2.9 MAF California Improvements

[CYBERFUKD]

I own a 1990 MAF California 2.9 that I endurance track race. Truck is run HARD for 8 hours at a time. It's a budget program, so we look for ways to make small improvements cheaply. The engine has headers, straight pipes and an airbox delete. Unnecessary accessories have been deleted and electric fan installed. I've read enough of these forums to be dangerous but don't want to take anything in the wrong direction. Appreciate any input you have.

One of the things recommended to me is to replace the valve cover cap and tube (I believe this is called the crank case breather) with a breather and plug the inlet on the intake manifold. Any issues with this?

The 86/87 Throttle body replacement seems like a no brainer. However, it seems like the MAF diameter is very small and may limit the TB increase?

One thing I found on my current TB is full throttle wasn't opening the butterfly valve completely. I corrected this by dremeling the stop. (I haven't seen this mentioned much around here, so thought I'd point it out for others to check).

We redid plugs a few months ago, planning on reverse flushing the injectors this weekend. If there are any other low hanging fruit, I'm all ears. Thanks for taking the time to read this.

 

[franklin2]

As long as you keep the PCV valve. The PCV valve uses engine vacuum to suck the bad stuff out of the engine on one valve cover, and fresh air comes in the other valve cover. This fresh air needs to be filtered, so whether it comes from the trucks original breather, or through a push-on breather with a filter that you add to the valve cover should not matter.

The original EECIV computer system is going to limit you somewhat. You can do a search, I believe there is a trick they used to use where they disconnected the engine temp sensor, and put a certain value resistor across the wires instead. This fooled the computer into thinking the engine was still in warm-up mode and in that mode it adds more fuel and doesn't look at the oxygen sensors. I believe it was worth a couple of tenths in the quarter.

 

[CYBERFUKD]

As long as you keep the PCV valve. The PCV valve uses engine vacuum to suck the bad stuff out of the engine on one valve cover, and fresh air comes in the other valve cover. This fresh air needs to be filtered, so whether it comes from the trucks original breather, or through a push-on breather with a filter that you add to the valve cover should not matter.

The original EECIV computer system is going to limit you somewhat. You can do a search, I believe there is a trick they used to use where they disconnected the engine temp sensor, and put a certain value resistor across the wires instead. This fooled the computer into thinking the engine was still in warm-up mode and in that mode it adds more fuel and doesn't look at the oxygen sensors. I believe it was worth a couple of tenths in the quarter.

Thanks for your feedback. My goal is to vent those bad engine gases to the atmosphere. I want to eliminate blow-by from entering the intake. It sounds like you're saying that's not a good idea?

 

[RonD]

Pre-PCV Valve engines just had a tube on lower block or upper oil pan that stuck down
The air flow when driving created a suction at the end of the tube to pull out blow-by while driving, and the oil filler cap was vented
This tube DRIPPED OIL lol

Blow-by vaporizes some of the oil on the cylinder walls and piston sides because its so hot, this is the ONLY place in the engine oil vapor comes from, nothing else is hot enough to vaporize motor oil

Which is why the tube dripped oil and why PCV valve gets oil condensed in it
Every one had a drip pan in their garage or driveway back then, because ALL engines dripped oil from that tube, fancy ones had a catch pan you could empty

Blow-by itself is just exhaust gases so helps to slow the burning of new air/fuel mix which lowers cylinder temps same as EGR system does
Doesn't effect power since a more aggressive spark timing can be used because with lower cylinder temps gasoline is less likely to ping/knock on compression

So you can just vent the blow-by, it was done that way since the first gasoline engines up to PCV Valves addition

PCV system has one more bonus, besides less pollution, it put a constant slight negative pressure in the crankcase and valve covers
So LESS CHANCE of an oil leak from these gaskets
Do not seal the engine, or Blow-by WILL cause oil leaks if pressure builds up, it must be vented

 

[franklin2]

Thanks for your feedback. My goal is to vent those bad engine gases to the atmosphere. I want to eliminate blow-by from entering the intake. It sounds like you're saying that's not a good idea?

