By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Allendale Jan 24th

3 cyl Pip engine

All Topics | Latest Posts

Search for:  in Thread Title in  
David K17/12/2018 19:06:52
258 forum posts
259 photos

Hi , I recently built a 3 cylinder 'PIP' engine from plans purchased at I wrote a build thread on another forum I use so I thought I may transfer it across to here. Bear with me as this forum works a little differently to the one I am used to.

First job is to make a 2mt taper with a 1/2 inch round boss on the end.
This will fit into my rotary table and my lathe nose and will enable me to
swap work pieces quickly while keeping them centred.
 Then machine a 1/2'' hole into my Cylinder blanks to fit the taper and also a 1/4'' grove
to use for holding clamps. I am making four cylinders so I have a spare in case something
goes wrong. The Cylinders are the most complex part apparently.
You can see the taper fitted into the last blank.
The first blank is mounted to the lathe using the taper and face plate.
First job is to open out a bore to .75'' , the combustion chamber is formed by a standard
118 degree 11/16 drill bit then the bore is opened out to .75 ready to fit a steel sleeve
later in the build.
The outside shape of the Cyl is then formed by turning a 30 degree taper leaving
a mounting boss on the end.

Edited By David Kenyon 2 on 17/12/2018 19:09:57

Edited By David Kenyon 2 on 17/12/2018 19:37:44

JasonB17/12/2018 19:12:39
18640 forum posts
2047 photos
1 articles

David once you paste the text from the other forum you will need to go through it and remove the IMG codes and cut and paste the URL between them into the Image icon at the top of the editing screen.

I'll do what you have already posted as you may not be able to get back to edit it.

EDIT, looks like you got there first

Edited By JasonB on 17/12/2018 19:16:41

David K17/12/2018 19:20:50
258 forum posts
259 photos

Hi , yes realised this forum works differently so I am just working things out so I can post the pictures.

David K17/12/2018 20:11:28
258 forum posts
259 photos
I ground a slight taper onto a 3/32 parting blade and rounded the end. This was used
to cut the fins and also reduce the thickness of the boss .
The DRO I fitted recently was a godsend for this job.
First one done , just another three to do
The 2mt was removed from the lathe and fitted to my rotary table then centred on my mill.
First cylinder fitted and the eight [2mm ] mounting holes drilled in the boss
Emgee17/12/2018 20:55:44
1650 forum posts
224 photos

Interesting topic, keep posting please.


David K18/12/2018 19:02:40
258 forum posts
259 photos

The rotary table is set up horizontal on the mill table and a milling cutter is used to
mill through the first two fins opposite each of the eight mounting holes.
This provides clearance for the mounting screws to be fitted later.

p1030340 (medium).jpg

David K18/12/2018 19:29:30
258 forum posts
259 photos

That's all the work from the bottom of each cylinder so I now part off each one from its mounting.
One mounting is then drilled and tapped m2 to match the cylinder boss and this will be used
for mounting the cylinders for future work on the top end.p1030342 (medium).jpg

David K18/12/2018 19:36:17
258 forum posts
259 photos

Had to make a jig to hold the Cyl for the top fins to be cut.
This consists on a large chunk of alloy rod with an expanding mandrel
fitted through at 90 degrees as below p1030528 (medium).jpg

David K18/12/2018 19:37:21
258 forum posts
259 photos

here you can see the set up with a cylinder bolted and the mandrel tightenedp1030344 (medium).jpg

David K18/12/2018 19:38:09
258 forum posts
259 photos

First the top of cylinder is turned to shapep1030348 (medium).jpg

David K18/12/2018 19:42:09
258 forum posts
259 photos

The same form tool is then used to cut the fins. The lathe is set to 70 rpm using the back gear and
the tool is fed in slowly whilst lubricating with oil. Took ages but quite satisfying listening to the tool
taking long shavings off a bit like a wood plane.p1030347 (medium).jpg

Ady118/12/2018 23:20:43
3810 forum posts
519 photos

You may find a lack of replies disconcerting at first, it's so we don't clutter a good build thread like this one

JasonB19/12/2018 07:52:55
18640 forum posts
2047 photos
1 articles

You are making good progress, I had to double check the drawings as I thought the fins were running the wrong way but the curved top runs front to back as the cylinder gets turned through 90 deg after machining the fins.

David K19/12/2018 15:12:13
258 forum posts
259 photos
Posted by Ady1 on 18/12/2018 23:20:43:

You may find a lack of replies disconcerting at first, it's so we don't clutter a good build thread like this one

That's ok, I am copying and pasting from another forum so it easy enough now I have sussed the pictures.

The other forum was not an engineering forum so you may find some of the explanations a bit brief / simplistic.

David K19/12/2018 15:22:27
258 forum posts
259 photos

With the lathe work complete the next step is to machine the holes for the
valve guides and hot plug using the mill.
The holes will need drilling radially at a 30 degree angle and enter the tight combustion
chamber accurately.
To help me set up the drill I had to make another jig seen below with a cylinderp1030353 (medium).jpg

David K19/12/2018 15:33:20
258 forum posts
259 photos

The jig is a copy of the internal bore and combustion chamber shape and is set up on the mill
at a 30 degree angle so the top is level . A taper is drilled dead centre of the flat using a centre drill
and this is then used to centre the jig on my mill as blow.

p1030457 (medium).jpg

David K19/12/2018 15:37:15
258 forum posts
259 photos

So with the first cylinder fitted in place of the jig I set the table to zero degrees
and line the top fins so the drill enters dead centre.
First hole is for the glow plug, a mill is used to turn down the fins until a flat is
formed on the cylinder head, then centre drill , drill and finally tap 1/4 - 32 thread.
p1030460 (medium).jpg

David K19/12/2018 15:38:26
258 forum posts
259 photos

The table is turned 120 degrees ready for drilling the valve guide seat. This is a bit more involved.
First mill a flat, then drill 7.6mm, ream 8mm, then drill down 9mm but stop about 1/16'' from the bottom.
Then tap M10 fine, again just short of the bottom. A 45 degree taper will be cut on the shoulder at the bottom
were the m8 is left.
The table is turned another 120 degrees and the second valve guide seat is cut.p1030466 (medium).jpg

David K19/12/2018 15:39:40
258 forum posts
259 photos

I then had to turn some threaded posts for the rocker arm pivots. They are just Silver steel with an M3 thread. p1030497 (medium).jpg

David K19/12/2018 15:43:39
258 forum posts
259 photos

Remember the set up on the mill was turned 49 degrees , that is because the rocker posts are
fitted at a 49 degree angle from the valves.
So while centred over the valve guide I offset the table 0.344'' and drill / tap a m3 thread, a post is
screwed in with permanent Loctite and then a slot is milled to accept a rocker. p1030478 (medium).jpg

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Latest Forum Posts
Support Our Partners
Eccentric July 5 2018
Eccentric Engineering
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest