Carpokes Porsche Forum

But the simple test it - does it pass oil out of the AOS? if so then its rebuild time, if its bone dry then leave it alone.

I'm afraid we're a little past testing that I've got the cleaned and disassembled AOS sitting in my kitchen (...). Are there any tea leaves on the block I could read?

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Basically oil leaks. most oil leaks are caused by pressurizing the crank case from ring blow by. You can get lots of oil into the intake/intercooler/turbo via the AOS lines. So if it was an oily mess then its time. If it was pretty dry then you were OK for at least another week before it starts leaking!

chris white wrote: Wed Apr 13, 2022 6:42 pm

Tom wrote: Wed Apr 13, 2022 6:37 pm Realistically, to replace the rods, the pistons need to come out.

If you can change the rods without taking the pistons out you're a magician!

I was indeed a magician from age 12 to 16 -- The Wizard of Altos! Did children's birthday parties at $40 a gig, which made me the highest paid kid in school until we were old enough to get real jobs. Then I got my drivers license and that was the end of that.

But I digress. Carry on.

chris white wrote: Wed Apr 13, 2022 6:46 pm Basically oil leaks. most oil leaks are caused by pressurizing the crank case from ring blow by. You can get lots of oil into the intake/intercooler/turbo via the AOS lines. So if it was an oily mess then its time. If it was pretty dry then you were OK for at least another week before it starts leaking!

Makes sense. Should've taken more pictures, but I don't remember it being particularly egregious. Not more than my old NA was, at least. Unfortunately I don't have a lot of references!

Tom wrote: Wed Apr 13, 2022 6:37 pm Realistically, to replace the rods, the pistons need to come out. Once the pistons are out, my confidence would be pretty low on either new or old rings working well on old pistons in old bores. If confidence is why you are rebuilding, I'd either rebuild the whole thing or leave the bottom end alone and just reseal it. Of course, it will never be easier than now to sleeve, hone, or coat the bores so you could install the forged rods along with new pistons and rings (and polish the crank and put in new main bearings).

And the scope creeps ever wider...This is something I'll need to have a good think about. And the relative value of just shopping that work out... There's depressingly little data on the longevity of cast 951 rods!

...I don't suppose anyone knows of a shop that'll do alusil near Seattle?


edit: for $40/hr I'll drive the block down to you tomorrow

four0four wrote: Wed Apr 13, 2022 11:13 am @Thom - you mean two versions of the 930 disk? I poked around in your history but only found pictures of those. The cup disk has been revised for sure, there's at least two slightly different versions floating around the internet.

Here is my photo of the 2 versions. As said the 4 spring version has worked great for me. I like that the friction surface is uniform.

four0four wrote: Wed Apr 13, 2022 11:13 amI don't think I'm in danger of approaching 500hp.

Yes, that's what we often try to convince ourselves with when doing the first engine (re)build!

Yes, you are on the edge of the slope! I stopped using stock rods in modified engines a while back. No way to know how much abuse they have seen and they are way too heavy. Of course the same applies to the pistons…so might as well just nikasil the block, get some Mahle pistons and good rods and get it all done right!
Welcome to the slippery slope club!

Reading your To Do list…. What about main bearings?

Edit: I will also ask Porsche vs Glyco? I have seen it mentioned that Glyco makes the Porsche bearings

chris white wrote: Thu Apr 14, 2022 5:29 am Yes, you are on the edge of the slope! I stopped using stock rods in modified engines a while back. No way to know how much abuse they have seen and they are way too heavy. Of course the same applies to the pistons…so might as well just nikasil the block, get some Mahle pistons and good rods and get it all done right!
Welcome to the slippery slope club!

I'm grasping at anything I can on the way down

(well, and taking measurements...)

gruhsy wrote: Thu Apr 14, 2022 8:35 am Reading your To Do list…. What about main bearings?

Edit: I will also ask Porsche vs Glyco? I have seen it mentioned that Glyco makes the Porsche bearings

Mains won't be touched unless I crack the girdle. Not sure which way that is headed to be honest...

I'm using neither. ACL make a coated bearing (is this the same as the LR bearings?), and I wanted to give that a shot.

I do have a Glyco set sitting around somewhere, but I wasn't planning on using them. If I did, I'd re-measure all of them and consider picking up another set to chase clearances with. You could probably avoid that by going with the Porsche part (which, iirc, are just re-binned Gylco?)

My ACL’s are Calico coated.

All the ACL’s for 944 are the same bearings….well with the exception of oversized and undersized of course

https://944store.com/?s=Rod+bearings+&p ... gwt_wcas=1

Best price

four0four wrote: Thu Apr 14, 2022 11:44 am
I'm grasping at anything I can on the way down

No need. This slope is uphill in every direction.

gruhsy wrote: Thu Apr 14, 2022 8:35 am Edit: I will also ask Porsche vs Glyco? I have seen it mentioned that Glyco makes the Porsche bearings

When I built my motor in 2008, I ended up ordering both Glyco bearings and Porsche-branded bearings (rods and main). They appeared identical. The Porsche-branded version had the Porsche logo and part number, but still had the Glyco logo stamped into it. While they apeared to be identical bearings, the reason I ended up with both sets is that the Glyco bearing sets had a few visible flaws, whereas the Porsche set looked perfect. I'm not sure if that was happenstance, or if Porsche insists on a higher QA process -- but I suspect the latter based on other Glyco bearings I've bought over the years. Seems like you can get to the same result cheaper with the Glyco branded bearings, but you may need to inspect closely and send back/replace the duds.

I wish someone like ACL or Clevite would make mains