Hmm... I really don't know, PFM. I'll defer to the real experts here, like Steve or Henry. I've been told, and have read in several references, that they are good to at least the mid 7,000's, if not a bit higher. I don't think you need Carrilos or Pauters until you are pushing 8,000-ish, but I could be wrong about that. I don't plan on testing it in my motor, and I don't have the experience with the number of motors under my belt that some of these guys have. Maybe one of them will see this and chime in.

SC rods aren't great, but they are better than 3.2 rods and will be fine for 7K. Just make sure you use ARP bolts.

I would like for the motor / cam combo to turn 7500 if the dyno says it makes power there. I am looking at a 3L RSR dyno sheet with PK power at 7800 RPM. I believe that motor had Carillo rods installed.

Any input on Raceware rod bolts? The pistons and pins are light weight.

Just looking for input not a guarantee.

PFM

PFM,

If you are going to run 7500 RPM, you need better rods than OEM ones.

IMHO, ARP bolts are better than Raceware ones.

Proper rods come with premium bolts; ARP or SPS ones. :)

You also need some extensive oiling modifications at those RPM's if you expect the engine to live.

Steve,

With my planned combo of 98mm 10.5:1, PMO 46mm, twin spark (looks like it's headed this way), DC60 cams do I need to look at new rods or just better rod bolts such as ARP?

Do I need oiling mods as well?

Thanks,
Darren.

If looking for 7500+ RPM, you will be well advised to get rods, cross drill your crank, drill the center main and groove your center bearing. In this case I REALLY like R&R GT3 spec rods. FWIW, Steve did the case and bearings for my motor which was designed for over 8K operation. He likes Pauter rods, which he can also provide.

It's worth the peace of mind, even if you might get away without them, to KNOW you did it right and never worry.

I agree that if you were building a race motor that the rods are subject. Also the oiling would need to be addressed if you were going to run 7,000+ for any length of time like racing. But we are talking about a street motor here and honestly 7,000 RPM is going to be every now and then at the most. Seven grand in second gear is already ticket territory!

My motor runs very well between 2,200 and 7,000 with an obvious increase at 4,000. From 4,000 to 7,000 it'll run with just about anything on the street. This is all I was looking for and I think D911SC would be very happy with this set-up. There is a point in the build process that you have to say enough is enough.

Don't get me wrong, I would personally love to have Pauter rods, a Henry Schmidt crank, shuffle pinned case, turbo oil pump, etc, etc, etc, etc. The list goes on forever. But this is a street motor with a builder on a budget.

Lindy

I had the same conflict for my spirites street motor. In the end, it has taken me 4 years to assemble the parts for my motor because:

It really gets no simpler than the above...you can't have it both ways. Rev limit to 7K on stick rods and ARP bolts or nut up...otherwise, you are rolling dice.

You will engage in all of the above...trust me! :D

I hear you.

I guess, for me at least, half the fun of these builds is the build itself and future upgrades to the original build. Unlike the guy who builds a stocker and doesn't want to touch it again for 150,000 miles, the prospect of pulling the motor next winter to add new bits and pieces so you can add another 500 rpm to the rev limit chip is exciting. Maybe I'm coming from a different perspective here but I enjoy having the motor on the stand when the weather is not cooperating. It also makes me a better wrench regarding the 911 motor and as they say "practice makes perfect".

In my case, 7,000 rpm is the upper limit of my power band so I'm not concerned right now with my rods. I do plan to improve the heads which will raise the limit and at that time I'll weigh the other upgrades needed. Like I said; rods, crank and case mods, pump and other goodies are on my wish list and will someday find a home in my 3.0.

Lindy

This is great input and really helps me out in planning the upgrade.

Given that this is a street car I do want to put a limit on how far I go. I am chasing a fast motor but it won't be raced, maybe a short stint on club track days at best. I doubt I will be pulling this down for further mods as there is plenty to spend on other parts of the car. So far this seems to be the current spec

1. 3.2SS using JE 98mm 10.5:1
2. DC60 cams
3. PMO's 46mm
4. SSI
5. Dansk 2 in 2 out
6. ARP or Raceware bolts on stock rods
7. Twin spark (insurance against detonation)
8. MSD Ignition
9. Rev limited to 7000rpm (more insurance!)
10. Ported heads (assuming this needs to be done as I believe I have smaller port SC heads)

Anything else I need to allow for in the rebuild?

