Monday, December 20, 2010

V4 Dimension (Error?) Question

Here's an e-mail from Patrick Lorenze.  I don't have an answer.  I'm sure Dad would have known, but in his absense, perhaps other V4 builders out there can assist:


I believe there is an inconsistency on the dimensions on page #7 of the plans and I'd like to make sure I understand which one is correct before I cut the Block.  The Oil Cover recess on the bottom of the Block is dimensioned .290" from the Oil Cavity wall which puts it at ".045" and .172" from the ends of the Block.  The drawing shows these 2 dimensions as .032" and .186".  I have triple checked and even scaled the drawing with calipers and I believe the intent is to meet the .045 and .172 dimensions.  I attached a pdf of the CAD file I am making so that I can create the CAM program to cut it on my CNC Mill.



Here is another way to look at what I am saying.
If the centerline shown for the oil cavity is also the centerline for the Oil Cover recess, then take the 1.540" dimension for the centerline......subtract half the width of the Oil Recess cavity (2.990"/2 = 1.495") .....and you get .045" .......not the .032" shown on sheet #7.
Hope this helps explain the concern.


There  is/was a problem with the dimensioning in the drawing. I brought this to Jerry's attention in an email. He corrected it in later drawing sets and sent me an update. Jerry scanned the new drawing and sent a PDF to me. 
I have drawing set #66.
Somewhere there is a web link detailing all the revisions. Maybe Allen can make that known to you.
 Allen should probably send you new copies of the sheets that have changed since your copy version.

Here is a copy of the email message he sent me. There were a couple of other issues I mentioned as well.
This may be confusing. There are my comments followed by his response (s).

I hope this clarifies the problem for you.

Dave Sage

"A couple of issues with the V4 drawings – errors - maybe not  - but anomalies none the less:

On sheet #6 the dimension of .307 should be .305 otherwise adding up all the given dimensions across the block comes out to more than the overall dimension shown of 3.285. I’m not sure how this could happen on a CAD drawing. (rounding errors ?) 

    You are correct, it should be .305".

On sheet #6 the width of the head deck (top of the block) can be calculated as 3.285 minus .077 giving 3.208. On sheet 7 the same thing can be calculated as 2.990 + .175 + .032 giving 3.197 a fair difference (11 thou). Not a biggy but still perplexing given it’s CAD. 

          The .175" dimension should be .186" instead, but if the other dimensions are adhered to it is moot. Granted

           the dimension needs to be correct anyway, or else just not included. I use the CAD for design as well as

           for output of the drawings. Some of these dimension errors are remnants of multiple design changes where

           some affected item dimension corrections were missed. Also contributing is 69 year old gray matter! All 
           the above will be corrected for all future plan sets along with a couple on Sheet #16 as well. The 3.210" to 
           3.208" and 3.080" to 3.078" due to assumed .002" added to the .128" for cleaning up the mill
           marks from Step #3 thus the .130" dimension. See below.......

If you look at the pictures of the finished engine, the heads seems to overhang the block an obvious amount all around which looks good. But given the dimensions above and looking at sheet 22 and 20 there will be no overhang on the ends and only 60thou on the top and bottom. The head is drawn as 3.200 long (only 8hou or so different than the 3.208 or 3.197 above)? 

          You missed the .128" of material milled away (plus .002" for cleaning up the mill marks) all around the gear 
          case cover on the flywheel end of the block in Step #3 on Sheet #16. This brings the length of the cylinder banks 
          to 3.078". With the heads at 3.200" long, there is .061" of head overhang on each cylinder bank end. 

Thank you for pointing out the dimension errors. I always want to know about them so I can correct them.


Jerry E. Howell"


Dad did maintain a revisions page.  It is referenced on the last page of the plan sets we distribute.



Hope this helps...



Thanks for the replies Dave and Allen.  I have plan set #188 and had already looked at the revisions page which shouldn't apply to the later set I have.  The dimensions still don't add up as I pointed out in my messages above.  I will do the best I can to figure out what makes most sense and go with that.

Dave.....Terry M. told me he saw you at the show with your V8 and said it was very cool. He also passed along some tips from your experiences which I appreciate.




Looks like you are correct. Those figures don't add up either. I didn't analyze your comment fully and just figured they were wrapped up in the complete block length issue I pointed out. As Jerry mentioned in his email - he probably changed something along the way and did not update all the incremental measurements. In any case it really makes little difference how big you make the opening as long as you keep it in mind when you make the cover. I would opt for enlarging the .032 measurement since .032 leaves a very thin edge between the recess and the outside of the block. I think mine is that thin and I'm always concerned with whacking it and bending or breaking it off.



