My statement/question was directed toward MexicBlueTurboS.

Any news/updates on whats going on with the knocking sound from your engine??

 

This was a 1966 912. Los Angeles - Spring of 1992. Car seemed to run well enough and I was told the sounds were normal for a Porsche. It was a 1600 mile trip where the car just got weaker and weaker every day.

There are some RLs I'd probably buy from but like friends and relatives, it's best to have an independent 3rd party to prevent misunderstandings or popularity contests if something goes south.

 

From the mechanic:

We have inspected and tested the following and find no indicators of wear or a problem. The slight knocking noise is still very present and will need a full tear down to locate.



We have scoped all cylinders, no adverse wear.

We have removed the drive belt to eliminate all ancillary items, no change

We have removed and replaced the chain tensioners, no change in noise, originals re-installed.

We listened to all areas of engine and determined the noise is coming from driver side rear of the engine area.



At this time, if you would like to scope the lower sections of the cylinders from the oil pan side it would require an additional 12 hours of labor.

I think this would be unnecessary as the upper portions look OK.



Please advise as to what you would like to do from here.

 

Now, my understanding is that bore scoring on the 9A1 is often from the lower portion of the cylinder bore, and thus can only be seen with the piston at tdc to see the lower bore where the piston skirt lives....really need sim guidance here as I have this deadline on the warranty.

 

whoa whoa....12hrs?? Time for Jake to pipe in

 

Jake has made it clear he's not one to step on toes of a competitor, and thus won't be weighing in here. Unfortunately, I'm on the clock here. I'm probably going to have to just swallow the 12 hours of labor and go ahead with it, as otherwise I won't have any recourse if there is a scored bore on the lower portion of one of the driver's side bank of cylinders. Open to any more insight here

 

When i was investigating with my pan off this is what it looks like in there. Oil pump is in the way and cant really see much. All the labor is probably for removing the oil pump which is run by a chain which would probably require to remove the tensioners which they had already done so. I would call other shops and see what they charge to scope from the bottom.

Attachment 1345746

 

I think in one of Jake's borescoring videos there is guidance/instruction on how to do this on the 9A1 and maybe a workaround? Worthwhile for you to search that out, but 12 hours seems excessive. Maybe you can contact Flat 6 personally for at least a confirmation on the amount of hours/time to do this. Maybe even contact LN engineering - they are all good guys at both shops from what I have read, and experienced on this forum.

 

My engine sounded exactly what you had in your video, I mean exactly, loud as well. Even the Porsche technician was concerned ( I could see it in his face) turned out to be the tensioner. That's it. Had it replaced and no more loud tick

 

Did you talk to the seller and explain the situation and ask about the warranty?

 

I hear you and I wish that it was that, but the tensioners etc have already been removed. At this point given that I'm under the gun and need the work done by Friday, I'm just going to have to bite the bullet and move forward. Not sure I can find another shop in the area that has enough time to do 12 hours' worth of work prior to Friday...if the bottom end disassembly turns out to come up clean, I guess I'll just drive it and send a UOA regularly. If it turns up with a scoring issue, then I have my answer. @lnengineering - would appreciate any insight if you can lend some...

 

@RacerWannabe I can promise you this. No one here feels good about this. No one here likes to see this.

It's not like when you see the other guy get pulled over for a ticket, and you're like 'Haha that's one cop who can't get me now'.

We're all susceptible to the randomness of mechanical failures - even when we do everything we can to avoid them.

Really sorry this is your experience right now. All the best.

 

I really appreciate it man. I hope to have an answer soon and will certainly share the outcome with you all. If it comes back clean, I'll likely just drive the car, enjoy it, send UOAs and set aside $$ for whatever comes next.

 

Thanks @bronz - getting additional estimates for the work would be ideal, but given my timeline here I'm going to go ahead and bite the bullet on the estimated 12 hours...

 

Thats odd. Jakes videos point out that scoring always starts at the bottom of the cylinder and may not be visible at the top of the cylinder until its become severe. However, if you are hearing a knock, you are at defcon 1 so should be seeing signs.

Cant comment on what it takes to scope the bottom of a .2. Anybody know if its possible to turn the crank by hand so you might get a little more context for each cylinder?

Did they check the fuel pump and water pump?

Cant you just return the car under warranty and be done with it?

I would get the mechanic to write in their report that there is confirmed, material and audible defect in engine operation which will require engine tear down to properly diagnose. Give that to the dealer/warranty company as proof and be done with it.