Real Fiero Tech

I am using a Camaro 3.4 in my latest project and will be retaining the SFI/DIS control system rather than converting it backward to the Fiero batch fired system.

Only problem (well, not the only one - it isn't going into a Fiero so there are many more) is that the cams on the OBD1 engines have a home sensor for the engine management that is lacking on the earlier cams, so I can't just order up a 2.8-3.4 cam from an earlier style engine - I need that later blank.

Does anyone know of any good after market cams available for the 3.4 using that blank? Preferably with specs that will work with the original programming (the OBD1 PCMs aren't 'chippable').

OBDI ECM's are extremely "chipable". In fact with a fairly minimal investment you can set up to make most of them fully programmable in real time.

if you are using an camaro engine 3.4 then you can use any aftermarket hydraulic flat tappet cam.

for the 3.4 go with the Crane 272 cam

When did the camaro come with DIS and SFI?

Maybe he means a 3400?

Like anything after 89 I believe. All the 3.4's camaro motors had SFI mang and used DIS. Where have you been?

Shaun41178(2) wrote:Like anything after 89 I believe. All the 3.4's camaro motors had SFI mang and used DIS. Where have you been?

Maybe my brain isnt working today...ive been fucking up alot!

Shaun41178(2) wrote:if you are using an camaro engine 3.4 then you can use any aftermarket hydraulic flat tappet cam.

for the 3.4 go with the Crane 272 cam

Except that the cam position sensor has nothing to pick up on an after market cam!

Im confused.

So let me get this straight.

GM makes a special cam for the camaro motor, but then doesnt' list it as a separate part number in their catalog?

Shaun41178(2) wrote:So let me get this straight.

GM makes a special cam for the camaro motor, but then doesnt' list it as a separate part number in their catalog?

My dealer says that the part number is different for the Camaro/Firebird cam than the 3.4 crate motor intended for S10 etc.

While their parts list doesn't describe exactly what the difference is, they believe it is the lump for the home position sensor and caution me that without that the SFI and DIS won't function properly. That is also what Comp Cams told me.

I thought the sfi cam postion sensor was in the timing cover and read off the timing gears....i must be losing it.

which is why I am curious as to what the part number is. I never saw anything in the gm parts book for this special cam.

I say ditch the sfi code in the computer if that is possible?

I found a picture of the front of a cam with the 'bump', or perhaps :knob: on it - right behind the front journal. Looks like I am stuck with needing that sort of blank in order to be able to use the SFI (which I do want to use). Ah well.

BTW, when I was researching possible cams with a friend in the business, we came up with a tried and true profile that is in the same range as the Crane 272 - the factory Chrysler 440 Magnum grind (which happens to be close to what I use in one of my British cars with American engine). If anyone wants something to try out.......

thats not a 3.4 camaro cam.

Thats a 3X00 roller cam.

That is definatley not a flat tappet cam.

Shaun41178(2) wrote:thats not a 3.4 camaro cam.

Thats a 3X00 roller cam.

That is definatley not a flat tappet cam.

Correctamundo - I just wanted to show you my knob! :thumbup:

That one is from Milzy, who specialises in 3x00 engines.

RSM have a similar non-roller version (presumably with the same :knob:

Shaun41178(2) wrote:So let me get this straight.

GM makes a special cam for the camaro motor, but then doesnt' list it as a separate part number in their catalog?

No, The GM cam Supersede's the previous cams. The old part numbers were replaced by the new one. None of the aftermarket flat tappet cams will work with the cam sensor used on the 60* V-6's with DIS. You can however use a cam with the DIS provision on the earlier engines since the engine doesn't care and mechanically there is room for it to fit. This is why on the application charts they don't list anything newer than 1986. In 1987 some engines used DIS and by 1989 I think all 60* V-6's went to DIS. When I installed the aftermarket cam into my 3.4L, I had to trim the cam sensor down so it would fit interfere with the cam. The cam sensor sits at the front of the block on the top edge. The section of the cam where the cam sensor reads is smaller in diameter than the stock non-DIS cam.

If you order a cam for a Fiero 2.8L from GM you will get the newer replacement cam. Same spec's but the DIS ring is on the edge of the cam.
If I recall, The same cam was used in numerous 3.1L engines as well which were all DIS.

I'm not sure if the aftermarket roller cams have the provision for the cam sensor. I suspect they should, but I don't know for sure.

Unfortunately neither Comp Cams nor Crane use the later blank - no timing lug! Blast!! :crybaby:

I have yet to see a cam WITHOUT that timing lug. or am I just mistaking what that little tab is on my CompCams 260, Crane 272, & ARI Phase II?

Hmmmmmmmmmmm it would make sense now wouldn't it?

I guess someone would have to compare an original 3.4 cam to the 272? Mastermind aka Orief has done this, maybe he could shed some light on this question?

Pyrthian wrote:I have yet to see a cam WITHOUT that timing lug. or am I just mistaking what that little tab is on my CompCams 260, Crane 272, & ARI Phase II?

I spoke with Crane this morning, and Comp yesterday. They both knew exactly what I was talking about and said that their cams did NOT have it.