# Holt 75 from Italy



## Foketry (Jan 6, 2019)

Hello guys
This is my first post, but I've been following this forum for years, to learn the techniques of engine construction .I live in northern Italy just a few miles from the Ferrari factory cars, Lamborghini cars, Maserati cars and Ducati motorcycles.This area in the north Italy is called Motors valley.
I also have mechanical passion and this is one of the first engines i am building.
Some of my friends here in Italy have already built the complete Holt tractor, fully working with the engine , 
and through them i had some suggestions to build an engine.
I had to build the foundry moulds to make alluminium and cast iron castings


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## Foketry (Jan 6, 2019)




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## Foketry (Jan 6, 2019)




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## Foketry (Jan 6, 2019)




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## k2steve (Jan 6, 2019)

Welcome to the Forum Foketry, I recently have been lucky enough to have  picked up a older casting kit of a Holt 75 kit.
I will be looking forward to your post on the one your making for tips about the build. I don't know much about making castings but yours look great to me.


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## e.picler (Jan 6, 2019)

Be well come to the world of model engines!
Congratulations for your castings looks good. Did you cast at home or used outsource foundry? 

About four years ego I spent couple days at your area. I visited Ferrary Museum and had a tour at the Ferrary manufacturing building (not inside the building)

Expect to see lot of pictures. Good luck.

Edi


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## Foketry (Jan 7, 2019)

Hi Steve 
The original aluminum casting is a single piece, my castings are made in 2 pieces ,top and bottom, in my opinion it is easier to make the seats for the bushings. 
It is possible to cut the original alluminium casting  into 2 pieces


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## Foketry (Jan 7, 2019)

Hi Edi
I'm glad you've been to visit the Ferrari museum, i live about 20Km from this museum
I hope you could also appreciate the food of this area, here is produced the typical and original Parmesan cheese, Lambrusco wine, and original Balsamic vinegar.
Both castings, cast iron and aluminum, were made by 2 small factories specialized in small batches , i only made wooden moulds.


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## Foketry (Jan 7, 2019)




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## Foketry (Jan 7, 2019)

my castings were full of aluminum  inside because i did not build the internal model , but only the external one
I preferred to empty the inner part with the end mill


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## Foketry (Jan 7, 2019)

the seats or support  for  crankshaft bushings


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## Foketry (Jan 7, 2019)

The seat  for  crankshaft bushings


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## Foketry (Jan 7, 2019)




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## johnmcc69 (Jan 7, 2019)

Nice work!

 John


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## gbritnell (Jan 7, 2019)

I built my Holt the same way with a two-piece crankcase except mine was from bar stock. It made it so much easier to machine the main bearings. Very nice work on your engine. Should you have any questions please don't hesitate to ask.
gbritnell


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## Foketry (Jan 8, 2019)

Hi G Britnel, before building my Holt i read your posts several times and i downloaded your photos, practically you were my teacher.
I also followed the advice of an Italian friend of mine who had aluminum castings some years ago from USA , after several problems, he divided the aluminum castings into 2 parts.
A small difference: you have fixed the bushings supports  on the upper part, i have them fixed on the lower part to facilitate the entry of  oil.
I suppose you made this choice to get more precision between the crankshaft and  cylinders.


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## Foketry (Jan 9, 2019)

I need some advice, in the original project of the heads the spark plug is very hidden, I'd rather hollow the head to bring the spark plug more towards the chamber.
In addition to this i would like to put a Viton OR to seal the head on the cylinder and increase the compression rate up to 8: 1.
Below you can see 2 drawings: original and modified


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## Foketry (Jan 9, 2019)

the spark plug is very hidden


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## Foketry (Jan 9, 2019)

the spark plug is closer to the combustion chamber  and there is a ORing  groove


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## gbritnell (Jan 9, 2019)