I agree with you except for the cam. Without big revs and port work, DC60s are a poor choice. You'd be better served with DC40s, DC44-102s or DC-GT2-102s. All will benefit from bigger ports, but don't need them, whereas the DC60s do. On a bigger motor, these make mad power and torque to 7000 RPM. The DC44-102s will make the most power and have the most headroom, but will require race springs. The DC40s and DC-GT2s can use stock springs. All can use stock retainers at these revs.

Thanks for the input kenikh. I suspected the DC60's were borderline but I have read plenty here about guys using them with similar configurations. I felt that these were still a good option for what I wanted to achieve.

What sort of power can I expect from DC40's? Where does the power come in as compared to DC60's?

Darren

What year is your SC? If it's a 78 or 79 it has the big port heads. Mine is a 78 which may be why the GE60 cams work so well in my build. There is always a better combination, no matter what you end up with. Someone will always be able to improve on what you have done. The big question is will the combination you have above satisfy your build requirements?

IMO, being that it's a 3.2 and then basically the same thing as what I just built, your motor will be fast and reliable. Not to say it will be optimal or perfect, but fast and reliable. That's what I have and it puts a very large grin on my face every time I fire it up.

Lindy

They will "work", but you would be leaving power on the table since you can't run them in manner they were designed. You can look up DC40 (also called GE40 and Mod-S) dyno sheets for 3.2SS on this site, as there are many that have been done.

The GT2-102s are the cams that Jeff Higgins uses in his 3 liter, which uses small port heads. Here's a dyno sheet from before he got the car's AFRs dialed in...he's at least 20 horses and a good bump in torque on this one:

http://forums.pelicanparts.com/uploa...1275509385.jpg

The DC44-102s are a favorite came of mine - I was the first to use them and John and I went back and forth designing these for a month. They've been so successful, they are now listed as a spec item on his site. For my 2.3L, they were designed to make 906 power, but without compromising on low end torque. They use a very aggessive ramp and .490" lift to get a lot of air into the motor fast. They ended up making 100HP/L at 7800RPM on the 2.3L and had a torque curve before 4000 RPM that looked like it was transcribed from a 'E' motor.

Given the propensity of larger motors to "soften" cams, you could expect these cams to make peak power around 500 RPM sooner, with torque everywhere. These cams respond really well to 38 or 39mm intake ports, but are perfectly happy with slightly smaller ports, which is why I suggested looking at them.

Your Euro 83SC should have the large ports. Keep in mind that you don't want to run a big cam if you can not support the intake airflow. The carbs will be fine but what about the head port diameters?

I agree that you will want twin plug. Compression ratio and large bore can create flame front issues with single plug. Besides, less timing is always a good thing.

I built a 3.2SS last year. I have 10.0:1 compression and twin plug. I run a DC40-108 in my car. The lobe center was set such that I have less issues with reversion in my EFI MAP signal. Peak torque is about 5800 with itbs and HP does not seem to fall much through 7100 (self imposed redline). I built the valvetrain to hold through 7500 or so but did not do the bottom end. My car pulls like a stock SC through 4K and then all comparisons are off. Just like any car with good cams it revs extremely quick at high rpm. I do not have any dyno curves. Its still on the list to do but not a priority of life. Really, the actual numbers don't matter to me. I just enjoy the "character" of the motor.

Jeff Alton used the DC44 in his 3.4. He reported peak HP just above 7K rpm and remaining flat through 7200. I don't recall seeing the dyno curve.

There are subtle difference between the DC40 and DC44 cams. For a street car I would go with the DC40.

I'll just add this for consideration.

I run DC-60's in my 3.0 RSR spec motor. It is basically the same as Darren is projecting with ported heads but with 95 mm 3.0 10.5 CR Mahle P&C's. I run a down-stacked gearbox with reduced ratios for 3-5.

The set-up is just wonderful. 285 HP at the crank and runs right up to 8000 RPM.

From 1K to 3K it feels like my old stock '82 SC. From 4K to 8K at WOT, it accelerates like a sport bike.

If you open up the heads a little and match your gearbox to the 3.5K-7.5k RPM, power band, you can use the GE-60 cams and you'll be grinning every time you put your foot in the throttle.

Are you using stock rods for this? From what I read 7500 is too hot for stock rods even with better bolts. Based on Steve's advice (Rennsport) that OEM and 7500 don't mix I don't want to be the guy that tests the theory!!

