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gbritnell
04-16-2010, 08:03 AM
Gentlemen, I finally have most of the bugs sorted out of my 302 Ford V-8 engine. It's been a long trip playing with carbs and ignitions to finally get it to this point. As most of you know, sometimes the building part of the job is the easiest. The fine tuning part takes almost forever. Anyway I wanted to share the latest video of it running. I will have it and 3 of my other IC engines at NAMES.
gbritnell
http://www.youtube.com/watch?v=O_vQp0gevh0

Michael Edwards
04-16-2010, 08:44 AM
That sounds great. Truly a fantastic piece of work. Thanks for sharing, that is inspiring.


ME

Willy
04-16-2010, 10:18 AM
Wow!
A beauty, lots of detail, right down to the Motorcraft oil filter. My BIL is a dyed in the wool Ford nut, wait till he sees this one. Lots of hours I'm sure but well worth it. I'd love to see some pictures of the build in progress if you have any.
Here's a pat on the back and a couple of "atta boys", well done, I just wish I had the patience to see a job like that through.

Black_Moons
04-16-2010, 11:34 AM
Very nice looking engine! Wish I had the motivation to start and finish such grand projects. Im amazed at people who can do such long projects to the very end.

m_kilde
04-16-2010, 12:12 PM
Most wonderful work.

I was thinking it could be a great idea to have such an engine mounted in the lawnmover, sure would make the neigthbors look - "maybe my grass is not more green, but my mover sure sounds better" :)

lazlo
04-16-2010, 12:18 PM
Stunning! We're not worthy :p

Even more impressive that you've got 2500 hours invested in it (!). That's focus.

Weston Bye
04-16-2010, 12:19 PM
Most wonderful work.

I was thinking it could be a great idea to have such an engine mounted in the lawnmover, sure would make the neigthbors look - "maybe my grass is not more green, but my mover sure sounds better" :)

Good idea! Could almost make a person enjoy mowing the lawn.:D

Smokedaddy
03-28-2011, 09:51 PM
Incredible, thanks for sharing.

-SD:

Black_Moons
03-28-2011, 09:56 PM
Wow, its starting to sound nice too. Gonna add a little muffler? :)

Carld
03-29-2011, 08:48 AM
Nice job, did you cast some of the parts or machine everything from solid?

vpt
03-29-2011, 09:12 AM
WOW! I was expecting an actual 302 in a car. That thing is amazing!


Not sure if these are like the big ones that need to warm up before running perfect. I have tuned many of cars both carbed and EFI. To me this engine sounds 1. cold, and if not cold 2. sounds like to much fuel or not enough air or both.

gbritnell
03-29-2011, 10:36 AM
Hi vpt,
I have tried every conceivable carb on this thing, some quite complex and the one in use today, very simple. I have built them similar to full sized carbs with floats and booster venturis with no better performance. There are several problems involved when carbureting these little engines. First is the small amounts of fuel they use and how best to meter it and second is there's no accurate way to 'read' the richness or leanness except by the old 'seat of the pants' method.
Another thing that would help the performance would be to have some kind of advance for the ignition. On this engine I have a Hall effect trigger with fixed timing. The engine will spin an honest 7200 rpm so to go from idle, 750 rpm, to top rpm with fixed time is quite a feat.
The carb I ended up with is one used on a model airplane engine. I got it dialed in quite close. I have to adjust the mixture screw minutely when revving it up, more fuel. After I got everything close I replicated the venturi, jet size, and airbleed orifice into what looks like a factory type carb. It runs about the same as the model airplane carb. As you can see from the bottom of the carb the bore size is very tiny.
http://img.photobucket.com/albums/v43/gbritnell/302%20FORD%20V8/302carb2.jpg
http://img.photobucket.com/albums/v43/gbritnell/302%20FORD%20V8/302carb1.jpg
http://img.photobucket.com/albums/v43/gbritnell/302%20FORD%20V8/302carb6.jpg
http://img.photobucket.com/albums/v43/gbritnell/302%20FORD%20V8/302carb4.jpg

gbritnell
03-29-2011, 10:43 AM
Here's a couple of pics of the engine. The first was a complete tear down because of leaking head gaskets. The second is with the intake manifold off to fool with the rocker oiling system. The last is just a front view of the block when I machined it. The quality of the pictures isn't good because they were scanned from old 35's that I had taken when I built it.
gbritnell
http://img.photobucket.com/albums/v43/gbritnell/302%20FORD%20V8/302FORDAPART.jpg
http://img.photobucket.com/albums/v43/gbritnell/302%20FORD%20V8/302FORDAPART1.jpg
http://img.photobucket.com/albums/v43/gbritnell/302%20FORD%20V8/302FORDBLK1.jpg
http://img.photobucket.com/albums/v43/gbritnell/302%20FORD%20V8/302FORDBLK2.jpg

Carld
03-29-2011, 10:53 AM
gbritnell, forget about making a real carb. Just use the the carb in the photo's and put the simple carb inside. Forget about making the real thing, just hide what works inside the authentic looking carb.

vpt
03-29-2011, 03:26 PM
That is amazing! Don't you hands cramp up from working with such small parts all the time?