When I first built my engine I machined the heads from the drawings. Like you I thought there would be an issue with the depth of the spark plug hole and initially made my own plugs with a much longer reach. When it was time to replace the plugs I tried a set of Rimfire plugs, the longest version and the engine runs just fine with those so I wouldn't work about trying to make a counterbore for the spark plugs. If you make it like you show on the model it would probably help.
gbritnell


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## gbritnell (Jan 9, 2019)

One thing you might consider while you're at this stage of the build is to see  if  you can adapt some type of seal (0-ring) into the front and rear main bearings. Even though my engine has very small clearances once it gets warm it does leak oil past the bearing. Another leak area which I don't think can be fixed without considerable modifications to the original drawings is the lifter guides. Here again even with a close fit the pumping action of the liter in the guide tends to draw oil up around the lifter and it seeps down the block. It's not bad but annoying. My engine is mounted to a set of skids made from wood and I have created 2 drip pans from brass sheet which straddle the skid. This help to keep the engine much neater when running. 
gbritnell


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## gbritnell (Jan 9, 2019)

Here are two pictures of my engine with the drip pans.


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## Foketry (Jan 9, 2019)

the roughing of  cylinder


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## Foketry (Jan 10, 2019)

roughing of the crankshaft on the milling machine


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## Foketry (Jan 10, 2019)

View attachment 106641




crankshaft turning after milling


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## Foketry (Jan 10, 2019)

Crankshaft grinding on lathe tool post


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## Foketry (Jan 10, 2019)

crankshaft assembled on crankcase


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## Foketry (Jan 10, 2019)

gbritnell said:


> One thing you might consider while you're at this stage of the build is to see if you can adapt some type of seal (0-ring) into the front and rear main bearings. Even though my engine has very small clearances once it gets warm it does leak oil past the bearing. Another leak area which I don't think can be fixed without considerable modifications to the original drawings is the lifter guides. Here again even with a close fit the pumping action of the liter in the guide tends to draw oil up around the lifter and it seeps down the block. It's not bad but annoying. My engine is mounted to a set of skids made from wood and I have created 2 drip pans from brass sheet which straddle the skid. This help to keep the engine much neater when running.
> gbritnell



Thanks for  suggestion, i keep it in mind
My crankshaft is round, maybe it will lift less oil qty than a flat crankshaft, i hope.... , i'm going to put  some Oring


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## necchiom (Jan 11, 2019)

Wow: Awesome project and realization! Bravissimo.


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## rodue (Jan 12, 2019)

One problem with the one I built and one my friend built is with out a oil ring  it throw a lot of oil. That may be brought on by the crankshaft Your construction of the crank may illuminate that problem. I built this deflector to help keep the engine clean


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## Foketry (Jan 14, 2019)

gbritnell said:


> When I first built my engine I machined the heads from the drawings. Like you I thought there would be an issue with the depth of the spark plug hole and initially made my own plugs with a much longer reach. When it was time to replace the plugs I tried a set of Rimfire plugs, the longest version and the engine runs just fine with those so I wouldn't work about trying to make a counterbore for the spark plugs. If you make it like you show on the model it would probably help.
> gbritnell



Thanks for the suggestion,  i ave already ordered the spark plugs long reach in USA (S/S Machine OH)






The partially worked heads




  partially worked heads


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## Foketry (Jan 14, 2019)

The electrode spark plug  is uncovered and not inside a hole as the original project ( this head is a casting scrap)


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## Foketry (Jan 14, 2019)

Manifold  TEE for wather manifold


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## Foketry (Jan 14, 2019)

Rocherarm pedestal


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## Foketry (Jan 14, 2019)

The  connecting rods


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## rodue (Jan 14, 2019)

great work its nice to have that equipment to mill I am doing the old way and too late to make changes.


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## Foketry (Jan 15, 2019)

rodue said:


> great work its nice to have that equipment to mill I am doing the old way and too late to make changes.


I had a manual milling machine and a manual lathe.
I bought Chinese drives,  italian ball screws and i did the wiring .
I converted them into CNC machines with great satisfaction
But i think  if i have been able to transform the machines, anyone is able to do this.

