NorthernDancer

Newbie here wanting to buy 993 but wanting to avoid a car with SAI issues. Here are my thoughts & comments welcome:

1. check carfax or Autocheck for failed emissions tests. Have evidence this pointed to 1 car needing top end overhaul ($7864.68).
2. ask owner about oil consumption [crap shoot owner will be honest]
3. ensure CEL light comes on with ign before start
4. good Porsche garage PPI will pull saved trouble codes

I have read the Ultimate Owners Guide on 993's by Jack Criswell

thanks in advance

Barn996

The latest Excellence magazine has an article devoted to the SAI issue and suggests 3 ways to fix it. Don't know about how to avoid buying a 993 without SAI issues.

JM993

Buy a 95. It might have have SAI issues, but they are complete irrelevant for emissions, driveablity, and all other purposes. Do a search on SAI removal for more info.

Cheers,
Joe

vjd3

With a shady seller, codes can be reset with a $39 tool just before you see the car and light will still operate normally. Readiness codes will not be set, however. A PPI may or may not catch that. Oil consumption can be all over the map, lots of cars want a quart every 1000 miles and they run beautifully with no issues. Others use no oil at all.

Look for a 95 and never worry about it, or find a 96-98 that has had the top end already done, and never worry about it. Or, make an offer with some room to deal with SAI problems in the future.

From my personal experience, if it's a 96-98 car, it's not a question of "if," it's a question of "when" the valve guides and SAI will become a problem. You can deal with the problem by flushing the ports periodically yourself, or you can have the valve guides done with the harder ones to eliminate the problem for a long, long time.

gtroth

For PPI, Excellence article recommends measuring lateral valve movement of the valve head when the valve is opened (lifted) 10mm off the valve seat. Should be < 0.80mm.
Can do this engine-in by removing valve cover, rocker arm, shaft and valve springs.

TMc993

Does this kind of recommendation make anyone else queasy from a seller's point-of-view?

You've got your car for sale and a potential buyer says, "I'm going to take your car for a PPI and 'while we're in there' we're going to pull the valve covers, rockers and shafts and valve springs to make sure you're valve's lateral movement don't exceed Excellence's recommendation."

If you agree to this (I would not), then get your car back with leaking valve covers or worse, you're screwed. When I read this type of article, I take everything written with a large does of scepticism and caution.

I understand and agree with the concept of a PPI, but there's a point beyond which I don't want just any wrench tearing into the engine of a car I am attempting to sell.

No HTwo O

Stay active on Rennlist, learn everything you can, and buy from a trusted Member over the next several months.

Also, increase your budget, and get a 993 Turbo. Very few have this issue, but it can happen to a much lesser degree.

Marco8

Agreed, but valve guides issue is the same for 95. So as far as top end needing to be done, valve guide wear is the key factor not blocked SAI.

vjd3

This is true ... a 95 will wear out its exhaust guides just as fast as a 96-98. However, failing emissions due to the SAI system can necessitate corrective action on the later car sooner, as there are plenty of 993s running around with worn exhaust guides that are doing just fine, aside from a little oil consumption.

The rule of thumb on any 911 that I was taught years ago was you don't really have to mess with the top end until the car starts drinking too much oil and-or fouling plugs. Not being able to get an emissions sticker throws that out the window.

A good friend who was a very experienced 911 mechanic liked to say, "stop worrying and just drive it."

I did the top end on my 97 at 58k miles so I wouldn't have to worry about it anymore. And the guides were pretty much shot.

JimPA

You can take precautions as others have recommended but there are no certainties with mechanical gear. Buying one with rebuilt top end is the most likely way to defer the problem for a long time.

I had the top end redone @80K. There was no unusual oil consumption but the valve covers were warped and leaking.

You never know what you may find when you open the engine. In my case it was some scuffed cams (I replaced). I also decided to replace the clutch to avoid pulling the engine again in 20-25K miles. These things and other while-you're-in-there outlays can significantly increase the cost you cited.

95 NC 993

Great post! No chance in hell would I let someone take everything apart for a PPI. If the buyer didn't like our test drive together or doesn't trust me or my documented maintenance from a trusted area Porsche mechanic, he can move along to another car. Next!

Mark in Baltimore

+95 993

Lorenfb

"How to avoid buying a car with SAI issues?"

The easiest resolution is to use a Porsche tester (PST2/PIWIS) and simply
"run" the SAI readiness test thru the tester. The test will evaluate both
the O2 sensors and the air injection. It's that simple!

Stealth 993

Here is what you do, purchase the Durametric Scanner software, install on laptop. When you check out a car, plug in the laptop, then run the SAI pump with the car off, it will push quite a bit of air out the exhaust pipes & make quite a bit of noise.

Or you can on the PPI, have them remove the valve covers & check the exhaust valves for play.

In the long haul ALL 993's will have to have the top end done, the crap shoot is, will it be 50kmi, or 300kmi? Having a working SAI system doesn't really let you know when.

NC TRACKRAT

In addition to the PPI, when I purchased the '98 C2S from a dealer, I had them write in the bill of sale that, if the vehicle wouldn't pass my state's emissions test, they would pay whomever I chose to correct the matter.