80cc DOHC V8

[pat1967]

[quote Very nice work!! ;D ;D ;D I have made a similar job 2 last years
[/quote]

Hi Tony,

Your engine looks fantastic! Thank you for sharing the pics of it. I would love to hear about any pitfalls or changes you made during the construction, it looks like it was made to the original plans. I love the 4 carby manifold too.

I'm at the point now where I'm trying to decide on materials for the remaining major components, and would like to know what you choose and how you found them in terms of durability.

Pat

 

[tonyengines]

Hi pat
for all the engine -- I to use aluminum 6061 it is fantastic resistant to the temperature (not to deform)

I insert photo of carby manifold

 

[LongRat]

Tony - totally brilliant engine. I'd like to know some more too - how does it sound when running, what is performance like... do you have any videos?
Those contemplating the Schillings book should do it, although on some areas there is a slightly frustrating lack of detailed info (like his fuel injection system for example) there is still a mountain of useful info. The section drawings could be used to get a long way towards a finished engine, while they are not full plans it would only take a little imagination to construct your own plans from them. I didn't realise Schillings was actually a commercial manufacturer in the 70s/80s. Over this time he sold 500+ units of his 40cc I4 and 80cc V8!

 

[tonyengines]

hello
I have used original plans v8 (with small modifications)and v10 of Schillings

Pat you have construction plans in order to use with CNC ?

 

[pat1967]

Hi Tony,

I have the same plans that you have in your picture there. I had a friend in Germany do the translations for me to purchase them from VTH on my behalf.

To build my engine, I've modelled it (about 75% complete) in solid works and generated dxf files for the various cnc operations.

 

[pat1967]

Time to buy some material ...

I'm looking at the cylinder sleeves and crankshaft and got some quotes today for some 4130 material
- 31.8mm Dia x 3.96mm wt 4130 tube for the sleeves
- 38.1mm Dia 4130 Round Bar

A little pricey, though I'm more concerned about achieving a good finish, and it's durability. I'd rather do it once and be done with it, then have to revist because of worn bores or a twisted up crankshaft. The engine in all honesty will likely never see itself mounted in anything other then a test stand.

Is this overkill? ... Should I be looking at something else?

Open to suggestions ...

Pat

 

[tonyengines]

Pat ......this system is the best one ;D from crankshaft

 

[kustomkb]

Very nice work on your engine Pat!

That block is first rate! Can't wait to see more.

 

[pat1967]

Thanks Kevin,

Will hopefully be tackling the underside of the block over the next week or so. Although a BAS has got me a little side tracked the last couple of days, but it'll be a few weeks before the test tubes arrive

Pat

 

[kustomkb]

Ha, Ha. I used the BAS as a break from my long term project too.

 

[aussie bruce]

Hi there Pat

Cromoly tube 4130 would not be my first choice mate as it is typically drawn over mandrel and has a lot of locked in stress.

4130 solid would not be my choice either its mill finished and typically not available in the annealed variety.

I would suggest either 4140 annealed bar / hollow which is basically EN19a http://www.interlloy.com.au/data_sheets/high_tensile_steels/4140.html

or my favouite 4340 bar which is basically EN24 http://www.interlloy.com.au/data_sheets/high_tensile_steels/4340.html

Or when i can get my greasy mitts on it for special bits EN 26 http://www.interlloy.com.au/data_sheets/high_tensile_steels/en26.html

But lets face it a nice piece of 4140 does machine very well i like it more than 4130

Bruce

 

[pat1967]

Hi Bruce,

Thanks for the suggestions, I'll get in touch with interlloy and see if they will sell me a small quantity. I must admit I have no experience machining this type of steel, the closest thing was machining my ball screws for my cnc conversion.

Pat

 

[pat1967]

Been a while since updates, so here's where I am ...

I followed Bruce's suggestion and found a local supplier (Edcon steel in blacktown) that would sell me the small quantity of 4140 I was after for the cylinders, that even had no issue with cutting it down into the blanks I asked for, great guys.

Machining the OD's went without a hick up, drilling the pilot bore through is where the fun started. I stepped drilled it 5mm/8mm/10mm/12mm/16mm/22.5mm in 30mm increments (tail stock travel). Small drills went fine, as I increased in size the chips started coming off hotter and hotter and ended up needing to continuously douse the bore with coolant to keep the spirals from turning a pretty blue. Managed to get through all 8 blanks and only had to resharpen the 22.5 drill.

I decided to try bore them to size in the mill, a combination of poor quality brazed carbide boring bars, lack of rigidity, and chatter half way down the bores saw a "rifling" pattern developing. I gave up and chose to move over to the lathe before I scrapped them. I didn't have a carbide insert boring bar, so I used the remnants of a solid carbide 3mm end mill, ground it up to shape and took a light cut through one of the blanks firsts few cuts were a bit iffy, then the continuous little spirals started streaming off. Went through each blank and brought them to size. I've given them a light honing and they feel quite smooth, but the machine marks are still very visible.

Still need to make a plug gauge, and determine exactly how close to each other I have them, before playing around any more on them.

Here's a few pic of the sleeves, in the block, and the blank ...

 

[gbritnell]

Hi Pat,
I'm not posting this as a negative to your build but as some helpful information.
Sometimes a picture really exaggerates what you're seeing. That might be the case with your cylinder liners. If they aren't totally smooth and parallel you might be in for some trouble. Any little valleys aren't too bad but any small ridges are terrible.
I would recommend using a solid hone and try to clean them until they are nice and smooth.
I have always used Schedule 40 cast iron or Durabar for my liners. It machines excellent, holds size well and has the lubricating qualities of cast iron.
gbritnell

 

[pat1967]

Hi George,

No offense taken and I appreciate your comments. Once I get the gauge machined up and I know exactly how much I have to play with, I'll try honing them clean.

Pat

 

[coopertje]

Hi pat,

I have plans to build a v8 in future. I did some testing with a 4 cylinder block and figured out my own way of working. First I cut the material for the 4 cylinders to length. In the lathe I drilled up to 23.5mm (bore should be 24mm), so I ended up with 4 undersized tubes. I put them on a mandrel and shaped the OD. I mounted the cylinders in the block with locktite and placed the block in the mill. I took a 24mm reamer, started the fluid lubrication on the mill and run the reamer through. The result was amazing, very nice finish and absolute Round boring (I checked with a 3 point micrometer). I found that the trick of using the reamer is to have it swimming in lubrication fluid. For me it's a very easy and convenient way to make the cylinder borings.
Hope it's clear what I mean and keep the pics coming!

Best regards Jeroen

 

[Alec Ryals]

Hi Pat,

Nice project! I have a V8 on my to do list, too bad daily work costs so much precious hobby time... I was wondering about your machining sequence. Are you not afraid that you get cutting marks on the surface of the piston due to the already made cut-outs in the side? In my (limited) experience I get a better finish when there is a constant "load" on the tool.
Keep the pictures coming!

Best regards Jeroen

Machine tool groves hold oil.

 

[Gotty101]

Sorry to bring up an old post but I would love to know of any updates. Im hoping to build my own and I have just ordered the book. Although when I went to order the plan it said "unavailable" at http://shop.vth.de/v-8-motor.html

Can anyone help at all?

Many thanks

Trev