A question, why did you put the bent copper tube in the exhaust manifold ?


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## Foketry (Jan 15, 2019)

A pair of cams (double)


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## Foketry (Jan 16, 2019)

The gear case








Distributor gear case


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## Foketry (Jan 19, 2019)

Timer Body


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## Foketry (Jan 19, 2019)

Exaust manifold , roughing and finishing


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## kuhncw (Jan 19, 2019)

You are doing very nice work.  I enjoy seeing how you set the parts up for machining.

Thanks.

Chuck


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## e.picler (Jan 19, 2019)

Hi Foketry!
What CAm are you using? I also would like to know what CNC comand you have on your Milling machine. Is it Mach3?

Edi


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## e.picler (Jan 20, 2019)

You are making a fast progress.

Edi


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## Foketry (Jan 21, 2019)

e.picler said:


> Hi Foketry!
> What CAm are you using? I also would like to know what CNC comand you have on your Milling machine. Is it Mach3?
> 
> Edi


Hi Picler
I used old Artcam and Mach3


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## Foketry (Jan 21, 2019)

the first phase of the intake manifold


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## Foketry (Jan 21, 2019)

The second phase of the intake manifold , i glued the manifold on a wood
base and took the references on the central hole ,drilled in the first phase
You can see a small displacement between the first and second phase.
 I corrected the profile with  file .

*The challenge is to make internal holes and close them with welded aluminum caps ...*


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## Foketry (Jan 26, 2019)

The piston rings


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## Foketry (Jan 26, 2019)

Piston ring grinding


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## Foketry (Jan 27, 2019)

Flange grinding for exhaust and intake manifold 
To get the 4 flanges all on the same plane without flatness errors, I mounted a 12,000 rpm spindle motor on the milling machine and with the grinding wheel  I finished the planes


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## Foketry (Jan 27, 2019)

After grinding


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## e.picler (Jan 28, 2019)

Hi Foketry!
Great job, you are making fast progress. 
At this pace, we will see it running pretty soon.

Congratulations

Edi


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## Foketry (Feb 19, 2019)

the water pump


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## Foketry (Feb 19, 2019)




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## Foketry (Feb 19, 2019)

radiator assembly


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## Foketry (Mar 5, 2019)

Finally the engine is running    

With  help of my friend Iader we have fine-tuned the timing and carburetion
I used a small Rc model carburetor which , they told me , was more reliable than a self-built carburetor


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## johnmcc69 (Mar 5, 2019)

A beautiful display & great runner!

 Congratulations!

 John


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## Johno1958 (Mar 5, 2019)

Love it. Great work.
Cheers
John


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## kuhncw (Mar 5, 2019)

Very well done.  Congratulations.  I especially like the low idle in the first part of the video.  Sounds great.

Chuck


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## k2steve (Mar 6, 2019)

I can't believe haw fast you completed a fantastic project as this.  I really enjoyed you post of the build.


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## bobden72 (Mar 6, 2019)

Hay that sounds really nice great tic over speed, congratulations.


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## e.picler (Mar 6, 2019)

Congratulations!
Very nice running sound. I also liked the low idle.
Great building.

Edi


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## bobden72 (Mar 7, 2019)

Lovely work and sounds great especially just ticking over well done.


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## rodue (Mar 21, 2021)

sorry  I am late with a reply, without a oil ring it spits oil on the engine so I added the tube, for easer clean up


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## e.picler (Mar 22, 2021)

Congratulations Foketry!
It really runs perfectly. The idle rpm is amazing.
Top Noch!

Edi


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## gbritnell (Mar 23, 2021)

Great job! The low idle is fantastic. Mine will idle down very slowly but not as slow as yours. 
gbritnell


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## gbritnell (Mar 23, 2021)

I don't have an oil ring on my pistons. Once the engine breaks in and the rings seat it should take care of that problem. I find that more of the spitting is from excess fuel buildup in the manifold. Add a little dirty oil to it and it seems like it's all oil but it's not. 
gbritnell


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