4d55's

[carlhunguss]

. dose any one have a rear sump 4d55 or 4d56 oil pan? i would love to trade for parts or just buy it out right . i also have some extra engines and a 4m40t i dont know what to do with . have any of you guys taken the secondary fule enrichment ring out ?i did and loved it so much i lowerd it the rest of the way and put a 12a compressor on it wow what a difference . got my 4x4 extra cab to 124 mph with swampers !! not safe i know . next i am thinking of having the injectors redone a lot fatter leaning out the pump and putting my td05h 16g on it . any ideas ?

[lordtrunks]

Keep an eye out for the ford ranger with the 4d55 those have the rear sump. Best way to keep the 4d55 alive is keep the rpms down

[4D55 Performance Inc]

Originally Posted by lordtrunks

Keep an eye out for the ford ranger with the 4d55 those have the rear sump. Best way to keep the 4d55 alive is keep the rpms down

It's actually quite the opposite, keep the rpm's high. When you keep the rpm's down, especially when going up a hill, the EGT's climb quickly. When going up a hill always keep the RPM's between 3-4K RPM's. This will keep your EGT's in the safe zone.

Your max torque on the 4D55 is 3000-3100 rpm's so it's ideal to keep your rpms right about 2500-3000 rpms for around town driving. I know Mitsubishi says max torque is at 2000 rpms but they are dead wrong. I"ve had mine dynoed over a dozen times in many different configurations and the one thing that always constant is max torque is always made around 3000 rpms. It's also critical to never lug the engine below 2000 rpm's. The trannies can't handle the punishment.

[sneakyninja]

And that´s why Mitsubishi changed to the 4M40, because the 4D55/6 couldn´t handle the high RPMs that the Montero operates at (between 3000 and 4000RPMs). Now i know the pickups are a different animal as they are geared higher from the factory and better suited for the 4D55/6 but if you go with low diff ratios and little tires (High RPMs) you will be looking at increased maintenance and shorter engine life.

Spence, If your engine sees 100k i´ll be surprised and if it breaks 200k i will eat my words and build a 4D55 to match your build otherwise I say if you want high RPMs destroke a 4g64 and push 10,000RPMs.

[88mitsu]

Originally Posted by lenross1

... Plans to apply your skills to a killer front bumper?

huh?

[4D55 Performance Inc]

Originally Posted by sneakyninja

And that´s why Mitsubishi changed to the 4M40, because the 4D55/6 couldn´t handle the high RPMs that the Montero operates at (between 3000 and 4000RPMs). Now i know the pickups are a different animal as they are geared higher from the factory and better suited for the 4D55/6 but if you go with low diff ratios and little tires (High RPMs) you will be looking at increased maintenance and shorter engine life.

Spence, If your engine sees 100k i´ll be surprised and if it breaks 200k i will eat my words and build a 4D55 to match your build otherwise I say if you want high RPMs destroke a 4g64 and push 10,000RPMs.

Yeah, only time will tell. Currently I have 80K on the motor and I still have great compression. I fully expect to get 200-300K miles out of the motor. I monitor the EGT religously and I always run Stanadyne fuel additive.

I don't think people realize how easy it is to overheat the 4D55. Heat kills these little motors.

[lordtrunks]

I will agree with you on the heat, i used to have a set of 4d55 pistions that the con rods tried to turn them selves into pretzels because of high rpms so consider yourself warned

[4D55 Performance Inc]

Anytime I hear someone bent a rod on a 4D55 engine, it's a clear sign they were using cheap Chinese parts. The OEM parts from Japan don't turn into pretzels. The valves will give out before the rods will if you are using genuine parts. Also be aware just because it has a Mitsubishi stamp on the part and comes in a Mitsubishi box, does not mean it's an OEM part.

Consider yourself warned, Chinese parts off eBay do not pay off. Always purchase parts from the dealer.

[lordtrunks]

it was the original motor buddy

[sneakyninja]

Maybe Colby will post up on this topic



Now the 4D34 is a power house of an engine and it was built to rev out, this engine would be the best choice for lower geared trucks.

[4D55 Performance Inc]

I find it hard to believe that the rods failed with the OEM parts. Was the engine modified or was the fuel turned up? Also how can you be so certain it was the original engine unless you're the original owner? When I bought my truck 8 years ago I was told by the original owner that the only engine work that had been done was to the head. But when I tore it apart, it had oversized pistons. Go figure.

The thing I am certain of, is the market is flooded with cheap Chinese parts for the 4D55/56 engines and they are selling them as OEM parts. While they look like the OEM parts and come in OEM boxes, these parts are made of cheap Chinese steel. Also it is very common for the Chinese pistons to be be too tall and the valves hit the pistons.

[Rockrenegade]

I say do whatever those guys in europe did to that deisel galant racecar. I think spence has the video. Team 2000 or something.

[city hunter]

I cant see any issues wqith a 4d55 getting 250k miles. That seems to be the avaerage lifespan around here before they need a rebuild.

[4D55 Performance Inc]

Originally Posted by city hunter

I cant see any issues wqith a 4d55 getting 250k miles. That seems to be the avaerage lifespan around here before they need a rebuild.

I agree, the life span is very adequate. The life span can be greatly increased if you upgrade to a watercooled turbo, roller rocker head, and an intercooler from a 4d56 engine. All of the short comings the 4d55 did have were addressed when they introduced the 4d56 engine.