DFMiller
03-29-2011, 04:14 PM
That is very impressive. I can't wrap my head around where one would start.
I truly enjoyed the pictures and the video.
Thank you.
Dave

A.K. Boomer
03-29-2011, 05:13 PM
That's unreal -- im looking all over for a size reference for the engine pic - I know you stated 1/3 scale, but would be handy to see something next to it that kinda gives a better Idea,,, Are those old plastic camera film packs off to the upper right corner of the engine pic?


I have no idea where guys like you find the time or the patience, nice work.

A.K. Boomer
03-29-2011, 05:15 PM
gbritnell, forget about making a real carb. Just use the the carb in the photo's and put the simple carb inside. Forget about making the real thing, just hide what works inside the authentic looking carb.


uhhh yeah --- something tells me he wouldn't be happy with that :p

Willy
03-29-2011, 05:19 PM
George when you started this thread last year I didn't think that you got the recognition that your project deserved.
I'm glad to see now that between your engine and the T-5 transmission projects that you are finally getting the exposure and accolades that are so richly dissevered.
Sometimes when a thread slips off of the first page of the forum it can easily get lost before it has the chance to receive the exposure it deserves.

Your engine's ability to run between 750 to 7200 rpm, with fixed timing no less, speaks volumes about your tunning and machining skills.
My own opinion as to why you can't quite get the carburetion as crisp as you would like has to do with scaling.

While it is one thing to scale dimensions down, it is quite another to scale down the dynamics of air/fuel mixture. All at once fuel vapor size, boundary layer air flow, and a host of other seemingly irrelevant details take on altogether different characteristics from their full scale counterparts.

Willy
03-29-2011, 05:22 PM
That's unreal -- im looking all over for a size reference for the engine pic - I know you stated 1/3 scale, but would be handy to see something next to it that kinda gives a better Idea,,, Are those old plastic camera film packs off to the upper right corner of the engine pic?


I have no idea where guys like you find the time or the patience, nice work.

AK, look at the video in the OP's first post.

Black_Moons
03-29-2011, 05:26 PM
Woah! awsome inside pictures! I don't think I have ever seen a tear down of a micro motor before, thats awsome. Looks just like a full size motor torn down.

gbritnell
03-29-2011, 05:29 PM
Thanks Willy and everyone,
To be totally honest I post my stuff to share with other people. A lot of people don't even know this kind of thing exists, even car people. I'm glad to see that it was resurrected. Over the years I have met some very talented and gifted craftsmen and have learned from them and by just digging in a trying things.
You're so right about the dynamics of miniaturization. Most of the physics can't be scaled effectively, flywheel size (centrifugal force) fuel flow (vacuum signals) etc.
gbritnell

A.K. Boomer
03-29-2011, 05:33 PM
AK, look at the video in the OP's first post.


I toughed it out and loaded the video (still have dial up)

it was well worth the 15 minutes! awesome. (and yes good size reference)

gbritnell
03-29-2011, 05:33 PM
Hi A.K. Boomer,
Here's a picture that will give you an idea of the scale and yes those are old 35mm plastic film canisters.
gbritnell
http://img.photobucket.com/albums/v43/gbritnell/302%20FORD%20V8/302e.jpg

A.K. Boomer
03-29-2011, 07:17 PM
Very cool - Hey, that is a one inch mic and not a three inch right? your not trying to pull a fast one on us are you?

plastic film canisters or garbage cans? ;)


Your an amazing talent GB, The HSM site has it's very own Pierre Scerri (and that is one hell of a compliment by the way as im sure you already know)

Boostinjdm
03-29-2011, 07:43 PM
What are you running for fuel? Is the cooling system functional?

I think you should build a small dyno for it. I'm sure everybody is curious about the power output. It would be cool to see if the power is to scale also.

Ken_Shea
03-29-2011, 07:47 PM
George, you've come a long, long ways since "plastic models, mini Bikes and lawnmower engines";)

Here is a rather nice write up on George.
http://www.craftsmanshipmuseum.com/Britnell.htm

gbritnell
03-29-2011, 08:07 PM
Hi Boostinjdm,
The engine uses 86 octane pump gas. The compression isn't too great, about 8:1, so I have never experimented with other octanes. The cooling system and oil pressure system are fully functional just like it's full sized counterpart. All of the oil passages were machined in. The oil pump is driven from a hex shaft coming out of the bottom of the distributor and feeds to the filter, which has a fine stainless screen in it, then to the main galleys, the mains, through the drilled crank and to the rods.
The cooling system was created by machining all of the area in the cylinder banks and then mounting a head plate onto the top deck. The iron sleeves were then pressed and epoxied in place. The heads were machined from a bar of iron so to get some water through it I layed out the end view of the head showing the ports, head bolts and pushrod holes. In the remaining area I drilled 2 holes the length of the head. The water openings were then drilled into these longitudinal holes. The water crossover ports were then machined into them so that the water would go through the ends of the intake manifold and back to the radiator.
http://img.photobucket.com/albums/v43/gbritnell/302%20FORD%20V8/302FORDHEAD2.jpg
http://img.photobucket.com/albums/v43/gbritnell/302%20FORD%20V8/302FORDHEAD1.jpg