Board index Flathead Power-Technical Questions, Answers, and Suggestions Shovels Sifton 103 cam

Sifton 103 cam

Moderators: Curt!, Pa

Post Tue Nov 06, 2007 3:07 pm
HK

Posts: 87
Location: Sweden
Does genuine Sifton products have any dependable tech support anywhere?

I need to know what the recommended static compression should be and also recommended valve spring forces for a Sifton 103 cam.
Engine is -69 Shovel with stock stroke and 3-7/16"+.060" pistons with approx 9:1 CR. Intake closing on the 103 cam is 57 degrees ABDC (@ .053"), lift 390" on both In and Ex.

HK

Post Thu Nov 08, 2007 10:54 pm

Posts: 646
Location: Detroit
Bro', unfortunately these days "genuine Sifton" cams are genuine Asian junk, and have been for a long time. Quality control is awful. About the best you can do if you want Sifton is try to find a Sifton made during the early to mid 70s, or else get a modern day Crane or Andrews. Actual quality old stock Siftons are stamped .412, .414, .440, .468, etc., not the 103 etc., designation. Crane and Andrews actually have English speaking knowledgeable humans who answer the phone when you call them.
New Knuckleheads? Thank, you, Jesus!!

Post Sat Nov 10, 2007 1:51 am
HK

Posts: 87
Location: Sweden
Krazy,

I thought this was a real Sifton cam as it is a known "old" cam, but it has the "103" designation stamped in so obviously not old enough!
That may be the reason for the variations in base circle diameters and lobe heights we found on this cam even though it don't appear to be worn...
I'll go for another cam.

Thanks!

HK

Post Sun Nov 11, 2007 5:19 pm
JIm

Posts: 801
Location: Planet Earth

Post Mon Nov 12, 2007 4:37 pm

Posts: 646
Location: Detroit
I would try an Andrews "A" grind. It bolts right in shovels with no head work, starts easy enough, and cranks hard. Use solids with an "A". Andrews has a version of the "A" for use with hydraulics, a "B" I think, but my own belief is hydraulics belong in a blast furnace, not a shovel engine. I also used an "A" grind in a 10 to 1 pan with UL wheels without notching the pistons and had no problems with it. At idle your engine will bounce around a bit more but you can't have everything.
New Knuckleheads? Thank, you, Jesus!!

Post Tue Dec 11, 2007 8:41 pm

Posts: 150
Location: Carver, MN

For what its worth, the A grind Andrews is a hydraulic grind, but will work fine with solids. The B grind is a solid lifter cam. The BH grind is the hydraulic version of the B grind. If you really have 9:1 compression ratio the B or BH would work well, but if the compression ratio is less the A will work better.

Post Thu Dec 13, 2007 11:45 am

Posts: 646
Location: Detroit
Here is Andrews' list for pan and shovel motors.

http://andrewsproducts.com/motorcycle/c ... N_Cams.htm
New Knuckleheads? Thank, you, Jesus!!

Post Fri Dec 14, 2007 11:50 pm

Posts: 903
Location: Hill City, Ks. USA

I always liked the Andrews F grind for shovelheads. I was bitching to one of their techs that it had been discontinued and he told me to take an A grind cam, press the gear off and retard it 7 degrees. It was a great cam for heavy bikes and for street use. I ran an A grind for years and you just had to wind it up too much to get into the sweet spot. I ran a BH for a while and liked it a lot. You have to run hi-lift collars or do a bit of machining to run a BH, but I recommend it highly. Much better than the A grind IMO.
BTW, I won't run or recommend anything but S&S or Andrews cams. The tech support and customer service from these 2 brands are head and shoulders above the rest of the industry. I've had Andrews replace cams that other companies would have laughed at you. To make a claim on a 4 year old cam is outlandish to most companies. Andrews replaced a 4 year old cam for one of my customers.
Curt!

Post Sat Dec 15, 2007 6:19 am

Posts: 3061
Location: Central Illinois, USA
A warning about "A" grinds:
You better have a damn good oilpump or the cam will let your hydraulics down at idle on a warm motor, risking your right motorcase.

An "A" should never be used with the early castiron Chubble pump and hydraulics, no matter what Andrews tell you.

....Cotten

Post Sun Dec 16, 2007 12:27 am

Posts: 903
Location: Hill City, Ks. USA

Thanks Cotten;
I'll file that tidbit of information for future reference. It does sound logical.
Curt!

Post Sat Jan 12, 2008 5:36 pm

Posts: 216
Location: Georgia
Has anyone ran a Competition Cams SVH 4000? I ran one for about 40,000 mi. in an 80" + .030" Shovel. It made 80" EVOs look silly. Especially the Fat Boys or Glides.

F

Post Mon Jan 21, 2008 4:40 pm

Posts: 8
Location: Will County, IL
Cotten wrote:
A warning about "A" grinds:
You better have a damn good oilpump or the cam will let your hydraulics down at idle on a warm motor, risking your right motorcase.

An "A" should never be used with the early castiron Chubble pump and hydraulics, no matter what Andrews tell you.

....Cotten


I keep my warm idle around 900-1000 rpm with an "A" grind cam. Good enough to keep oil flowing properly?

Post Mon Jan 21, 2008 5:48 pm

Posts: 3061
Location: Central Illinois, USA
Not by my experience.

I am not a fan of the big "A" for many other reasons as well.
It's been much too expensive in the long run.

...Cotten

Post Mon Jan 21, 2008 5:54 pm

Posts: 8
Location: Will County, IL
Cotten wrote:
Not by my experience.

I am not a fan of the big "A" for many other reasons as well.
It's been much too expensive in the long run.

...Cotten


Are those reasons something you are able to share? What are better recommendations to the "A" over a stock cam? Rebuilt '79 74" FLH .020 over, S&S "E", drag pipes with HP baffles. Not looking to race but good all around power increase over stock.

Tom

Post Thu Feb 21, 2008 4:11 pm

Posts: 646
Location: Detroit
The "A" pulls a lot harder; the faster you go the harder it seems to pull. If you really want a rocket, try a Sifton 468+, but either you need 90 cubes or at least 82 cubes with a slightly underjetted carb. Just be sure to use a real 468+, not a modern day manufacture. A quarter turn throttle and a 468+ is extra cool.
New Knuckleheads? Thank, you, Jesus!!


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