Please help! Can I swap 2006 and 2003 engines for the Pilot?

[goodguy]

Hi everyone. I greatly appreciate any help and advice.

I had a great running pilot. 2006 EX AWD Over 150K and not a singe major problem. Heavy use: camping, offroad, trips, towing etc... Now I need a new motor. My cylinder 5 lost compression and am hearing piston slap. Unfortunate... Anyways, I need to rebuild or swap motors. I have two options:

1. Reuild using new pistons and rings and even bore/sand the cylinders for about $1000 parts and labor.
2. I have a deal to get a transmission (which I would keep as spare) and engine from a 2003 Pilot AWD with around 65K on them. This would cost me around $1200 parts and labor and I would have a spare transmission with 65K on it.

My problem:

After much research I see that there are several engines for the pilot: J35A4 whic is used in 03-04 Pilots, odysseys, and 2010 MDX. J35A6 and a J35A9 which my pilote has.

My question:

All my research shows that these three engines are practically the same with no significant difference. Will the engine from the 2003 Pilot (J35A4) fit smoothly with my pilot and replace the (J35A9) if I keep everything else intact?

Thanks!!!

[rocky]

It's one thing to fit, another to get it to work. The electronic of the 06 with its variable cylinder system did not exist in 03-05 pilots. You mention the 10 MDX in the same breath as the earliest Pilot. The 10 MDX has a 3.7 liter engine.
What's stopoping you from pulling the head off the offending cylinder and looking to see if say a valve has problems or the gasket has gone?

[goodguy]

Thank you for the reply. I have found that the 2010 MDX useds the J35A4 3.5 but that may be incorrect. That's not the most important thing.

We did take off the valve cover. The valves are fine, clearance is good. I have low compression in cylinder 5 (35) and kind of low compression in the front head block. (100-145) This is much lower then what I had at 85K miles (200 psi). I drove it today from Oregon to California, made it... The piston slap is there, so I most likely have issues with rings and a piston in cylinder 5. If we were to take the block apart, with the ammount of work and mileage it would simply make since to do a complete rebuild or at least get new bearings, valve caps, pistons and rings.

As far as I understand my pilot does not have the variable cylinder electronics. That would be 2WD in 2006. Am I wrong?

[94eg!]

It is a federal regulation that you may not swap in an engine that is older than the chassis. Of course who is going to know right. The only time it will come up is if/when you get a VIN or CARB inspection. Most regular smog inspections won't go as far as checking your engine number. Kinda depends on what state your living in.

[krazykarguy]

'03 Pilot transmission AND engine are different than in the '06+ Pilots. Will not work without a significant amount of work.

Rocky also mentions the variable cylinder management, but this was only on the 2WD Pilots IIRC.

Your best bet is to find a '06-'08 motor/trans and swap it out.

[samc]

I think it would cost you more then your $1000 investment to get it to work.

Another thing to consider is that most states will not allow you to install an older engine into a newer chassis (the car itself). ... Someone beat me to it

Why not just find a low mileage block off an 06 pilot and call it a day? Btw 03 trannys were the ones with problems (I think there was a solution? not sure) but why would you want that headache?

[whizmo]

Who is going to rebuild your engine for $1K?

- Mark

[krazykarguy]

Maybe it's just some states (certainly doesn't include Vermont), but you're telling me that I couldn't put an '06 Honda Pilot motor in an '08 (even though they are identical otherwise)??? Something doesn't sound right on the claim that you can't put a motor older in a newer car.

I can understand that in some instances, putting an older motor into a newer car will cause all sorts of emissions issues (like say putting a 1994-95 OBD-1 B18C motor into a 1998 Integra will effectively disable any OBD-2 abilities the '98 car should have had). What about the THOUSANDS of 60's & 70's resto mods out there with older, more desirable engines installed in newer frames?

However, if I have a 1991 Civic with a grenaded D16A6 motor, I couldn't legally install a 1990 D16A6 motor in it? WTF kind of BS laws are these???

I know that at the repair facility I managed for a while that we did several motor swaps, and that the "swap matrix" (that tells you what motors fit what cars as a "plug and play" worked both forwards and backwards in years...

[N_Jay]

CA is strict, and other states are catching up.

The issue is there are little changes in the emissions laws year to year, and an older engine may not meet the car's year's code. (I know mostly a bullsh!t excuse to give people a hard time)

[94eg!]

These are federal regulations (not state). You would be surprised what the federal government says you can and cant do.

