Antique Engines and Old Iron
[Home] - [HELP] - [Forums] - [Library] - [Photo Gallery] - [Groups] - [Classified Ads] - [Subscribe] - [Links] - [Books] - [Sponsors] -

Go Back   SmokStak > SmokStak® Shop Equipment Tools and Techniques > Machine Shop and Tool Talk
Forgot Password? Join Us!

Notices

Machine Shop and Tool Talk Shop Equipment, fabrication, repairs, how to fix it, which tool to use for the job. Machinist shop talk, straight to the point.

Machine Shop and Tool Talk

Re: How it's Done 3-5


this thread has 106 replies and has been viewed 33563 times

Reply
 
Thread Tools Display Modes
  #21  
Old 08-14-2015, 06:37:07 PM
OTTO-Sawyer's Avatar
OTTO-Sawyer OTTO-Sawyer is offline
Subscriber
 
Join Date: Nov 2008
Location: Scioto Mills, Illinois USA
Posts: 8,491
Thanks: 17,203
Thanked 7,291 Times in 3,501 Posts
Photo Re: How it's Done 2-1

Looks like a very interesting and informative thread.

Don't know if this will apply to your motorcycle engines or not, but for those of us playing around with antiques I figured I'd repost a shot from an old 1920s automotive book I have where it talks about cylinder offsets.

An old drag racer trick used to be (maybe still is) to put pistons in backwards because the wrist pin is offset a little to cut down on piston slap and installing them backwards gives you a better rod angle on the power stroke.

What those 'racers' probably didn't know is that in the early days of engine building the entire cylinder was offset from the crankshaft for that very reason.

While the racers were happy to achieve .060 to .090 offset on a 4 inch piston, the old engines (as per my book) were offset "Up To" 1/6th the bore diameter.

That's a Full 1 inch offset on a 6 inch diameter bore, or a 1/2 inch offset on a 3 inch bore.

That .090 offset is childs play in comparison.

Attached Thumbnails
Click image for larger version

Name:	off-set boring.jpg
Views:	74
Size:	113.6 KB
ID:	231975  
__________________
I just keep coming back again and again like the Evil Twin of a Bad Penny !
http://www.youtube.com/user/oldSawyer?feature=watch
Reply With Quote
The Following User Says Thank You to OTTO-Sawyer For This Post:
Sponsored Links
  #22  
Old 08-14-2015, 08:04:26 PM
John Tice's Avatar
John Tice John Tice is offline
Subscriber
 
Join Date: Jul 2015
Location: Portland, Oregon, USA
Posts: 121
Thanks: 3
Thanked 73 Times in 38 Posts
Default Re: How it's Done 2-1

Otto; I’m so glad that you brought this up. I’ve always wondered who might know about such things & could mathematically show results from various offsets? Different leverages & such?
JT
Reply With Quote
  #23  
Old 08-14-2015, 08:30:10 PM
Pat Barrett Pat Barrett is offline
Subscriber
 
Join Date: Nov 2004
Location: Brookhaven, Mississippi, USA
Posts: 2,605
Thanks: 653
Thanked 1,590 Times in 959 Posts
Default Re: How it's Done 2-1

On the old 130 5 hp Briggs Go Kart engine, we could offset the bore to the valve side or the off valve side, or front. Offsetting to the valve side seemed to improve bottom end, and toward the front, improved top end. We also would anle bore them, to enhance either bottom or top end. Also, on a flat head, such as these, we'd angle cut the deck more to the valve side to increase flow.
Reply With Quote
  #24  
Old 08-14-2015, 08:55:41 PM
John Tice's Avatar
John Tice John Tice is offline
Subscriber
 
Join Date: Jul 2015
Location: Portland, Oregon, USA
Posts: 121
Thanks: 3
Thanked 73 Times in 38 Posts
Default Re: How it's Done 2-1

.03mm = .00118"? 1mm= .03937"

---------- Post added at 05:38 PM ---------- Previous post was at 05:30 PM ----------

Pat; thank you for the ideas. Did you ever run some DYNO comparisons on any of your ideas? It would be nice to see what happens to the torque curves. If a DYNO isn’t available some track time averages are just as telling.
JT

---------- Post added at 05:55 PM ---------- Previous post was at 05:38 PM ----------

Quote:
Originally Posted by slip knot View Post
Very informative. I've always sent my machine work out to get done but never actually saw how any of it was accomplished.
Slip Knot; By following along with the thread, you will gain some more knowledge so you will know what kinds of questions to ask your Machine shop. Thank you for the comments; we can all learn from one another.
JT
Reply With Quote
  #25  
Old 08-14-2015, 09:18:53 PM
Pat Barrett Pat Barrett is offline
Subscriber
 
Join Date: Nov 2004
Location: Brookhaven, Mississippi, USA
Posts: 2,605
Thanks: 653
Thanked 1,590 Times in 959 Posts
Default Re: How it's Done 2-1

