Author Topic: My '59 Enfield /Indian 750cc Chief High Compression Build  (Read 161222 times)

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Offline Briz

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Re: My '59 Enfield /Indian 750cc Chief High Compression Build
« Reply #45 on: December 11, 2013, 05:59:14 PM »
I think you need to read up on balancing.

Yeah; that. Spinning a crank up to balance it doesn't replicate reciprocating forces.
If you're working with Falicon on the crank, I think you'd be well advised to discuss the possibility of a billet crank.
Hell, you're in the US! getting someone to make a billet crank is easy! :-D

Offline wobblywalrus

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Re: My '59 Enfield /Indian 750cc Chief High Compression Build
« Reply #46 on: December 12, 2013, 12:03:07 AM »
My experience is with BSA and Triumph twins and mainly the unit construction ones.  It was essential to blueprint those motors.  These were checked and rectified as needed:

crank centerline parallel to crankcase deck
crank centerline parallel to cam centerline
cylinder base parallel to cylinder deck
bores at right angles to cylinder deck and base

Hopefully Enfield has better machining practices than BSA and Triumph.

The Hinckley Triumph I run is a fully developed race motor and far stronger than any of those old ones.  It can run up to 9,000 rpm without blowing apart.  Engine life is pretty short at those speeds.  The rev limiter is set at 8,500 rpm and it is never run over 8,000 rpm through the mile, and I like it to be around 7,300 to 7,500 rpm.  The reason:  sometimes it takes a whole lotta miles at full throttle to do what needs to be done.  The engine needs to stay together through all of this.  The point of saying this is that land speed engines lead hard lives.  This needs to be considered when they are set up.

(7,500 / 9,000) x 100 = 83%  The engine is set up to run continuously at around 83 percent of its maximum rpm and this is what I usually use.
(8,000 / 9,000) x 100 = 89%  The engine will run at 89% of maximum, and this is not done unless it is essential to snag a record.

Anyway, this is how one guy out of hundreds of us does it.   

Offline Scottie J

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Re: My '59 Enfield /Indian 750cc Chief High Compression Build
« Reply #47 on: December 12, 2013, 10:22:37 AM »
Billet crank?  That sounds awesome!  And awesomely expensive.

Panic - Tom Lyons at Ace Cafe is doing my head work and helping me crunch the numbers.

wobblywalrus - I like your thinking about how you run your motor.  That makes perfect sense and will take into consideration with the blueprinting.

I did a little research also, and I an definitely going to running EFI and probably a Garrett G1241 turbo.  Probably shoot for a 9:1 DCR and start with 4-6 PSI of boost.

Scottie

Offline TheBaron

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Re: My '59 Enfield /Indian 750cc Chief High Compression Build
« Reply #48 on: December 12, 2013, 03:11:56 PM »
Hi Scottie,
    I've been following your build as I've been doing something somewhat similar...

Wobblywalrus is so correct that rpm will hurt our old motors faster than about anything else, ,, boost is not that hard on the motors if the heating issues are under control....

I'd go for 5 psi minimum and 7.5 psi max to start with...You will not get any net power increase till you are past 2/3 psi as it is going to take that much boost to offset the drag of the blower...

Don't spin the blower any faster that necessary to reach the boost level you need as it will waste power and puts even more heat into the compressed fuel mixture.

Use an electric fuel pump to maintain fuel flow or you will wish you had,,,gravity feed will not cut it 99% of the time. Efi will do it as it will have to have a pump...

I think you should consider dropping the compression ratio way lower....You could realize more power "down the road" by working up the boost levels to put back the compression and the heating problems you will have will be less abrupt . Put in a CHT gauge and watch it like a hawk....
Air cooled engines are good at 350 to 400 degrees F  Cylinder Head Temp.  Redline should be 425 to 450 degrees depending on the quality of the cylinder head alloy . Don't push against the redline on a long pull or you will kill your motor....You can get away with murder at a drag strip with the motor temps because of the short run time... WFO for mile after mile is way different...