Yes Pat:

Terry and I had quite along discussion. It's too bad this forum did not exist earlier - or better yet ,Jerry was still around to discuss the issues with.
 I believe we discussed the combined intake manifold / water passage issue. Since I have a temporary intake at the moment, I've pretty much decided to make the water passage (which is twice as long for the V8) a separate block below the intake that can be screwed down to ensure the water connection to the block without the balancing act of having the O-rings seal AND the intake runners line up at the same time. The intake will then be made slightly higher to clear the water passage block.
 The other issue with the current design is that it is generally a no-no to heat the intake manifold and the intake charge. Although it helps to get off-the-choke when starting it usually hinders performance to have a hot fuel intake mixture later.
 I had problems Sunday afternoon with my engine at Cabin Fever. The epoxy let go on the flanges of my temporary intake, probably because of the extra pressure on them caused by compressing (in my case) two O-rings which caused a water leak. The water collected and threatened to go inside the block around the lifter bushing. I stopped running it and mopped up the water.
 I'll fix this up and post another topic with my results. Not sure what to do about an intake since I still haven't decided if I need two carbs or not. I'll probably make one like Terry's. I like his work.




Thanks for the feedback on the design and sharing some lessons learned from your build.  Terry has done the same for me.  The Internet is great isn't it!  I decided I will probably transfer all the designs into my 3D modeling package (Alibre which is compatible with Solidworks) to reconcile all the dimensions and part fit ups, adjust the dimensions to the best of my ability and then buld the parts.   


I use Alibre as well, although I'm a rookie at it so I don't rely on it. I'm designing my new intake with it.
I do use AutoCad all the time for the simplist and since I'm building the V8 I've re-drawn a lot of the drawings to check dimesions resulting from the conversion to a V8.
I also use it a lot to solve trig problems. I find it easier to draw the problem and measure the unknown than to calculate and likely make errors.



I use Alibre to calculate trig answers too.

The program is really powerful and if you stick with it (I recommend the tutorials) it will suddenly click and you'll be able to use it for all its 3D power effortlessly.  Doing the assemblies is very powerful as is creating the drawings with no additional effort from the 3D models you create.  I use it to keep myself honest and find errors before I make chips.  I'll stop now because this is starting to sound like a commercial.


Friday, October 29, 2010

Tuesday, August 17, 2010

TIM-6 tip from Bill Mitch

I just finished building the TIM-6. It is now a TIM-3.6. If anybody asks, tell them to leave out the diode and put a wire jumper where it goes. This diode is a safety so you can’t hook up the batteries backwards but also limits the voltage to the coil.

Bill Mitch

Thursday, August 5, 2010

Terry Mayhugh's V4 fabricated intake manifold

I just finished  machining an intake manifold from scratch. I modeled the block and heads in SolidWorks and was able to use the assembly feature of SolidWorks to design a two-piece intake manifold that looks identical to the original cast version. It uses six dowell pins and Loctite high temp bearing retainer to hold the two sides together. I cnc'd the two halves on a Tormach mill (about three hours machining time). I still need to do the secondary machining, i.e. bring the arms to final length (I left them .020" long just in case my model in progress wasn't exactly the same as the prints) and to machine the water cavity and o-ring. I'll post some photos in the next few weeks on the Tormach website and post the URL here since I don't think I have enough space to post the photos here.
My original plan for the exhaust manifolds was to just fab some stainless tubular headers like I did for the V-twin but I think I'm going to try to design a pair of them in the same way I did the intake manifold. I think like the looks of them in the photo of the model built by the Craftsmanship museum better than the headers I had in mind. - terry


Here are some pictures of the intake manifold that I designed from scratch for the Howell V4. I made it in two halves and then joined them with 8 dowell pins and high temp Loctite bearing retainer. The seam is invisible in the final finished part. I still have the water cavity and its o-ring groove to mill, but the manifold fits the three head/block surfaces perfectly with no daylight between them even without the required o-rings. I made two sets of halves but only finished one out since I haven't yet (at least) screwed the first one up. I was planning to produce and offer the halves for sale, but each set required three hours of machining time on my Tormach running even with the high speed spindle; and I just don't want to get into any kind of production with that type of efficiency. It is now very clear to me why Jerry decided to cast these parts.
After I receive my .046" endmill to machine the bottom o-ring groove I plan to start on a set of exhaust manifolds. I have a reasonable preliminary model so far with these parts as single pieces as I am concerned about the possibility of exhaust heat causing a pair of halves to separate. It will require a precision bored and plugged workpiece though from which the parts will be milled from two sides in order to keep the exhaust runners similar to the original castings. - Terry

