facepalm

G'day all, new to the forum, and have a burning question to ask. I've got a 2007 MDX with a anchor for an engine, and looking to replace it. Problem is junk yards think the things are worth their weight in gold (they're not!), and I was wondering if there's a different block I could use, a more common, more plebeian one that's 1/3 the price. A j series block like one of the many 3.5 vtec engines out there. I don't care that they have 10% less hp, as long as it fits and doesn't send the 3.7 ECU into conniptions. I've done this before - I once had a mazda 6 with a spun bearing and the only wrecker who had one this side of the rockies wanted $3500, about what they are asking for an MDX engine. I was able to replace it with a $700 Ford Fusion one, which shared the same block. That was a good day.
I know a 3.5 isn't exactly the same as a 3.7, but aside from swapping a few parts over, can you shoehorn one in without too much trouble? Or do they have different wiring, different electrical components and connectors, etc.

Skirmich

Probably the J35A9? Just guessing here, no one has done it AFAIK.
But 10% difference? no... More like almost 55HP and 30ft-lb in an already heavy 4500lb crossover is like losing 2 cylinders. The J37 was "Adequate" for the 2G MDX, and its worth its weight in gold because its Still TODAY the most powerful stock J Series ever made (TL).

facepalm

Why the J35A9, specifically? Others in the J35 series range from around 240 to 285 hp. The J35A5 was in the 2003-2006 MDX and sell for 1/2 the cost at 35 hp less. I really don't care about ancillary components as they can be swapped, it's really the core block that's most important. Heads, bellhousing, engine mounts etc.

RDX10

My 2 cents is that Acura made a whole new engine for the MDX in 2007 rather than sticking to the J35 for a reason. Like Skirmish said, the J37 is barely adequate and I couldn’t imagine dropping that much in power. Putting that aside, I think I recall that the transmission bell housing on the 2007 MDX will not hook up to the old J35 (skirmish correct me if I’m wrong here).

Skirmich

Because of the Bell Housing. Neither the J35A3 or J35A5 will bolt on to the 2G MDX Transmission..
I mentioned the J35A9 because it was bolted to a SIMILAR Heavy Duty 5 Speed transmission in the 2G Pilot... Although again this is just guessing, I haven´t seen ANYONE trying this swap before so you are diving into Unknown territory.. You have to remember that the 2G MDX was a very specific vehicle with specific components.. The J37 Engine was basically developed for it and the transmission and AWD are all specific to the 2G MDX so finding components that will bolt on is not an easy ask, Let alone finding a weaker engine to fit the transmission which is not something 99.99% of the people in this forum would do.

Skirmich

AFAIK it wont... The J37A1 uses and updated bell housing so only modern J35s should work (Ones with VCM).

facepalm

Okay, thanks big time. So Have a good look at the butt end of a honda pilot engine to compare with the 3.7 and look for other models that carry the same 3.7 engine, but might be less expensive cars and so parts sell for less.

Skirmich

But again this is not confirmed...
The best thing you can do is to draw a diagram of the J37A1 bell housing out of the car so you can compare it to engines at the junkyard.
You must have:

1.- Complete Bell Housing Diagram that match the donor engine.
2.- Half Shaft bracket holes to be the same length from the bell housing mating end in the donor engine.

Having those 2 you can find engines that will fit.. As for the engine mounts that is easy almost all J-Series share the same engine mount locations so that is the least of your worries.

Skirmich

There was a Guru on J-Series engines at the TL forum side but cant remember his name.. You can probably ask around the 4G TL Side for more info on Bell Housings and compatible blocks, Just inform that you are researching there as there isn´t information on the 2G MDX forum on engine swaps.

facepalm

Thanks for the info and leads. I did a lot of digging and going to most options doesn't really get me ahead. They want almost as much $$ for the ridgeline or pilot engines as the MDX. J35A3 engines can be had for a song, but you're saying they won't mate up, and neither will an earlier gen MDX J35A5. Pity. It would be a nice hack and I could see lots of others doing it.

Skirmich

The reason those don´t fit is because they are basically 3.2L blocks that are stroked to 3.5L.. They are not "Real 3.5Ls blocks".
Those engines are pretty popular swaps for my 2G TL-S. Honda used the same block from the J32A to make the J35A3 and J35A5 they even share the same part number block! that is the reason it wont fit any J37 transmissions..
The J37A1 is not a stroked version of the J35, is a complete new block from the get go specially designed for the J37.

So Newer (Say more expensive) J35s are proper 3.5L engines which should work with the J37 bell housing design.

facepalm

But then there's the J35A6 in the 2005-2010 Odyssey and it has the same bore and stroke as the J35A9? It shares the same block?

Skirmich

I do not know if those do share the same block part number or even design.
I can only confirm the J35A3 and J35A5 uses the same block part number from the J32A1/A2.

facepalm

I found some close up pics of 2007-2010 Odyssey blocks and same era MDX blocks where they bolt to the tranny and they appear the same. The earlier < 2007 Odyssey blocks have a very different mating surface for the bellhousing.

Skirmich

Weird... The J35A6 (LX and EX) and J35A7 (VCM equipped for EX-L and Touring) are both engines installed in the 2005-2010 Odyssey..
So how is that the -2007 models have different bell housings when they have the same engines all the way to 2010?

On a side note, What happened to the J37? Is it impossible to repair?

facepalm

That's what I thought too, but everywhere I looked the 2005-2006 had separate engine listings and the housing is totally different.

