supercharged V12 2 stroke

[Neil WyattModerator @neilwyatt]

Welcome back

Neil

[John OlsenParticipant @johnolsen79199]

A link was just posted on the RCME site to a video on Youtube about the manufacture of RR Merlin engines. I thought it might be of interest to those following Deans build, although the gear RR use is rather larger than Dean has!

**LINK**

Thanks to Jon Harper who posted the original link.

regards

John

[HomeUseParticipant @homeuse]

Hi Dean – Glad to see the update – keep them coming as it is a great project

[dean clarke 2Participant @deanclarke2]

 

So life it seems is never simple or easy and often fraught with danger and frustration. It seems so also is model engine building or more precisely the use of machine tools! I was working away on the manufacture of the pistons for the v12 when suddenly there was an extreme excess of machine oil in the immediate atmosphere around me. The seals on the quill of the mill decided that it was time to not do anymore sealing, consequently i have spent the last little while stripping the mill machine head down and giving it a good clean and regrease and replaced all the seals. So now it's on with the show. The photos below show the progress to date on the making of the pistons.

Hopefully I will get a bit more time in the shed to complete them this coming week so thats all for now folks

Cheers

Dean

Edited By dean clarke 2 on 18/10/2015 05:42:35

[Danny M2ZParticipant @dannym2z]

Good to see you back on the job Dean.

Piston material looks like cast iron – excellent.

Seeing as how you have made a piston holder for lapping the pistons, and as no two cylinders ever come out precisely identical in dimensions (tenths of thou), I have found that lapping a piston to fit the largest bore first is the way to go.

If you are a little bit over keen then it might fit one of the other cylinders and by the time that you have all 12 done you shall be quite good at judging the fit.

Tallow (rendered fat) is very good for testing piston-cylinder fit.

I shot a large feral pig to obtain my tallow (.444, twice size a Dirty Harry .44 Magnum) but your local butcher might be more useful than my Marlin lever action pig hunting gun.

Keep up the good work, a lot of people are interested (check the views)

Regards from Down-Under

* Danny M *

[HomeUseParticipant @homeuse]

This may be a stupid question but is there any reason for some of the pistons having a domed recess in the bottom of the bore and other do not (8 do 4 do not)

Keep up the good work

[dean clarke 2Participant @deanclarke2]

LOL, Um i would love to have some highly techo reason for the domes but the simple truth is they were pilot bored with a ball nose cutter which i found to be much quicker than the drill and turn option i started with. the pistons are not shown finished, just at the first stage of machining. the next stage is to machine the skirt off on the back side and then mill in the recess for the conrod to sit in. then its onto the non-expanding end of the fixture to be turned to diameter for lapping and turning the crown down to final length. Then its machine the step for the transfer into the crown and finally lapping to fit the liner. Each piston is fitted to its mated liner. I will endevour to have them all done by the end of this coming weekend.

Cheers

Dean

[HomeUseParticipant @homeuse]

Thanks Dean – “I had vision of massive calculations to adjust the weight of each piston “ – But I really knew that it was a stupid question.

Hope the final lapping goes well

Regards Mike

[dean clarke 2Participant @deanclarke2]

Well here we are at the next stage of machining the pistons, The first step in stage two was to cut the step into the piston skirt. There are three reason for this, firstly to allow clearance for the piston at BDC from the center main bearings and secondly to give a sealing skirt over the exhaust ports at TDC.Lastly just for some lightening effect. Next they were set up centered in the mill to machine the conrod little end space into the underside of the piston and then lastly, all pistons were machined at the crown end to the final overall length. Photos below show progress to date.

This photo shows the setup to machine the conrod little end recess.

Don't ask about the piston on the left………………… Yea lets just not go there OK.

The photo below shows the fixture used to turn the crown down to length, which will also be used to turn the diameter to lap to the liner

Here are the 12 pistons finished to the end of stage 2. Next is to machine the transfer advance step into the crown, the object of this is to advance the transfer timing so that it opens approx 10 deg's before the exhaust and therefore stays open 10 deg's after the exhaust. The point of this is to allow a small amount of exhaust gas into the transfer port to reduce the loss of fuel mixture out the exhaust on transfer. With approx 25 psi boost pressure there will be plenty of SUPERCHARGE in the combustion chamber on the compression stroke.