Monday, July 19, 2010

Tom Bak's Vintage

Hi Allen,

 Attached are some pictures of the “Vintage” stirling cycle engine I recently completed from your excellent plans. I really enjoyed building the engine and found it actually more challenging than the Miser. I suspect it is likely due to the greater number of parts soldering some of them together and the added machining of the cooling system and associated pluming.
As you can see I made a few changes but basically stuck with all the dimensions on the plans.

The main differences are:
Made the main frame from ½ inch aluminum because I had some.
Modified the main frame to extend at the rear to allow the mounting of the water pump.
Mounted the water pump on the frame and used a friction drive to turn it.
Cross drilled the pump to get the water flowing the right direction due to the reversed rotation.
Mounted the crankshaft bearing holder to the mainframe with 6 2-56 screws.
Eliminated the outboard frame.
Added a standpipe (as mentioned in the plans) on the base to so water can be added to the cooling system and the air removed, it also makes it easy to monitor water flow. 
Streamlined the water fittings on the cooler body just for the look of it.
Attached the power cylinder head using 6 0-80 screws.
I am very pleased with the design and the modifications I made with the exception of the water pump drive.
I am planning on replacing it with a gear drive as soon as I figure out the whole gear thing. I’ll send you a picture when done.

Thanks for the great plans and support, the miser runs great on the heating ring. What to build next…

Best regards,
Tom Bak

Tuesday, May 18, 2010

Farmboy Hit and Miss Theory??

Here's an email I received May 18, 2010:


Hi all! I am new to the hobby, but have about 20yrs machining experience, (mainly CNC) and am very keen on building a farm boy. Before i get the plans there is a few queries i have. Firstly can someone please explain the HIT AND MISS theory to me? Secondly would this engine be a good first project?
I like the idea of working with bar stock materials, had enough of castings over the years! LOL!
Thanks in advance to all!!!


Dad ranked the Farmboy the third easiest of the 6 internal combustion engines (see Levels ).  It could be done as a first project - it just all depends on your skill level.

As far as theory, I assume you mean the 'hit and miss' gearing, and not general internal combustion theory.  In a nutshell, a centrifugal ball governor (see ) will hold the exhaust valve open until the engine RPM's slow to a set point.  When this set point is reached, the govenor will release it's hold on the exhaust valve, thus allowing the next IC cycle to fully complete and the engine will fire.  More information is available at

Hope this helps!


Wednesday, April 28, 2010

Earth Day at IU East featuring Superfan & Misers

My son Mark Howell has been working on a 1.5x size Superfan project for the past year at the local university.  He was asked to participate in the "Earth Day" activities on campus a couple of weeks ago to demonstrate alternate forms of solar energy.  The idea is to power the fan by using a large magnifying glass, thus of transforming solar energy to mechanical energy (they did this outside - not in photos).  Also in the photos are Dad's original Superfan, Miser, and mini-Miser.

Here's a youtube video of the project:

Tuesday, March 23, 2010

Tom Bak's Miser

Hi Allen,

Attached are a few pictures of the Miser engine I built. Although I am a little inexperienced at machining, like any good hobbyist I made some changes to make it more difficult to build!
It is the first engine I have made and I am very pleased with the results. The plans were great, as was the service.

Best Regards,



Tom - Congrats on completing your first engine.  Looks good!


Thursday, March 18, 2010

From the Craftsmanship Museum: First Pop of our Howell V4 engine

Dear Friends of Craftsmanship,

March 16th was a big day in the Joe Martin Foundation machine shop. After starting the build in September, 2007, Tom Boyer finished the Howell V4 engine and made the first attempt at starting it. With Joe Martin, Pam Weiss, Tom, Craig and our realtor Justin present, we held our breath while Tom switched on the ignition and turned the engine over with an electric drill for a starter. Within a few tries the engine sprang to life briefly, running for a little over one second and then stopping several times. While technically a "run," it was late in the day and Tom wanted to think about it overnight before going further, hoping he had not forgotten something important.

