FLH cam , valve springs , compression , pistons

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63 Duo

FLH cam , valve springs , compression , pistons

#1

Post by 63 Duo » Mon Sep 11, 2006 4:20 pm

I have a 63 FL i am assembling . The bike is going to be mostly original adding a S&S oil pump and 73 -up oil modification . I do have a stock rebuilt Linkert carb NOS pistons and rings and acccess to NOS FLH piston rings and also have a NOS "Victory " cam to put in. The question is :
I know i will have to put the FLH harder valve springs with the VICTORY cam correct?
The FLH motor has a compression ratio of 8.00 :1 which i know is greater than the FL motor compression. How is this accomplished int tne FLH ? Different pistons? different springs or both? What if i don t change the pistons and stay with my stock FL compression?
I ve read that the FLH is harder to start . Is it because of the higher compression (more effort to crank ) or because of cam timing and lift?
My heads also use stock exhaust valves but have been modified to later early shovel bigger intake valves.
Thanks



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#2

Post by VPH-D » Mon Sep 11, 2006 4:41 pm

The FLH used higher compression pistons, stronger valve springs, and the 'Victory' cam. The Victory cam is nothing special, performance wise.
VPH-D

63 Duo

#3

Post by 63 Duo » Mon Sep 11, 2006 8:18 pm

Thanks. I am not looking for something really special , just a knotch of better performance and good like stock reliability and ease of use.

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#4

Post by Cotten » Tue Sep 12, 2006 1:38 am

You can't go wrong with the Factory formula.

I lost count of the customers that I have made very happy by replacing their damaged andrews cam with a common "H", usually found still on their shelf in their garage.

Too many "performance" hop-ups add up to nothing more than bragging rights at the bar.

Alas, the original Sifton line is extinct, as they really made people happy!

....Cotten

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#5

Post by 63 Duo » Tue Sep 12, 2006 12:16 pm

Thank you all. So actually if i want to go to 8:1 compression i ll have to go to flh pistons right? As far as aftemarket pistons , i ve been running 10.5 :1 in my moderately modified 94 Springer and 10 years and 50.00 miles later she s running great not a hinch of oil smoke burning through.

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#6

Post by 63 Duo » Tue Sep 12, 2006 6:12 pm

Forgot to mention , it is Keith Black pistons i am running in the Springer.

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pistons

#7

Post by Pantony » Wed Nov 08, 2006 5:38 am

Yes but your 94 EVO is not a panhead with Iron cylinders, a diffrent oil system and if all you want is good usable power and not bar bragging rights as Cotten has so stated then, as he said, "stick with the factory formula" put all FLH components in there unless you can locate a REAL Sifton cam. Your bigger valves are going to be usless if the engine isn't balanced as far as flow and cam profile, carburation and ignition. as many times as you hear it some people just build themselves right out of the ballpark. those big intakes are just going to kill your low end torque. depending of coarse on your cam selection and just how big they really are.

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#8

Post by fourthgear » Wed Nov 08, 2006 5:32 pm

I'm using KB pistons in 9.5-1 ratio and have no problem starting CV carb. , Mallory ign. and one kick starts warm or cold , I've got about 6000 miles on them and all is fine.

Cams

#9

Post by Cams » Thu Nov 09, 2006 10:43 pm

I have a question while the subject of cams is being bounced around.
I have a cam that I assume is OEM because I can find NO markings at all, would this be normal for an fl or flh cam? if so how does one tell the difference?

