Exos's build

[Exos]

Could you please post these specs, or email them to me? : [email protected]

[dwg86]

Reed cams profiled the cam for me.

Mopar Performance P4529230AB:

Adv duration intake/exhaust: 260
dur @ .050 int/ex: 200
valve lift with 1.6 rocker: .453
Lobe separation: 108 Intake centerline: 104

Timing [email protected]
int valve opens: 26
int valve closes: 54
ex valve opens: 62
ex valve closes: 18

spring pressure closed 80-100 open 250-280

The one thing I just noitced is is says lobe separation 108, intake centerline 104. That means they advanced the cam 4 degrees when they profiled it. I'm not sure I would run this cam 4 degree advanced, since it's not that big a cam. The timing events represent the cam advanced 4 degrees with the valve .006 off the seat.

Reed Cams must have gone out of business. The phones have been disconnected and thier web site doesn't work. I hate to see that, as I have used thier cams before. They had great customer service, and even gave me a tour of thier shop.

I printed a list of some of the grinds they offered. They had some grinds that were real close to the MP 30AB cam. They had a profile that was 202 [email protected] with .453 valve lift with 1.6 rocker ratio. With a 1.7 rocker the valve lift was .481. Or a 205 [email protected] with a .459 valve lift with 1.6 rocker, .488 with a 1.7 rocker.

They also had some cam specs I thought would be better to use with the bigger displacement of the stoker, but still have good low end torque: 210 dur @ .050, .470 valve lift with 1.6 rocker, .500 with 1.7 rocker. Or 214 [email protected] with .480 valve lift 1.6 rocker, .501 with 1.7 rocker.

The one thing I like about going with a custom ground cam is you can choose any grind for the intake and exhaust. Either the same profile for the int/ex or different combination for the int/exhaust. You can choose your lobe separation, and have the advance ground into the cam. You could go with a narrower lobe separation, like 108, if your duration is smaller, and no effect the vaccum because the valve overlap is small.


Maybe some other custom cam companies have specs that are close to the MP 30AB cam.

[dwg86]

Bullet cams has a list of grinds on thier web site. This list is for .904 diameter hydraulic flat tappet. http://www.bulletcams.com/Masters/HClobes.htm

They have a cam that is [email protected] with a cam lift of .2880. Multiplt .2880 by 1.6(rocker ratio) that gives a .460 valve lift. or a [email protected] witha .460 lift.

I've never used a bullet cam, so I don't know anything about the company. I just did a yahoo search for "custom cam grinds".

[dwg86]

I just called Bullet cams. They do grind cams for the Jeep inline 6 cylinder. He said that a lot of cam companies were out of the Jeep 6 cam cores, and he just got a shipment in yesterday. Bullet cam charges $175.00 for a custom ground Jeep 6 cylinder cam. http://www.bulletcams.com/

I was looking at thier price list. They show $85.00 to regrind an automotive cast cam. This may be an option if you wanted to keep the later style cam with the retainer plate instead of swaping to the earlier style with the spring and pin. This would also keep the wider lobes. You can get a performance regrind on a stock cam as long as you don't get too radical, and you stock cam is not worn too bad.

When they regrind a stock cam, the lobe base circle gets smaller so longer pushrods are required, but this may not be a problem if you are having your block decked for a better quench and the head shaved for flatness. When you deck the block and shave the head, shorter pushrods are reqired.

[Exos]

...When they regrind a stock cam, the lobe base circle gets smaller...

Does this mean I would need oversize bearings for the cam? If the answer is yes, then it's not an option, I just had new bearings pressed in.

[dwg86]

They don't grind the bearing journals. The lobe base circle is ground smaller so the rise of the lobe is taller. I don't really know how to explain it. Try doing a google search on "cam lobe base circle". There should be some articles with some pics that will explain it better than I can.

Here is a pic of base circle...http://www.lunatipower.com/Tech/Cams/CamSpecTerms.aspx

[Exos]

No, that's all good, I understand now. So that will affect lift also, right?

[dwg86]

The cam lift, duration, and lobe separation can be changed. They can't move it much though. It all depends on how much lobe they have to work with. A cam grinder will be able to tell you what they can do with it.

[Exos]

So theoratically, I could keep my stock cam LSA and duration, but add a little more lift to it... That would be ideal. Thanks.

[dwg86]

You will also be able to add some more duration. They might be able to move the lobe separation a few degrees. The only downside I see using a reground stock later model cam is, a double roller timing chain set is not available for it.

[Exos]

I already bought a double-roller chain from JP perf. You mean that it wont fit my '93 cam?

[dwg86]

Sorry, I thought you had a 1997 and later engine. You JP timing chain will work with your stock cam. The later model engines used a retainer plate to hold the cam in. The front of the cam was changed to do this. All of the after market performance cams are made using the earlier cores. So if you have a later model engine and you want to use...lets say a comp cam, you have to use the early model timing set and the pin and spring to retain the cam.

[Exos]

I'm buying remaining parts, and I have yet another question : Does the intake/exhaust manifold attach package (P4529680 ) work with a 93 block?

[SilverXJ]

I don't know if it will work or not. What I do know is that the 91+ only uses two studs, the kit has 4.

Edit: It looks like Lunghd used it on his built with a 93 head and 99+ intake manifold http://www.lunghd.com/Tech_Articles/Stroker/Stroker.htm

[Exos]

Well, I've opted for my first idea after all : I bought the Comp Cam 68-232-4 with lifters. I hope I won't regret it. It makes my DCR right where I want it, the torque should be great, and the price is good with lifters included. And I (hopefully) won't have to deal with machining errors that can come with a custom grind. Let's cross our fingers, despite what hapenned to some with Comp, like SilverXJ.

And regarding that intake attach pkg, it seems really hard to find, the guy at moparstore.com told me no dealers in his area has it. I'll try to find it locally, or I'll reuse my old bolts and nuts if feasible.