The next morning, March 17th we tried again. The engine gave a few brief bursts as it had the day before, and then after one final adjustment of the fuel tank needle valve it suddenly sprang to life and kept running. After a minute and a half or so of running Tom closed the needle valve a little further and it stopped, but it was now just a matter of fine tuning to get more run time out of it. Today Tom changed the crankcase oil and tried again, and after advancing the timing a few degrees it fired up again and is running even better now. It still needs a throttle lever and an advance lever plus a finished wood display base, but to the relief of all it now runs and has already been demonstrated for a few visitors to the museum.

A video of the "first pop" and the first significant run can be seen on YouTube at The video is about 4-1/2 minutes long. Today I also filmed a short 30-second version of it running, and links to that can be found on the Howell V4 page in two file formats—WMV (large and small screen) and MPEG1. While you can click on the link and play it directly over the Internet, we suggest you right click on a link and select "Save Target As" in the pop-up window. Save the video to your desktop or "My Videos" folder, then play it with your favorite media player. This will eliminate any problems with pauses during the replay.

Our congratulations to Tom Boyer for an excellent job on overall construction and assembly of the engine. It is certainly a job worthy of display in the Craftsmanship Museum. Thank you also to the others who helped make parts for the engine, including Joe Martin (camshafts), Pam Weiss (fan blades), Larry Simon (tools, fixtures), Adam Kritchbaum (skid support rails), Dave Eggert (air cleaner) and Bob Seigelkoff (pistons). We only wish the late Jerry Howell were still alive to be able to see the engine he designed come to life. The excellent plans for this engine are still available from his family at

Sincerely Yours,
Craig Libuse

Monday, March 1, 2010

Dana Hall's "Beamer"

Hi Allen...
Dana Hall here in Florida...

Just finished making the "Beamer" stirling engine...
Runs as smooth as a Rolex watch...

Only deviation I made from your father's plans was the flywheel...
I borrowed the idea for this flywheel from Joe Kalke... He used this
flywheel design when he made his "4 in1" engine... Hope he doesn't mind...

Enclosed are 2 pictures of the "Beamer" I thought you might like to see...

Take care,

Sunday, February 21, 2010

John Meredith's Howell V-Four SN-009

Here's an e-mail I received from John

Hi Allen

I have completed my V4 (no.9) and thought you might like some photos of the finished product.

With any of these little engines one has start up problems. The biggest problem was the exhaust oil.
It was as bad as a 2 cycle glow plug model airplane engine. I had heard about the empty groove in the piston as an oil control means but didn't know the design details so I built the piston per the drawings. I really don't understand how it works. So my solution to the problem was to make new pistons with an oil control ring and that works well.

The next problem, I could not lean the carb. out properly. So, I did the initially runs with a Perry
model airplane carb.  It ran ok but would not operate at all rpms without mixture adjustments. My answer to that problem was to install a Perry type drum throttle and jet with a mixture enriching feature when the throttle is advanced. I also removed the idle jet.

On the distributor I did not see the magnet spacing problem your dad had. I used 45 degrees and statically the mag. switch fired at the 45 degrees. Dynamically, that may not have been the case but the  engine runs fine at all rpms. However, I was not using a Carter type ignition system. I used Mike Neal's CDI system.

It's a cool looking and a great running engine and the use of o-rings sure makes it easy  to work on ( no gaskets to mess with). Other neat design features are the mag. drive on the water pump and the oil pressure relief system.

A neat project!


John Meredith
Livermore CA

Saturday, February 20, 2010

Electric motor sources

I get e-mails from drill plans purchasers wanting to know where to get the electric motors to run the Mini Drill and Micro Drill projects.  It would seem that some of the sources Dad mentioned in the plans are no longer available.  Those of you who found a motor, can you share with us where you got it? (if they are still available) 

I went to Mendelson's in Dayton (one of Dad's favorite places to search for various items) to look for any surplus they might have, and did not find anything matching Dad's specs, as most of the motors they had there are AC or stepper motors.

For Micro-Drill, Dad calls for: 12 volt DC, 1-1/4" long x 7/8" diameter with a 1/8" diameter shaft.  If you can't keep the motor from turning by pressing on the shaft with your index finger and thumb at 6 volts, then it should have enough torque.

For Mini-Drill, Dad calls for: 24-28 volts DC, min 3000 RPM, permanent magnet, ball bearings, 2-1/4" to 2-1/2" diameter and a 1/4" or 5/16" diameter shaft.

