Must of missed this, and pardon my memory - so you removed the rods, and then put them back on the crank with new bearings? Did you use ARP rod bolts, and I guess you could not use a stretch gauge so went with the burnish/torque method?

Its funny that the large rod bearings were very worn - how bad was it? (and again, pardon me for asking, there are other rebuilds happening in the background where I am answering via emails/PM's, and its easy to get confused). I would suspect that, even with wear (and no failures), it would add to the metal content of the oil but not the pieces you are seeing here.

Cheers,

Mike

Yes, lot's of info on here. Easy to get distracted. To answer, Yes. I sent the rods to Steve. He re-conditioned them and installed the new bearings plus he added ARP Rod bolts and used a stretch gauge.

I will have to go and take a picture of the old bearings. IIRC, they were less than 1/2 the depth of the new ones.

Here are a couple of pics. I also measured them and they are in the range of 1.4mm to 1.6mm thick. Does anyone know the depth of these when new?

Wait, how can you use a stretch gauge on installation without splitting the block, there is no room? You mean you measured the torque required for the right stretch while the rods were outside the block, and then on installation you used that torque? (just checking).

Did you do a clearance check on the rod bearings using Plastigauge ? (this is a bit controversial since it will pre-crush the bearings before installation - but its the standard way). What was the brand of bearings supplied?

The good thing is you, if you have to dig this deep, can remove the rods and reuse the Arp bolts - unlike the stock Porsche bolts.... the bad thing is if you need to go that deep ...

Cheers,

Mike

I did not use a stretch gauge at installation. Steve pre-installed the ARP bolts at his place using a stretch gauge. What I did during installation was lube and torque to ARP's spec.

Regarding plastigage... I was advised not to use it. Steve does not like plastigage. Instead, I measured the crankcase journals which were all near top of spec. Regarding the brand whatever Steve would usually supply, probably Glyco.

Okay, good. Like I said its controversial, but I think Steve is in the minority in this case. Ok it should not be a likely failure spot.

I am lucky to have a few large I beams in the shop (by large I mean 16"!) and I can use that to hoist the engine onto the stand using a trolley and chain block. Wow, impressive doing it manually!

Cheers,

Mike

I've been following but got lost recently. Were the old rod bearings severely worn? This would be unusual. If so was the cause determined? The crank was okay and measured with a mic and found to be on size? Did you verify the rod journal bearing clearance and if so, how was this done? Just trying to get the facts straight so all can make useful suggestions. :)

Matt, I already asked those questions and got answers - just read back a few posts. One thing is bothering me though - if I would have found high wear on rod mains, I would have considered splitting the case - lets see how it goes though, he is taking it apart now..

Cheers,

Mike

I may be way off base here, but I sense a tension on Mike J's part concerning Steve Weiner's input. Both of these guys give way beyond what we could ever expect of them to our little problems. After all, they make their living fixing the problems we have with our toys. Having had 911's since 1987, I see Steve Weiner as a giant in our community. Mike J is new, but he is a generous contributor, and I'm surprised he finds the time to make his many posts. What bothers me at the moment is that Mike J feels the need to snipe at Steve. These guys should be the ultimate allies. They seem to want the same thing, enlightened 911 ownership, they both have impeccable reputations. I really appreciate Mike J's contribution here, I don't like his suble sniping at Steve. Just my opinion.....I really love both guys.....Chris

FWIW, I don't see any sniping going on. People have different opinions on things and that is as it should be. Mike J has been absolutely great in helping me - THANK YOU MIKE! Plus, his website is a great help to many. Steve is also a fantastic contributor here along with countless others. It's all good...:rockon:

I didn't get that. Everyone is just trying to help troubleshoot.

We didn't hear back as to exactly how all of the measurements were done. However, it is a mute point now as they can be remeasured if the damage isn't severe. Re: high wear - yes, this is important to know before deciding on a course of action. Was there a pre-existing issue perhaps? Its a tough one as rebuilds are expensive and doing them twice would be quite a set back for most of us. Hopefully it turns out to be minor and reassembling and reinstalling will not seem like a big chore!

No tension, everyone has an option and I am just expressing mine. Lots of opinions on measuring vs Plastiguage, pre-crushing bearings, etc. Its gets a lot wilder over in Pelican on the engine rebuilding forum - it's all good. Anyways, I am sorry if I came across like I was sniping, that was not the intent.

As for me being "new", lets see, was on PorschePhiles, then PorscheFans, then PorscheList (which changed into rennlist) and Pelican, and on this forum and contributing steadily since 2001 (and practically none of my posts are in OT - its all technical), been taking 911 apart for decades - now I feel old! :icon107:

Cheers,
M
Mike

Totally agree! Are you also thinking that perhaps the rod bearings might be the source of the knocking sound?

This has been an interesting thread, and with much of my engine in pieces it does raise some concerns as I start the rebuild process.

I would be concerned at finding bearings that were between 1.4 and 1.6mm thick. Generally the tollerance we are looking for here is in the 100's if not 1000's of a mm. I have measured all of my rod bearings and they measure between 1.479 and 1.482mm. With 2 bearings at 1.4mm you are going to have massive clearance which could quite easily show up as knock. The only way to measure these is with a micrometer, a vernier caliper is not accurate enough for measuring clearances.

Measuring clearance with plastigauge is really the only option if you are not splitting the case, as it is impossible to put a micrometer in to measure the rod journal.

If the old rod bearings were as damaged as you say I would be concerned that there may be damage to the crank as well. How out of round were the rods?

As for the metal pieces, Is it possible you broke a ring on install? It could explain a bunch of things (Oil on Piston, Low compression etc)

Good Luck...

Can you shoot me some pics of the rod bearings? I'd like to see the inside surface of each one and it would helpful if I knew which cylinder was which.

The case needs to be split and EVERYTHING cleaned out very very thoroughly along with the oil tank, lines, thermostat, cooler, and all oil passages in the cam housings and case. The galley plugs should be removed and all passages scrubbed out and flushed.

The crankshaft also needs its oiling plugs removed and then ultrasonically cleaned.