Ferrari Engine design and build

[retunga]

A little bit of sad news, I have glued 10 of the 12 heads in place and what I have found is that the engines crank is not going to be able to take the torque required to have the engine turn over. I am still going to do the engine timing so that it is correct.
Even if I made the the crank bearing shafts thicker the crank shells would have failed next.

 

[Rhaven Blaack]

OUCH!!! That is bad news. I am sorry to hear that.
However, I am glad that you are going to continue the model (even if it will be a static model).

 

[Marman]

It would have been one heck of a feat to get the engine to run, but the model along with it's detail alone is a masterpiece.

 

[retunga]

I have now got all 12 heads in place, I have had a good look to see why the engine does not want to turn over and the problem is the gearing in that with me having to make the gaps and holes of the gears more on the open side of the tolerence scale which is fine for a free moving model, but when a load is added those open tolerences do impact the movment of the model and the gears then start to jam and that is the main reason for the model not working and also I have tried a few different valve springs and I also had springs made and it also is problem at the end of the day.
Really is sad, but when I do the next engine design with the desmo valve setup of the V-twin engine it should turn over....

 

[Revell-Fan]

Isn't there a way to make the gaps smaller? Maybe by glueing some pieces of thin paper to the surfaces?

 

[retunga]

Having a good look that may help fix the gaps, but there is so much play on the whole model that would fail somewhere else, of even wear itself out, I only figured out why I was having thin paper shavings coming out of the model as I also did not take into account the direction of movement and by having two edges working up against one another it would wear out as well.

There has been a lot lessons learnt here so when I do the desmo engine I should get that one to work...

 

[zathros]

Why not run some wooden dowels and connect them with wire under the counter balances? You could try filling it with "Great Stuff" too. Just some ideas.


OMG!! You are doing the Desmo engine!! You will become a Legend!! Awesome!!

 

[retunga]

The wooden dwells have been used in the V12 engine already but only in the cam shafts, I was going to join the cams one by one with filler rolls but that would also not have worked and the dwells was the next best thing. but what I should have done is used the dwells for the gears for carring the load and also it would have helped with the gear meshing.
But that will be ideas that I will carry over when I start the Desmo engine, but that is most likely next year's design project and build.

The biggest trick of the Desmo engine is just getting the cams and timing spot on the rest has been designed and works with the V12 engine already, one thing the pistons will be a lot bigger than the V12 as to get the cylinder head and the Desmo system to work smoothly.

R

 

[zathros]

I think laminating with 1 mm stock to get the parts (cams, etc) built up, with copious amount of cyanoacrylate will get you what you want. You could build the crank lobes up like this, sand to shape, and use wooden dowels for the Rods. I found this picture of an older (1956) Desmodromic Valve train set up, so some who aren't familiar with a spring-less valve train will know what it can look like. Have you decided which engine you will be doing?

 

[retunga]

Thanks for the photo Zathros, I can see how the engines have changed over the years with the placing of the cams for the desmo setup.

Now days Dutati combines the cams into one cam assembly as to cut down on the number moving parts.
I may at the end of the day combine both the new version and old version that uses gears to get it to work out in the best way.

 

[zathros]

From what I understand there is a spring in there now, for valve lash. I don't begrudge that. I road a Ducati Pantah at 130 mph revving at 10,000 rpm. That is unreal for most engines, and for a two cylinder, well, it's a Ducati!!

 

[retunga]

You found the picture that I had in mind that I saw some time back , for the model I will no include the spin as it is not really needed and if I do it is more just to get better tension on the rocker :cigar:arms. :cigar:

 

[zathros]

By "spin", do you mean "shim"?

 

[retunga]

oops :banghead::wacky: :bag: Thanks Z

 

[zathros]

I really am excited about this. This will be a classic!

 

[retunga]

Well after all of the work that has gone into the cylinder heads and assembly to the engine, not forgetting the wiring up of the engine for the LED spark plugs, it is now time for a project update photos as the model stands right now.

now the next part of the build is going to be the timing cover for the engine with it's cutouts to show the gearing.

Retunga

 

[57townsman]

Wow!:jawdrop:

 

[Rhaven Blaack]

THIS IS BEYOND AMAZING!!!

 

[zathros]

This is a work to be very proud of!!

 

[retunga]

Update time, the model is now 90% COMPLETE !!!
I have now added the timeing cover, the exhausts, inlet ports, and the fuel injection rail.
This would now complete the Block and Head assemblies. I have just the Bell housing and Airbox to complete and the model will complete.
Here is a few photos.

Enjoy

R