What gear ratios are you running?

I have already bought DC60's but may not use them, still haven't decided. One of the issues is driveability on the street which new gear ratios may resolve. The other issue is the added expense of making this thing survive higher revs that the DC60's need.

At this stage I am 99% certain of the other components so I will start to 'squirrel' these and make a final decision on the cams at the end. If I choose DC60s then they are there ready to go. If not I'll just have to sell them and put in something else like DC40s or GT2-102's

I really appreciate all the comments and contributions here. You guys have loads more experience and expertise than me so it really helps.

Anyone got some new 98mm cyclinders or PMO 46mm please let me know. I can arrange shipping at my end. :)

Darren

According to Bruce Anderson, stock rods are good to 7800 RPM. I'm confident that with lighter pistons (JE's are lighter than stock) and any rod bolts (stock are fine here as well IMO), you could rev your street engine reliably to 7500 RPM. I race a "stock" SC motor with carbs and rev it to 7200 RPM with CIS pistons. The class I race in uses stock rods and some of our 2.7 engines rev to 7500 RPM and more. Use a rev limiter set to 7500 and have fun with your awsome motor.

-Andy

I place a 7500 rpm redline on stock 3.0 liter rods with arp bolts. It's a reasonable redline for those rods. If it was a 3.2/3.3/3.6 rod, I would not run them above 7000 rpm even with ARPs. FWIW a 72S redline is 7300 rpm with stock rods and bolts...same stroke as the 3 liter.

The DC60 is a great choice for the 3.0 liter/3.2SS. It brings back the early S feel that Porsche had to give up. With proper compression and twinplug ignition, it's a great combination. I perfer around a 40mm port for this combo.
Build it and enjoy!

I manually limit my redline to 7500. Stock rods, ARP bolts.

It does require proper attention while accelerating as the motor will continue pulling right past 8K.

There is plenty to play with from 4k to 7.5K

I don't trust myself without a rev limiter! You are a better driver than me Tom. It's good to know that some guys are running 7500 on stock rods. I'd probably still err on the side of caution but something like 7300 seems safe enough but still giving me a long enough in the 'power zone'. There might be more HP with better rods but I have to limit the $$ somewhere. This engine is already looking like costing more than my wedding, but don't tell my wife.

There's definitely mixed reactions about this DC60's. Aaron - when I'm getting closer to the build I'll have to get in touch re a suitable distributor.

Anyone got any videos of a car running with this kind of setup? It would be interesting to see how it idles and drives.

Yeah....Mine cost as much as my daughter's wedding :-)

Your combination with GE 60 cams is as street-able as it gets for a hot-rod. It is very easy to drive and acts very stock under 3,000 rpm; it's hard to tell it's a hot rod. Anyone who tells you that these cams aren't street friendly hasn't driven this combination. As I have said many times before, it's what makes you happy and if you already have the cams purchased use them. Any change in cam at this point IMO is throwing money out the window.

I'm not trying to make any personal attacks on anyone's opinion here just trying to share with you that the cams you already have are a great choice. Perfect? Maybe not but neither is anything else. All cams are a compromise.

Lindy

My c3 rebuild just made 270 @ 6000 revs with dc62s its perfectly streetable and pulls clean in any gear low down
A lower rocker oil leak stopped play before any ignition tuning etc.Its back on the dyno Friday for a map at full revs,will post charts later

Thanks again Lindy. As I mentioned in an earlier post I have been watching your build with keen interest.

As you say I have already bought the DC60's and the most recent comments from yourself and others about these cams has me very keen to use them.

Driving like a stock car under 3000 and then feeling like a hot rod after that is the kind of engine I'd like to own!

When I do the build I will get another thread going.

Thanks for all the comments.

FWIW, it would be fun to try them. No harm, no foul right? Since you already have them, the worst that might happen is that you might decide that some port work is in your future one day. The net-net is that is sounds like the motor would be fun, so I'd say go for it.

Thank kenikh - I have already planned some porting. Seems like it is a 'must do' with this mod.

Then I would be remiss in not recommending Steve Weiner's magic ports. MAGIC.

http://i25.photobucket.com/albums/c7...n/IMG_0487.jpg
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kenikh,

The ports look good from Steve. What is the valve size and what are the flow numbers? The real numbers I would like to see are the port velocity numbers mapped across the ports, in and out. And what size motor are they designed for?

