[categimperat]

Hello again,
After taking my 2008 v6 6 speed coupe to the dealer, they found that it had zero compression on cylinder 2. They didn’t bother testing any cylinders beyond that. They’re saying the misfires on all cylinders are due to the lack of compression on cyl 2.

Can anyone speak to how hard of a diy job would it be to take off the head and fix the bad valve (assuming it is a bad valve/valve seat and not a bad piston ring)? I have done plenty of work on cars before but never cracked an engine open. I don’t want to write off this car just yet.

alternatively might it be cheaper or easier to find a different j35 to swap in?

 

[mtts60]

(assuming it is a bad valve/valve seat and not a bad piston ring)

It could also be a hole in the piston itself. That is an 'interference' engine; when the timing belt breaks/skips a few teeth, valves hit the pistons.

Or the piston/valves are fine and you have a blown head gasket.

Cylinder #2 is the middle one on the back side of the engine, making it a bit more difficult. That said, I've never had a 6-cylinder Honda, and have never had to remove a head, so I don't know how difficult it would be.

 

[97trophy]

alternatively might it be cheaper or easier to find a different j35 to swap in?

Gets my vote

 

[categimperat]

Gets my vote

well a valve replacement probably shouldn't cost more than a couple hundred dollars while a whole engine could cost $1-2k. i also don't have a garage or even an engine crane. i feel like i should at least try my hand at a valve job since it's doable with the tools i have.

that being said, do you know if any j35 will just drop in? i do know the j35z3 (mine) has no VCM, which might cause issues? i'm totally new to j swaps.

 

[WiiMaster]

You can do a leakdown test to figure out where exactly the compression is escaping, which would confirm a top end or bottom end issue. You would hear air coming out of the tailpipe or intake if it's a valve issue.

How many miles on it? Ever adjusted the valves?

Removing the cylinder head is no small job (and doing the back head can be tricky on these), but I also doubt you'll be able to find a J35Z3 ready to drop in very easily given that it's an engine that was only used on the 8th gen 6-6 which is rare to begin with. I'm not an expert with J series compatibility but I don't think there's another engine that will drop right in without changes. I would have guessed the J35Z6 from the TL/TSX, but that has a higher compression ratio which could introduce problems.

 

[categimperat]

You can do a leakdown test to figure out where exactly the compression is escaping, which would confirm a top end or bottom end issue. You would hear air coming out of the tailpipe or intake if it's a valve issue.

How many miles on it? Ever adjusted the valves?

Removing the cylinder head is no small job (and doing the back head can be tricky on these), but I also doubt you'll be able to find a J35Z3 ready to drop in very easily given that it's an engine that was only used on the 8th gen 6-6 which is rare to begin with. I'm not an expert with J series compatibility but I don't think there's another engine that will drop right in without changes. I would have guessed the J35Z6 from the TL/TSX, but that has a higher compression ratio which could introduce problems.

yup i will be ordering a leakdown tester and compressor. i will go ahead and assume the engine is beyond help if it turns out to be a block issue since i have no tools for pulling and working on an engine outside the car. 220k miles, not sure if the valves were adjusted, i bought it quite recently. if it's a just damaged valve, shouldn't i be able to keep the old head? based on its ownership history and usage i don't believe it's ever overheated although i'm sure the head gasket will be a better indicator of that.

 

[Mr.Cannon]

Private shops nowadays are charging $70/hr+ for work so your quote is very low for the amount of disassembly and parts and valve adjustments alone. Also they will usually CYA by requiring replacement of wear items and seals so they're not held responsible if you suffer an unrelated failure soon after their work. This could include; cam & crank seals, timing belt & tensioner(s), valve cover seal, and other deferred maintenance you don't presently know about.

Where you should start as mentioned is a compression & leakdown test to confirm the diagnosis before anything else and if that checks out then at your age & mileage you may just need some basic maintenance. There are threads here about multiple misfires which you can review against your own symptoms to get more direction.

And lastly, yes, you should get the proper J35 w/o VCM. There are differences and you can spend a lot of unnecessary time and money to swap in an engine that you have to make work. There are J swap guides here and elsewhere that you can read to get the bigger picture.

Good luck with the repairs

well a valve replacement probably shouldn't cost more than a couple hundred dollars while a whole engine could cost $1-2k. i also don't have a garage or even an engine crane. i feel like i should at least try my hand at a valve job since it's doable with the tools i have.

that being said, do you know if any j35 will just drop in? i do know the j35z3 (mine) has no VCM, which might cause issues? i'm totally new to j swaps.

 

[WiiMaster]

if it's a just damaged valve, shouldn't i be able to keep the old head?

Sure, but generally when you pull a head off it's considered good practice to get it machined before reinstalling, though not necessarily required.

 

[categimperat]

Sure, but generally when you pull a head off it's considered good practice to get it machined before reinstalling, though not necessarily required.

fair enough, i'll look into getting it resurfaced on my kitchen counter by a machine shop. thanks for the tip