FMS cam specs......coming soon

[firebush357]

Awesome, I just picked one of these from Yelo Festiva a couple days ago. He told me that someone had the specs on the Forum. Can't wait to put it in!

[jawbraeka]

http://pages.ebay.com/motors/link/?nav=item.view&id=190780919814

Found these (and 3 others that are similar) and was thinking, is there an equivalent for our little beasties?

Sorry to OP for the slight hijacking.. I thought it was only fitting to add this in as its about custom/modified camshafts...

[jawbraeka]

http://pages.ebay.com/motors/link/?nav=item.view&id=190780919814

Found these (and 3 others that are similar) and was thinking, is there an equivalent for our little beasties?

Sorry to OP for the slight hijacking.. I thought it was only fitting to add this in as its about custom/modified camshafts...

[blkfordsedan]

Not sure what your asking. Send me a PM and I'll try to help. Keep in mind that I am far from being an expert on any of this and my methods are crude at best. This whole experiment was as much for fun and my own learning as anything. Up to this point, we had no idea of the specs on the FMS cam (since no one has ever received a spec card). This at least gives us a reasonable idea of what we have.

[jawbraeka]

Before we dig into this any deeper, there are a couple things we need to place in context.

FIRST: OHC "follower" type cams play by different rules than the traditional OHV V8 design. In the OHV design, you have the lifter that is captured by the lifter bore in the block. The lifter can only travel in one plane, and it's contact point with respect to the centerline of the camshaft never changes. This makes measuring and mapping an OHV camshaft relatively easy. The stylus of the dial indicator can be positioned on the pushrod, or in the pushrod seat of the lifter, and measurements can be derived with a minmum of geometrical error. A .050" lift at the tappet (lifter) equates directly to a .050" lift at the pushrod end of the rocker arm. The rocker arm ratio does not come into play except for measuring maximum valve lift. In the case of the OHC "follower" design, the cam lobe acts directly on the pad of the rocker arm. The lobe ramp makes contact with the follower pad on the leading edge and continues across the face of the pad until exiting at the opposite end. The contact area changes in relation to the rocker arm shaft (pivot point). The result is a variable rocker ratio.....from high to low or low to high....depending on if it's the Intake or Exhaust (which are on different sides of the cam).

This makes it extremely difficult to measure duration at a given value of lobe lift and be able to correlate it directly to the "standard .050" value that we use on OHV V8 engines. You can not get a good reading by setting the dial indicator on the rocker arm, since the motion of the rocker arm pad is in an arc, which introduces geometrical errors as well. Running the dial indicator directly on the cam lobe can be used for determining duration, but there are two problems with this method:

A) The lobe profile geometry does not correlate to that of an OHV lobe.
B) The valve timing events can not be accurate. They change, depending on the angle and position on the cam at which you measure.

Because of this, most measurements were taken on the face of the valve (from the combustion chamber side). To derive the duration and timing events at ".050" lobe lift", I converted it to .087" valve lift, based on a constant rocker arm ratio of 1.75:1 which is the ratio at max valve lift. This is not 100% accurate, but I figure should be pretty darn close. I spoke with Engineers from both Crane & Comp Cams this morning, and they confirmed my theory and method.

I also found that Sealed Power advertises their stock replacement cams as being 205* duration at .050" lobe lift. When I measured the stock cam, I found that I had to be at ~.0325" valve lift to achieve 205*. For reference and comparison, I measured the FMS cam at .0325" valve lift as well. I also took measurements for "seat-to-seat" and .004" valve lifts to represent what is commonly listed as "advertised" duration......which means absolutely nothing. Which brings us to....

SECOND: Duration without any kind of lift specification at which it was taken means nothing. Lazy lobe ramp angles, especially at the transition from the base circle, have a huge effect on "advertised" duration with little effect on actual flow. Comparing the seat-to-seat duration and .050" duration can give you good indication of how aggressive a cam profile is. The point is this...do not judge a cam's performance based on "advertised" duration. For a detailed explanation, you can follow the link I gave earlier in this thread.

Sorry to be a pain in the ass and all that, is there a diagram similar to the picture for the FMS camshaft at all. it's just good to have these as a visual knowledge is all.

[blkfordsedan]

I thought they were supposed to be new grinds as well. I'll measure the base circle again when I pull the cam back out. The run-out on the base circle is pretty good, like <.001". I was thinking about the Aspire cam as the base if I was to ever have a custom re-grind made. The roller followers may allow for more agressive ramps....as well as being more compatable with modern oil. Neither Crane nor Comp Cams said they could do a custom re-grind. Comp Cams suggested going to Web Cams.

[FestYboy]

i remember them being advertised as NEW, not a re-grind.

at any rate: the aspire roller rockers are NOT an option (been there, done that).

