Alright a bit of a cross post but I’ve heard I can get better info on this forum.


so I got an 11mdx with rod knock on rod 6z so I purchased a replacement j37a1 out of an 11 mdx (allegedly) from the junkyard.

I got the motor in after cleaning up all of the milky residue in the oil that was there and checking the crank for bad bearings. I called the yard and they chalk the milky mess to it being started after it sat for a while and guaranteed it’s good and wanted me to proceed with the install to see. I didn’t want to but a full refund is in the table so sure I did it.
Put it all together and ran into every top end road block there was.
injectors didn’t plug in so I swapped over my rail
Coil packs them didn’t plug in so I swapped them over
The whole intake was wrong and missing some vaccum ports so I swapped it over and then noticed the throttle bodies were very different in size.
also the vtec solenoid didn’t plug in.
This made me curious as to why so much didn’t plug and play if this motor came out of an 11 mdx and I have an 11 mdx.
So I started looking at the heads and the part numbers and they did not match the part numbers of my motor.
My motor came out and had a casting of R70-9 on the heads
The motor I put in is definitely a j37 block but the heads read a casting number of R70-2

after some research it seems these are j35 heads and the fact that my coils injectors intake manifold and throttle body are all different from what came out leads me to believe this is an entire j35 top end.

j37a1 has a bore of 90mm
I suspect these heads are from a J35z2 and they have a bore of 89mm.

this doesn’t seem right too me. Anyone got thoughts or more insight on Honda part numbers and j37 to j35 comparability?

after swapping everything over it fired up but I had a few codes for the maf and the vtec solenoid (didn’t swap)

anyone know of any long term issues I’ll run into having what I think is j35 heads on a j37 block in an mdx

 

I think the only candidate that might suit you is

J35Z3[edit]

• 2008–2012 Honda Accord 6MT Coupe

J35Z5[edit]

• 2009–2014 Honda Ridgeline

J35z2 It has VСM and does not have i-VTEС, so you will have a Check engine light.

I would disconnect and insulate the VTEC solenoid connector so the car doesn't try to turn it on.

 

thanks for the reply, I’m not specifically trying to put j35 heads on a j37. But I currently have a j37 with what appear to be j35 heads.

any issues or concerns that I should be aware of having this setup?

 

If your oil pressure is OK and you used head gaskets from J37, then everything should work perfectly fine. It would be nice to somehow disable VTEK so that there is no check engine light. It would not be bad if the VTEK to open the intake valves worked like the VTEK on the VCM, in which case it could be turned off by installing a resistor in the antifreeze temperature sensor circuit.
I wonder why you got a code for the MAF?