Sticky valve that frees up with temperature.....the "loud tapping" is the valve lifter smacking the valve when it fails to close on time.

Crap franky, i hope u get ur car running.... dammm 32's scary v6 kompressor i have 78k miles now, reading ur problems scares me ****less

Frank - You must stop driving the car until this is diagnosed. You are going to damage something - valve hit piston etc. It could just be a dirty valve but you need to know. You might still have a broken valve spring - valve assemblies rotate constantly & that might be why the noise comes & goes. Depends on the orientation of the springs. Please compression test & I advise getting that head off for full inspection. I'm not saying it's not build up on the valve tulip - American fuel is not great & we don't know the condition of the valve guides & stem seals - but if you are using Techron - running slightly rich should not cause problems. It should help clean the inlet tract. Build up on the tulip is usually a combination of fuel crap & burnt on VI improver from the oil leaking down the guide. If you continue to run with excessive clearance on one valve you will wear a flat on that cam lobe. You might have a damaged valve collet - Good luck!

problems problems sigh... maybe is time for us to sell the 32 take a lost ...

damn frank, the car is takin a big hit on you.. goodluck wit everything

it's not gonna depreciate more than it is right now.

it's turning into something i only drive once or twice a wk car anyway.

Don't even think of selling it - If it's just head work - fix it - not a major train smash - It's when you loose a block on these engines that you have to wonder whether repair is worthwhile - then better to find a secondhand engine.

just one of them hiccups. all good.

God dammm money pit, think of the things you can do in Taiwan and the fun you can have with the money repairing the c32.

airline tickets too expensive man...lol

it only made me change the wires that I wanted to change for a while anyway.

and when asked when did I change out the plugs was a very good question because I thought I only did it 20k miles ago, but searching around I think it was more around 35-40k miles ago.

so so far i've only spent on necessary maintenance items.

+1

My lil sis went back round trip ticket 800. hahahaah i wanted to go back sooo bad, but, tons of work to do. Let us know the results of engine problems.

ran STAR. misfire on #4. all electrics checked out. the readout shows something 5.6-6.7 in the "smooth engine running" menu in the STAR.

suspect it's the valve sticking or not closing (valve spring probably died). erratic vacuum read. did not have time to do compression test.

Erratic vacuum reading is almost certainly a valve.

hopefully it's the valve spring and not the valve stem itself.

Damn. You already know about the compression/leak down tests.

A borescope can also reveal if the valve(s) and piston have made contact.

I sure hope not…

i wouldn't think so based on what bullejo said what his symptom was.

does anyone have repair manual for M112 replacing the valve springs?

Frank - I don't think you've had a hard touch if at all. If you had bent valves you would know - big noise!!! & terrible running. Damn I bent a lot of Alfa valves in the old wild days.

I don't have a manual or procedure - sorry - This is all I have for the C32. Let me know if you need pics of front chain case & all.






Good Luck

Does this mean you verified a broken valve spring? I've heard of similar valve spring replacements being done without removing the head. They used air pressure to keep the valve in place while compressing the spring and installing the collets (or is that how everyone does it now?). How about subscribing to All Data for the tech info? However you do it the information will be better at hand.

Replaced valve springs on Detroit iron in situ without too much effort.

MB’s procedure…

thanks john. that looks like PAIN to DIY.

I'll ask around to see how much repair will be. already got one quote.

thanks glyn for the graph as well.

on my older bro's 97 528 we had a broken valve spring too and we were able to DIY it without much trouble, but everything on this M112 seems over engineered to a point you are asking ...WHY? lol

BMW made the same power with a 3.0L inline 6 on single spark 4 valve design and it is more fuel efficient as well. why the heck did MB's engineer decide to go twin-spark and 3 valve. lol in truth not very efficient and cost grip to repair and replace parts.

glad on the M272 they made it simpler.

[QUOTE=splinter;3624347]Replaced valve springs on Detroit iron in situ without too much effort.QUOTE]

Yep - Achieved the same with Italian ALUMINUM when I had bent nothing. Bloody Alfa had dual valve springs to add to the angst.

So FrankW could "drive it like he stole it"

At the time the 112 was developed they were determined it enjoy LEV (low emission vehicle) status in Europe. Hence the twinspark. Kraut engineering for the sake of engineering if you ask me sometimes.

Their auto trannys are a masterpiece in simplicity - especially the 7G for what it achieves I think cost is driving simplicity in the new DB regime & that is good.

The bolded part of your quote I think pretty much sums up why they did it. I'm sure the thought was that "if" anything like that were to go bad, they make money on people wanting to repair the m112 engine, rather than having to buy a new car or get a whole new engine. Logically speaking, I could only think that they would do it to make more money on people trying to fix the car, rather than make it more efficient / cheaper for the consumer.