Frequently Asked Questions

When people start looking at performance cams, the first mistake most people make is assuming that bigger is better. The best way to figure out what cam you need is to look at the desired rpm range. Also characteristics you want in your engine. Daily drivers, going with a cam that has a lot of duration will usually greatly decrease low rpm performance. Going with a short duration camshaft will usually create very good throttle response, low rpm torque increases, better fuel economy and less smoke.  Typically the 178-208 is the best choice for most builds. The 188-220 starts to be a better choice when you go over 4,000rpm often. The 178-208 has made 1,100hp on a stock head with a single s400, 1250 with bigger valves on a 6.7l. Believe it or not, but the 178-208 made 1588 @4500rpm with a ported head with a single s-400 and power was still climbing when we let out. It is very capable, is 49 state EPA approved on most applications, and is my personal favorite on any 24valve engine for fun or work. 

We have been working with performance diesels for almost 30 years. We have looked at every angle for performance and efficiency, conducted thousands of dyno tests. Our cams have accumulated tens of millions of miles in real world use.

The first 5 minutes of operation of your new camshaft is very important. Ninety percent of all issues arise in this period and have to do with inadequate lubrication.

To make sure that you have no issues during break-in, follow these few suggestions.

– Make sure that the cam has a Liberal amount of quality assembly lube applied, we also suggest adding lube to the block on journal 6 and 7 as most of the assembly lube is rubbed off as the cam slides in

-DO NOT let the engine start without oil pressure

– When this is a new engine, be sure to put a liberal amount of assembly lube in the oil pump and prime the oil filter

–  When the filter and oil system are already primed, engine will get oil pressure much faster than if the oil is changed at the same time. For this reason, if you are just installing the cam on an existing engine, start the engine with the old oil for 30 seconds. After this change oil and filter

-Disconnect the fuel system and spin the engine with the starter until oil pressure can be read or until oil is coming out of the rocker arms on cylinder#6

-Do not let the starter run for more than 10 seconds at a time

– Once oil pressure has been verified, let the engine start and run for five minutes at 1200-1500rpm then shut engine down

-Adjust valves (.010″ intake/.020″ exhaust) then you are cleared to abuse your engine. Enjoy the added airflow

-if you need to re-torque or “hot-torque “the head, do so before adjusting valves. Re-torqueing the head changes the valve lash setting, so it is important to set lash last.

2-3 times a year I get calls from customers that have lash starting to get loose on the last 3 cylinders. This is caused from poor lubrication at the time of initial start-up. In this case the cam literally eats its way through the block away from the force of the tappets. Assembly lube and oil pressure on start-up are a pretty big deal to your cam. Don’t let this happen to you.

The OEM Cummins camshaft is a chill-cast ductile iron material. Due to the chill-cast process it has a very hard surface that allows it to have a long life in the extreme environment in which operates. Though it has a very hard exterior, it has a somewhat softer core. Your cam can handle torsional forces without fracturing in a wide number of applications. Issues arise however when the cam that was designed for 200hp and 2,800 rpm starts getting pushed beyond 4,500rpm. Additional issues can arise when large injection pumps, heavy springs and high-lift profiles are used.

High-lift camshafts, heavy springs and large capacity injection pumps create cyclical torsional forces much greater than what the cam was designed to handle. In many cases the camshaft will fail between the nose and cylinder number 2. Also between the nose and whichever journal pushed through the hydrodynamic film of oil and seizes in the block. A steel camshaft will stop most all breakage due to torsional harmonics but is still vulnerable to breakage due to journal seizure. The Cummins B, ISB and ISBE engines, depending on CPL, have either one or two bearings for the seven journals. The other five or six journals ride directly on the block. Where big lift cams and high spring pressure are used, the cam can push through the oil film that separates the cam and block and seize. Having the block line-bored and installing journal bushings will ensure this does not happen.

If you are running a cam with more than 210 degrees of duration @.050″, more than .340″ lobe lift more than 420# nose pressure or getting close to 5,000rpm there is a benefit with having your block modified to accept cam journal bearings to run a steel cam

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. 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. Creating 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.

Most diesel oils are not adequate for a performance flat tappet diesel camshaft. Oils have been formulated to balance wear, economy, cost and emission system life. It is not easy to do all of these simultaneously. Even if you start with a great base oil, the additive package could be inadequate to keep the tappet and the camshaft separated. Zinc and phosphorous in the form of ZDDP were the go-to additives for years (1200-1500PPM) until DPF systems were mandated. These additives can plug the DPF as some oil is burned off of the cylinder wall during operation. The solution to DPF health was to greatly reduce ZDDP(1000PPM or under) and other additives that can plug the DPF. This solution, greatly reduced flat tappet cam lifespan. The good news is that MODTC or Molybdenum is a great benefit in keeping flat tappets alive. Although we have not tested every oil on the market, we have found a few winners to help your cam. Valvoline Premium Blue 15-40 is our go to with 39ppm Molybdenum. If a synthetic oil is necessary, we suggest Schaeffer 700 series 15-40. For the sake of your flat tappet, run one of these oils. ZH