Hey all, figured out the bogging issue. Combination exhaust leak at the manifold, distributor cap was loose (still isn't as tight as I would like it).

Here's the kicker. #1 wasn't firing at all, take a look and you'll see why.

First, there is a thread insert for the plug, somebody did a job getting one in or out at some point so a insert was added. But you can see from the plug that it cracked and burned, can't be good?

 

wow, can't say I've ever seen a spark plug that looked that awful.

I dunno but I think at this point, I'd be looking for a replacement head

 

At the very least I have to get in there and see if pieces of this spark plug are in there. The good news, I think, is I needed to do the timing belt.

Should I need to go that route, any idea where to get one? Besides a used one at a junk yard, any refurb ideas?

I believe I have the B230f?? Just searched ebay real quick, actually two on there.

 

if its a non-turbo newer than about 1982, you almost certainly have a b230f. if its a turbo, its a b230ft (and the fairly rare 16V DOHC is a b234f, but this is a totally different head). The turbo and non-turbo heads are identical, but the turbo has sodium filled valves to better handle extreme heat (and uses a different cam, but the head normally doesn't come with the cam).

a head ready for installation should look something like...





that has been acid dipped, and machined and is basically ready to bolt on.

a head thats ready for the scrap pile looks more like...



(not really visible in that picture, but there's hairline cracks between the valves and the spark plug holes in several cylinders, this one was beyond repair, hence got replaced with that other one, which I scored off someone on this forum IIRC)

 

It is a 1993 240 Wagon, non turbo, and I just popped under there and saw B230 stamped on it, so I guess that's it lol.

Quick search on eBay found this one.

Probably better just to replace it since that plug was annihilated, it was impressive. Thankfully got it home and in the garage. Guess the Benz is on hold now. As a bonus too there was some leaking from the head gasket. Killing a bunch of birds with an RPG on this one!

 

that picture looks severely corroded, like it sat outside a long time. you can (and probably should) use your camshaft, but if all the studs and stuff are corroded like that, its more work for you. and if the aluminum is pitted, ugh.

replacing the head is a top end rebuild for all practical purposes, I would without hesitation use a new timing belt, tensioner, and all engine gaskets and seals. and probably the water pump unless yours is nearly new. real volvo seals work much better than the aftermarket (chinese) stuff.

 

Yeah that thing looked pretty nasty, off a "85 too. Timing belt/water pump all needed to be done so it all sort of worked out pretty good. Got next week off, guess I know what I'll be doing.

I put a post on the "wanted" section, hopefully someone is parting something out.

I'll take lots of pics and hopefully I don't screw it up too bad.

 

You might also consider a . Solid insert, superior to a helicoil, permanent repair. Depends on the condition of the spark plug bore though. Might be too far gone judging by the condition of that plug.

 

I tried something similar to that and had a sleeve in there too. Something obviously didn't go right. The problem now is the tip of the plug is gone, somewhere inside I'm sure, so I have to take it all apart to find the pieces and hope it didn't do too much damage.

So it's now a project car. New head, timing belt, water pump, distributor (maybe), plugs (obviously), seals etc.... and she should be good as new.

Or I'll be using it as an apartment when my wife kicks me out.

 

Oh, so you did that. Hmmm. Did you cross thread the plug too?

What exactly does "something similar" mean. Some kind of home brew repair?

How could you not notice the misfire as all the combustion gases blew by that spark plug for hundreds of miles?

 

It was the version by OEM, not the greatest but at the time did the trick, sort of lol.

I can take the head off and see if I can tap it again while it's off then if not look into a new head, unless of course it's cracked/warped too bad.

Had a ticking noise before all this too, so can take care of that while it's open.

This will be a pretty good how not to/how to project. Pics forthcoming of course.