With my engine nearing 330k miles, a replacement is unfortunately in the future for me. I purchased a used 4.0 engine out of a 175k mile 2007 4runner for $1200. Guy was originally selling it for $1500 because his son rolled the car into a ditch and insurance totaled it. Claims it ran fine with no problems before the accident.

The 2007 engines use a different cam timing system because of their updated VVT-i, so I will be swapping 2003 cam timing gears and cam position sensors so my computer works with this engine.

The engine looks good, no gunk build up or oil leaks as far as I can tell

The plan is to just direct swap this engine into my truck since its in good condition and not worth the time and money to do a complete rebuild. Is this a fair assumption? Just replace some of the typical wear-and-tear items and leave the actual engine alone? With 175k miles, I'm assuming that's about half of its 350k life. And assuming I average 15k miles per year, that's still 12 years left on this engine

My list of parts to buy will be in the next post, anything else I should get while I'm at it? Anything I should be worried about with a rolled engine?

Lastly, what are y'all's opinions on DT long headers? OEM headers are $1k, and that's pretty steep. I don't trust 3rd party aftermarket cause I don't want them to crack in a month (like my current ones did). That leaves me with DT long tubes since I don't have quality OEM cats worth welding on to short tubes. Or any other suggestions for an exhaust header setup that doesn't break the bank?

I've heard long tubes come with problems though. If you manage to get a successful 02 emulator, you can get rid of the constant CEL, but then the engine can't properly read/adjust air fuel ratios, so you end up running rich/lean. To solve that, you can get a tune, but I haven't heard of anybody offering tunes for a 2003 4runner. So what's the move?

Thanks everybody!

Parts:

Main Timing Chain- 1350631010 / 13506AD010 - $80
Cam Timing Chains - 1350731010 /13507AD010 - $25 (x2)
Timing chain Main Guide - 1355931010 / 13559AD010 - $16
Timing Chain Guide NO.2 - 1356131010 - $37
Timing Chain Main Tensioner - 1354031011 / 13540AD011 - $43
Timing Chain Cam Tensioner - 1355031010 / 13550AD010 - $50
Timing Chain Cam Tensioner #2 - 1356031010 / 13560AD010 - $19
Cam Timing Gears - 1305031010 - $112 (x2)
Cam Position Sensor - 9091905026 - $55 (x2)
Cam Exhaust Timing Gear - 1352331030 - $14 (x2)
Timing Gear Idler Sprocket - 1353031011 - $10
Timing Gear Crankshaft Sprocket - 1352131060 - $13
Main Timing Chain Dampener - 1356231010 - $9 (x2)
Timing Cover Oil Seal - 9031142036 - $5
Oil Pump Gasket - 1519331010 - $2
Oil Filter Bracket Inner Gasket - 9672224030 - $2
Oil Filter Bracket Outer Gasket - 1569231010 - $3
Water Pump - 1610039406 / 1610009471 - $126
Exhaust Gaskets - 1717331010 - $10 (x2)
Spark plugs - 9091901235 - $3 (x6)
Air Surge to Intake Manifold Gasket - 1717631160 - $8
Intake Manifold to Head Gasket, NO.1 - 1717731010 - $5
Intake Manifold to Head Gasket, NO.2 - 1717831010 - $5
Valve Cover Gasket NO.1 - 1121331030 - $12
Valve Cover Gasket NO.2 - 1121431010 - $12
Belt Tensioner - 1662031013 - $115
Idler Pulley, NO.1 - 1660331040 - $34
Idler Pulley, NO.2 - 166040P011 - $30 (x2)
Engine mounts Front - 1236131081 - $67 (x2)
Water Inlet Pipe, O-Ring - 9676135031 - $2
Water Inlet Housing Gasket, NO.1 - 1632531010 - $1
Water By-Pass Hose, NO.1 - 1626131020 - $4
Water By-Pass Hose, NO.2 - 1626431010 - $4
Water By-Pass Hose, NO.3 - 1626731010 - $6
Water By-Pass Hose, NO.4 - 1628131011 - $4
Water By-Pass Hose, NO.5 - 1628231010 - $4
Throttle Body Gasket - 2227131012 - $3
Thermostat - 1603131011 - $25


All that puts me at $1400 with shipping, plus $1200 for the engine. So $2.6k doing it this way, vs 4k for a junkyard rebuilt

Here's the engine:

Why not swap to an ECU that matches the motor?

Re: LT's, they're great.

You won't be able to get the O2 Simulators anymore, URD stopped selling them... Maybe they'll sell 'em to yu if you buy the LT's from them too.

But, the O2 sims don't go on the upstream O2 sensors, they're for the downstream O2 sensors. Downstream sensors are only checking to make sure the cats are working correctly.

The upstream sensors are responsible for reading AFRs so the ECU can make adjustments. The sims won' interfere with these sensors if installed correctly.

Won't need a tune after O2 sims.

Personally, I'd recommend a setup like I have where Cats are installed into a y-pipe. You get the benefits of the LTs, but the benefits of running cats (not stinking up the trails, treading lightly, etc.), and not having additional hurdles to get rid of the downstream O2 sensor codes.

