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newbie wants to know when you need a vavle adjustment
is there a way to tell when you need a valve adjustment. miles??? timeframe??? car only has 30,000 miles, but last service before i got it running (new plugs, oil, fuel filter, etc.) was '99.
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Dave Black 1985 911 Carrera M491 |
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Now in 993 land ...
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Miles - that's the only thing you can go with. Noise not so much, as the gap actually gets smaller with miles. Do you have the mileage of the last service?
If it were my car, I'd just go check / adjust them. Takes only an evening and a couple of beers. George |
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Join Date: May 2005
Location: Phoenix, AZ
Posts: 203
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Valve gap get smaller with miles???
"Noise not so much, as the gap actually gets smaller with miles."
And how does that exactly happen?? |
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Join Date: Nov 2005
Location: CA
Posts: 7,286
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I think he meant "bigger".
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Fat butt 911, 1987 |
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Quote:
It does not make sense, the wear of rocker metal on cam metal and heat cycles should result in a larger gap. My experience is limited to about 10 Valve adjustments on a single engine. I hope someone with more experience will share. Shane
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78’ SC 911 Targa - 3.2SS, PMO 46, M&K 2/2 1 5/8” HEADERS, 123 DIST, PORTERFIELD R4-S PADS, KR75 CAMS, REBEL RACING BUSHINGS, KONI CLASSICS |
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Now in 993 land ...
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I actually meant that the gap tightens:
The valve seats and valves wear. This means the valve sinks into the head, which in return moves the valve stem closer to the rocker arm. The wear on the rocker arm, valve stem and cam is significantly less than the wear of the valve and seat. Also, this wear is mostly happening on the exhaust valves, due to the much higher temperatures. If you do not adjust your valves for a long time, the exhaust valves will not close any more with full force, because they will wear to the point where the gap is nil. Then the exhaust valve gets hot because it doesn't cool right any more in the valve seat and you will burn them up. So, get a couple of beers cold, get on your back and at least check the exhaust valves. In addition to the valve check this will also give you a check on the head studs - those can break any time - regardless of mileage. ![]() Hope this helps, George |
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Join Date: Jun 2009
Location: Manhattan Beach, California. Factory Delivery-Original owner-Retired engineer
Posts: 5,238
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According to "prevailing" wisdom, for "normal" usage, every 15K miles.
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1986 911 Targa. Per Road and Track magazine: Only in L.A.: In the window of a bar in Hermosa Beach, California. "Happy Hour prices during all car chases." |
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Fleabit peanut monkey
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Don't bank on finishing it in one night on your first time.
Take your time as it can be frustrating - you will change the gap when you tighten the adjusting nuts so multiple passes are required for the uninitiated. Look at youtube videos of how this tool is used. It's pretty cool. Tried my new "VAS 911" valve adjust screwdriver with 36 degree pointer.... |
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Formerly known as Syzygy
Join Date: Mar 2008
Location: Calgary, AB
Posts: 4,420
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My first took me about seven hours with some other stuff like changing the fan belt, and general putzing about. The one this spring took about nine hours, but I did pretty much everything: valve adjustment, oil change, fuel filter, air filter, spark plugs and cap and rotor. I also took some extra time playing and experimenting with the VAS 911 tool, and the back side method.
With that in mind, I imagine every spring will call for the same thing with an oil change or two in the middle. I figure that after the 12000 miles I put on this past year, it should be rewarded with a valve adjustment and other loving touches. If it's only half a weekend a year and a couple hundred bucks, what's it gonna hurt?
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Kevin 1987 ROW coupe, Marine blue, with a couple extra goodies. The cars we love the best are the ones with human traits, warts and all. |
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Now in 993 land ...
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I sure don't miss those valve adjustments.
![]() You get more lift, generally, after re-adjustment, so there you go 5 hp seat of the pants at any rate! George |
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muck-raker
Join Date: Jan 2009
Location: Coastal PNW
Posts: 3,059
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every 15K miles, religiously.
For a first timer, I would recommend setting aside a weekend. Not that it takes that long, but I would do the following on the first day: drain oil, remove a/c compressor, heater blower motor, and any other things that will get in the way. Remove intake and exhaust valve covers. Clean everything up for reinstall. On the second day, I would adjust the valves, taking care to make sure the gaps are correct...there are lots of threads on this subject. After adjusting the valves, put everything back together, start the motor and enjoy the fruits of your labor...and be smug in the knowledge you saved yourself $200-$300 in the process. On the second
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STONE '88 Cabriolet, using EP Slick 20w50 partial synthetic Snake Oil...just as Rommel intended. ![]() Deny Everything; Admit Nothing; and Always Make Counter-accusations ![]() |
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Join Date: Oct 2004
Posts: 15,612
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Most people time it to coincide with an oil change. Having said that, it works out to about every other oil change, or around 15,000 miles +/-.
If you have a lot of valve noise, then do it early. If you have a loss of power or a smog test coming up, do it early. |
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Join Date: Oct 2006
Location: MYR S.C.
Posts: 17,321
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i dont need one yet, but i will let you know.
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86 930 94kmiles [_ ![]() 88 BMW 325is 200K+ SOLD 03 BMW 330CI 220K:: [_ ![]() 01 suburban 330K:: [_ ![]() RACE CAR:: sold |
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