964 cams on 3.2

[quint22cp]

Due to low compression on No5 I will be undertaking a rebuild of my 3.2 late this summer and I'm also considering an upgrade to 3.4L.
I have been advised to use 964 cams.

Question: Wayne's book stops off at 1989 so doesn't cover timing a 964.
What are the differences between a 3.2 cam and the 964 cam?
How do I time the 964 cam in my 3.2 (3.4)?

[Jeff Alton]

You set the 964 cam to its factory timing spec, 1.26mm off the top of my head. The 964 cam is a little more aggressive than your stock cam, slightly higher lift numbers and a little more duration with the same lobe seperation making it emmissions freindly. I have them in my 3.2 and think they are great. IF you have to get your cams ground anyways, it is a no brainer to have a 964 grind done. I am sure Camgrinder can give a few more specefics, but that is it in a nutshell....

Jeff

[wilke3169]

Camgrinder did mine for my 3.0 rebuild. Timing was not an issue, exactly what catca said, 1.26 is correct. It is a cheap add-on during a rebuild.

Kevin

[camgrinder]

964 cams work great in 3.2's and for the 3.4 upgrade. Depending on your other modifications, you might want something a little more aggresive.

[Jeff Alton]

Wow, it's like I am psychic or something..........

Jeff

[RSupdate]

I was facing the same question last summer....go with 964 or...for a little more power go with the Web-Cam 20/21 grind...which has the same duration as the 964 but with increased lift for both I/E.

your needs & desires are probably different than mine....but looking back I am really glad I went with the 20/21.

Next step up from this would be the factory 3.8 "Super Cup" with a tad more lift and a bit tighter lobe center....I just didn't have the guts to try it....but those with much more knowledge say it will work no problemo on a stock 3.2....just be prepared for the power to come on later.

good luck!!

[911-32]

I went with 993 Supercup cam in my 3.2 top-end rebuild. The only reall downside is that the idle is pretty lumpy so your car sounds like a tractor (to the uneducated ear) or like a nasty, cammy race engine (to the educated ear). I wouldn't describe the cam as peaky, in fact the power just ramps up from 3,000rpm onwards. It certainly pulls harder over 5,000rpm than the std cam.

I get it dynoed on Saturday and hopefully remapped during July. My mechanic and I think it desparately needs the remap as it feels like it really wants to "go" but something is holding it back.

I think the Supercup cam needs a backdated exhaust to really breath properly and get the full benefit.

RB

[s5uewf]

OK all you 964 cam guys...

I'm considering 964 cams on my rebuild vs. DC21 or DC22 cams...

Here is my engine spec:
3.4Liter single plug
9.5-1 CR
stock intake
stock valve train (but can upgrade for cam if needed)
Euro premuffler
Bursch exhaust
SW chip & 93 Octane

Need to pass smog.

My goal is to make the most of the rebuild by making sure I
have the best cam profile.

I use it daily driver, but sign up for every DE I can and expect and enjoy driving the hell out of the car at the track.

Those of you with 964 cams - still a thumbs up?

Seems the 964 cam timing can be set to 1.26mm or so to maximize powerband for track - maybe that is all I need?

What do all you 3.4 liter engine rebuild pioneers think?

I hear the SCup cams are trouble for smog, same with the DC22 cams - due to the increased overlap...any first hand experience out there?

Thanks!

Emery

[slotcar]

I'll be watching this thread...I might go down the same path. What pistons will you use?

[Jeff Alton]

Okay, don't want to speak for John here, but I have picked his brain about this enough that I may offer my opinion...... John, jump in and correct me if I am wrong. Every area seems to have different smog testing standards so check yours and decide accordingly. In my area I think we are a wee bit lenient, but with the 964 cams, Steve W chip and no cat I passed no problems at all...... The last 3.0 with 964 cams I built that went to CA passed with no problems. Now, for a 3.4, IIRC, you should be able to pass with a DC20 (very similar to a 20/21) and you could pass with a dc21 or 22 depending on your state requirements.

I went with a DC44 for my 3.4, but is high CR twin plug and ITB's and I am doing a "work around" of emissions testing.

