Meridian Boxster Rebuild Project '24

[Homeoboxter]

Originally Posted by Newsguy

The engine I'm assembling had oil starvation since the previous idi--owner drove it after the cam tensioners had disintegrated. There was debris blocking the oil pickup pretty much completely. The only effect was one main bearing toasted and the others had a little heat. The crank needed only a polish on the one journal.
I reassembled the bottom end and found a tight spot. Looking at it again, there were high spots in one shell. I'm going to follow professional advice and just try smoothing with some grey Scotchbrite.
Otherwise, I'll just get another shell.
Did you use the ARP bolts for the crankcase? I found it helpful since they are reusable and I have definitely used that feature!

Yep, worn cam tensioners is a typical failure, one of my previous Porsches had to be rebuilt for the same reason, the tensioner wore off, fell apart, then the chain jumped over one or more teeth.

These high spots are surprising because the whole unit is pretty robust and should survive some extra heat without being damaged. Did you tighten the bolts down to the secified torque in the correct order? The bearing carrier halves have to be perfectly and evenly bolted to each other so the clearances will be the same all around.

I used genuine bolts.

[Newsguy]

Originally Posted by Homeoboxter

Yep, worn cam tensioners is a typical failure, one of my previous Porsches had to be rebuilt for the same reason, the tensioner wore off, fell apart, then the chain jumped over one or more teeth.

These high spots are surprising because the whole unit is pretty robust and should survive some extra heat without being damaged. Did you tighten the bolts down to the secified torque in the correct order? The bearing carrier halves have to be perfectly and evenly bolted to each other so the clearances will be the same all around.

I used genuine bolts.

Since that post I have been fortunate to work with an experienced mechanic close to one of the major M96 sources (and worked there.)
He was worried the crank was bad so we had it checked. It's good so we are going with new bearings. He doesn't like the coated bearings and thinks that is the problem or there is an issue with the carrier.
I had really aimed for getting this on the road this summer, but as these things go, that is looking less likely.

[Homeoboxter]

Originally Posted by Newsguy

Since that post I have been fortunate to work with an experienced mechanic close to one of the major M96 sources (and worked there.)
He was worried the crank was bad so we had it checked. It's good so we are going with new bearings. He doesn't like the coated bearings and thinks that is the problem or there is an issue with the carrier.
I had really aimed for getting this on the road this summer, but as these things go, that is looking less likely.

Yeah, it takes a lot longer than one would think.. Especially if you get lost in the details. What are those coated bearings like?

[Newsguy]

Originally Posted by Homeoboxter

Yeah, it takes a lot longer than one would think.. Especially if you get lost in the details. What are those coated bearings like?

They look like bearings to me, but I'm not remotely an expert! All I know is they are substantially more expensive than your basic Clivites!
Yes, it has taken longer than I thought. I've been amassing parts for a while, and in fact, noticed a box dated 2020 just yesterday. But there are a couple of factors like a 1000-mile move and a second bad engine, but we'll skip over that.

[Homeoboxter]

I had some progress with the engine in the past weeks (months?), starting with some clean-up. Case halves drying in the sun.



Ready for the crank assembly.



Here it goes.



Chains...



Gapping the new rings.







Torquing down the rod bolts.



Case halves rejoined.