No, John, never did. Did this for some folks, and later got a dyno, but didn't do any of the offset bored engines. Did take some stock bores and angle bored them, took a .030 bore to clean up the angle bore. Could angle bore more if I bored and put sleeve in, but never did that. Wish I would have tried it when I had the dyno. Some of the best gains I saw on the dyno was flowing the carb and getting the jetting to what the engine liked. Exhaust also showed good gains with one matched for engine use. Other things that worked for me, using the Wiseco pistons was to cut clearance down to .0015 or .002 and finish cylinder with a nylox brush to finish the cylinder.
Reply With Quote
  #26  
Old 08-14-2015, 10:19:14 PM
I like oldstuff I like oldstuff is offline
Subscriber
 
Join Date: Jan 2012
Location: Milwaukee, Wisconsin, USA
Posts: 4,831
Thanks: 1,041
Thanked 4,582 Times in 1,928 Posts
Default Re: How it's Done 2-1

Pat, your post brought back memories of the aluminum bore briggs engines.
We had a problem honing them after a bore as they would gall with a hone.

After boring to size I'd simply glass bead the bore and put them together. Worked a treat and they ran well with zero oil consumption.
Reply With Quote
  #27  
Old 08-14-2015, 11:00:13 PM
John Tice's Avatar
John Tice John Tice is offline
Subscriber
 
Join Date: Jul 2015
Location: Portland, Oregon, USA
Posts: 121
Thanks: 3
Thanked 73 Times in 38 Posts
Default Re: How it's Done 2-1

Pat; Interesting that you made the comment about the tight clearance & a Wiesco piston. When Dover bought out Wiesco & put it under the PMI name with ProX & JE pistons, they did some exhaustive testing on the Wiesco brand. The Wiesco engineering folks kept fitting a piston tighter & tighter until the piston finally seized. I was told that the skirt clearance was very close to zero before the cylinder finally stuck. I prefer to purchase parts directly from the factory; conversations from the sales people get a little friendlier over time & information like this usually enters the discussion. Wiesco has come a long way since the early days & their JUNK cast pistons.
Reply With Quote
  #28  
Old 08-15-2015, 02:03:54 AM
John Tice's Avatar
John Tice John Tice is offline
Subscriber
 
Join Date: Jul 2015
Location: Portland, Oregon, USA
Posts: 121
Thanks: 3
Thanked 73 Times in 38 Posts
Photo Re: How it's Done 3-5

We still get an aluminum bore Briggs on occasion; They hone fine with a 280 grit stone & an oil flood. Most of the time we just sleeve them with a 1/16” wall liner & put them back to standard bore size.


A gentle heat to 500 deg. Being careful not to melt a fin


Measuring the cylinder


With a step machined at the bottom, the new sleeve drops in with a -.003” shrink fit.


Good as New

Last edited by John Tice; 08-15-2015 at 03:26:54 AM.
Reply With Quote
The Following 2 Users Say Thank You to John Tice For This Post:
  #29  
Old 08-27-2015, 10:57:40 AM
930dreamer 930dreamer is offline
Registered-III
 
Join Date: Mar 2009
Location: Amarillo, TX USA
Posts: 227
Thanks: 13
Thanked 56 Times in 37 Posts
Default Re: How it's Done 3-5

Not sure if this will be in the correct thread but here goes;

I have a 1957 Kellogg American air compressor that I want to rebuild, it's already apart.
Question #1 How do I find out what the original bore is? Looking at cleaning the bore and new rings etc.

I can't see any pictures?

Thank you
Reply With Quote
  #30  
Old 08-28-2015, 01:08:46 PM
John Tice's Avatar
John Tice John Tice is offline
Subscriber
 
Join Date: Jul 2015
Location: Portland, Oregon, USA
Posts: 121
Thanks: 3
Thanked 73 Times in 38 Posts
Thumbs up Re:Compressor skirt clearance

Most compressors & American made engines have bore diameters in standard increments; ie 3”, 3- 1/2”, 3-3/4” etc..

Look at the cylinder at TDC for a ridge in the bore; no ridge, no wear.

Next measure the skirt clearance of the piston; most times a set of feeler gauges will work.

Lastly is checking the rings for wear. I don’t know how much end gap is necessary for a compressor but I’m sure someone else will chime in for that.

For closer measurements, you’ll probably need to go to a machine shop who has the proper measuring tools.

You will probably need to re-ring the cylinder; also a de-glaze job with some kind of brush or ball hone.

JT
Attached Thumbnails
Click image for larger version

Name:	image-212.jpg
Views:	35
Size:	72.3 KB
ID:	233064   Click image for larger version

Name:	image-134.jpg
Views:	29
Size:	105.9 KB
ID:	233065   Click image for larger version

Name:	image-135.jpg
Views:	31
Size:	56.0 KB
ID:	233066  
Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

F o r u m Jump


Use "Ctrl" mouse wheel to change screen size.
All times are GMT -4. The time now is 07:44:50 PM.

Smokstak and Enginads site search!


All use is subject to our TERMS OF SERVICE
SMOKSTAK® is a Registered Trade Mark - A Community of Antique Engine Enthusiasts
Copyright © 2000 - 2016 by Harry Matthews P.O. Box 5612 - Sarasota, FL 34277