I have a 2011 Fit Sport with 100k miles. The #3 cylinder spark plug thread is blown out and the helicoil repair has also failed. So there is no real option to fix it. I'm not sure if I should sell the car as-is, or decide to replace the head, or the whole engine. If I attempt the repair, is it easier to just swap out the whole engine or do just the head? Looking for advice. I could possibly have access to a lift and all the needed tools. What kind of time would either of these take? Thanks in advance for helping a brother out with some advice!

 

I would take the Head off, and have a machine shop repair it, not hard to do for them, and put the head back on.
I bought a boat with 2 stripped out spark plugs, and helicoils were also messed up.
Took the head to an engine shop, had the head back the next day, cost me $100. That was 3 years ago, not a problem since.

 

Removing a cylinder head isn't too fun. There are lots of annoying elements such as cleaning, fluid replacement, surface inspection/prep, and the need for new head bolts (not sure if that applies here, but I assume so.)

Used cars are worth quite a bit at present and mechanics shops are all packed. If you could manage the job I'd say repair or replace the head with a junkyard head. It's hard to find a welder for cast aluminum, but not impossible.. not sure how damaged yours is, but if it's fixable go that route.

Anywhat, at 100k miles I'd say your engine aught to still be in good health. I'd prefer the known evil myself. Can't remark on time, but if everything goes smoothly it could be handled pretty quick I'd set aside a weekend for it with a call ahead to the machine shop and the new bolts n head gasket, exhaust manifold gasket boxed in the garage. there are a fair number of consumables that go along with a job of this sort. Having everything ready to go saves loads of time.

Apologies if you already knew all that.

 

realistically replacing the cylinder head and swapping the engine will take the same amount of skill. Both require special tools, if it was me I’d remove the cylinder head and take it to a machine shop to see if they can repair it.

 

When you say the helicoil failed what do you mean by that? Basically walk me through the steps you took and how you determined it failed.

 

I'd imagine the coil won't sit properly, either in the right orientation or just not enough to stay in, possibly due the the base thread being stripped and not fully cut/cleaned out.

I wonder if using a larger sized threaded insert would work. Of course, it would need to be the type that cuts a bit of the shoulder so the spark plug doesn't end up sitting too far away.

Which reminds me... I need to work on the spark plugs of my Fit one of these days.