ALFAGTV6.COM

How does one identify the 164s 12v cams?

Thank you,
Scott

I asked this same question during one of my rebuilds. There ar S specific marks on the cam towards the gear end...unfortunately, I can't remember if says 'S' or there is a number... I know it's in one of my posts somewhere...

I have been told by a reputable source (thanks Greg G) that the intake lift of the "S" cam is about 10mm measured as difference between the small and large dimensions of the lobe itself. I came up with 9.8 using dial calipers.

scott

I also found "3033" on the left cam. I don't have the right one out yet.

i was told 164 cams will have a notch in the end for the dist drive

This is how my S cams looks

Yes, these are the best 12v factory V6 performance cams. They were used in the Motronic 75, 164, SZ/RZ.
I took a picture of two that I have here showing the raised markings. Alfa p/n is 60548163 and 60548164 and they have the distributor drive slot, since they first appeared in the 164. Measured with calipers will give you ~9.9mm but true intake lift is 10.4mm, not 10.1 as usually noted (even in Alfa literature!)
Jim K.

Jim, I am loosing you here.... Are you saying the standard 164 cams are better than 164S cams?

Greg

just reminds me i need to pull the covers off the gtv6 and ID the cams in it..that lil 2.5 is nuts

Mine have the same raised markings 3031 and 3033, but no slot for driving the 164 dizzy, and measure 9.82mm.

So what do I have?

Ok, I can see we're all getting somewhat confused here. It looks like the best way to do this is to accept a few things based on your observations and mine and combine them with the official factory literature: the factory had cam blanks cast somewhere and the rough casting numbers happened to be 3031 and 3033, meaning nothing in the AR numbering system. These blanks were then finish ground to whatever profile was desired for the specific applications intended. This may explain the bickering between 3031 and 3033 owners regarding lobe sizes. Your NA 'S' designation does not appear anywhere in AR factory literature. I've been dealing seriously with compiling all official V6 cam part nos. and sure enough 'S' is nowhere to be found. The 164 Quadrifoglio (64301 engine) with 200hp (advertised) was the first (European)model to use the 10.4 cams (therefore the slot was there from the start). The 'S'designation referred to the car model 164S which was exported to NA in 1990 and also had engine number 64301 this being the only 164 engine to carry the 10.4mm camsand have 10:1 CR. Engines 6410 and 6412 (in 164 cars) never had the good cams. The 164 Quadrifoglio was sold in Europe in 1990; the same cams appeared in the 75 Motronic in the same year and also in the SZ. The 164S was sold in the US with an advertised 197hp instead of the 179-184 of the previous cars. Note that this version also had the big afm 0280203035 and the 0261200130 ecu. Btw, there is no S stamped on any of the four 10.4mm cams I have here. All this clear enough? I'd be very interested to hear from owners having the 10.4 cams as to what engine number they have (provided the cams were originally there).
As for measuring cams with calipers...will only give you a rough indication of lift as at 90* to max lift the ramp has already started to rise. The only proper way is dial indicator, follower, protractor and a lathe or (more practically) a spare head.
Jim K.

i thank you very much for makeing that clear...ive been trying to understand the "s" cams for some time now

Thanks Jim,

I have a lathe and dial indicator....will measure that-a-way.....This is MUCH clearer now.

The casting/ forging number thing makes sense...I've seen it when I worked in foundries.

Thanks again,
Scott

Scott, since you are going to use the lathe (I'm not trying to insult anyone here!) make sure you first zero for runout (chucks usually have some runout and a little tapping always helps!) Then you can zero the dial indicator on the heel of the lobe and measure true lift. If you use a protractor, and want to graph out lift vs angle, you'll have to fix a follower on the tip of the indicator as thats the only way to measure cam lobes of this type. The indicator tip just won't do. For this particular measurement I believe having a bare cylinder head is the best deal: Install one valve. For a valve spring, I use the springs found inside plastic toilet paper roll holders (laugh all you want, it works great!) All you have to do then use a shim that will leave the valve open just a bit, fix the protractor on the cam and a wire pointer and measure valve movement with the dial indicator. Voilá, zero the indicator on the 'closed' valve and you're ready to graph out true cam lift!
Jim K.

Fan tas tic!

Of course this whole thing would be easier if Alfa had stamped part numbers into the cams in the first place

Thanks Jim,

Scott

Scott,

For a valve spring, I use the springs found inside plastic toilet paper roll holders

...sounds like a great idea, just don't lick your fingers in between measurements...