another HEMI project

[OUTBOARDER]

Started a making chips for a new project today.:)

[OUTBOARDER]

Loaded And Debugged Outside Profile Program.......................

[Powerabout]

removeable combustion chambers?

[Master Oil Racing Team]

This will be an interesting project to watch come together. It's hard to tell exactly the thicknesses of the thin and thicker aluminum pieces, but I'm guessing that's how you make the water jacket??? Milling out the water path of the components, then mating a thick piece with a thin one???

[850cc racer]

what is this to fit? omc or yammie?..

[OUTBOARDER]

finished session 4 will make chambers next week................

[leehall91]

Could you build a set for a tohatsu 50 d?

[Powerabout]

Nice work

What are you going to do for chamber design, experiment, software?

Cheers
Thanks for the PM

Powerabout

[Mark75H]

Probably a good guess based on Gordon Jennings' book ;)

[50hptiller]

oooooooooooowwww looks good keep us up to date

[OUTBOARDER]

Nice work

What are you going to do for chamber design, experiment, software?

Cheers
Thanks for the PM

Powerabout

Sam knows I use Blairs program, calculates squish velocity for a particular application taking , rpms,compression,port timing and several other engine design factors into consideration. The reason for the interchangeable domes is to make the head for different applications/fuels. Will make some for omc 49ci & 56ci in the future.

[OUTBOARDER]

Hurricane/Tropical Storm/Tropical Depression = Danny Missed:)

Each cyl dome will have indvidual water in and out, consistent chamber temp!
Will go back to shop to make domes next week, Stay tuned;)
Anthony

[OUTBOARDER]

I can see the light at athe end of the tunnel now and am almost done.

[Powerabout]

When you say band do you mean the clearance or the band as in area?

[OUTBOARDER]

Is it up to the customer to set the squish band on these heads? :confused: :eek:NO

ALL Cylinder Head Chamber Geometry is based on:

Bore
Stroke
Rod Length
Deck Height
Exhaust Port Timing
Exhaust Type
Target RPMS
Fuel Type
Apllication
Max Squish Velocity
Cooling System details

and knowing what will work for a particular application ...........:cool:

[David Mason]

That's a lot of measurements that I'd have to know before I could order one of your heads. How does one measure "Max Squish Velocity"?

Ask a motor builder.

[Bill Van Steenwyk]

David:

Several years ago you could purchase Blair's book and computer programs from SAE (Society of Automotive Engineers). At that time the book and programs were approximately 4-500 dollars. Expensive, but well worth it, as it tells you most everything you need to know about hi-performance 2-stroke tuning and design. There may be revisions out now with more up to date info. Try the SAE web site and you will probably find something. I'm sure if you "Googled" high performance 2-cycles or similar, you would also find a wealth of information in addition to the squish band info you mentioned.

[Seagull 170]

Bill, I'm sure someone will correct me if I'm wrong, as it's several years since I delved into Prof. Blair's book (all the software was MS Dos) but weren't his squish calcs mainly working around his own patented deflector piston.

I've worked on several of his engines & the cylinder/piston geometry is very very different to the looper we're talking about here, at the point of ignition the squish is moving gas at very low velocity almost straight through the spark plug gap increasing in speed as the burn progresses towards TDC,
as his design gives a very simple one directional flow you can almost see the way the turbulance & flame path would move, unlike the insanity that must be happening in a looper head.

In the early 80's British Seagull who I think were the only outboard manufacturers to work with him, were getting about 1 Bhp per cubic inch at 4500 revs with very low fuel consumption, from a mass produced, very low tech, stock fishing motor almost as crude as every other Seagull you've ever seen.

[Powerabout]

Here ya go

http://www.bimotion.se/

click cyl head
and


http://books.sae.org/author/1073416002

[Seagull 170]

Thanks for that, I've never seen the Bimotion stuff before, looks very interesting.
Seems like I'll be spending & reading, before I get my hands dirty again!
Have you used that software, what did you think? in terms of user friendly.

Many thanks

Charles

[OUTBOARDER]

I can see the light at athe end of the tunnel now and am almost done.
More domes, had to go to the lathe to hold tolerances close!
Can't wait to get these on the water and running:)

[OUTBOARDER]

Well it will be test wheel soon and will see what it is.
Until then I will have to wait..................

[OUTBOARDER]

Test #1
Jetted way rich and pulled 3 deg of timing out:eek:

Still picked up 550 rpm over "modified" stock head:D with CC's between the two very close!

Test #2
TBA

Thanks for watching

[Jackson]

When R U going 2 B Selling them?

[Fast Fred]

Jackson When R U going 2 B Selling them?
17 Hours Ago 11:48 AM in OMC 56 cuber.:cool:

[OUTBOARDER]

I will start 56ci on Saturday!

I guess yall want more compression!!!
Will get going on this and put up pics!!!



Anthony
Will have to hurry I start school again in the summer and OT at real job:mad:

[formeone]

ide be interested in heads for the 49.9 3" bore /850 /form-e class....dont know if possible to o-ring them??...cheyney

[OUTBOARDER]

When R U going 2 B Selling them?

I want to finish up testing and look at it one more time!!!
What engine did you have in mind?

Anthony

[OUTBOARDER]

ide be interested in heads for the 49.9 3" bore /850 /form-e class....dont know if possible to o-ring them??...cheyney

Yes can o-ring head if you do not want to use a head gasket.
When do you need it?

email modifiedoutboard@hotmail

Thanks,
Anthony

[formeone]

similiar to the 56 cuber but the 3" bore ..head bolt pattern different,,, the 70 hp evinrude we all run in form-e/850 hydro...

[OUTBOARDER]

TEST # 2 (Picked up 650 rpms over "modified" stock head ):cool:

Went down 1 jet size and gained 100 rpm vs test 1, Still rich @ 800F egt ,
Timing still backed down 3deg vs base line "modified" stock head.

TEST #3 TBA:D


Test #1
Jetted way rich and pulled 3 deg of timing out:eek:

Still picked up 550 rpm over "modified" stock head:D with CC's between the two very close!

Test #2
TBA

Thanks for watching