QUOTE(Lucky9146 @ Aug 18 2017, 12:23 PM)
Thanks Larmo63! I have been following your thread as well and can relate to your ups and downs. I see your engine is going in soon. Best of luck!!
As mentioned earlier my engine sat for years and that is not good it appears for rockers and cam shafts.
No pic of cams (very very minor on cams but going to DC 40's anyway) and here is my worst case rockers....
Click to view attachmentReconditioned rockers from Henry Schmidt via Ken @ 911 Vintage in Fallbrook CA.
Apparently Henry is doing rockers for Nascar and has developed a great process.
And if you have not met Ken he is a great guy and I always enjoy the drive up for the in person experience and a poke around his shop.
Ugh! Another unplanned expense!
Click to view attachmentDecided to do new timing chains. why not?
Seems like everything else is being changed out! Simple operation and worth every penny of insurance. Basic stuff I know but there may be those out there that have not done some of it. In fact this was my first timing chain change out on a 3.0.
Click to view attachment Just feed the new chains through following the old chains out using the new master links and good to go!
Click to view attachmentFirst off, you are doing a great job on this rebuild. I'm loving the attention to cleanliness which is key to a great build. Having spent hours cleaning parts on my 3.6 build for my 993, I really appreciate what you are doing.
Second, comments on the pitted rockers. As you noted, this was probably due to leaving the engine with old oil inn it for a long period of time. Since one of the products of combustion is sulfurous acid, it's imperative that oil be changed on a regular basis......not necessarily mileage. As I've seen many places, oil needs to be changed annually or every xxxx miles; whichever comes first. So, the pitting is corrosion and the only way to prevent it is to keep the oil clean. That's why it is best to change out oil just before putting your car away for the winter months or for any extended storage period.
Galling is another thing and is usually due to the poor formulations of today's oils. It's been explained ad nausium the cause of galling; but, the thing to remember is to run an oil that higher levels of ZDDP. You need at least 1300 ppm of that additive to prevent galling of the rockers. To get those levels, you need to run oils meant for off road or racing use. You can also get the correct level of ZDDP by running Mobil 1 V-Twin, which is their oil formulation for motorcycles. Since motorcycles do not need catalytic mufflers, the higher additive levels are permitted.
On my teardown of a 3.6 motor from my 993, there was significant evidence of galling on a number of lobes of one of the cams. That was at 107k miles. All the bearings in that motor were perfect which is an indication that oil changes were proper. Research showed that galling failures are beginning to be seen in the air cooled motors.
One question: Since you elected to split the case of your motor, why did you opt for split cam chains? There is nothing wrong with the chains that have a removable link, but the continuous chain eliminates the potential for the link coming loose.