New machine (to mer) up and running

[AlfaGTA]

92 series Detroits are a little bit similar ... the liners extend out of the block a few thousandths, the bottom of the head is flat tho, and they use o-rings to seal the coolant. Seems like Pegaso took an okay idea and screwed it up

Some liner projection is common ...But almost always going against a flat surface.....Here the liners project into a counterbore that is over .500 deep......

Also notice how the valve seat is to the step that the liner seats on.....Gotta do the valve job (once the seats are installed) with a torque ring that emulates the liner....one at a time...
If not done the head will have over 30% leak down per cylinder.


Cheers Ross

 

[jariou]

Ross,

I was wondering initially if you had made that indicator setup yourself. But it sounds like this came with the machine.

Just one idea here. Couldn't you modify a standard co-ax indicator to get something more useful?

I must admit I do not understand all the details of the problems at hand. And my idea is just that, an idea, a direction in which to look to solve the problem differently perhaps.

Good luck. I enjoy all of your posts here.

Jacques

 

[AlfaGTA]

Jacques:
Your impression is correct in that the indicator arrangement is standard kit for this machine.
My thoughts on a "better" indicator setup would be to avoid having to rotate the indicator within the overarm bushing.
The problem there is that the indicator body is relatively long and any force applied to the indicator while rotating it influences the reading.....

My solution would be to make a housing that fit the overarm bushing snugly.....and have that housing carry a pair of ball bearings supporting a central spindle, that would carry a conventional test indicator at one end and have a knurled knob at the opposite end....
The idea here (not unlike your co-ax idea) would be to keep the housing relatively short and use the ball bearings to provide accurate indicator rotation in line with the overarm bushing...
The setup would reduce the effort to rotate the indicator and thus the tendency to affect the true position....

Cheers Ross

 

[AlfaGTA]

So i have been working with this machine now and it is not giving me a warm and fuzzy feeling regarding the accuracy of the work produced!

I can get the bore size i want (within .003" or so) which is fine. But i don't have any real sense of how straight the bores are in alignment to each other....

This setup is not a typical line bore that makes a line between supports at the far ends of the part, so all bores must follow the line described by the boring bar...
Here to get reasonable finishes without chatter the supports must be moved along to keep them close to the bearing(s) that are being bored....
The straight of the bores is a total function of the ability of the support arms to move and repeat along a "straight" master way.

So i started to wonder ,just how straight was the master way....And did the support arms really point exactly at each other.....

Bit of checking using a qualified straight edge told the ugly truth.....The master way was not really straight.
To top that the manner in which the boring bar fit in the support arm bushings made me believe that they did not point exactly at each other either.....

Of course like everything the first thing i needed to do was make some tooling........
Piece of mild steel made flat and true on the surface grinder....Then some milling to add the required features....

When all was done i had a plate that emulated the machine's reference way..../

Finished 60* "V" at the top with a 90* notch on the lower edge to provide for the clamps on the support arms....
All surfaces (except the 90* notch) finished ground....Drilled and tapped, then mounted to the face of a 2-4-6 block held in the vise .....
Indicated to be true to the machine "Y" axis.....

More to follow.....
Cheers Ross

 

[AlfaGTA]

With a reference surface , same as that on the machine, i removed the bushings for the boring bar and mounted the overarms ...side by side.....
Indicated to find the average center, and trued up both housing bores....
Tool here is a long reach "anti vibration" Sandvik "Capto" bar...Has micrometer adjusting insert tool. Bought this tool several years back to use on 4 cam Porsche case boring projects i was doing....
Bar is pretty magic...has long reach and makes nice holes, very controllable.

New bronze bushings were made and installed, then finished in the same setup.......

Final chore was to get the reference way flat and straight....Not my favorite job!
Somewhat tedious...scraping the vertical surfaces on the flat side of the way....And hoisting my camel back straight edge up to make a print taxed my aging arms....

End result:

Original ways were not ground or scraped, but rather milled leaving some texture.....not so nice

Cheers Ross

 

[AlfaGTA]

Here is the top 60* "V" that locates the top of the overarm supports....

Shows the fit to the overarm.......

And of course the new finished bushings.....

Feeling a bit better about this machine now.....
Cheers Ross

 

[Dan from Oakland]

This is why I have 4 overarms for my Tobin Arp- I really don't like moving them after the bar is aligned to the bores. With 4 overarms, I don't have to move them.
Not the best solution, but it works for me. Nice job Ross!!

This should probably be posted in the Tobin Arp / Sunnen forum!

 

[AlfaGTA]

Dan:
Wish i had 4 overarms.....Thought about making some...but at present i have already invested too much time in this thing.
Cheers Ross

 

[AlfaGTA]

Dan:
So i am a bit confused.
I see having multi overarms....but on this machine the overarms are fixed, no adjustment....
If yours are similar wouldn't the overarm still follow the master way? You can only dial in each end of the part, correct....no dial up in the middle, so the overarm will just follow the way, and if its
not true won't the overarms tend to push the bar to follow?
Did not know there was a Tobin Arp/Sunnen forum...
Cheers Ross

 

[Dan from Oakland]

Sorry, the Tobin Arp/Sunnen forum thing was my attempt at some humor.
Yes, my overarms are adjustable, and I use the bar to check alignment if I can.
The TA 14's and 15's have an alignment fixture to set the arms to each other.
Its not 100% but...……. Just fundamentally, I assume if you can move them, they might not end up exactly where
you want it or where it should be, so safest is to not move it at all.

 

[AlfaGTA]

Yes i remember the adjustable arms...I had a TA 14 the early version with the flat top way when i was at Griswold co.....
The head machine is not adjustable, the arms are a single piece casting....

No offense, but i am glad i don't still have that machine.(TA 14)...
My Berco is so much nicer, not as flexible however.
Cheers Ross

 

[gappmast]

When Sunnen bought Topin Arp the machine did not have adjustable parallels on the cradle. The indicators were always a issue as one person stated they operate off a ramp and the ramp had too much contact area so they would stick. The trick to using the indicator was use the cutter micrometer and set the indicator to bore size. You would set them so zero on the indicator was the bore size, this made it easy to adjust the head.

Replaceable bushing were never available for the arms instead you would send the arms to Sunnen for repair. They would press in a bushing and bore it to size on a fixture that made all the arms ever manufactured.

 

[gappmast]

Yes i remember the adjustable arms...I had a TA 14 the early version with the flat top way when i was at Griswold co.....
The head machine is not adjustable, the arms are a single piece casting....

No offense, but i am glad i don't still have that machine.(TA 14)...
My Berco is so much nicer, not as flexible however.
Cheers Ross

I used a TA 14 in my younger days and like you was frustrated. Later in life I had one on one with the design engine from Tobin Arp. The biggest issue with the machine was training he should me some things that made it a dream to operate.

 

[gappmast]

Yes i remember the adjustable arms...I had a TA 14 the early version with the flat top way when i was at Griswold co.....
The head machine is not adjustable, the arms are a single piece casting....

No offense, but i am glad i don't still have that machine.(TA 14)...
My Berco is so much nicer, not as flexible however.
Cheers Ross

I used a TA 14 in my younger days and like you was frustrated. Later in life I had one on one with the design engine from Tobin Arp. The biggest issue with the machine was training he should me some things that made it a dream to operate.