Degree Camshaft for Low RPM Torque

[Martin6107]

I have been looking at a lot of threads discussing camshaft setup for a NA 96 Cobra. Many of the threads are focused on optimizing for peak power. This particular car only gets used on weekends when the weather is nice. The car will not see track time or any boost. Peak power is not what I am looking for. My goal is to optimize torque in the 1500-4000 range with a preference toward smooth idle and drivability.

The engine is getting a new set of heads this winter. I have a pair of 96 Mark VIII heads going to the machine shop for a valve job. Plans call for a new set of springs and seals from Brian Tooley along with a 106060 cam set. I plan to degree the cams during installation this spring.

Most of the cam setup threads are focused on creating peak power or idle sound, which just isn't me. I am just looking for a fun car to drive on the weekends. The car does not have long tube headers nor a tune. I am not sure that either will help on this build.

If I degree these cams to 108/118, will I achieve my goal (optimize torque in the 1500-4000 range with a preference toward smooth idle and drivability)?

 

[98 Saleen Cobra]

Just wait for NASVT to step in or PM him.. He's a genius

 

[RPM4DAZ]

You will definitely hear a lot of opinions on the cams. I personally think they will make some nice performance replacements for a street car. As for set up I think I would install them on a 112' l/sep +4. That is 108 l/c intake and 116' l/c exhaust. They will have a slightly noticeable idle change ,but nothing that will cause any drivability issues. Since you have a spare set of heads, you may want to consider some bowl work on them if you can swing it. Good Luck!!!

 

[na svt]

If using old mark 8 heads you will need to get later model mark 8 or cobra retainers.

Mill the heads .040" and install the cams at 107/110.

 

[Martin6107]

Thanks for the recommendations on cam settings. I'll add a set of retainers to my Christmas list.

Will I be able to run this setup without a custom tune? Would headers be worth the cost?

 

[na svt]

Thanks for the recommendations on cam settings. I'll add a set of retainers to my Christmas list.

Will I be able to run this setup without a custom tune? Would headers be worth the cost?

Sock retainers will work, no need for high $ pieces. Headers are a must if you want low end and midrange power.

 

[RPM4DAZ]

How many cc's do you think the chamber will lose when shaving heads .040"? OP, Let us know how it works out the cam locations you choose. I am sure a lot of members would like to hear.

 

[na svt]

How many cc's do you think the chamber will lose when shaving heads .040"? OP, Let us know how it works out the cam locations you choose. I am sure a lot of members would like to hear.

.040" will take the chamber to about 47cc. The midrange hp and tw will increase drastically so steep gears won't be needed.

 

[Martin6107]

Thanks for the input guys.

Springs and seals have been ordered from Brian Tooley. I also ordered spring retainers and keepers from autonationfordwhitebearlake.com (formerly known as Tousley Ford) for about $1.21 per valve which SURE beats those high price aftermarket options. The Mark VIII heads will be stripped down to prepare for their trip to the machine shop after the holidays.

Spring will be here soon enough. This thread will be updated with results after the build.

I'll keep an eye in the market board for some headers in the meanwhile.

 

[mwolson]

You will want a tune with the long tubes. You need to increase the O2_Transport_Delay_in_Revs value in the tune to compensate for the new, more distant O2 sensor location. Closed loop operation will be sub-optimal if you don't.

 

[na svt]

You want 1 5/8" primary's and a 2 1/2 " collector

 

[Martin6107]

Mill the heads .040" and install the cams at 107/110.

Removing 0.040" from the head sounds like a lot. Is it necessary to account for block decking to prevent piston to valve clearance issues? The block was decked previously, but do not remember how much was removed. The machine shop decked the block to prepare surface for a good gasket seal. There was no reason for them go crazy removing material from the block.

Assuming the pistons to be stock compression, what would you estimate the final compression ratio to be with 47cc chamber volume?

 

[na svt]

Removing 0.040" from the head sounds like a lot. Is it necessary to account for block decking to prevent piston to valve clearance issues? The block was decked previously, but do not remember how much was removed. The machine shop decked the block to prepare surface for a good gasket seal. There was no reason for them go crazy removing material from the block.

Assuming the pistons to be stock compression, what would you estimate the final compression ratio to be with 47cc chamber volume?

First, I wouldn't recommend something like this if I hadn't done it (as well as others). With stock cams there is no chance of PTV at the lobe centers I'm recommending. The CR will be around 10.6:1.

 

[Martin6107]

First, I wouldn't recommend something like this if I hadn't done it (as well as others). With stock cams there is no chance of PTV at the lobe centers I'm recommending. The CR will be around 10.6:1.

Your advice and practical experience is highly appreciated for sure. You know-the more I learn about this engine the more I realize just how little I know.

Heads will be going to machine shop in January. I'll order the 106060 cams next month too. More posts to follow.

 

[RPM4DAZ]

A couple of other things to consider on the decking of the heads. The chamber will obviously be slightly shallower. That makes for a better cleaner faster burn. Meaning less timing needed for a given compression and reduced valve shrouding too!

 

[Martin6107]

I have been looking at a lot of threads discussing camshaft setup for a NA 96 Cobra. Many of the threads are focused on optimizing for peak power. This particular car only gets used on weekends when the weather is nice. The car will not see track time or any boost. Peak power is not what I am looking for. My goal is to optimize torque in the 1500-4000 range with a preference toward smooth idle and drivability.

The Mark VIII heads are ready to go to the machine shop next week and I am finalizing the camshaft plan. This thread started with 106060 cams in mind. Given the objective above, is there any reason for me to consider 106100 cams for a street car that is unlikely to run over 5000 RPM? Torque and smooth idle are more important on this build than peak HP numbers.

 

[na svt]

The Mark VIII heads are ready to go to the machine shop next week and I am finalizing the camshaft plan. This thread started with 106060 cams in mind. Given the objective above, is there any reason for me to consider 106100 cams for a street car that is unlikely to run over 5000 RPM? Torque and smooth idle are more important on this build than peak HP numbers.

The 106100s make peak power well after 6000 so they will not fit your needs. For a smooth idle and low rpm power install the 060s at 106/116.

 

[mark23svt]

Thinking about this myself with a SRI at the same time.

 

[scarlett98]

What about the 106200s

 

[na svt]

Thinking about this myself with a SRI at the same time.

A short runner won't help with the low end power.