Use boost and not rpm to make power and life will be way easier later on....

Best of luck with everything,
Robert

Offline panic

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Re: My '59 Enfield /Indian 750cc Chief High Compression Build
« Reply #49 on: December 12, 2013, 03:26:17 PM »
I had to guess at the rod length, but 16:1 with IVC at 77° ABDC is much lower than 13.5:1, closer to 11.2:1.
I assume that with the turbo the cam choice goes back on the table?

Offline panic

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Re: My '59 Enfield /Indian 750cc Chief High Compression Build
« Reply #50 on: December 12, 2013, 03:43:32 PM »
X2 on boost vs. RPM, the motor will stand more stress from just cylinder pressure than pressure plus inertial load.
Since you have T120 spec primary (ISO 06B-2) a small blower could be run off this; Triumphs ran blowers in front of the engine.
The small engine size dictates a small blower to reduce parasitic loss and improve sealing, such as an Eaton M24. More about this in my article:
http://www.victorylibrary.com/supercharger/super.htm

Offline thefrenchowl

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Re: My '59 Enfield /Indian 750cc Chief High Compression Build
« Reply #51 on: December 12, 2013, 04:57:57 PM »
Hi, Interesting!!!...

I'm usually tuning my side valve, 5.5 to 1 static, and have great pain to understand the race towards higher CRs on boosted engines...

A simple calc will show anybody that the lower the static CR on a boosted engine, the more mixture you can cram in (capacity plus head volume every 2 revs so, if CR is lower, head volume is bigger...)

So it boils down to: is it better in the same cylinder to burn "some more" at a boosted 10/1 CR or burn "some less" at a boosted 14/1 CR???

Stresswise, I'll always opt for the lower ratio!!! Last time on the Salt Flats, an average 2 mile run took me about 1mn1/2 (1mn to get to the start of the 2nd mile, second mile over 120mph = about 20 seconds) As mentionned before, all that on a fully loaded WOT vintage engine...

Another thing to consider for your engine and its longevity: to get to 200mph, how many miles will you need... Traction was a bit poor this year. On my best run, I entered the 2nd mile at 118mph and exited at 123mph, 5mph gained in 1 mile and I tried my hardest to go faster but the rear tyre just wanted to spin on the salt. 123mph with a 135mph gearing/engine speed, the difference was tyre spin.

Patrick,

PS: see most of you again next year, I'm a fully grown addict now...
« Last Edit: December 12, 2013, 05:16:12 PM by thefrenchowl »
Flat Head Forever

...What exactly are we trying to do here?...

Offline panic

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Re: My '59 Enfield /Indian 750cc Chief High Compression Build
« Reply #52 on: December 12, 2013, 06:54:59 PM »
More about "balance the rotating assembly to at least 10,000 rpms".
"Balancing" is adjusting the flywheel mass to (partially) compensate for the distribution of weight between rotating and reciprocating components, and for the general layout of the engine (single, parallel twin, V-twin, L4 etc.).
RPM is not a factor in balancing, so balancing to 10,000 RPM is the same as 10 RPM.

What may wreck this engine is not out-of-balance forces (although important) but torsion-induced vibration, which cannot be removed or even reduced by balancing.
This force is always present during operation, and can be predicted to some degree as to exactly when the forces are large enough to cause damage.
In automotive (and some motorcycle) engines this is addressed with a harmonic damper (improperly called a "balancer"), which if properly selected suppresses vibration at specific RPM points. The RPM at which these points occur is greatly affected by engine design, and by the rigidity of the flywheel (very good, in this case).
RE engines don't have anything like this as OEM, and none have been offered in the aftermarket TIKO.
One might be constructed and attached to the engine sprocket, but it's an engineering project on its own.

