Bad HG or a Cracked head??

[IronFreak]

Well I pulled in apart this weekend.........guess what it was?!

AN INDIVIDUALS LACK OF ABILITY TO PROPERLY REBUILD AN ENGINE!!!



Someone must have tried to "refresh" the top end.....but didn't understand the process of using a torque wrench. The HG was fine, I'm pretty sure it was the 3 or 4 bolts in the middle of the head that weren't properly torqued.



You can see in the above photo that cylinder 4 and 5 is the area of the loose head bolts. I also found this problem (lack of proper torque) when removing the exhaust manifolds. On the plus side it looks like someone forked out money to have this head redone, or its a reman.



Super clean, no wear at all of the valve train for a motor with 176k, and the valve guilds look brand new.



I'll be pulling the lower end and tranny this weekend. Look for a sale thread, I'm going a different direction with the car.

[IronFreak]

I was starting to suspect work had been done to it. I had noticed a new valve cover gasket , newish looking sensors new hoses and belts.

Thanks for your input, you've been a big help.

[jlevie]

The BMW OE gasket is not a VR, as far as I know. That being on the engine means the head has been off in the past. That and the condition of the coolant suggests a healing head gasket. The junk in the coolant and the sludge in the hose could be from oil, or some sort of stop leak.

If the engine was filled with coolant, not just water, the smoke in the picture above is condensation, not vaporized coolant.

On a side note.......what would a m20b25 / 260g sell for?

That depends on mileage and condition. A good lower mileage engine & transmission (~100k or less) could bring about $1000. A high mileage engine considerably less.

[IronFreak]

So........a little slow going, question though? Victor Reinz head gaskets weren't factory right?.........I'm guessing not. I haven't gotten the head off but I can see one of the tabs on the HG sticking out and it says "VICTOR" on it.

On a side note.......what would a m20b25 / 260g sell for? I'm thinking of going in a completely different direction with the car and wanted a feel of what I could sell the whole package for.

[IronFreak]

Thank you, I'm stopping at a shop right down the street after work to talk to them. As far as the springs go, what kind of numbers would I be looking for on a compression rate? Would that be listed in the Bentley manual?

[jlevie]

If you are going to pull the head, tear it down all the way and have the shop check the valve guides, grind the valves and install new seals in addition to a check for cracks and warp. Since I have never seen a used head that had no warp, I always have it surfaced. Oh yeah, have the cam checked for wear.

[IronFreak]

Been a really busy week but I'm going to log some time in the garage tomorrow. I'm going to have the head checked by a local shop, check for cracks, deck it, the good stuff. A few questions there, how much of the head will have to be taken apart? Everything or just the cam, nothing? I've heard different things so I wanted some input from guys that have ACTUALLY done this, if you haven't no need to weigh in. Also, what should I replace on re-assembling the head? I was thinking about checking the springs with a tester, check for general wear and (or) pitting and use my own judgement? My Bentley manual is sitting on the front porch as we speak so I'll be diving into that tonight.

I have started to formulate a plan for the motor, so while I have it open I want to cover a few things. The more I read and study this engine the more I like it. coming from domestic cars, I really appreciate the relative simplicity of the thing and the outstanding amount of engineering that went into it. It has it's flaws, but it's potential outweighs those IMO.

[IronFreak]

Good to know...

[travish325]

all m20s are noisy. Sounds like a sewing machine.

[IronFreak]

Well I made a little more progress last night, kind of slow going, freakin blizzard here made me make sure everything was ready to go before I opened up the garage to run the vehicle......

first I pulled the thermostat...........



nasty, you can see that brown sludge crap around the edge of the housing. then I made a temp gasket.......



I also pulled the coolant reservoir out drained it and washed it out 4-5 times to make sure it was clean, the hose that comes off the bottom of that was packed with that sludge. I also pulled the block plug and drained it, this is what came out.



normal.....RIGHT?:crazy:?

I put the flushing chemical in, and then topped it off with piping hot water and turned it on, let it get up to operating temp. then shut it down to cool. I snapped a shot of the exhaust at operating temp.



Still pretty smokey.

While the car was cooling, but still warm I did a compression test. These are the numbers I got.



They don't look to bad to me? Once I was done with that test I drained all the flushing chemical and water, it was still pretty dirty. I filled it up again and called it a night. I'll probably flush it 2-3 more times until it comes out clean.

Side note, the valve train seems a bit noisy, is that normal on m20b25's or is that a good sign they need adjustment? They'll get it anyways because I'm going to pull the head, but for future reference?

[IronFreak]

is that expansion tank crap some kind of stop leak additive?

Im not sure, when i was as the parts store buying the flushing chemical i noticed there are all kinds of additives to "fix" leaks......

I prefer to do stuff the right way and not toss chemicals into my system assuming itll fix the problem. If it plugs a hole in the radiator, what else is it plugging.....idiots.

[IronFreak]

if the engine is cold and so is the ambient air, the exhaust will look like that

see if it still smokes like that once it warms up

Yeah, it does it during operating temp as well.

[rkettner]

is that expansion tank crap some kind of stop leak additive?

[SpecM]

if the engine is cold and so is the ambient air, the exhaust will look like that

see if it still smokes like that once it warms up

[IronFreak]

The plugs do look like the engine is on the lean side. But not really like coolant washed. And besides, if the engine had coolant getting into the cylinders you would have dense white smoke in the exhaust, not just water.

YEAH......the dense white smoke fits the description better. kind of like a sewer grate in the middle of winter in downtown New York hahaha.


I'll snap a picture of it tonight.