M96 DIY ish engine rebuild
 

Hi guys (and sorry Mr Raby for spiking your curiosity and wasting your time if you are looking in on my meagre thread). I dont mean to scrounge your knowledge, but of anyone willing th share experience.

I am a 36 y/o English guy and have adored Porsche since an early age.

I now have a nice 02 986S, 93k (miles) on the clock( my first Porsche). All internals original apart from the dealers did an IMS seal swap at 45k. Why they didnt do the bearing would be obvious time/money saving on a factory warrantied car I guess?Shame

Any who...

I have plenty camchain rattle on start up ( pretty sure its not valve followers) that lasts a split second then clears. It puffs a bit of smoke out on some starts too.

I have acquired a 3.4 996 motor that has been stripped for diagnostic purposes and would appear salvageable.

I am doing all the reading I can before myslef with the skill of my Porsche Indy do the rebuild. THe tech I refer to has rebuilt many aircooled engines and transmissions and has a fair experience with working in M96/97s....albeit not major rebuilds.

I am thinking I may aswell go big or go home, so 3.6 minimum, with LN liners, nice pistons and if the budget allows....nice conrods.

I eagerly await Mr Raby's forthcoming book, but until then, I am open to any advice on tips on rebuilds, regarding tricks that the facory seem to have missed.

Is the maching of the banks/liners to accept the pistons a job any seasoned engine machine shop can do?

I will replace all the cam timing gear. Is the IMS a part to check for wear......I read one guy thought his was out of tolerance regarding concentricity so bought a new one.(pre emptive....not post fail).

It will obviously be fitted with an IMS bearing fix.

I would like to use a SMF/LWF, so will need to balance the whole assembly together. I knoe reputable engine shops that will balance FW to crannk assembly. Will a flat 6 be much different?

I know the majority will read this and having read many posts on Flat 6 innovations FB page will be thinking....why bother man...its not a DIY job.

Well I have to do this DIY for budget, but I perhaps have a little more enthusiasm and commitment to make it happen, along with no little amount of respect for the size of the task and the knowledge required.

Thanks

You need a set of chain tensioners. Install them and change the oil, and you'll see that issue go away.

Thanks Jake for the reply.
Do the cams/TDC need locking for these tensioners to be changed?

Not if they are removed at TDC#1, which is the unloaded point for the entire valve train

TDC valves closed #1 I guess?!

With the engine static, all valves are off lobe at TDC#1.

Thank you Jake.

So on to the rebuild questions folks.

I intend to keep the standard 3.4 crank.

What displacement is safely achievable with new liner and pistons..3.6...3.7?

lnengineering.com

Boxster section shows what you need & why & how much the parts cost.

The website seems to be under reconstruction.

Thanks though.

By the end of this next week our completely new and updated site should be up. Sorry for the inconvenience - we had server issues that required extensive re-working.

Hey Charles an unrelated question, are you guys going to be tomorrow at the Hilton (LAX) for the Lit and Toy Show?

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Mine makes that sound for a fraction of a second on start up. Wouldn't this be expected when starting a car with a TON of cam chain and very thin oil?