To be honest, I didn't think of that. I didn't think it was quite that simple because in the few threads I found of putting an 05-09 engine in an 03-04 truck, everyone has swapped the cam gears to make it work - I haven't heard of anyone swapping the computer, so I'll have to look into that

Edit: I was wrong, those people did try swapping the computer and it didn't solve the problem - it seems swapping the cam timing gear and sensors is the only thing that works

Awesome, thanks for the help! Yeah, I noticed URD doesn't have them listed on their site anymore, but I was planning to contact them and see if I could still order a set. I've also found threads about homemade ones using a few resistors and capacitors, I wonder if they work.

I know the 02 sensors go downstream of the cat, so long tubes leave the A/F ratio sensor upstream unaffected. But I had read problems of people running rich after long tubes and needing a tune to actually gain the benefits of LTs, so I thought the computer used a combination of the A/F and 02 sensor readings or something like that

That might be the move so I don't have to sell a kidney for OEM headers. I'll have to do some planning to work that out though cause I would need to find a new cat first

To make sure I follow though, you're suggesting LTs>Custom Y-Pipe>Cat>Muffler>Exit, correct?

Ah. Makes sense. I don't know much about the V6's so figured I'd ask.


Interesting, I wasn't aware of the running rich... But check out OrangeVirus tuning, they support some models of 4th gen 4R's.

Yep. I used a DT y-pipe and simply replaced the resonators with cats.

https://www.toyota-4runner.org/3679983-post7.html

For some pics and more details. Also, I highly recommend the cats in my signature. They're way overkill for our trucks but will last for a very long time. I think I sold my OEM cats to rrcats.com for a decent amount as well to offset some of the install costs.

Well the problem is, I don't know if its a true problem, or a misdiagnosis or something. Because it seems I keep reading contradictory stuff, some say you can run LT's fine, others say you wont have a proper A/F ratio and need a tune, so idk which is true

It looks like they unfortunately only support the 06 and newer 4runners - also a little too expensive to make it worth it imo - Thanks for the tip though!

I think that would be an ideal setup, but its just too much money for right now. Long tubes would probably be best, to help squeeze a little more mpg and power out of my struggling v6, but it seems like there's so much unknown regarding them, and I don't want a stinky truck

I was looking at some magnaflow cats - The point of this is to try and get a cheaper than OEM setup, with OEM reliability - so I may just go with some JBA short tube headers and have some standard grade magnaflow cats welded on

Like mentioned already, since you're only tinkering with the down stream sensor that is validating a functioning cat I don't see any impact on A/F ratio because of this particular setup.

The setup could very well be running rich, and sure, tuning it will get the most out of the setup, however, I'm hard pressed to believe that the rich situation is caused by the LT header and removal of the cat. Are they calling it rich because of the smell? Or are they legitemately measuring A/F ratios before and after the swap? Doubtful if you ask me.

Any "tuning" gadgets that URD offers/offered related to the upstream sensor. Long story short, long tube headers aren't out of question as an option, and can be made to work with no CEL. A lot of people have had success with spark plug non-fouler/spacer method for the downstream O2. You just have to play around with the setup so its not too far out of the stream, but just enough out to get a good reading.

The other option, like mentioned, is getting some high-flow cats. I've heard of guys running them without issues/cel with headers, however, there is a cost perspective to this as well, and I don't know how long I would expect them to last compared to the OEM route... I don't know about you, but if I do headers on my car, last thing I want to hassle with 2 years down the road is taking them off to cut off the cats to replace (no experience/data to back this up, however I just can't see an aftermarket cat lasting VERY long compared to OEM)

I agree, the more I research into it, the more it sounds like the "running rich" is a misdiagnosis from people jumping to conclusions or not knowing what they're saying

I haven't seen anyone show data graphs to back their claims, so I imagine its only from the smell - further backing my misdiagnosis theory.

While we're on the topic of smell, can anyone describe just how much LT's change the smell? I don't want a truck that I can't stand to smell

Agreed. The more I add up prices, getting a pair of short tube headers and high flow/aftermarket cats seems to only slightly offset OEM headers, making the work to assemble them not worth it

If you're concerned with smell just make sure the rest of your exhaust is up to par and vented out of the back/backside of the car.

I haven't ran a cat on my 95 supra since 2006.. haven't looked back. If anything I have noticed a stronger fuel smell, but absolutely nothing terrible.

That's good to hear! LT's might be the way to go then, thanks!

Everything behind the y-pipe is good to go, magnaflow muffler with the resonator cut off and dumped right behind the rear tire - My headers just leak more than a strainer right now pos amazon headers

If you can live with the smell of leaky headers, catless headers should be an improvement ;)

Oh, then I'm golden, cause those puppies have constantly been causing a P0420/P0430 code forever now

Just to update this thread:

Settled on LT's and purchased a set of sliver ceramic JBA Long Tube Headers from URD. Went ahead and got some 3° retard exhaust cam gears while I was at it too

Hoping this helps push a little more power from the engine, and help with mileage - every little bit counts with a truck like mine averaging about 12mpg

Ordered all the engine parts I plan to replace from Partsouq too. Now its just a waiting game for everything to get delivered and me to have time to get all the work done

I’d probably do a head gasket and new head bolts while it’s out, too.

Everything is easier when it’s out.