Full R50 engine rebuild advice!?

aussie4wheeler · July 2, 2015

Hey guys. I am conducting a 48 state road trip next summer in my R50 02 pathy and she has just hit 181000. Next week I am doing a full engine rebuild including oil pump, timing chain, water pump, new pistons etc. While the motor is out is there anything I should pay special attention to or replace???

Rebelord · July 2, 2015

Why a rebuild? What is warranting the project?

Make sure to replace all vacuum lines and water hoses. There is a bypass hose in the back that's a PITA to get to. But if the engine is out replace it. Do your power valve screws.

If the budget allows. There are custom Cams and tuners out there for the 3.5 just are pricey.

Sent from fat fingers on S6

aussie4wheeler · July 2, 2015

Thanks for the tip! The main reason for the rebuild is the last 2 vehicles that I have bought have given me nothing but problems after the first 6 months or so and I end up pouring all my money into them, I have a buddy who is a master mechanic who needs some money and offers to do the whole rebuild for $800. I pay for parts and I'll practically have a brand new pathy. With the 48 state trip over 30,000 miles with little money and no resources I want to minimize the risk of some thing major going wrong in the trip. Can you recommend a specific brand or type or hot cam/tune. What about converting to direct injection??

Rebelord · July 3, 2015

Cam and tune. Just research Maxima and 350Z forums. But with those mods can come trouble. So stay stock.

Honestly these engines are pretty bullet proof if taken care of. Many members have well over 150k on em no issues. My 3.3l Pathfinder has 212k miles.

Only thing some guys have is a little oil consumption. But just keep it topped and go on.

Here is a tip. Under your truck passenger side. About right under between the two doors there is a wiring harness. Inspect it. If its wet and reddish. Then it's the seal for a turbine sensor on the top of the transmission. With engine out. Replace that sensor and seal. It fails and thr fluid wicks it way through the harness to that spot.

Very common especially in the Xterra side.

Sent from fat fingers on S6

ferrariowner123 · July 3, 2015

What about converting to direct injection??

Slow down there turbo.

Have a gander at this article, its might answer that one for you.

http://thechronicleherald.ca/wheelsnews/26226-direct-vs.-port-injection

You'd have to completely redesign the head, and while i have seen custom heads made for the L-series engine (made into dual cam), its takes MONTHS of work, countless machines (ranging from ten of thousands to millions of dollars), and then the know-how to do all this. So yeah, not happening.

I'll say what others have said, go stock. You put it nicely, its a 30,000 mile road trip. With any road trip, you want reliability i had a friend drive his 150,000 mile 95 pathfinder all the way to mexico (3800 miles round trip), 2 weeks after buying it, had zero issues. Keeping it stock, with quality replacement parts, is the way to go.

Look into Variable Geometry Turbo's, Doppelkupplungsgetriebe transmissions, and 2 way differentials after the road trip. :aok:

-Kyle

aussie4wheeler · July 3, 2015

Cool, thanks kyle, my intention always was originally to keep it stock. I got pressure from buddy's to tune it up/d it a cold air intake do this do that etc etc but I think its really a great designs as it is, no real need to go changing to much, im not gonna be towing anything but a canoe and some bicycles so it makes plenty of power as it is. If I throw money at anything I think it needs to be at suspension/tires and some of the accessories I have planned like light bars, CB, radar/laser jammer, aux battery/on board refrigerator etc. I appreciate all the input fellas, if you guys are ever in the northern MI/WI area hunting or traveling etc hit me up. I got a spare room abd plenty of tracks to go wheelin

jyeager · July 27, 2015

So have you completed the rebuild yet? Or is it yet to be started?

If done, let us know how it turned out.

If not...then I would throw a new idea out for you to think about. Others suggested cam change for increased power, but really the types of cams they were talking about would increase top end power which you don't want in an SUV.

In fact, I think these trucks were cammed like cars in that they make too much top-end power and too little bottom end power.

So if you went with a different cam, one that's tuned to make maximum VE around 2500 rpms is ideal. Peak torque might be at 3k.

Does your friend's $800 rebuild include the typical machine work? Hot tanking the block, honing the cylinders (preferably with a torque plate) and the whole head rebuild (springs, retainers, and all that good stuff)?

If you have the heads ported and polished and perhaps matched to the intake ports for a few hundred $ more, it can pay dividends in improved torque for years to come (just don't have them increase runner volume at all)

aussie4wheeler · November 5, 2015

Thanks jyeager, I'm actually halfway through the build. I am sending the block and heads to a racing shop up in bloomer WI for hot tank and honing etc. I have all new valves and seals etc and .020" oversize pistons and rings. Do I still need to have the heads matched to the intake ports?