Got a 98 4.0 OHV engine that's starting to get the notorious valve tick. Got me thinking - when I go to change rockers and pushrods, what other performance upgrades can I make while the engine's apart? I found some roller rockers with a 1.8:1 ratio, but I'm not sure how much better those are than the OE rockers in terms of ratio. In other areas, I'm thinking maybe porting the exhaust valve outlet a few thousandths of an inch, maybe some porting on the air inlets in the cylinder heads. Not sure if it'd pass smog with those upgrades, though (I live in Cali.) What do you guys think?

 

BoomShotz00

Welcome to the Forum. Cali is by far the strictest emissions state.

The other side of engine tuning is through the OBD 2 port on the truck. Pricey Flashpaq meters can change things even easier. Than installing aftermarket parts. Like it can change your shift points. That will give you more out of the engine. This is a spot you might want to find a performance tuning shop. They can help with the right shift points to get your motor running better. Also without changing emissions. In most cases.

I know others will also have ideas. I would first fix whats broken. With OE parts.

Other things to do before you change things. Regular engine tune up. New fuel filter. If yours is located on the frame outside of the tank. Check condition of the lines from and to the fuel filter. New spark plugs. New spark plug wires. New air filter. Nothing special. Just a new air filter. Clean the inside of the air filter box. Because of there location they can get dirty. Fuel additive to clean the inside fuel injectors. Lots out there. I would do that every 3000 miles. With an oil change. Change transmission fluid if it has been a while. Change fluid in both transfer cases if it has been a while. 2 if 4X4. Only 1 if 4X2. Change antifreeze if it has been a while.

I might get a lot of laughs from this list. But things like the above effect the engine.

Jim

 

Using electric fan on radiator and removing mechanical fan frees up horse power and increases MPG, and no emissions issues.

Increasing the amount of air an engine can use per RPM increases its power, because more fuel can be added.
A 5 liter engine has more power than a 2 liter engine because it can use 3 more liters of air every 2 RPM(4 stroke engine).

But you can get close to the same power out of a 2 liter engine by forcing more air in, i.e. turbo or super charging.
Forcing a 2 liter engine to use close to 5 liters of air every 2 RPM

Changing Cam dwell or offset rockers can increase the air the engine can use every 2 RPM so more fuel can be added and more power gained

This, in theory, should not effect emissions that much since engine computer is still adding correct amount of fuel for the increased air flow and Cat converter is still cleaning the exhaust.

Read here on 1998-2000 heads and exhaust ports: Rebuilding The Ford 4.0L Pushrod V6, Doug Anderson, Automotive Rebuilder, April 2001

 

Some of the engine tune-up advice, I have already done. I mentioned roller rockers because I'm going to have to change them out anyway, since they and the pushrod tips don't get lubricated properly. I found a complete kit for 900, but I don't know if it's worth it. An electric fan upgrade would be worth looking into, and I'll definitely need new spark plugs and wires soon. Still need to do transfer case and front diff fluid changes. Won't be doing forced induction of any kind, or putting in a new cam. JBA makes a set of headers for a little over 500. Those would probably compliment roller rockers nicely. Any other advice, comments? Maybe even criticisms? Lol. Also, I appreciate the suggestions that have already been laid out before me.

 

If you really want the most out of the engine. I would say check out a Performance tuning shop. They also can make it so you can go faster than 90MPH. People that race cars. Do both sides. The engine parts and the OBD programing. You can also get a device that can plug into your OBD port. It will show you MPG. Miles till empty. If you have an andriod phone. Check out the App Torque. There are so many add on apps for it. You can also use your phone as a heads up display.

Jim

 

Probably the best way to go. That way I can talk to people who know how I can get the most out of my engine while still passing the emissions test.

 

The tuner shop will tell you what can be done and still stay emission compliant. They will have a good knowledge of your engine. As engines get older they loose HP. From the start Ford gave the engine modest shift points. What tuning can do is improve shift points and make your engine better without killing the engine.

Some places can even put your truck on a Dyno. So they can show you what you have now. Show you the points they can change to make the engine give you more. Also there are plug in devices. They have the program you want on them. You plug in under the hood. As long as the little box is plugged in. It will run the program made at the tuner shop. You can then unplug it at any time to return it to stock instantly. Like emission tests and all. So many options on the computer side. On board displays that allow you to make changes while driving. This sector of auto custom is really advanced. Enjoy.

Jim

 

Thank you for all of that information. Would be miles easier to simply use computer tuning versus undergoing the task of buying and swapping parts. Still need to do some of that regular maintenance stuff you previously mentioned though, so I'll get to that as soon as I have the time.