Model engine build Challenger V8

Ok my first post here at cnczone.
I have been following the excellent work Steve Hucks has done on his demon v8 build and, Steve´s engine together with cforcht´s beautiful larger version has inspired me to start building an v8 model engine.

Thought I could share some pictures of it so far.
It´s a challenger v8 (Yes know its old:))
I have a long way to go still but hopefully it will run in the end.

Machining on the block is completed and i managed to fit the liners to it. Had to machine to bore after pressing in the liners as they got a "bulge" at the water jackets.
The valves and lifters are ready.
Crankshaft is started and I plan on making this as a cross plane instead of a flat plane as is stated on the drawing.

My machines to help me on the way are 2 lathes emco V13 and maximat mentor 10. Milling machines a CNC converted ZAY7045 and a converted x1 both running mach3.

looks great, keep us updated.

These Challenger engines sound "really great"...tempted to build one myself after the success of the 25cc four cylinder I designed and built.

Just curious why you would want to change the crankshaft and therefore cam as well..??
I think the reason for the "original sound" is the way it was built.i.e. change the timing arrangement and the exhaust cycles and the engine sound changes. I've seen some that come out sounding like a sewing machine, not really the effect you want after so much work.

Excellent work by the way.

Did you cast the block..???

We do our own here and realise how much work is involved, not only in the patterns but in the casting also.

Not sure how you made your cylinders, but when we do ours, we make them undersize for most of the "fit" and then a "step" for the last 100 thou or so of the press. Avoids pressing all the way and bulging as you experienced.

Awesome, Henken! Thanks for sharing.

bluejets,
It was a thought I had since the raw material started with was round, there was material to make it into this design with the crank pins 90° apart.
But having heard some on you tube and I agree they do sound great, maybe i have to think twice on this..

No did not cast it myself. Wish I had the knowledge but i don't. Bought it as a casting kit from Coles´Power Models.

Good tip on liners.
Actually there was no problem to get the liners into the block. Heated it in the oven and cooled the liners in the fridge and it feel in place without any extra force applied. Used some locktite also to be sure it´s sealed.
The problem was when it had cooled. Measuring the bore diameter showed it was larger in the middle than in the top and bottom.
Im guessing this was due to the shrink fit and the block design where the liner only has support in the top and bottom.

I use 4140 round bar also, and mill flat to maybe 13mm depending on size required.
Big job but flat bar is not available here. I can see your point with the round bar but as you said, many things to consider.

Yes, shrinkage will do that every time when cylinder liner is oversize.
When using loktite there is no real need to have the liner any larger than the bore size. The liner is designed to be held down by the head anyhow. all that's required is a fit to stop the cylinder rattling around and leaking water. :)

Don't worry, I've made the same error and I'm guessing many others also.
Agree, the sounds on those videos are certainly an incentive.

Castings and patterns are a big job and as one would imagine, add to the build time quite considerably, but it adds also to the feeling of achievement at the end.

No points off on your part though for using a pre-made casting.
Once again, great work.

Hey Henkens,
Any progress on this build?
I'm very interested in this engine.
Nice work from what's posted.
Ozzie

Some progress has been made as can be seen on the pictures attached.

Cam gear housing, cam gear cover, distributor is completed.
Water pump is almost completed except for inlet and outlet holes.
Cam shaft and one gear is machined.
Started the work on the oil pump/crank bearing as can be seen in the last picture.

Unfortunately I broke the drill bit when drilling the oil feed holes in the crank and I did not manage to get it out so this crank shaft is ruined. :(

However I have made a new one which is a flat design. No oil feed holes drill yet....

/henken

Made some progress on Con rods and pistons.

Nice machining work!

Thanks dynosor

Some more pictures of bits and pieces.
It is not going fast, but I am getting forward.

/henken

Thanks for all the pics.
I see that the Coles site is not working. I'm thinking the problem of water jackets would mean this could not be built from billet. Anyone have ideas on that?
Also, how were the valves adjusted, were there hydraulic lifters?
Ozzie

Quote:

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Originally Posted by ozzie34231

Thanks for all the pics.
I'm thinking the problem of water jackets would mean this could not be built from billet. Anyone have ideas on that?

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I built a billet V8 block and it has water jackets. The jackets are machined and drilled in then steel liners were pressed into the cylinders.

Hello Steve,
What about the flat heads? Do you think they would dissipate enough heat or do you have a thought on how to build them with a jacket?
Thanks,
Ozzie

There are 2 ways most people cut water jackets. Slot with an end mill, and machine them in and sleeve. Heads are the same way. The heads on my V8 are too small but in a 1/4 scale or bigger you can drill water jackets into the heads. Problem with that is some passages need to be drilled and the entry hole be plugged. The other way is to mill passages in the surface. Problem with that is they need to be milled around combustion chambers and mounting hardware. Not really a problem for anyone on this site. All that said, heat is one of the things that doesn't scale down. You will need to have a way bigger than scale radiator to keep it cool. If your going to actually use a water cooled model engine you might want to consider a boat. Can't get a bigger radiator than that.

Cool. I had thought of drilling, but somehow milling the passages didn't occur to me. In a full size auto flathead is there water above the combustion chamber?
Though thinking about it I'm not sure I'd run it a whole lot!
Ozzie

I have a flat head but I am not sure where the water jackets are. If I modeled it I would exclude water in the head. Like you, I dont run them for very long.

http://i770.photobucket.com/albums/x.../MODELAM2s.jpg

Thanks Steve,
If I made the heads from aluminum and perhaps made the fins a bit deeper, ,,,,,,,,,,,,,,,,,,,,.
The Coles site is back up, sorta. Looks like a new owner and maybe the plans or castings are available, not clear on the site.
I'm old, sorta, 76, and the old flat heads interest me. But the previous casting price seemed a bit salty, well over $500 plus shipping. And if one errs, the piece might be scrap. Maybe billet would cost as much but it doesn't seem like such an outlay. I have a small bunch of 6061, but I'm sure all the wrong sizes; Murphy you know.
By the way your work is flabbergasting!
Ozzie

Thanks Ozzie and best of luck on your project.

Hello
It's been a long time since posting sorry about that.

stevehuckss396
Thanks for filling in with your experience.

ozzie34231
The valves are adjusted with a screw that is threaded into the cam follower. The screw is secured with a nut. The adjustment can be accesed through covers located inside the v.
Have you got a hold of the plans from Coles?


Finally got the engine started and running. However the road there was not easy.

First problem was the valves. The where not sealing properly which resulted in low compression. To solve this a special tool had to be made and used to recut the seats in the block.

The second problem was the carb. The walbro carb that I had planed to use was not working good. I was not able to adjust the mixture correctly to get a good running engine. After several hour trying to adjust the mixture I gave up and decided to try a rc carb from a airplane engine. It was working better but the problem now was that i had placed the fuel tank below the engine and used a electric pump to get the fuel up to the carb. To prevent the pump from flooding the engine I needed a float or some kind of reservoir on the carb. I decided to make a new carb with a float incorporated. The dimensions for the venturi and was copied from the rc carb. A new needle was made to get correct air fuel ratio for gasoline as the rc carb was set up for methanol.


The engine is working quite good with this carb. Maybe the needle can be tweaked a little but at the moment i think it is as good as I can get it.
A very short and shaky video
Miniature Challenger Flathead V8 - YouTube