When mine was still a 3.2 with the 964 cams and SW chip and SSI's I set the timing to 1.26 and thought the power band was the same profile as stock, just a bit stronger.

With the 3.4 you should be able to use a DC 20.

John, how close am I here?

Cheers

[JeremyD]

I think you are pretty "spot on" there Jeff - from all I have read.

[Jeff Alton]

I forgot to mention that John is "the man"!! He does all my cams and regrinds my rockers as well......

Cheers

[camgrinder]

Originally posted by catca
I forgot to mention that John is "the man"!! He does all my cams and regrinds my rockers as well......

Cheers

Thanks Jeff! I agree with your post. You are spot on.

My choice for Emery's engine is the 964 profile. To use a more aggresive camshaft, (DC 20 or a 993SS type) I would like to see higher compression.
My thoughts are, with a stock intake manifold the HP peak seems to be in the 6000 to 6200 range. The larger cams fall off less past 6200, but the peak is still in the same range. Going to a longer duration cam without increasing the compression ratio hurts the mid range torque, and acceleration.
I think Emery is looking for some feedback on how well the the 964 cams work in a 3.4 litre. How the powerband feels etc. I believe he wants an engine that has a definate "comes on the cam" feeling.

[s5uewf]

If I recall correctly, with Jeremy's 3.4 with 993SS cams & a 9.5 CR:
- HP & torque look similar to a regular 3.2 below 3000RPM
- power comes on after 3000RPM
- big jump in power after 5000RPM
- more power up top than a 964 cam

The 964 cam seems to dampen the power bump up top
in exchange for minimal increase in torque and power
in lower and mid ranges. Sounds like an engine I'd want in
a taxi cab, or a powerband I'd expect from a Buick.

Trying to find out if anyone enjoys using a 964 cam grind at DE's.

Still looking...

[quint22cp]

Calling all UK readers.

Can anyone tell me where in the UK I can get my 3.2 cams reground to 964 profile or maybe something wilder.

[JeremyD]

Originally posted by s5uewf
If I recall correctly, with Jeremy's 3.4 with 993SS cams & a 9.5 CR:
- HP & torque look similar to a regular 3.2 below 3000RPM
- power comes on after 3000RPM
- big jump in power after 5000RPM
- more power up top than a 964 cam

The 964 cam seems to dampen the power bump up top
in exchange for minimal increase in torque and power
in lower and mid ranges. Sounds like an engine I'd want in
a taxi cab, or a powerband I'd expect from a Buick.

Trying to find out if anyone enjoys using a 964 cam grind at DE's.

Still looking...

For comparison, here's my 3.4, in blue, compared to Ralph's 3.5, in red, compared to a bone stock 88 3.2 with a euro premuffler and stock chip, in green.

Pretty sure Ralph has the 20/21 grind



Oh, and my cams are from John (camgrinder)

[s5uewf]

Thanks Jeremy, I could not find your graph when I was looking for it last night. It is a great way to compare some of the variations.

It looks to me like the stock 3.2 is pretty weak below
3000RPM and it really croaks just above 6000RPM. It looks like
your SS cams and the 2021 grind do not give up anything down low compared to a stock 3.2 and really extend useable power
well beyond the range of a stock 3.2

That extra range seems to be very useful.

I am assuming since the 964 cam is similar to the stock 3.2 just
a wee bit more agressive, that it will deliver useful output
in the same relatively small range as the 3.2?
Is this a correct assumption?

I am starting to conclude the 3.4 would really be a fun engine
on an increasing scale using the DC 3.8SC, DC20, DC21...?

[tctnd]

If you are interested I have a new pair of 20-21's for sale.
regards,
Phil

[Jeff Alton]

Yes, I liked them at the track. It is only a cam, not a turbo, gains are mild unless you change induction and compression and displacement all together.....

Cheers

[MBEngineering]

HI try www.bsmotorsport.co.uk for info/getting the cams ground hear, if not send them to camgrinder, if not the PORSCHE autojumble is on on sat at woburn just off the M1 J13 you could pick some up there s/h.

regards mike