[blkfordsedan]

I don't think the intake bowl is tooooooo bad (once it's cleaned up anyway). It does have a slight off-set to it, but the swirl in the chambers kinda plays off it. You might be right, it may not be able to support much more than 120 or so. I would think the exhaust would be the weak spot, considering the 90* short radius and low, flat floor. Either way, I agree, I don't think its the runner volume that would hurt it, but rather the runner shape. The use of some ITB's or side draft Webers would be sweet.

I would like to see what the FMS "race" cam looks like. From what it looks like to me, the FMS street cam I have is a re-grind (?). The base circle seems smaller, and the lobe for the fuel pump drive is fully machined. The stock '89 B6 cam has the lobe cast in, but not machined....
Seems kinda strange to me, considering they advertised the cam for HLA's only. Makes me think it was re-ground on an early carby core? The odd-ball geometry of the follower style rockers may limit the ramp profiles. Maybe a regrind using Aspire roller followers would be better.

[FestYboy]

you mean like this? i (from what i remember) thought the intake port on the b6 head was fairly large enough for 120+ hp numbers, but the bowl area is nasty and the runner to throttle body is way small for those numbers. also the cam needs some real attention (i.e. bore out the cam bearing bores and add lift and more aggressive lobe profile (quicker ramp up and down for longer durration at max lift)).


also look HERE

[blkfordsedan]

I wish I knew what the actual head flow was, or better yet, had one of those flow bench things that uses a shop-vac. I bet there are things that can be done to these SOHC heads that can really make them perform. The low & flat exhaust port floor reminds me of a Ford 4V Cleveland head. I wonder if some of the port plates or port floor inserts like they do to the Clevelands would help? I would love to have an old head, some epoxy and a flow bench......and a week's vacation.
I'm sure we could see 120+ out of a well built N/A B6. The hard-core British "classic Ford" guys get some pretty impressive numbers out of the old overhead valve 1600cc Kent engines in the '60s Ford Cortinas and Escorts. They can get 140+ streetable HP out of them, with some of the nasty race ones pushing 180+ HP naturally aspirated.

[FestYboy]

i used the .087" numbers for my sim.

realisticaly, with a proper cam and mild head work, with a useable intake (i.e. matt dickmyer) we should easily crest 120 hp from a B6 especially if we can wind it up to 7000 rpm or so. the intake and through put of the head are the 2 factors keeping up from making real power, the exhaust (even the B3 cast piece) isn't hurting us that much.

[blkfordsedan]

Is that the DynoSim5? Sounds like it's a lot nicer than the old Dyno2000. Without solid head flow info, it's all a guess anyway. I think my flow #'s may still be a little high at the low lift, but they're probably in the ballpark for a ported B6 head. When I run it for the 9.5:1 B6 with ported head, FMS cam, small tube header & mufflers, I get like around 107hp @ 5500. IIRC, Dennis said his similar B6 (N/A) dyno'd at 96whp.....sounds pretty close.
When I decrease the head flow by about 10%-ish and use 9.0:1 compression, hi-po manifold w/muffler and the stock cam specs, (i.e. stock B6) I get just shy of 80hp. Do you think it's pretty safe to say that a mild B6 (stock shortblock, ported head, FMS cam and header) can put out 100-110hp and 100-115tq?

I usually just take a picture of the screen with my camera phone, LOL. Actually comes out fairly well.

Did you try using both the .087" and .0325" lift specs for .050" timing? The .0325" specs seem to provide a little more HP and less torque due to the increased duration.

[FestYboy]

ok, need to figure out how to copy a screen shot to post here, but i think i have something of useable value.
i used factory dimentions for the block, your headflow #s (i think the exhaust flow is a bit optimistic for an untouched B3 head). 9.5:1 C/R with a 13.3:1 A/F and pentroof design chamber (though a hemi-side plug design may be more realistic), auto timing (assuming 0 knock). 250cfm TB. HP manifolds with cat and muffler (figuring on the cast B3 manifold) and then the FMS cam specs.

i get a peak VE of 77%, peak HP/tq of 81/97 and power good to 6000 rpm.

now if i insert those same specs and Scrappys long block.... B6, with ported/shaved 10:1 head, carby intake, same 250cfm throttle flow, 13:1 a/f

now i get: peak VE of 75.7% peak HP/tq of 103/118 and power good to 5500 with more power under the curve and torque flat down to 2000. the odd thing here is if i stay in it to 7000, i'll get another "kick" but it doesn't show in the graph on the sym.

[FestYboy]

inputing info now...

[blkfordsedan]

Here's the estimated head flows I'm playing with in Dyno 2000.
Lift. I. E
.100. 50. 51
.200. 88. 73
.300. 117. 92
.400. 128. 112
.500. 137. 120
These are estimated from head flows I found for stock Ford 2.3L and 1.6L Kent heads. The Kent head has same valve sizes as a B6. My flow #s are actually less than the Kent head by about 5 percent less, and about 10 pct. Less than the 2.3L head. At one time I also found what appeared to be B6 head flows, but it wasn't very clear. Even though my numbers are less than all these, they still may be high. Sometimes LESS head flow can improve power as well. In any event, its fun to play with.