utkinpol

Hi,

as we have here plenty of real mechanics who work on those cars - I would like to ask your opinion about this.
I was pretty stunned initially by my mechanic who told me that in case of any issue those m96/m97 motors are not even worth opening, it is cheaper to buy a new motor outright and get it installed.

Do you do any m97/m96 repairs? And if so - what are usual costs for whole ordeal, based on what type of a failure? Obviously the question assumes that work gets done in a shop and you got to pay for labor, not for free in your own garage.

Regards, Paul.

Palmbeacher

I'm sure there are types of failures where that's the case, such as when the IMS bearing lets go and destroys so much internally that a small shop would have to tie-up their top mechanic for several days...if in fact they even have someone capable of such a job. But essentially that's a business decision. Obviously, somebody does open them and rebuild them, so it can be done. It's just more economical because those specialty facilities do it on an assembly-line model.

My indie shop builds racing engines, so they have no problem opening these motors. Still, they say if there's that much damage, and you just want a factory stock motor, it's definitely more economical to buy from a rebuilder. That's the case with most any car nowadays.

997_rich

I'm not a porsche tech but I used to be a tech for a euro indie shop years ago. Can you elaborate? I haven't dug into an M96 other than things like water pumps.

My suspicion is that most shops would dig into the top end to replace bad lifters and maybe a bit of valve train stuff or oil pump but if the crank bearings are shot for example, they'll just be buying a crate motor or reman motor and sending the trashed motor out for core. Somewhere there WILL be someone rebuilding these and taking trashed ones as a credit but that often takes special knowledge you won't find in a local shop.

Does that answer the question?

utkinpol

i know some caymans had their engines opened to do racing upgraids like rod bolts, balanced cranks, but now as i understand with DFI based cayman r on a market no one even cares to mess with that as it is kinda pointless?

utkinpol

partially...
it is just kinda weird for me as i am from that generation that did most work on your own and i myself was assisting my uncle to machine cylinders and replace rings in old bwm motor.

so it is kinda shocking to hear that it is $6K just to drop off engine and put it back, plus extra $ for all other work. i think i just need to buy a lift and engine cradle and get my hands dirty in case if anything happens. should be cheaper than to spend $20K outright on a new engine.

997_rich

If you've changed engines in other cars I don't see why you couldn't do an M97 but I think you might need piwis to get it running again at some point... there are a couple of how-to manuals around on the internet. Sometimes you'll break a few things along the way like an injector etc and need to replace so that plays into the cost.

I did the heads on a modern BMW with variable valve timing recently and I can tell you that it's much more complex that you remember from the 70s/80s (guessing your age) with 4 valves per and the variable valve timing unit. I actually got the timing chain off a tooth and bent a valve as I torqued the head down. I noticed right away but I had to pull the head back off and buy a new valve. Digging deep into modern engines requires a lot of specialized measuring tools, pullers etc. It can be done though.. it's just time and money.

AYHSMB

A few points :

1. Porsche has been subsidizing the cost of M96/M97 replacements. This is sort of their way of showing "goodwill" about the whole fiasco. The cost of replacement engines that most people pay is typically $8k-10k , which is way cheaper than the cost to buy a new motor (more like $25k). Obviously if Porsche offers you the subsidized price, it's an easy decision to just replace it rather than try to repair.

2. The labor cost to fix these engines is astronomical. Labor cost on Porsches in general is very high, but there are even fewer people who know how to fix them right, which means not much competition. There also aren't standard replacement parts for a lot of the issues, we don't have a big 3rd party supplier of parts the way the more common cars do, so the major engine rebuild shops (autofarm, hartech, flat6) have had to create their own parts and machinery.

3. I know some people on the 996 board have done their own engine rebuilds, so it is possible, and maybe there will be more "how-to's" on that in the future and it will become more common. But it is just massively more labor time than something like an old front-mounted V engine.

Some of the problems are the typical things that you can open up and replace (IMB bearing, chain tensioners, etc), but the most fundamental problems are inherent to the engine and hard to fix - cylinders cast from bad material, bad coolant flow pattern, deck that easily deforms.