Well that's all folks see you again soon

Cheers

Dean

[dean clarke 2Participant @deanclarke2]

Well here's next step in the process of fitting up the conrods and pistons. I have managed to fit all the rods to the engine and have finished and lapped 1 piston, this could end up taking a while!!!! maybee i need to just work a bit faster? photos below show the progress to date.

That's all for now

Dean

[Ian S CParticipant @iansc]

Don't rush it, or you'll get finished and have to think of what next, great work Dean.

Ian S C

[dean clarke 2Participant @deanclarke2]

lol, halfway through the piston lapping and finishing at the moment, will post photos when all done. Next project is already under way.

Cheers for now

Dean

[David ColwillParticipant @davidcolwill19261]

Dare we ask what it is?

Looking good so far. Keep up the good work Dean.

Regards.

David.

[dean clarke 2Participant @deanclarke2]

Well that would be telling now wouldn't it? needless to say i will be doing some drawings before i start this time.lol

dean

[dean clarke 2Participant @deanclarke2]

Well here we are with a bit more progress, slowly but surely I am getting there. Photos below show the advancements to date………………

Yea, all there bar one, just had to be one that didn't want to play the game…………. oh well better make another one.

cheers for now

Dean

[Dave Powell 2Participant @davepowell2]

What a fascinating project, can't wait to see the next bit!

[Nick_GParticipant @nick_g]

.

Awesome. ………….. Truly awesome.

Nick

[dean clarke 2Participant @deanclarke2]

Yea me too!!!!!! (can't wait to see the next bit that is,lol)

Thanks for the kind words Nick

Dean

Edited By dean clarke 2 on 10/12/2015 21:10:44

[Howard LewisParticipant @howardlewis46836]

INCREDIBLE skill and patience!

To ask a stupid question, how do you plumb four carburretors to feed six cylinders per bank?

On naturally aspirated four strokes, two carbs give equal induction pulse intervals, but often three are used.

So are all four outside the blower, feeding mixture into a common gallery to it?

Howard

[dean clarke 2Participant @deanclarke2]

All four carbs feed mixture into the intake off the blower, then all six crankcase cavities are feed directly from the blower exhaust through six separate ports. each pair of cylinders in the v configuration is running in a sealed off crankcase cavity with the conrods running on a single big end journal. This gives 5 main center bearings and 6 big end journals. As the blower is one single unit there is an evening out of the mixture internally and therefore an even distribution of mixture to the cylinders.

Hope this explains it clearly?

Cheers

Dean

[SkelParticipant @skel]

This is very cool.

[dean clarke 2Participant @deanclarke2]

SUCCESS AT LAST ,,,,,,,,,,, Finally I have been able to get all the pistons lapped in to the liners and ready to run so to speak YAY what a saga that was but all dun now and it's onto the glow plug inserts/combustion chambers, photos below show progress to date

here's the glow inserts/combustion chambers….

Cheers for now

Dean

[dean clarke 2Participant @deanclarke2]

Well, having been able to spend a couple more nights in the shed this week I have been able to complete the next stage of the engine build. Tonight saw the completion of the glow inserts/combustion chambers and the final assembly of the cylinder heads. I have also been able to modify the fuel rail and freed up the throttle linkage movement. Photos below show the progress to date……………………….

 

 

 

 

Last photo below is the front view of the engine so far, all that remains to be done is the 4 fuel needles and the ignition rail. I think it will then be time to breathe life into the beast (hopefully)

 

Cheers for now

Dean

 

Edited By dean clarke 2 on 23/12/2015 08:40:12

[Michael GilliganParticipant @michaelgilligan61133]

Dean,

I have run-out of superlatives to express my admiration.

… Now just looking forward to seeing & hearing it run.

MichaelG.

[Ady1Participant @ady1]

looking forward to seeing & hearing it run

Don't forget, it's a them run, not an it run because he's going to knock out a flat 12 at the same time, scratch built of course, heck, it gave him something to do

Edited By Ady1 on 23/12/2015 10:30:41

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