Engines such 1FZFE & 3RZFE and others… need a little help. Part of the answer is… a “ditch cut cam.”

One of the techniques is to regrind the exhaust cam profile in such a way that it reduces the exhaust temperatures and allows the exhaust valve to grow in length without shutting the tappets clearances down.

What most people don’t appreciate is how much the valve clearances will reduce in an LPG engine.

You can carry out a simple test yourself in your workshop by simply getting an  exhaust valve, standing it up on the work bench, and getting a dial indicator with a magnetic base. Place the plunger of the dial indicator on the tip of the exhaust valve then get your oxy torch fired up and heat the head of the valve. We guarantee that before the head of the valve turns light red, which normally happens within 10 to 15 seconds. The dial indicator will show that the valve has grown more that .018 thou; depending on the valve material it could be more than .024 thou.

Usually the factory valve clearances are set at approximately .013 thou. So you can imagine what has happened to the tappet setting when the valve is growing so much in length from the application of a small amount of heat?

Our cams are reground with proprietary profiles which have served our customers very well and given the vehicle owner cylinder head longevity as well as great value for money.

One other advantage from changing the profile has been an increase in torque!  Your customers will comment that they can “climb the hill 1 gear better than before.” One thing you will need to do is check the tappets on regular intervals; keep the tappets set to our recommended intervals.