AOW162435

Mike,
Would this be enough to explain two cylinders without compression? Honest question.


Andreas

Jeff96-993

Andreas, that was my thought in my first post... I can't see how that difference occurs just due to cam timing. I can see left or right being different, but within the same bank each cylinder should be the same.

I'm wondering what additional issue is causing that difference.

Mike J

Good question, do not know. Intake/Exhaust spacing is of course fixed, so if the cam is twisted out of timing, it possible that you hit a place where at least one valve is open when the piston is close to the top. But to do it for BOTH sides, failure analysis would show its less likely.

I talked to Travis on the phone, he will try to get a boroscope and check the pistons, as well as do a preliminary timing check to see how far out the cams are. We talked about the use of the impact gun, it sounds to me like it was not very hard to get the pulley nut off, so the impacts were not substantial.

I am trying to see if I can get the time from home to run down to Seattle (road trip!) and help him setup the timing if we conclude its indeed the issue.

Cheers,

Mike

Ponchobroke

I have also just finished this activity and am listening with great interest. My line of thought follows the last couple of reply's. It sounds as though there is a cam timing issue and perhaps (for some reason) the cam bolt was not tightened sufficiently on one side allowing for slipping or no minimal cam rotation. This is exactly why I put in pins even though I was advised against it, fortunately, my engine (95) was built with the 964 gear/sprocket assembly and all I needed to do was but a couple of pins.

Unfortunately, I have a leak at the cam gasket and need to drop the engine again to fix.

Best of luck...

axl911

Mike,

Wouldn't the easier check be to line up TDC on #1 and conduct a leak down? It'll tell you where the leak is, if there is a leak.

Another step is to remove both intake and exhaust rocker arm while conducting the leakdown. This tell you if the valve kissed the piston and is now bent.

If test #2 is good while test #1 is bad, then you just have to re-time the engine. Either way you HAVE to conduct a leakdown to see if there is any bent valve from the cam slip.

Mike J

Great idea if he has a leakdown tester AND a compressor. I am skyping him later today, will talk about it.

Keep it coming guys!

Cheers,

Mike

MarkD

just to add a little more data to the pile, Porsche put keyed cams in some 993s all the way to MY97
We even saw one 97 with one keyed cam and one non-keyed.

really good of you to offer drive down Mike!

Stealth 993

Mike, let me know if you come down.

Just got a email about this being on sale, was thinking about getting it.

http://www.harborfreight.com/catalog...lt?q=borescope

AOW162435

Mike,
Your offer to drive down and assist Rennlist's newest engine-dropper speaks volumes about your character.

Also, your nuts arrived in today's mail. Thank you!


Andreas

Mike J

So that is where they went!!!

Turns out I can get the time, so its a matter of if its needed, and logistics. Weather forcasts put snow starting tonight. I would have to take the truck down, which is good from a weather point of view, lousy for fuel (damn V10's!!).

I am going to talk to Travis tonight and we will figure out a game plan.

Cheers,

Mike

Mike J

Looks good! My wife got me an inspection camera a few years ago, very hand on the car, but the head is a just a tiny bit too large for the spark plug hole. I can peek in, but not see much inside...

I will post if I am coming down for sure, have a few people to visit as well.

Cheers,

Mike

TravisB

I actually just got home with one of those. However I think the camera head is going to be too big to get through the spark plug holes..but hopefully I can get a look at the tops of the pistons to look for contact.



Yes, this really is a great community here! I forgot how exactly I found Rennlist (was a lurking member for a while before pulling the trigger), but it's been a joy to be a part of. I am looking forward to being able to contribute more, but for now I still have plenty to learn.

Anyway if Mike winds up coming down, anyone is more than welcome to drop by for a mini get-together, I can get some beer and pizzas or something like that..

Mike J

Did not know that! It must be the suppliers and their stock. One of Porsche's sillier moves to remove the indexed sprockets - I guess it saves a few bucks.

We may need a few indexing pins this weekend if we retime, and he does not have any. I can use the head off a sparkplug in a crunch, anyone local to Seattle have indexing pins?

Stealth 993

Let us know how well it works. It's the cheapest camera on the market, but a good margin.

Yes, it's a great community! Sadly, we are also very spread out.

Jeff96-993

I've never seen it done any other way... go old school, use the plug as God intended.