Offline wobblywalrus

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Re: My '59 Enfield /Indian 750cc Chief High Compression Build
« Reply #53 on: December 12, 2013, 10:35:07 PM »
An Indian/Enfield twin set a record at BUB this year in the 750-P-PV class at 79.451 mph.  There is a nice full page picture of it in Sccoter's book. 

Offline Scottie J

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Re: My '59 Enfield /Indian 750cc Chief High Compression Build
« Reply #54 on: December 12, 2013, 11:30:01 PM »
Thanks for the clarification on balancing panic.  And as far as I know there are no harmonic dampers available for REs.

An Indian/Enfield twin set a record at BUB this year in the 750-P-PV class at 79.451 mph.  There is a nice full page picture of it in Sccoter's book. 

That's pretty lame.  I've had my '58 Trailblazer to 92 mph on my GPS and it's geared super short.

Scottie

Offline Briz

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Re: My '59 Enfield /Indian 750cc Chief High Compression Build
« Reply #55 on: December 13, 2013, 08:23:50 AM »
Dont forget that at the elevation of Bonneville and its lower air density, you're automatically down about 10-20% on power.
Lots of folks (me included!) have shown up at the salt thinking its going to be easy and gone home with tail between legs!
A 92mph bike will be lucky to go 79 at Bonneville.

Offline SPARKY

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Re: My '59 Enfield /Indian 750cc Chief High Compression Build
« Reply #56 on: December 13, 2013, 09:08:36 AM »
S J  I think the boys are trying to tell you  Welcome to the LSR school--- My buddy Russ Mack bike was called "Bonniville Elementary Skool"

Some of us have GEDs others PHDs but for most of us we share a common bond for most of us we got nearly a graduate degree in engineering whith what we had to learn to get there   YMMV
Miss LIBERTY,  changing T.K.I.  to noise, dust, rust, BLUE HATS & hopefully not scrap!!

"Security is mostly a superstition. It does not exist in nature, nor do the children of men as a whole experience it. Avoiding danger is no safer in the long run than outright exposure. Life is either a daring adventure or nothing."   Helen Keller

We are going to explore the racing N words NITROUS & NITRO!

Offline bak189

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Re: My '59 Enfield /Indian 750cc Chief High Compression Build
« Reply #57 on: December 13, 2013, 11:00:42 AM »
Hey, I am going to tell you what the other posting here apparently are to shy to tell you....There is NO way you can get that Enfield to go 200mph.................Sorry, but that is a fact............
Question authority.....always

Offline Scottie J

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Re: My '59 Enfield /Indian 750cc Chief High Compression Build
« Reply #58 on: December 13, 2013, 11:06:05 AM »
Dont forget that at the elevation of Bonneville and its lower air density, you're automatically down about 10-20% on power.
Lots of folks (me included!) have shown up at the salt thinking its going to be easy and gone home with tail between legs!
A 92mph bike will be lucky to go 79 at Bonneville.

I live in Denver, I'm about 1,200' HIGHER than Bonneville.  Once I rejetted the carb I'd actually pick up a couple mph if anything.  And for the bike I'm building now will EFI with laptop interface so I can program the fuel map to whatever I need.

Hey, I am going to tell you what the other posting here apparently are to shy to tell you....There is NO way you can get that Enfield to go 200mph.................Sorry, but that is a fact............

Yee have little faith.  I might not hit 200mph my first time out.  But I WILL hit it one day with this bike.  Thanks for your motivational words of kindness.    :-D

Scottie

Online sabat

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Re: My '59 Enfield /Indian 750cc Chief High Compression Build
« Reply #59 on: December 13, 2013, 02:09:13 PM »
Hey, I am going to tell you what the other posting here apparently are to shy to tell you....There is NO way you can get that Enfield to go 200mph.................Sorry, but that is a fact............

Even with a blower, methanol, and a fancy fairing? I have zero experience with pushrod engines, I'm curious how far off you think this combo would be?