Regards,

PFM

Heh heh. You are right to be skeptical, as I have seen some BAD port jobs that looked good. I think those aftermarket billet heads are some of the worst POS CNC hunks ever, but they aren't priced that way.

But the fact that the name Steve Weiner doesn't immediately elicit blanket respect belies a little noob. :D We were all there, but Steve is one of the good guys and by sticking around a while, you'll certainly absorb more than a fair share of useful nuggets from him.

Let's put it another way: these heads on Cam Arnott's 2.25L motor dynoed 225HP at 7500RPM (HP peak is actually 7800, but he cut the dyno short). The torque curve looked like a twin to 2.2E until 4000 RPM, after which it went straigh up like a rocket and looked like a 906. Yup, cake and you get to eat it. Amazing. :cool:

These heads are the real deal.

Woops forgot to add a link to answer your other questions:

http://www.early911sregistry.org/forum/showthread.php?t=22220

Forget the port specs, as the heads are cut 3-dimensionally as a tapered venturi from port to valve. If you measured them, they'd be 39mm-41mm depending on where you measure them. They are VERY special indeed.

DC62 idle Tick over after 1st mapping session on Vimeo like a pussy cat
DC62 up to 6000 revs dyno run to 6000 on Vimeo

Do you have the results of the dyno pull and would you please post them?

Lindy

270 on that run an oil leak stopped play before any real tuning so going back Friday

270 Hp at the rear wheels with GE60 cams at 6,000 rpm; Wow! That kind of debunks the notion that these cams require high revs to make power. Can you share the torque numbers?

Thanks!

Lindy

fwhp ;)

Here's a table of the varying overlaps of these cams. Lower overlap typically means more low end grunt and lower peak HP RPM.

http://forums.pelicanparts.com/uploa...1276014960.jpg

Found the dyno sheet:

http://forums.pelicanparts.com/uploa...1271892309.jpg

Cam being an Aussie, it is in kw not HP. His caveat is that the carbs were not well tuned for this pull, so it looks looks like 182 RWHP for a corrected 210 DIN HP...RS territory. So the 100 HP/L number he initially thoughts was a little high, but not too far off. What is amazing is how they keep making power over 8K, given the torque curve! Other than the little blip that is likely due to the carbs, that curve is FLAT.

I actually designed the motor and was going to build it, then decided I wanted more displacement. They heads are '69S, w/ '69S valves and the motor is 2.25L (85x66). Let's just say that the amount of time I spent in design left no stone unturned in pursuit of power extraction. :)

The only difference between the motor cam built is that mine would have used my taper bored MFI stacks and custom blends TBs and purpose designed headers, also from Steve Weiner. My guess is that trimmed to my spec, peak HP would have been up another 10HP and torque would have been even fatter down low due to improved scavenging. Cameron ended up using PMO carbs and SSIs.

Damned impressive for carbs and a restrictive exhaust!

As far as the heads go, the ports are custom scaled to fit your motor spec, so if you wanted these on a 3 liter, they'd be scaled to suit in the computer model then cut.

Don't want to milk this thread too much but I couldn't resist posting these pics of what arrived in the mail today!

There is no turning back now ;)

Thanks to JD of Dougherty Racing Camshafts for answering a couple of questions I had about these.

Also thanks to Lindy911 for prompting me to look at these. Looks like we may be building a very similar motor.

http://forums.pelicanparts.com/uploa...1276169738.jpg
http://forums.pelicanparts.com/uploa...1276169780.jpg

I know this will probably start a new debate over usefulness but here goes anyway; I had my piston tops coated with a thermal barrier polymer from Poly-dyne in Houston. I also had the sides of the piston coated with an anti-scuffing coating from the same people. To date, I don't have an auxiliary oil cooler mounted, just the engine cooler. My motor has not been more than 2/3 up the temp gauge! Now I haven't run it that hard yet but I'm convinced this is a good thing to consider.

It cost about $200 to get the pistons done and another $100 to do the rod and main bearings with the same stuff as the piston skirts. The piston thermal barrier effectively keeps the combustion heat from soaking through the piston crown, therefore reducing the heat transferred into the oil via the squirters. This is a good thing considering these motors are know for running hot.

More food for thought.

Lindyhttp://forums.pelicanparts.com/uploa...1276174875.jpg
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Coatings are good! I coated every moving part in the top end of my motor as well.

My motor runs very cool and very efficient. I definitely think it is worth it.