Why you should replace Dual Mass Flywheels ...

[SidewaysSteve]

Pictures hopefully .....

 

[keithm]

[] Absolutely brilliant post and well done that man []

 

[GOOFY]

Steve I am truly awestruck ! As someone who has in the past stripped beetle, vr6 engines, I have always been intrigued as to how easy it would be to work on a Boxster engine. Your thread has been most enlightening! Just a few questions if you could indulge me : 1 Did you really remove the engine by yourself ? 2 How do you jack a Boxster up so high ? 3. What do you think about the feasibility of putting a 2.7, 3.2 into a 2.5 ? I'm tempted to pick up a s/h engine 2.7 or 3.2 for more power, but not really into exchanging the car. Best regards Goofy

 

[SidewaysSteve]

Hi Goofy, Yes indeed I did, my dad who is also an engineer and has stripped plenty of beetles and vee dub campers in his younger years was on hand some of the time to help with lifting and the likes as with the boxster you cant get in with the engine crane. But other than that it was all moi. Ive done plenty of engines over the last few years in jap cars myself and with the odd hand here and there more just from a get it done quicker point of view. So this was by no means my first engine removal/stripdown and its safe to say that it was certainly not the most tricky one I have done either ! try doing a rotary engine, now there fun !! LOL Its easy enough to get the car up high enough, you can do the majority of the work on drive on ramps but when your ready to drop the engine out you have to jack it up and have it on good tall axle stands. When you remove the rear crossmember it lets you slip the engine out fairly easily. My understanding is that both the 2.7 and 3.2 are effectively the same engine as the 2.5 with internal alterations such as bore and stroke changes. That means externally it should be identical and therefore you should be able to do a swap with no major hassle. The wiring may differ slightly as will the ECU however these parts are also simple to replace as long as you get the whole loom and ECU etc for the engine your trying to fit into the car.

 

[Laurence Gibbs]

Great Post. Missed this when it was fresh of the press. Must read the Boxster forum more often. If your still on the forum would be interested in how you go about the clutch change as I think i have this in my future. Nice to see someone else having a go.

 

[bazhart]

Sorry I missed this post earlier - but well done - a good job well sorted out. At Hartech we have very similar equipment and background and I guess you now can see that without a lot of engineering background and some machinery it would be very hard to re-build these engines. If anyone is interested - may I just add that this failure is common amongst engines we rebuild - but not caused exclusively by the dual mass flywheel wearing out - but by its excessive weight and a relatively weak crankshaft. Unlike any other engine I have seen - the drive for the camshafts is taken from the rear of the crankshaft (not the front) and this makes the length of the rear overhang much further from the rear main bearing - so any loading at the outside of the flywheel face when engaging gears etc - changing down for corners etc - is massivley increased as a bending load. The morew worn the flywheel - the more contact is at one part of the outside - jerking the flywheel face and twisting the crankshaft. That bending is resisted by the metal between the crank pin and the flywheel face and if you look closely it is not that big - so - unlike its air cooled predecessors of similar cross sectional area - the extra averhang results in more crankshaft flexing than previous air cooled engines or most other engine designs. You probably also already noticed that the rear main bearing is narrower than could have been fitted in the space available - so this could have been improved on if the rear mains had been wider. There have already been failures in the Boxster race series (as a result of this increased loading through racing stresses) and they are presently considering allowing a solid flywheel to be substituted on reliability grounds (as it is in the 968 series - which also had a dual mass flywheel standard). Furthermore the crankshafts are nitride hardened so cannot just be reground (not enough case depth and no factory undersized shells available anyway) - although we have successfully done that and so far tested special wider undersized shells we manufacture - and we re-harden the crankshafts accordingly. This would not suit a bent crankshaft but some of those just damaged through shell failure can be repaired. Unlike many tradditional shells - more recent shells from Porsche don't appear to have any bronze plating under the white metal either and we often find them running on the steel underneath. It is lucky that you intercepted the failure early because the more usual scenario is that the rear two main bearings fail (due more often to crankshaft flexing than bending as described) and wear out the shells - and this lowers the oil delivery pressure and volume (as the increased clearance allows it so seep out of the side of the shell) - and as you will have noticed the rear main feeds the number 6 big end - which then dries up and being under more load than the crankshaft we usually end up with a siezed big end snapped rod, half welded to the crankshaft and the rest destroying the head, piston, crankcase etc. We still manage to rebuild them but the parts cost obviously goes up. It takes more guts to take on this sort of rebuild than many would realise - athough if you are a good engineer with facilites - it is not that difficult - so well done indeed on all fronts! Nice pictures by the way. Baz

 

[Neil Haughey]

ORIGINAL: SidewaysSteve Fitting the pistons to 4, 5 and 6 would have been impossible if I had not had access to make up the special tool for inserting the pins and the clips but luckily being an engineer I have access to a machine shop and was able to make up the tools on a lathe with no real difficulty

Brilliant thread, I started reading through it and thought hang how is going to fit the pins. Kevin Eacock gave me a little lesson on how to do this and the special tool required one Saturday when I was up at EMC. I have to say my eyes started to glaze over at about step 2 [], but I do remember plenty of insert the tool through the side of the black, bang in pin, if it goes wrong the pin drops in the engine and its a long night etc. etc. I have helped my brother rebuild 2 A series engines, those are easy, these engines do not seem easy at all mate so hats of to you sir [].