Higher Egt's after 178/208 Cam install

Anyone care to explain why it doesn't work to just line up the notch and key and call it mac?
 
Stack up of allowable tolerances can move your centerlines from ideal position. I'd be curious as to the tolerances that Cummins and the aftermarket cam builders have for their key positions.
 
If the cam timing was off would there always be smoke/haze at all rpm's not just down low right?
 
fatty said:
Anyone care to explain why it doesn't work to just line up the notch and key and call it mac?
Click to expand...

If the crank gear has moved or was a little offset from the factory it will cause the cam to be out of time. This happened to me on my personal truck, the crank gear spun into the line up dowel enough to cause my cam to be 3* off. Ended up replacing my crank gear and line up dowel and welding it to the crank.

Also not all cam gears are cut exactly the same this is why it should be common practice to always degree your camshaft.
 
Can someone describe how a common rail truck will act if the cam is off timing through all rpm ranges.
 
Last edited:
Found this

If the timing is out the engine won't be running efficiently. The power output for a given amount of fuel will be less but it will still be burning the same amount of fuel. So a larger proportion of the fuel used will be turned into heat instead of usefull work. I would agree, if the timing is retarded it will run quieter but be more difficult to start, it will also produce more heat and smoke and less power as explained above, if over advanced the efficiency won't suffer so much but it will be noisey.
 
Last edited:
Straight from Hamilton's website

In most instances our cams do not need to have the centerlines moved. Our cams are ground on a CNC grinder to ensure that each cam is on the correct centerline. That being said, there is a +/- specification that Cummins uses during manufacture of the crank and cam gears. Usually there is less than 1 degree of variation from engine to engine and in rare instances 2+ degrees. Issues arise when people start to switch crankshafts and cam gears from different engines and year models. This creates an instance where the cam might be installed on a centerline that might allow piston to valve clearance or performance issues. To remedy incorrect camshaft installed centerline, call our office and order an offset key. We have keys that will offset the cam centerline from 1.5-5degrees.
 
Let's say i am 100% sure the cam was installed and timed correctly. That being said the cam and tappets were the only thing changed, nothing else. What else could be causing the excessive smoke down low and the higher than normal egt's? Bad cam? Tuning needs to be adjusted. Trying to start with the easiest first before i go tearing the truck apart again.
 
Last edited:
You are not 100% sure if you have not put a degree wheel on it.
 
Rhett24 said:
Found this

If the timing is out the engine won't be running efficiently. The power output for a given amount of fuel will be less but it will still be burning the same amount of fuel. So a larger proportion of the fuel used will be turned into heat instead of usefull work. I would agree, if the timing is retarded it will run quieter but be more difficult to start, it will also produce more heat and smoke and less power as explained above, if over advanced the efficiency won't suffer so much but it will be noisey.
Click to expand...

That's related to injection timing not cam timing.
 
On hamiltons webiste it says that all their cams install like a stock cam. Has anyone ever installed a hamilton cam on a truck? Where did you line your 0's up according with the crank gear? What were your results? Did you have to adjust tuning after you installed?

If the cam was off timing wouldnt the idle be off or wouldnt it sound different?
 
Rhett24 said:
On hamiltons webiste it says that all their cams install like a stock cam. Has anyone ever installed a hamilton cam on a truck? Where did you line your 0's up according with the crank gear? What were your results? Did you have to adjust tuning after you installed?

If the cam was off timing wouldnt the idle be off or wouldnt it sound different?
Click to expand...

Thats like saying pistons fit the stock bore. While its generally true, without measuring pieces, you don't actually know the fit. That's where you are right now. You know the pieces, but you don't know how they fit.
 
You must log in or register to reply here.
Back
Top