Sadly, this engine is toast, It blew a plug a few months ago, but either that event messed up the cylinder or the subsequent helicoil installation, but the result was deep scoring, uneven wear and now piston slap. So much for aluminum cylinders. Just about anything in an engine can be fixed, but badly buggered cylinder walls are non starters.

zeta

iTrader: (1)

facepalm, I see your profile resident state as California? The reason I ask is when I search car-part.com specifically for a 2007 MDX 'engine', I'm getting year ranges between 2007-2009 as well as cost ranges between $900-1850 (with various miles, of course) just for the state of CA. When you expand the search further, as you would expect, the selection increases.

I undertand from your original post that you are interested in trying to figure out any, if they exist, other J engine configurations that you may be able to 'shoe-horn' in; however, when push comes to shove, and the eventuality sets in, what would be your reasonable budget price for a 'salvage' year appropriate MDX engine to get yourself back on the road? Just curious?

facepalm

California? I wonder why it says that. I live in Victoria, BC, Canada. Just got off the horn with one wrecker and he quoted me $3800. Cheapest I can find is $2000 plus shipping for a 2007 MDX engine. When I asked why they are so pricey he says the hulks they buy are so expensive. Usually around 5 grand, and all they ever sell off them are engines and rear tailgates.

What is the difference between J35A6 and J35A7? The latter are far more common and cheap. I found a J35A6 for $850.

zeta

iTrader: (1)

My mistake. I looked at the Letters 'CA' and thought you were from Cali. Now I know why the engines are so expensive, lol.
Carry on.

Skirmich

A7 has VCM

facepalm

Is that feature integral to the block or electronic add on?

Skirmich

Special heads allow VCM to work.

facepalm

So presumably it could simply be ignored/not connected and it would run like an ordinary engine without that feature? For some reason these engines are far more common.

01acls

Both.

Carpayment4life

If you are saving the cost of labor, by making the engine and motor mount swap yourself, you should spend the $3k.
If you have to pay someone to do the work, you should buy another used MDX and keep the old one for parts. Hopefully, you buy one with a torn up interior, so you can get it cheap, then transfer your good parts over.

01acls

If a use motor is too expensive, what is stopping you from just rebuilding the motor?

teh CL

iTrader: (1)

There's a bunch here in Ontario for under $1500 CDN on car-parts.com.

I definitely wouldn't down grade to a 3.5..

Skirmich

Cant tell you for sure...
AFAIK VCM does have its own system to engage but I dunno if it has an idle feature that requires constant action to work as a normal engine?

facepalm

The engine will fit it seems. My final concern is the fuel injection system - I know that its a feedback loop fuel metering with MAF, throttle position injectors and 02 sensors, but the MDX has 11.1:1 compression while the odyssey has 10:1. Different air volumes are pulled into the different engines. Would the system be able to adjust for the different airflows or would it be preset to the great airflow for the 3.7 and inject too much fuel, throwing a code as it would register as too rich via the O2 sensors?

Folks seem really concerned about power but you have to remember that our hunger for more and more power is a recent phenomenon and learned behaviour. Hell, my previous vehicle was a mitsubishi Delica, that weighed as much as this Acura, and had a little 2.2 diesel with 90 hp and 140 ft/lbs of torque, and I had no problem with it's sedentary nature. My other car is an AWD Ford Freestyle with just over 200 hp and 207 ft lbs of torque and it weighs 4,000 lbs.

teh CL

iTrader: (1)

It's the torque more than anything but if your at peace with a J35 you might as well get the best one which is the J35A8 out of the 05-08 RL/07-08 TL Type S.

It has the updated bellhousing design & would need minimal stuff swapped over.

facepalm

Sadly, those engines are rare up here and almost as pricey. I have managed to track down a stock MDX engine delivered for 2 grand. Given the uncertainty around the conversion, I'm thinking of going that way. I'd love to pop an $800 3.5 in there just to say I did it, but an everpresent check engine light due to mismatched fuel trim is a much bigger concern for me than power.

RDX10

facepalm

I pulled the pin yesterday. I bought a 145k kilometre engine from Nova Scotia for $1600 delivered - coming from the other side of the continent. Cheapest I could get locally was $2500 delivered (one local guy quoted me $3800, plus tax). The next lowest price was from Calgary at $2000 delivered. AT $1600 didn't make sense to mess around with trying a new engine. The old engine just had a timing belt installed, so all that stuff will get swapped over.
I pulled the head and had a look at the cylinder wall - although scoured by detritus from that plug blowing out, either from that event or the subsequent repair, what really shocked me was the degree of out-of-round the cylinder had become. You could laterally rock the piston in the cylinder over a mm. Aluminum cylinder walls are just a bad idea, IMO

Is there any demand for the engine parts at all? The heads are still good etc. I hate tossing stuff that's still useful.

teh CL

iTrader: (1)

Cams & crank for sure.

$1600 shipped isn't bad at all

Skirmich

Do the REAR MAIN SEAL of the crankshaft (Transmission Side) while you are in there! replacing that seal is very expensive once everything is installed.

zeta

iTrader: (1)

That's a deal, considering its location. I got the impression you were strictly trying to stay 'local' with your deal; otherwise, like teh CL stated earlier Ontario had the best selection that I could find as well. Nothing like the motivating factor of the 'eventuality setting in' to consider less entertaining options. Here's to finding above average compression readings on your salvage engine.