Changing valve springs
 

I think I know the answer to this, just looking/hoping for another answer.

Short version

Can you change valve springs on a 964 3.6 w/o taking out the cams?

Long version

I'm interested in a car with upgraded cams; rs cams in a 3.6. Everything I've read says you should upgrade the valve springs when you run these cams. The seller says the only modification is the cams, no mention of anything else. Considering this car has been and will be tracked, if the experts say upgrade the valve springs, I should upgrade the valve springs. Before I get worked up about this car and buy it, I want to figure out what it needs so I can budget accordingly. It already needs an upgraded exhaust, and engine drop/teardown isnt what I have in mind.

Thanks for any suggestions

Valve springs are in the heads, which will require removal of the cam towers to access.

Don't know much about the RS cams and the 3.6 configuration, but if the cams provide much more lift than stock, then the valves will be that much closer to the P's. Hopefully the PO/shop did their piston/valve clearance checks during the upgrade and fell within the 'safe' range (May want to do some homework here if you can).

If the p/v clearances are fine and the redline wasn’t changed, I'd leave them alone (personal opinion), as valve float won't be an issue with stock RPM's and not even super-macho valve springs will save you from the dreaded $$ shift.

There are ways to change the valve springs (retainers and stem seals if you are going in there) w/o removing the heads. Again, I haven’t been into a 3.6, but even trying this on a familiar 3.2 or older would be a PITA. But, if you can get the rockers removed, springs compressed (?) and the retainers off, you are golden. There is a tool specifically made for this task that screws into the spark plug hole and feeds compressed air into the cylinder to hold the valves closed.

Thanks guys. I am still new to engine work on 911s, still spoiled from my days working on lessor engines. I remember putting valve guides in my dads truck(mitsu), in the driveway. Just took off the rocker, filled the cylinder w/ air, grapped the old seal w/ vicegrips and then knocked a new one with with a deep socket. That was maybe 50k miles ago. Not sure that's the best idea with a 3.6 though. :)

From what I've read, the supersport/rs cams like high rpm, a lot. The commonly recommended upgrades are better rod bolts, stiffer valve springs and bigger exhaust. The car in question has ssi's, which would seem to be greatly limiting potential HP. We'll se what happens with this one.

hmmm.....

"Tool can be used with the cylinder head on or off the engine"

http://www.pelicanparts.com/catalog/...03/KD-3271.jpg

http://www.pelicanparts.com/catalog/...CAT583_pg6.htm

The price is sure right! I may have to buy it just to have it. Kind of like that insurance. :D

Something tell me that thing isn't going to fit on the intake valve spring with the engine in the car. It'd probably work on the exhaust valves with the exhaust and heat exchangers are removed. Pure speculation, mind you, as I've never even thought about changing the valve springs, much less attempted it..

Chris, I agree. The tool is helpfull for sure, but not Porsche specific.

I think these are the two tools you need. one is for the intake, one is for the exhaust. I don't know why you would need two since the cam tower and heads are symmetrical and they use the same springs. I am not sure if they will work on a 3.6.


http://cgi.ebay.com/ebaymotors/ws/eB...spagename=WDVW

http://cgi.ebay.com/ebaymotors/ws/eB...spagename=WDVW

I recall one that looks like a pry bar that used the cover bolts with a nut as the fulcrum (I can't spell). Same idea as the one shown on e-bay, but without the screw turn. Don't loose the spring retainers. Nothing worse than not knowing where something like that ended up!
Nothing like a challange!