chris walrod

I know what you are saying. I feel there is more than just the very scientific 'wiggle test' that should determine if its guide-time or not. Leakdown, oil consumption trends, noise, performance, and in the case of 96-98 993's, SAI errors. Even past smog results may shed some light on what is happening with a particular engine.

For the money involved in top end work (which can often lead to bottom end and other while we are there work), valve springs can be removed to enable a higher quality valve guide assessment, without much disassembly.

In a nutshell, I wouldnt necessarily do a top end just based upon someone wiggling my valves-- <<<<wow, that doesnt sound right?

Burt Goodwin

There has been some discussion in past issues of Pano of additional value for resale of 993's if top end work has been performed for SAI/CEL issues, valve guide replacement, etc. I am interested in the opinion of other members re how much $, if any, you feel appropriate for such repairs when offering the car for resale.

mborkow

well, since every MY96-98 993 is a likely candidate to need top end work for SAI troubles between 60 and 80k miles (and all 993s might need valve guides replaced anyway), if the problem has recently been addressed then you know that you won't need to do it for some time (and therefore you will not have to spend ~$5k to fix it yourself).

btw, devek's quote of $5k is pretty good. i payed closer to $6k when i had mine done at another local shop in the same area.

TheOtherEric

I would value the additional premium by multiplying the $5000 cost by the odds that a prospective buyer will have to do a top-end rebuild. From my point of view as a buyer, I might put a 20% chance on that; but this depends on the buyer, mileage, how long they'll own the car, etc. But roughly, I'd say it's worth about $1000-$2000 premium. Just my WAG. I certainly wouldn't pay $4000 more.

Adrienne

First of all, welcome to the Top End Rebuild Club!! We're getting more members all the time!!

Second, here is a link to what I considered (and mostly did) in my rebuild:
https://rennlist.com/forums/993-forum/160349-valve-guide-replacement-and-iwhile-your-at-itn-repairs.html

chris walrod

TERC-- Its just like the nursing home business model, sooner or later, they're gonna get your business

long_beach_968

so the thought of the SAI issues has lead me so prepared that every time I turn the key, I am expecting the light to come on. So my question is reguarding a DIY. I am a qualified technitian for just about any job, I have a lot of experience with restoring 60's musche cars, did every conceivable job on my 968 from lifting the motor to a clutch and in between. But I have never torn down a 911 engine in my life, only know theory on the car, and dont likely have access to a lift, so is this a job reasonable for me to tackle DIY? anybody here done it?

Adrienne

Mike J did an entire series on this. Check his threads...

trojanman

FWIW, I was told after my top end that there really was no "break-in" period needed... I would guess that doing cylinders, rings, etc. would require a similar break-in as a new car.

Acropora

Is there an intermediate shaft bearing issue w/ the NA's?
Beware the slippery slope. I ended up splitting the case to be certain but new jugs, flame rings, carillos, cams- all the 'good mods' jacked up the price a LOT.

foxfrc5

I've just got my 1996 993 C4S back from a top and bottom end rebuild (valves, seals, bearings, gaskets, etc.) plus clutch, engine mounts, etc. The work was carried out by the main Porsche dealership in Singapore and took about a month. The car had done a relatively low 69,000 km (about 43,000 miles) before it started leaking two months ago.

The service advisor recommended a break-in period of ideally 3,000 to 4,000 km (about 1,800 to 2,500 miles) during which there should be "no aggressive driving" and the engine should not be taken over 3,000 to 4,000 rpm, to allow the valves to bed in nicely.

Mike J

A 993 engine rebuild is entirely within the scope of a good home mechanic (gee, how would I know that?).

You will be needing a good machine shop that can do the guides and any machining that you need.

The quick way is to strip the engine down to the heads off and do the guides and work you way back up with all new seals/gaskets.

The slower way is to split the case and check everything. I doubt if you will have any wear hardly at all except for the lay shaft...on my car with 75,000 miles the lay shaft bearings were showing some wear. This is normal for a 993 apparently. The main bearings were hardly worn. Rings and piston specs were excellent. Wrist pin bushings has some minor wear. Piston barrels had zero wear and had the original scoring marks. I did have some oil leaks between the barrels and the case so I would have gone that far tio cure those so at the end I went all the way I don't regret it.

You actually don't have loads of money doing it yourself...you need a proper engine stand (which for the 911 is expensive), some special tools and lots of time. If you time is free then its cheaper. There is the bragg'n factor as well.

Here are my posts for your reading pleasure on my adventure into the bowels of my engine.....I am glad I did it but I am not ready to repeat this process for a while...its quite intense and it takes lots and lots of time...

Part 1 - Part I
https://rennlist.com/forums/993-forum/246553-diy-engine-rebuild-part-1-a.html


Part 2 - Cams and TIming
https://rennlist.com/forums/993-forum/246763-engine-rebuild-part-ii-cams-and-timing.html


Part 3 - Heads and SAI Passages
https://rennlist.com/forums/993-forum/246767-engine-rebuilt-part-iii-heads-and-sai-passages.html


Part 4 - The saga of the valve guides - and Carbon
https://rennlist.com/forums/993-forum/247279-engine-rebuild-part-iv-the-saga-of-the-valve-guides-and-carbon.html


Part 5 - Into the Depths
https://rennlist.com/forums/993-forum/247992-diy-engine-rebuild-part-v-into-the-depths.html


Part 6 - Exploring the SAI Passages
https://rennlist.com/forums/993-forum/249641-diy-engine-rebuild-part-vi-6-exploring-the-sai-passages.html


Part 7 - Cleaning, Cleaning, Cleaning..
https://rennlist.com/forums/993-forum/252373-diy-engine-rebuild-part-vii-7-cleaning-cleaning-cleaning-cleaning.html


Part 8 - Rods and last minute checks before glue ; - )
https://rennlist.com/forums/993-forum/254718-diy-engine-rebuild-part-viii-8-rods-and-last-minute-checks-before-glue.html


Part 9 - Sealing the tomb...
https://rennlist.com/forums/993-forum/256730-diy-engine-rebuild-part-ix-9-sealing-the-tomb.html


Part 10 - Piston's a puimping

https://rennlist.com/forums/993-forum/261227-diy-engine-rebuild-part-x-10-piston-s-a-pumping.html


Part 11 - Its all in the timing eh!
https://rennlist.com/forums/993-forum/262993-diy-engine-rebuild-part-xi-11-its-all-in-the-timing-eh.html


Part 12 - Messing up the looks of a clean engine..
https://rennlist.com/forums/993-forum/263215-diy-engine-rebuild-part-xii-12-messing-up-the-looks-of-a-clean-engine.html


Part 13- It would be part 13 eh?
https://rennlist.com/forums/993-forum/264001-diy-engine-rebuild-part-xiii-13-it-would-be-part-13-eh.html


Part 14 - Holy Crap!
https://rennlist.com/forums/993-forum/264329-diy-engine-rebuild-part-xiv-14-holy-crap.html

Cheers,

Mike

ceboyd

WOW!! I just looked through that whole DIY series.. (took me almost 3 hours) and it was darn educational! I'm no mechanic but it sure as heck was facinating to see all that!


I can't believe I missed out on seeing that before! WOW! Excellent to see here on rennlist!!!!!

Mike J

Thanks Chris!

It was a lot of work but it was pretty fun too...and the list was VERY supportive with lots of good comments. The car seems to run well now but I only have about 500 miles on the engine...so far so good. Not broken in until 1000 miles.

Cheers,

Mike

delanobe

Hi Mike,

Is your car ok now because I thought you had a problem with it after the rebuild?

regards