They have also completely outlawed japanese import replacement swaps in recent years. You can only install motors with a US block code. This doesn't mean people don't do it (I did). It doesn't mean you will ever get caught. What it does mean is.....you need to be aware. If you ever decide to move to a different state that requires a vin inspection to register your car, you will run the risk of having to pull your motor (depending on how thorough the inspection is).

My point is, keep any swapped car far away from the DMV unless you've specifically discussed with them what is specifically required to get the swap "certified" before even attempting. If you have a different engine in your car than the one that came with it, it does require a DMV certification with the associated sticker under your hood to be considered "legal".

Here in NV things are getting harder. We did a Japanese motor swap in my friends civic. When it came time for his second smog check, the tech actually noticed the swap (usually they don't) and said he had to get it certified at the DMV before he could test the emissions. My friend, being a big dummy, drove straight to the DMV. They took one look at the block code (B16A instead of B16A2 or B16A1) and said he had to pull the motor. Now he cannot register the car anywhere until he gets at least a US engine block put in.

[goodguy]

Well, I don't care too much about the fed. regulation as I really doubt that a smog tech will ever be able to tell the difference. The thing I do worry about is the ECU not being very happy, and additional modifications/replacements which may have to be done to get this to work.

To answer some of the questions. I have a friend who is an engine specialist, a highly experienced and talented mechanic and is able to rebuild gasoline or diesel engines without hesitation. However, he is not a Honda specialist, so he does not deal with hondas every day. He would not know the difference between a jA34 and a JA39 until he saw them. This is how I can get this done for $1000.... If I buy the tranny and and engine from the 03 Pilot I would have an engine, sell the transmission + old motor, pay the labor and according to my estimates would be at around $0 for the entire process. So it is important for me to know if the swap will work. Financially this would be amazing!

[rocky]

An 03 engine and tranny will not work in an 06 without further extensive work.

1: 03-05 used old fashioned throttle wire on the accelerator. You will have to source all the appropriate parts to covert the 06 (a drive by wire) to the 03. This will extend to the accelerator pedal. There may also be changes in the firewall that we don't know about, that may trigger additional requirements.
2: You will need to replace all the electronics used by the 06 with 03 electronics. These electronics control the engine and transmission and link up to the OBD2 port etc.

Don't do it. Its guaranteed to be more hassle than its worth. Get a real 06-08 Pilot engine. That will be plug and play.

[N_Jay]

Why not put in the motor and trans as a package. It should make the swap at least little easier since the same ECU runs both. (I believe).

Make sure you get the ECU with the new motor and trans.

[whizmo]

Originally Posted by goodguy

I have a friend who is an engine specialist, a highly experienced and talented mechanic and is able to rebuild gasoline or diesel engines without hesitation. However, he is not a Honda specialist, so he does not deal with hondas every day. He would not know the difference between a jA34 and a JA39 until he saw them. This is how I can get this done for $1000.... If I buy the tranny and and engine from the 03 Pilot I would have an engine, sell the transmission + old motor, pay the labor and according to my estimates would be at around $0 for the entire process. So it is important for me to know if the swap will work. Financially this would be amazing!

I think there is the theory and then the reality of the situation.

It is possible to buy used engines and make swaps like you're talking about and actually make money, but it is a lot of work and not for the faint of heart. And there is a lot of domain-specific knowledge about this sort of work that needs to be acquired - more than you're going to get from this forum.

As to your $1K engine overhaul, I guess it depends on what is going to be done, but just the machine work and parts for a competent overhaul would run way more than $1K, forgetting any labor charge whatsoever. Maybe your guy is working for free. I also think that overhauling a late-model Honda engine is not something that should be done without a very good shop, a lot of special tools, and a lot of specialized knowledge. Pehaps your guy has all three.

If I were in your situation, I'd sell the car "as is" and go buy another used Pilot. But perhaps your time is free and you want a project. Regardless, good luck.

- Mark

[94eg!]

You can send the block to be diamond honed to a perfect 60* cross-hatch. Other than that, everything in a rebuild is very doable at home in your garage with hand tools. A good torque wrench, plasti-gague, micrometer and a set of feelers should get everything done. Honda isn't some sort of mythical one-off. It's all spelled out in plain English in the OEM service manual. Heck, the rods crank and block are even stamped to make bearing selection as easy as adding 1 + 1.

T-belt & water pump set ($170), and gasket sets ($250), new rings/pistons ($450), and new bearings ($200).