Cam selection.. isky.. engle... lunati

[gradon]

So yall think that the obd2 couldn't deal with the +4* of overlap compared to stock(43*)? It's only 1* more than a 91-95 cam(46*) and I'm sure someone is using that earlier cam in their obd2 strokers(that would be the stock cam of my choice). Or would it be the higher lsa than the stock's 107* that is the issue? I'm an amateur when it comes to cams so I'm just throwing this out there.

[SilverXJ]

I don't know. The stock cam has a 107* LSA, and 43* of overlap. For a stock cam that does seem excessive. I really don't know at what point LSA and overlap contributes to a rough idle and PCM issues. Personally I have only ran 4 cams. CC 68-232-1, CC 68-231-4, stock, and some Crane grind that Titan tried to squeak by me. I did have a slightly rough idle with the 68-231-4, however I didn't have time to play with things such as spark plugs. And it really wasn't that rough to complain either.. it did idle smoother than my 93 ZJ with 189k miles. It would be nice to know exactly where issues come up... but I'll stay on the safe side. Plus.. its a jeep.. things rattle.. and that bugs me.

[SilverXJ]

Purchased the cam yesterday. $168. And I forgot to ask when it will be ready.

[Muad'Dib]

They also suggested this if I wanted to try something different:

Intake:
Adv. duration: 264
.050 duration: 214
Centerline: 103
Lift: .480"

Exhaust:
Adv. duration: 270
.050 duration: 221
Centerline: 117
Lift: .496"

LCA: 110*

Overlap: 47*

I think this might be the cam ill go with depending on how well your cam works out for you silverxj...

The ONLY thing im not sure about is the amount of lift..

[SilverXJ]

You want more lift?

What I learned is that each cam manufacture has a number of grinds that they can do on each lobe. I.e. if you look at Iskys cams they have 3 in stock grinds. http://www.angelfire.com/my/fan/Jeep4.0Camshafts.htm. They can do any combination of those grinds on any LSA. But they are still restricted to those grinds. If you look earlier in this thread it will show a cam that I cam up with.. however they couldn't grind this because it didn't fit their grinds.

Also, the cam is advanced 4*. While playing in Desktop dyno it seemed to 2* advance (-2* retard from the cam) as the best. I asked Ron at Isky about this and he says that they usually grind in 4* advance because of timing chain stretch. When you time it in with anew chain it will be in spec. However after the first few hours the chain and gears will break in and stretch a little, reducing timing 2*. So, I guess when I install the timing I will be installing it straight up and seeing where it falls.

I think I will like this cam. Its going to have a quieter valve train than the cam, and have more top end. It will be missing some off idle power though. I would just like to see how the PCM would react with a wider LSA.

[Muad'Dib]

I am more concearned that it has too much lift.

[SilverXJ]

Oh.. I didn't read the cam you were Talking about. I'm going with this cam:

Intake:
Adv. duration: 258
.050 duration: 208
Centerline: 108
Lift: .464"

Exhaust:
Adv. duration: 264
.050 duration: 214
Centerline: 116
Lift: .480"

LCA: 112*

Overlap: 37*

I decided against the larger cam. Desktop dyno didn't actually show that much of a difference. While it isn't prrof positive it was enough to persuade me not to take a chance on the larger cam.

[Muad'Dib]

I would probably do the same with obd electronics.. however, im going to be running RENIX.... which seems to be much more flexable.