Again, if anyone knows of a source for these motors that match these specs, or if you used a motor with different specifications with good results, please reply here, or send me an e-mail to



A builder responds:

"I found a good motor for the mini drill from Zoro on the internet. You can power it with a lap-top type 24v 10 amp supply, but you will need to create a starting device. The resistance before starting is 1.2 Ohms which will draw a 20 Amp surge when starting, looking like a short to the power supply. One way is to put the switch on the ac line side so the power supply and the motor ramp up together. Better to add a 2-3 Ohm 5W resistor shorted out with a relay after a second or two.

Or you can get a big power supply and put it in a box, resulting in something the size of a bread box. Not cool.

The motor I got from Zoro is their # G1958126. 24 V, 6 Amp, which fits nicely."

Tuesday, January 26, 2010

Farmboy Gear dimension problem?

I received this e-mail from Curtis Strong:

"My name is Curtis Strong. I purchased the plans and started biulding my Farm Boy engine almost a year ago. I just finished it resently and it looks and runs very well. I did run into one problem on sheet 3 the rear frame. The dimension of 1.026 from the center of the crankshaft to the center of the camshaft may be too short.Although this is the first time I have made gears, I did folow the plans and did end up with very nice looking gears but when I tried to assemble them to the frame they were to tight to assemble. I took a long hard look at the plans and did some figuring which led me to believe that the plans actualy put the gears at apox. .003 interference. after doing the math using trig I figured the dimension on sheet 3 should be aprox 1.034. The fix was fairly simple. I just enlarged the cam shaft bore in the frame and changed the center of the larger bore to 1.034 then installed a press fit alluminum bushing. This dimension has produced a clearance that has resulted in the proper gear engagment. If there is somthing I may have over looked please let me know.
Thank you, Curtis."

If anyone can shed some light here, it would be appreciated.




Hi Curtis, I built serial #3 (Finished it March 19, 2009) and went by the plans and everything came out just fine. I did the math also and by my calculations the distance between the crankshaft C/L and the C/L of the camshaft hole is 1.1203 " and doing the pitch diameters the distance between the centers of the gears the distance is 1.1220" . That's a difference of .0017". When I run the numbers with 1.034" I come up with the gears being .0056" too wide? I think the numbers on the drawings are well within tolerance.

Jim G

Saturday, January 16, 2010

Ralph Ervolino's cast Farmboy

From an e-mail sent to me:

"... Here is a picture of my farm boy. I made patterns and casted the frame and cylinder. Also casted a base under frame to get flywheels off the wood base.
         Sorry for your loss (Jerry). I learn a lot from his work, and look forward to building the other engines from plans I got from him. I built a inline 4cyl., it runs great, but it's not pretty. Your father's plans showed me how to make them look good too.  The farm boy is like a sewing machine. I can't wait to hear it run. Thanks so much. Ralph"

Thursday, January 7, 2010

Farmboy Ring Groove Question

I had a caller a few weeks ago who stated the plans said to make a piston ring groove .105" wide by .110" deep for a .094" section by 1" diameter Buna-N "O" ring.  Sure enough, I checked the plans (Sheet #5), and this is what it shows.  The callers question was how could this seal the cylinder?

Does anyone have an answer for this, or is there an error in the plans?

Please advise.




Yep, the sizes are correct. I thought they were incorrect also. But after making the groove to size everything works just fine. I have noticed that the "o" ring swells when in contact with acetone or alcohol.
I wouldn't change a thing on the plans as there correct.
Jim G


Jim - I wondered if the perhaps the "O" ring would swell up to make the seal.  Now I (and future builders) will know!



Wednesday, January 6, 2010

Dana Hall's Super-Duper Fan! (SUPERFAN)

From an e-mail he sent me:


My name is Dana Hall and I am in Florida...

I would like to pass on my condolences as to the passing of Jerry...
I never met him, but we exchanged a number of emails, and he was always very prompt with his replies back to me... And his knowledge on the engines he designed is very impressive...

A while back I built Jerry's Super stirling engine and it works beautifully... Then I thought I would build another fan but doubling all of the engine dimensions times 2...

The pictures are deceiving as to the size of the fan... The blade diameter is 18 inches and from the bottom to the top of the fan blades is 31.5 inches... It has a maximum rpm of 245 and runs quite nicely on a .5 inch tall flame... The base stand for the engine is my own design...

Enclosed are 2 pictures of the fan...
I thought you might like to see them...

I would like to thank you for keeping Jerry's web site and business going...
His plans and engine designs are by far the best on the Internet market...

Dana Hall