964 cam timing in a 3.2

[TT Oversteer]

I'm running 964 profile cams in my 3.2 combined with a Wong chip, George's headers and M&K GT3 muffler. Stock heads and 9.5:1 compression. On the recommendation of DRC I set the cam timing at 1.8mm. I talked with Steve Wong who recommended the stock setting of 1.1. Supposedly the advanced setting of 1.8 is supposed to provide a more torquey character to the engine. I'm in a bit of a quandary now as I have two different recommendations from two well regarded experts in their fields. I have to admit, I'm a little disappointed in this engine's top end performance. It feels soft over 5k and I'm missing that top end "rush" to redline. Now I'm considering resetting the timing to 1.1 for a snappier top end. Looking for opinions from those of you who have a similar setup.... Am I splitting hairs here?

[Flat6pac]

Spec on the C2 cam is 1.25 with the window 1.1 to 1.4. I have set them as high as 2.0 on valve relief pistons like JE but on Carrera pistons, make sure you have valve room at 1.8.
Bruce

[irobertson]

I set my 964 cams to 1.25, and my otherwise stock 3.2 pulls strong to redline even with the stock exhaust. I do notice the idle is a tad more lumpy though. Can't wait to upgrade the exhaust and get a chip from Steve.

[JFairman]

I carefully set my 964 cams at 1.26mm. It seems a good mid point for all around use and it idles perfectly smooth.

This is in a 3.3 liter turbo motor with B&B headers, gutted B&B muffler, CIS Flowtech modified fuel head for around 20% more fuel, brand new Mahle pistons and cylinders and rebuilt cylinder 930 heads with ported 40mm intake ports.
With 7:1 compression and the slow reacting throttle response of k-jetronic mechanical injection it doesn't have much low end torque anyway. From 3500rpm on up it goes pretty good.

[brighton911]

I am running a DRC 964 grind in my 3.2 A cat bypass and a Steve Wong chip are the only non stock additions. As per John's written recommendations, and with a double check email to him, I set the cam timing at 1.8mm. It idles about the same as before and the powerband is similar to stock - the usual rush above 4000 to redline but I find it stronger throughout. So for me, 1.8 works great.

[johnman001]

I'm in the same boat here. I bought and just installed 964 cams in the track car 3.2 and started out with the 1.8mm lift at overlap per the sticker on the box indicated. This seemed funny to me, so I looked it up and ended up setting them to the stock 964 timing of 1.26mm at overlap. I spent the time to get them really close (had to jump chain teeth on the cam chain sprockets). In any event, I am for good or bad running ours at 1.26mm lift.

I tried to contact John Daugherty, but haven't yet heard back from him concerning where to set these cams. Our original email communications showed 1.26mm, but the sticker on the box with the cams stated 1.8mm.


Our car is a 914-6 with headers. I haven't gotten a response from Steve Wong on a chip request I sent to him a few weeks ago.

[Determined]

I'm doing this soon, subscribe

[CEO]

I have a 3.0 that is stock except for 964 cams and exhaust and I set to 1.9mm with no clearance issues. Remember that if you use a new timing chain it will stretch a bit and retard your timing over time. But that being said, I love the way the 964 cam feels advanced with all the torque down low and still pulls like a mad past 4k. I just wanted more grunt below 3 as well.

[fred cook]

I built a 3.3SS engine a while back using 964 cams. I set the cam timing at 1.3 for each camshaft. End result was an engine with good bottom end torque (displacement and compression) and one that pulls like a freight train on top end (big port Carrera heads). Very happy with the setup.

[rsscotty]

I just had a 3.2 stock engine on the dyno. I changed the timing from 1.1 to 1.7 and saw a dramatic loss of power in the higher rpm band, with very little gain in torque in the midrange. If I had more time and wanted more top end power, I would have liked to see what a setting of .8 would do.

It also would be interesting to see if doing this same test with the 964 cams would yield the same effect. In the future, this is something I will try just to find out what it does.

[JFairman]

When setting the cam timing it can take time to get them both perfect because the pin fits loose with some slop in the holes and slots it slides into. Once it's in there you can see it rock back and forth a little if you turn the crank shaft over one way and then the other way a little while the 19mm bolt or big nut is loose.

I wanted it perfect and exactly at 1.26mm intake valve lift TDC on each side with the dial gauge. I used the Z block and high quality German made analog dial gauge I bought new from pelican.
It takes a little time and patience because the sprocket moves a little and the pin can move in it's hole a little when you tighten the bolt. I found that when you find the right hole in the sprocket for the pin a little oil under the 19mm bolt head on the big washer and a smooth steady pull on the torque wrench with one hand while holding the sprocket from turning with the special wrench with your other hand will get it perfect and spot on after some repeated tries and then checking the valve lift with the dial gauge while turning the crank in one direction slowly over TDC a few times to make sure.

