I know we've hashed this one many times, oh wait maybe i should say we've kicked this dead horse before. anyway, i'll preface it with this. the motor is a replacement from rutlands by the PO. as i was getting ready for the supercharger and replacement of the pullies i decide to measure the cams. now i've also purchased a set of early carbed cams, which are now useles to me -more on that later. the timing events i got off my current set up are as follows: Intake: 7.6mm(.300in) lift 240* duration and a IC of 104* Exhaust: 8.3mm(.325in) lift 230* duration and a IC of 108* all measured at .020" (0.5mm) th intakes are definatly injected however the exhaust are not. and they have no ferrari part number but a yellow inked stamped seal with 'made in itally' might be custom, dunno. now onto those early carb cams. i noticed that they are not the same layout as what i have. i've taken pics, maybe someone knows where they belong. here's the part numbers on them and the measured data. Intake: A108892 A108989 lift .350" Exhaust: S109438 S109440 i'll measure the duration later. and now the pics.... Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
I dont know what that camshaft is out of, but I dont think its out of a 308. The lobes and bearing journals dont have the same spacing. The head looks like a normal 308 head, but that cam is way off.
see what i mean paul. i called rutlands on the cams and they say that they do belong to the 308 but an early 75'. my heads are stamped 74' but have 81' cams, intake at least.
Scott, When you measured the cams, did you have the lash set to zero? You'll get wrong numbers if you didn't...your duration looks correct though so I'm guessing you did it correctly. On the odd cam, it's right as the early carb engiens don't have an air pump. Now I'm told the carb cams won't work correctly with CIS anyway because the CIS can't handle the reversion....although I don't know anyone who has tried it.
Kermit put some wild cams in Randy M.'s 2valve and got it to idle ok, but I think closer or right above 1000 rpm. With head porting that thing was like 230+ at the wheels iirc!
Just going by the pics. I think those are twin distributors cam for 308s, the dist. shaft fits inside the end of the cam. Regards, Vern
i ran adial gauge on the cam itself for total lift. on the duration i ran the gauge on the tappet, and started the degree measurement from .020" of lift. 3 cams have aluminum threaded plugs in them. and 1 is setup for the dizzy. i think these are euro single dizzy cams. if i can get them to work i will but most likely it'll take some custom machining of ends to seal up the oil leaks. i have a friend who used to work on ferraris' and feels the cams can be used if we dial out some of the overlap. bring the lowend and midrange up and the blower will take care of the upper. as for reversion on the NA it would be an issue, as it is with my current setup i have a hard time holding a smooth idle below 1000rpm. with the FI it may help smooth out the reversion once under boost, but then again it may not. i'll fiddle with the cams after i get the 'stock' setup working. just a shame the cams i bought won't work. costly too.
Scott, Ferrari makes a plug for the ends of those cams the part no. is 114069 for the US cam and 108915 for Euro cams. IIRC these pluge were a revision to the early cams because they had problems with the little O-rings on the end of the dist. not holding the oil back. If you have access to an old 308 parts book you can see what they look like. A blower on a 308 huh? Hummm...sounds interesting. Regards, Vern
vern, you should check out the supercharger thread in the 308 section i have going. should have it ready for monterey. the cam hav ethe plugs in them, the issue is the lack of journal ends for the seals. i could mill out some aluminum peices to thread in but it may not be worth it. find another set i guess.
Unless I am seeing some optical illusion, the cam lobes seem to be "off" in relation to the others, in that with the middle one lined up, the cam seems to appear longer at each end. In speaking with Scott he tells me that the cam will NOT physically set down into the heads bearing journals, and the cam caps would need machining to clear the cam. Its not only too long, the journals are not in the same alignment.
Sorry Scott thought you were looking for the plugs, miss read what you posted. Checked out the thread on that...cool sounds like fun. Regards, Vern
Scott, When you did the duration measurement, did you replace the shims to get zero lash first? If not, your duration number will be low by about 20 degrees.....ask me how I know that.....
zero at what degree? i'll admit i don't follow. i checked it like i usually check my other motors. as soon as the cam lobe has pushed the valve open by .02" i start the reading on the degree wheel. i did check the tappet clearance and those are within spec. the duration number i get should be the accutual duration the valve sees. i can check total duration off base circle directly from the cam, but that will vary just from grinding differences. is that the number your reffering to?
Not sure if this is answering one of your questions . . . . the cam your holding looks identical to the front bank (5-8) exhaust bank on the '81 motor I'm rebuilding. Should be putting the whole lump and rebuilt gearbox back in this weekend . . . .400" lift on the intakes and .350" on the exhaust . . . Haltech E6 for engine management . . . can't wait!!!!! Sean
Bringing this back to life... Scott and all, I bought these cams from Scott a few years ago and am finally going to do the install. I noticed the same thing, that the journals and lobes did not line up. I took the valve cover off the rear head (cyl. 1-4) and layed the cam next to the installed one and yep, different. I then took the cams that were labeled "front" and they seemed to all line up. Could these have been mislabeled? The "front" cams and "rear" cams have different spacing (lobes and journals), is this correct? For these to work in my US '78 GTS, I would have A108892 as the intake cam on the rear head (cyl. 1-4) and S109438 as the exhaust cam. I have not removed the valve cover on the front (cyl 5-8) , but I would assume that if the above cams would fit on the rear head, then A108989 (with the distributor drive) and S109440 would fit on the front head. Is this correct? Also, any thoughts on keeping my existing US exhaust cams in with the euro intakes? The only reason I mentiion this is I measured the lift on the US exhaust cams and they were 7.5mm. The euro exhaust cams were 7.59mm, not much difference. I know that the duration and timing are probably a little different. The other reason is that the US cam has the drive for the air pump. I still need to smog my car every other year and I doubt it would pass with euro cams and no air pump.
There used to be a place, thought it was in California, that you could send them your cams and they would rework them to virtually any set of specifications you wanted. If I recall correctly, it was called "webcam.com" or something like that. I did a fast search and putting that in to Google got me a bunch of sites that had nothing to do with automobile cam shafts. Maybe someone remembers the name of that place. I had looked into having the cams on my '78 308 reworked when we were doing the engine, but couldn't justify the cost, so kept them stock. Anyway, the point is that if the cams you have are not set up to the specs you want, rather than drive yourself crazy, just figure out what it is you want and have these cams reworked.
Thanks Tex...I've considered that. Do you have any idea what pump (make/model) would work on the 308?
Here's a link http://www.webcamshafts.com/ Great place, they have been around since long before the term "webcam" came to mean something else.