Yes, it's not good idea. The PCV system keeps your oil cleaner. One of the by products of combustion is water. Some of this water will get by the rings into the crankcase and into the oil. If you run a thermostat and get the engine hot, it will "cook" this water out of the oil and then the PCV system will suck it out. Then you won't get that chocolate milk stuff laying inside the engine.

This is all street engine stuff. If you are going to be tearing down and rebuilding the engine a lot from racing, it won't matter too much. But like was said, just venting to the atmosphere does make a stinky mess. I think the racing guys make a special evacuation system that uses the exhaust flow to draw it out. Here's a link to one. https://www.moroso.com/crankcase-evacuation-system25900/

 

[CYBERFUKD]

Thanks for sharing that link. Very interesting system. we change our oil every race weekend (VR1 synthetic 50 weight).

We hope the next time this engine is removed is for a 5.0 swap. In the event we keep and rebuild the 2.9, I will definitely be installing that evacuation system.

 

[alwaysFlOoReD]

One of the guys racing in a class above me had an exhaust activated crankcase breather. On hard corners there would be a brief, large cloud of blue from oil splashing up enough to get sucked out.

 

[CYBERFUKD]

Not a fan of that for endurance racing. Thanks for the info.

I bought a 2.5-2.75 silicone reducing elbow to use as a short ram. The battery is relocated to the rear. I also built a Watts link for it.we were in a pretty big wreck last year and cut the front off of another ranger (that’s still sitting in our driveway, much to my wife’s delight).

repaired:

Before:

Watts, we have shorter tubes on it than this photo:

 

[CYBERFUKD]

Another question for the experts here. What is a safe amount of timing advancement? Stock is 10 degrees. The engine has fallen behind to about 8 degrees. When we set it, what are the thoughts on advancing it to 12 or 14 degrees? Seems like 12 is definitely safe, is 14 pushing it too much? If we go 14 should we also push to 89 or 91 octane? Reminder, we run at 3000-5000+ rpm for 8 hours, with a couple of fuel stops.

 

[franklin2]

Each combination is a little different. More timing advance is better till get into detonation. If you have a loud exhaust, you may not be able to hear detonation.

Another problem is hot starts. It may not crank over well with the initial set too far advanced.

You will have to experiment with it. The higher you go the better. Sometimes it can mess with your minumum idle air and the TPS settings if you try to tame the idle speed from a advanced timing setting. More experimentation. But it's worth it.

 

[CYBERFUKD]

Thanks. She does have an issue with hot starts already. I’m thinking that it’s due to heat soaking the starter. Installing a heat shield before the next race.

I’m also wondering if a gear reduction starter is a good idea.

 

[franklin2]

Thanks. She does have an issue with hot starts already. I’m thinking that it’s due to heat soaking the starter. Installing a heat shield before the next race.

I’m also wondering if a gear reduction starter is a good idea.

If you have the extra money to spend, they always turn a engine over easier in my experience.

 

[CYBERFUKD]

So, we ended up blowing off 3 belts during the last race. Long story, but we sheered the pully off the alternator. Not entirely sure how we did it. All the threads on the alternator shaft are stripped. We overheated it 4 times, but still ran the final 6 hours without issue. She has no guts left. Not sure if its due to the timing be too far retarded (15 degrees) or cracked head. Either way, its time for more power. I'm not a mechanic, so any advice is appreciated.

Here's my plan:
Pull out the 2.9
Buying a 1993 4.0 OHV
Do a leakdown test to check the cylinders. That will determine if I need to re-ring.
Buy some aftermarket 95+ Heads.
Find a wiring harness from a 91/92
Do minor gasket match porting
Reinstall the 2.9 headers on the 4.0.

What aftermarket heads are recommended? Looking to not break the bank. Thanks in advance.

 

[franklin2]

I would run the stock heads if they are not cracked. Get them checked and redone at a machine shop.

 

[CYBERFUKD]

I was thinking the fast burn chambers and additional compression would be beneficial.