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-   -   Centerline 11.1 cam (https://www.alfabb.com/bb/forums/engine-repair-diagnostics-rebuilding/678154-centerline-11-1-cam.html)

180OUT 04-12-2019 09:21 AM

Centerline 11.1 cam
 
On our Fall tour, my long-serving (30k miles w/ two different Alfas) ported head developed a catastrophic crack, the resulting failure of which prompted a engine rebuild. We did the work at my old friend Bob Fernald's little shop in Austin. It took awhile but was a memorable experience for me to again work with someone with his skills. When I told Bob this was just like old times, he told me there was a big difference: he can't easily get off the floor and I can't easily kneel down on the floor . . .

So, anyway. I bought a good replacement head from my friend Howard but, when it came to cams, we had in a dilemma. Our solution led us to a very satisfying result. Please read on. My previous head used a Delta A474 12mm intake cam which necessitates cutting notches the cam follower bores. Since this head was to be a temporary replacement while I prepared a new ported head, I decided to fit the Centerline 11.1 cam I'd used as an exhaust cam on the intake side of this replacement head. Mainly as an expedient let's-use-what-we-have-here solution we decided to use a stock 2.0 fuel injection cam on the exhaust side of our head. So: we had the Centerline 11.1 x 254 duration (I think that's right) coupled with a stock FI cam. Basically, all I was hoping for was a decent running motor which I could use until i got the replacement ported head done.

Taking my Super out for a short drive, I immediately noticed an instantaneous throttle response combined with bags of torque and a smooth delivery of power all across the rev range. Well, I thought, this is a satisfying surprise. On my drive back to San Antonio from Austin I took some back roads so I could do some break in miles. Frankly, I couldn't be more impressed with this dumb luck choice of camshafts. With 10.1 Motronics, 40mm Webers w/33mm chokes (restored by Gordon Raymond), balanced bottom end, headers, ignition, and light flywheel my new engine has plenty of torque and a very satisfying increase is unsable power. If you are interested in building a performance street 2 liter, this accidental combination might not have occurred to you but I can strongly recommend using the Centerline 11.1 cam combined with a stock 2 liter fuel injection cam.

dutcherstiles 04-12-2019 02:30 PM

Interesting

JoeCab 04-12-2019 04:22 PM

Jim I'm so glad you're pleased with the cam.

The practice of running an asymmetrical cam set-up is a tried and true way to get a very nicely balanced street motor. We often sell our 11.1mm cam for the intake paired with a 10.5mm cam for the exhaust. It sounds like you got very similar results with a stock cam on the exhaust side.

goats 04-12-2019 04:30 PM

on a garden-variety street motor, with head not cut (or if so, only skimmed), can the 11.1 cam be dropped in without head modifications? ie no relief of follower pocket/ etc

I realize that the piston to valve clearance will need to be checked

Looking for some cam improvements without head work over and above 10548 euro cam for a SPICA injected (Wes modified) motor

180OUT 04-12-2019 05:41 PM

Quote:

on a garden-variety street motor, with head not cut (or if so, only skimmed), can the 11.1 cam be dropped in without head modifications? ie no relief of follower pocket/ etc

The head we used had some port work done on the intake side only and used stock intake and exhaust valves. Only the port runners had been modified while the valve-throat pocket---a critically important area to work on when doing port work---was left alone. The opened up port runners most likely contribute some extra hp to the engine's performance, although I think the ported intake manifold, 40DCOE carbs with 33mm chokes, the raised compression and cams are more significant. I think you would find this camshaft combination well suited for use on an otherwise stock engine. The 11.1 cam can be used (we set both at 102 degree lobe centers) without modifying the cam-follower bores which is something you'd need to do with, say, the Delta A474 12mm cam that was in my failed head.

I would think this combination would also work well with a Wes Ingram modified motor. I should add that the Centerline cam gives a smooth 700 rpm idle, coms on strong at about 3k rpm and makes good power throughout the rev range. Judging from the position of my gas gage's needle, I also think I'm getting a lot better mileage than the 18-20 mpg I was getting with the previous camshaft combination. With stock pistons or Motronics I don't think you'll run into clearance probolems with the Centerline cam. Keep in mind that I was running a 12mm cam with 10.1 Motronics and didn't encounter clearance problems.

alfaparticle 04-12-2019 06:27 PM

1 Attachment(s)
Quote:

I realize that the piston to valve clearance will need to be checked
Piston valve clearance puts a limit on cam timing but it is unlikely to limit performance with these cams. Use RJ's method of slipping a couple of cable ties between the piston and the valve and feel for it being pinched as you rotate the motor thought TDC. Exhaust valve timing has less effect on the power curve than intake timing. If you read posts about engine setup for motors that dyno'd big numbers you will find that about 98 intake and 108 exhaust give the best results but some piston/cam combo's will not allow you to set the intake below about 101. I recently did back to back dyno runs with two different performance exhaust cams at the same lobe center and the results were quite similar.
The attached chart shows the effect of moving the intake cam LC from 104 to 98.

slowcreek 04-12-2019 08:36 PM

Just did this exact thing. Centerline 11.1 intake cam and stock Spica exhaust cam 102* lobe centers on both.

180OUT 04-12-2019 11:00 PM

Quote:

Quote:

Originally Posted by slowcreek (Post 8399940)
Just did this exact thing. Centerline 11.1 intake cam and stock Spica exhaust cam 102* lobe centers on both.



And . . .? :exclamation:

slowcreek 04-13-2019 06:31 AM

Quote:

Originally Posted by 180OUT (Post 8399964)
And . . .? :exclamation:

Runs good and strong.

I don't have an apples to apples comparison on this car because I only drove it around a few blocks before buying it.

My Spider has Shankle 7L cams and Webers. That's what I'm used to.

That said, at 5500 foot elevation, the Alfetta pulls strong through all the gears and I've backed off at 100 MPH in fifth gear only because the I was running out of straightaway and had horrible rear shocks. I have new Koni Yellows on the rear now and will do another high speed run. I'm happy with the cam.

quadrifolio 04-14-2019 01:00 AM

Quote:

Originally Posted by 180OUT (Post 8399716)
we decided to use a stock 2.0 fuel injection cam on the exhaust side of our head.

this was your lucky shot, fit a truely Ex cam with a true ex lobe design

Alfar7 04-14-2019 06:42 AM

Exhaust cams
 
Just FYI...
The exhaust cams in all the Spica, Weber and FI engines are the same lobe design as the intake in those motors. The exhaust cams in them are not good designs for that purpose.
In engines built for the Motronic FI system with the large diameter BC intake that exhaust cam is a much better exhaust lobe design and the one I suggest using with the likes of the 10548 cam, and mild aftermarket cams on the intake.

slowcreek 04-14-2019 07:49 AM

So me and 180OUT dodged a bullet?

alfaparticle 04-14-2019 08:21 AM

Quote:

So me and 180OUT dodged a bullet?
No, just torque and HP.

slowcreek 04-14-2019 08:59 AM

Quote:

Originally Posted by alfaparticle (Post 8400288)
No, just torque and HP.

Oh, okay.

alfaparticle 04-14-2019 10:32 AM

Slowcreek, I think that you could pick up maybe 5 HP with a change of LC's. I would advance the intake one hole to about 99 and verify that you have at least .050" piston-valve clearance then retard the exhaust two holes to about 108 and check that you have at least .100" clearance. Then take it back to the dyno.


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