52WLCnFL

cams

#10

Post by 52WLCnFL » Wed Nov 29, 2006 8:48 pm

Cams (guest),
I miked the height and width of an original FL camshaft that has no markings on it indeed. All lobes are 0.240 inch taller than the base circle diameter. That brings 0.360 inch valve lift with the 1.50 panhead rocker ratio.
Another easily discernable pecularity is the difference in lobe profile between intake and exhaust. Look at lobes two and three (lobe one is closest to the gear). They point (approximately) in the same direction, but three (front intake) is somewhat wider than two (rear exhaust). In other words, there is more intake duration than exhaust duration. Quite an unusual feature, which has possibly to do with the long and winding intake tracts in our pans.
Not easily discernable is the timing diagram. I miked it, but I don’t know how to post pictures. It shows the long intake duration and the identical intake timing for front and rear cylinders. I never miked an FLH cam, but according to most aftermarket cam manufacturers lists, ‘stock’ cams (their words, they almost certainly refer to FLH cams) have different front and rear intake timings, allegedly to compensate for the unequal suction intervals between front and rear cylinder. I wonder why none of the other big twin ohv HD cams nor any aftermarket cams show this feature....

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#11

Post by VPH-D » Thu Nov 30, 2006 5:41 pm

I believe the FLH cam was stamped with an 'H'.
VPH-D

halh4hd

cams

#12

Post by halh4hd » Tue Dec 05, 2006 5:14 am

the stock flh cam has a h on the back lobe and the valve lift and duration is different between front and rear for cooling as well as the reach and angle of the pushrods to the heads. I had previously installed a bh grind andrews and regreted it with a passion once i found a stock cam the bike came alive and ran better than it ever has. always started 3 kicks cold(2 priming with choke full on and ignition off) open the choke 1 notch from full and started first time every time.

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Re: cams

#13

Post by panheadron » Thu Apr 10, 2014 11:31 pm

52WLCnFL wrote:Cams (guest),
I miked the height and width of an original FL camshaft that has no markings on it indeed. All lobes are 0.240 inch taller than the base circle diameter. That brings 0.360 inch valve lift with the 1.50 panhead rocker ratio.
Another easily discernable pecularity is the difference in lobe profile between intake and exhaust. Look at lobes two and three (lobe one is closest to the gear). They point (approximately) in the same direction, but three (front intake) is somewhat wider than two (rear exhaust). In other words, there is more intake duration than exhaust duration. Quite an unusual feature, which has possibly to do with the long and winding intake tracts in our pans.
Not easily discernable is the timing diagram. I miked it, but I don’t know how to post pictures. It shows the long intake duration and the identical intake timing for front and rear cylinders. I never miked an FLH cam, but according to most aftermarket cam manufacturers lists, ‘stock’ cams (their words, they almost certainly refer to FLH cams) have different front and rear intake timings, allegedly to compensate for the unequal suction intervals between front and rear cylinder. I wonder why none of the other big twin ohv HD cams nor any aftermarket cams show this feature....
Hi. You are right about your cam. It is a stock FL cam. I recently looked at the difference of the two cams side by side. The FL cam has longer durations on their intakes as compared to the exhaust. The FLH is the opposite. Andrews offers an A grind & an AB grind. The AB has a longer duration exhaust for cooler running? There's the reason. Fl cam came out in 48. 8 years later...FLH. Must have been an improvement.

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Re: FLH cam , valve springs , compression , pistons

#14

Post by 58flh » Fri Apr 11, 2014 2:23 pm

If your looking for a daily runner--You cant go wrong with this combo!--I put on a lot of miles yearly,& I use FLH cam--(they are marked with a H).CAST PISTONS-8.5 to-,comp. & Hastings Iron rings!.--Stay away from FORGED PISTONS & anything CHROME-MOLY!--(you wont be happy!)-The OEM heads are best left ALONE!--just a sanding mop to takecare of any casting nerds in the ports!.--DONT try to port them & play JERRY BRANCH!--It will run like crap!--If you can PUT your stock size valves back in!--UNLESS its oversized because of TO many valve jobs & sunken in to far!--Bigger valves in a pan DO NOT WORK!--YOU just burn more fuel & screw-up your TOURQUE!--Remember these are TOURQUE MOTORS!--If anything change the tranny sprocket to a 24 tooth.-It helps kepping the motor in the Tourque band at 60mph.---CHECKOUT the k-BASE real good!--(great info there!)---RESPECTFULY---RICHIE

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