996 Lifters: Recommended Testing / Assembly Procedure?

[hankster66]

1 hour ago, JFP in PA said:

That bearing is decidedly on its way out, small amounts of ferrous particulate indicate it was already on its way to failure.  If you have not already pulled the sump cover in preparation to do the retrofit, I would do so now.  You will be looking for similar fine ferrous grit in the sump.  If you find none, you are golden, but if you find it there, it is everywhere inside the engine.

Thanks for looking it over. I had pulled the sump early on as part of the LN checklist, including borescoping, etc. Found some particulate in filter (normal levels) but the sump was clean, except for some plastic from chain guides and a quarter-sized non ferrous piece of metal that everyone confirmed was a leftover from the manufacturing process. That's what drove me to go into the lifters to eliminate possible issues there. Like here, I had sent pics to LN to verify everything was ok before proceeding. As I tore down the engine, I did not find any particulates elsewhere in the engine... nothing in the heads, cylinder walls, on the chains, and never saw anything in the oil draining in the collection pan under the engine as I rotated it on the stand to do work.

 

Everyone was speculating that I had the dual row, which is not always the case in these 2000s from what I've learned. Fortunately it was the more robust one that kept this engine going this long (90k). I guess I was lucky to have the clutch go out so soon after purchasing the car as it forced me to do this work probably much earlier than I would have otherwise.

[JFP in PA]

If that is the case, you got lucky. 😉

[hankster66]

Hi JFP, is there anywhere I can find valve specs to check guide wear, install height, etc. ?

[JFP in PA]

10 hours ago, hankster66 said:

Hi JFP, is there anywhere I can find valve specs to check guide wear, install height, etc. ?

Unfortunately, Porsche never published internal specs for these engines, primarily because they did not want them serviced in the field.  Probably your best potential source is someone like Jake Raby, who along with building some of the most powerful versions of these engines, is running a school to teach proper engine assembly, has published both DVD and printed matter on the subject of engine assembly.

 

A lot of us out here in the real world have had to learn a lot of hard lessons on how to care for these engines through trial and error because there is no technical support available from Porsche; even the dealers do not attempt to do internal engine repairs, they get a car with bad valve guides, the owner gets a factory reman head.

[hankster66]

I hear you... I borrowed his video from a friend and it has great detail on assembly, but does not go into the build specs... I'll check it over again in case I missed it. Thanks.

[Silver_TT]

JFP spot on as always.  Raby is going to be the best source for this.  If you paid for the video I would contact jake.  He’s usually a very nice guy when the questions aren’t stupid (which is why he left Rennlist)

[Silver_TT]

One final thought is that Lee Jenkins of Hartech in the UK could also be an excellent resource.  I have seen his work and it is outstanding, he is very very good.

[hankster66]

On 7/18/2022 at 7:14 AM, JFP in PA said:

There is only one place I would send Porsche water cooled heads: Len Hoffman   Hoffman Cylinder Heads  Len will go through them and tell you what is needed, he is one of the best in the business. 

 

If you read what I have said about bolts, you already know where I stand on this subject.  Bolts are cheap compared to having to do the job twice.

 

Hi JFP,

 

Project Update... good news, bad news. First, I just want to thank you for all your advice along the way. I did end up sending the heads to Len Hoffman; unfortunately, not until after doing some DIY trial and error that could have been saved if I just sent it to him to begin with... but better late than never.

Good news: Got the car up and running. Felt great completing the project, and getting the car on the road with nothing "blowing up"!

Bad news: durametric telling me a slightly different story about my results. Throwing o2 sensor fault codes ahead of cat P0150 (bank 2) and P0130 (bank 1). More concerning is my timing being off: Bank 1 -4.97, while Bank 2 is 0.00. I had taken the car for a few short drives to ensure fluid levels, oil pressure, etc. I put the durametric on it after a 30-minute drive at idle. On background, I changed all the IMSB/RMS, tensioners, chain guides, cam-to-cam chains, lifters, springs. Before the work my deviations were Bank 1 (-10.44) and bank 2 (-5.64). Don't know if it's coincidence or means something that the difference between the two banks is roughly the same before/after, and bank 1 continues to be the only/bigger problem. I find it interesting that I could even get bank 2 to perfect 0.00.

Some have suggested that the long chain may be at issue, but since I'm in spec to just leave it alone (for now). Bank 1 seems to be on the outer end of the spec, so I wonder how long it will be before it's out of spec again. Curious if you have any thoughts or suggestions.

[JFP in PA]

The cam deviation specs for your engine are +/_ 6.00 degrees, so technically, the engine is within specs.  A slack long chain can contribute to deviation issues, but it is not a common phenomenon. At this juncture, I would leave the engine alone and just put some miles on it and check it again, preferably after a drive of quite a few miles.

 

We see some cars regularly that are in the 4-5 degree range that have been there for many miles and which have not gotten any worse.  Their numbers move around a bit, but always fairly “deep” into the spec range, but are otherwise doing fine.