NickG]

Loving this project and now can't wait to see your next! :bow: I've always wanted to do a hit & miss engine. Only problem with this site is I'm always looking at everybody elses wonderful projects when I should be in the garage working on my own! ???

Nick

 

[Philjoe5]

Bob, to put this in perspective for me, what is the size of the screws that secure the cylinder block to the crankcase?

Cheers,
Phil

 

[Maryak]

Nick,

Don't say that ;D I'm having enough trouble containing myself as it is and it has only been 18 hours. :

Phil,

The bolts holding the cylinder to the head are 5/32" x 2 3/4" long - 6 off and the cylinder OD is 1 5/8".

Thanks to both you and Nick.

Best Regards
Bob

 

[Metal Mickey]

Bob great stuff. Have you chained down your container for when it starts? Also there is the problem of Australia actually moving towards New Zealand or are you facing towards the Philippines? You could give a whole new meaning to continental drift! :big: :big:

Good work though! :bow:

 

[steamer]

looking great Bob.....Need video of this beast running when the time comes.....

Make sure its LOUD AND PROUD!

Dave

 

[malcolmt]

Hi Bob
I just checked the stats on this thread before reading the latest update, 7400 views, you sure do capture many peoples interest when you are posting. I really enjoy catching up with your progress and the way you document everything with great pictures, very much appreciated. Keep up the great work.

Kind regards

Malcolm

 

[gjn]

We need notice ahead of the run though, Bob is down near the port, I'm about 20 miles away up in the hills - I want to be outside when he starts it up so I can hear it run........

 

[Maryak]

Thanks Guys, :bow: :bow: :bow: :bow:

Enjoyed all the comments :big: :big:

It's probably suffering from an overdesign problem as far as power/weight ratio is concerned. I intend to make a starter out of a rubber door stop which will fit my electric drill and keep me and my fingers a safe distance away - just in case it starts.

Nil report for yesterday as I spent some time watching the pour of our foundations, (see Mrs Maryaks Mansion).

Best Regards
Bob

 

[Maryak]

I managed to finish the Aluminium part of the cylinder head today.

Below is a photo of the head fitted to the assembly

New week coming up

Best Regards
Bob

 

[rleete]

I just checked the stats on this thread before reading the latest update, 7400 views, you sure do capture many peoples interest when you are posting. I really enjoy catching up with your progress and the way you document everything with great pictures, very much appreciated. Keep up the great work.

Exactly. While this kind of engine isn't necessarily my cup of tea, the excellent documentation of the build is. It's a self contained how-to. He could be making just about anything, and I'd still follow along.