Issues after cam install

[Drothgeb]

I haven't really be on Compd much lately, but I just came across this thread and thought I throw my $.02 in.

Changing a cam, changes the whole dynamics of an engine. It's not a one step process, especially one as large as the 188/220. And it is a large cam. Too me it's too big for most street trucks, especially if you run a tight converter. It's more of a cam that will open up your mid and upper rpms. If you don't use mid and upper rpms, I'd think twice about using this or any other similar cam.

Your low end haze is in large part due to your engine's loss in dynamic compression from the cam's longer duration. Your loss in low end power is due to the lower compression and the exhaust valve opening earlier. Those are both facts of longer duration cams. On a gas engine, anytime you install a larger cam, you need higher compression pistons to compensate. On a diesel the loss of compression can be made up for by higher boost, once you have boost. Before you have boost, about the only way to address it is to raise the static compression. If you add a thicker head gasket to make the cam work, it's a double whammy.

On my current build that includes a 188/220, I actually run over 18:1 to help compensate for the cam on the bottom end. It works well, except it limits the boost that I run on the top. Ultimately it cost power, but it drives better and smokes less.

 

[fatgraderman]

I haven't really be on Compd much lately, but I just came across this thread and thought I throw my $.02 in.



Changing a cam, changes the whole dynamics of an engine. It's not a one step process, especially one as large as the 188/220. And it is a large cam. Too me it's too big for most street trucks, especially if you run a tight converter. It's more of a cam that will open up your mid and upper rpms. If you don't use mid and upper rpms, I'd think twice about using this or any other similar cam.



Your low end haze is in large part due to your engine's loss in dynamic compression from the cam's longer duration. Your loss in low end power is due to the lower compression and the exhaust valve opening earlier. Those are both facts of longer duration cams. On a gas engine, anytime you install a larger cam, you need higher compression pistons to compensate. On a diesel the loss of compression can be made up for by higher boost, once you have boost. Before you have boost, about the only way to address it is to raise the static compression. If you add a thicker head gasket to make the cam work, it's a double whammy.



On my current build that includes a 188/220, I actually run over 18:1 to help compensate for the cam on the bottom end. It works well, except it limits the boost that I run on the top. Ultimately it cost power, but it drives better and smokes less.

I wondered about the dynamic compression myself (my history is with the gassers- dirt street stock), but have no first hand experience with the diesels. Have you ran "your current build" yet? Is it a CR? Did the raised compression help light the turbo? Some of the pullers are saying that the extra compression has helped "get on top of the turbo". How did you go about raising compression on yours? Mines a 07 5.9 and I've been throwing around possibly throwing the new Carrillo 6.4 rods in and then taking down the compression height of the pistons to match. But that screws up the nozzle to floor height. And if I retain the cr head, then the injectors can't be shimmed up accordingly. The new Hammy street head might be the fix there when it hits shores. But once everything gets converted over there- rail, lines, top feed injectors and all- really hard to say if it would be viable. But if a guys looking at $1700 us for porting anyways and rebuild costs above that, side entrance manifold, and still your big injectors, it may not be that much difference, and the top feed has room to grow further.

 

[Drothgeb]

It's a 12v. Hasn't made a pass yet. Hard to compare it to my last build as far as spooling, completely different turbos, IP, torque converter and etc. Running pretty low timing until it's broken in too.

My background is building marine engines. Wouldn't think about buying a part to start a build until I decided on a cam and calculated the dynamic CR. Always puzzled me that I never see it discussed. I never could find the info needed to calculate it for the 188/210 precisely, but I'm guessing it's more than a point with stock pistons.