[TT Oversteer]

Originally Posted by rsscotty

I just had a 3.2 stock engine on the dyno. I changed the timing from 1.1 to 1.7 and saw a dramatic loss of power in the higher rpm band, with very little gain in torque in the midrange. If I had more time and wanted more top end power, I would have liked to see what a setting of .8 would do.

It also would be interesting to see if doing this same test with the 964 cams would yield the same effect. In the future, this is something I will try just to find out what it does.

Can you give us some numbers on "dramatic"? HP vs RPM?

[safe]

Originally Posted by rsscotty

I just had a 3.2 stock engine on the dyno. I changed the timing from 1.1 to 1.7 and saw a dramatic loss of power in the higher rpm band, with very little gain in torque in the midrange. If I had more time and wanted more top end power, I would have liked to see what a setting of .8 would do.

Interesting!
I went from stock cams at 1.2 to 993SS at 1.8 and lost 10 hp. Lost torque and power everywhere...

[TheSt|G]

What are the ~expected gains from 964 cams?

[JFairman]

Compared to SC grind cams the power band is moved up a little and there will be a little more top end horsepower when they are timed correctly.

[sp_cs]

Gents

I've a similar question re the dc20 cams on my 3.4 - they've been verified at the upper overlap mark of 2.4mm (range 2.2-2.4mm).

When the engine was was first rebuilt with dc20 cams, it's was delivering 270bhp/240 lbft - after a second rebuild, it's now delivering 240bhp/230 lbft

Could cam timing have such an affect on output? I don't know anything about cam timing, and do not know what it was set to during the first rebuild. It doesn't feel like it lost 30 odd bhp, but this is what the dyno is suggesting (same one it hit it's higher figures on)

Aside from fitting ssi's and an early dansk 2in 1out, it's the same spec/build as before

[johnman001]

We completed the first DE with the 964 cams timed stock (1.26mm at overlap). We had a noticeable improvement over stock. The engine pulled well in 3rd, 4th, and 5th. We spent more time in 5th than we had ever done so.

I believe that it is time to get Steve Wong to create a chip for us that provides more fuel at higher end. I plan to keep the stock redline, but increase fuel delivery. We feel that the combination of the 964 cams and the 914-6 race headers require more fuel to get more gain from the cams.

We are pleased with the results so far.

John

[BURN-BROS]

Gents



I've a similar question re the dc20 cams on my 3.4 - they've been verified at the upper overlap mark of 2.4mm (range 2.2-2.4mm).



When the engine was was first rebuilt with dc20 cams, it's was delivering 270bhp/240 lbft - after a second rebuild, it's now delivering 240bhp/230 lbft



Could cam timing have such an affect on output? I don't know anything about cam timing, and do not know what it was set to during the first rebuild. It doesn't feel like it lost 30 odd bhp, but this is what the dyno is suggesting (same one it hit it's higher figures on)



Aside from fitting ssi's and an early dansk 2in 1out, it's the same spec/build as before

I would think that the SSI's are preventing the peak hp.

[sp_cs]

Originally Posted by BURN-BROS

I would think that the SSI's are preventing the peak hp.

My mistake, the last figures were taken with a set of 1 5/8" headers fitted which actually felt great on the car.

Ssi's have now been fitted to eliminate the headers from the power loss, and as you've stated, with a negative impact on top end but with what feels like an improved lower-mid range

I'll ping John an email for his thoughts on optimal overlap for a 3.4 running 10.45:1CR, ssi, single plug, but was keen to know if anyone thought a lower overlap could be prudent with my setup

Sorry for the hijack

[TT Oversteer]

Can't believe it's been almost 17 months since I posted this. I finally jumped in and reset my cam timing after dragging my feet and debating the value of this exercise. I had the exhaust off and the timing covers were just sitting there....exposed...daring me to remove them. So I did, two nights before Rennsport! Sometimes self-inflicted deadlines are needed to motivate me, I guess....

Once I began, the job of resetting the cam timing only took a total of about three hours excluding the exhaust removal and installation. The job was completed with the engine in place; I did not even do a partial drop. I just removed the rearmost engine tin, intake valve covers and timing case covers and went to work. Access was easy but I have no heat or AC to get in the way.

So I reset the timing from 1.8mm to 1.26mm. And I have to say that I believe it does run better. According to my butt-dyno there was no noticeable loss of low to midrange torque. In fact, it feels like the engine pulls harder and revs cleaner from mid rpm all the way to redline. Since this engine hasn't seen a dyno this is strictly my perception at work. But those of us who are so intimate with our cars know when things feel "right" or not. I do plan to put this car on a dyno at some time for air/fuel ratio numbers but I do realize actual dyno numbers are not particularly significant as they are so variable.

So, based on my experience with this particular engine build, I would recommend setting 964 cams to the stock value of 1.26 rather then 1.8. Is it a huge difference? Night and day? No. Is it noticeable? Yes. Worth doing over? In my opinion, yes.