Can't get at the valve spring under brake master cylinder

I'm putting new valve stem seals in my engine because my #7 spark plug keeps fouling with oil and my rings seem to be ok, so it must be the seals.

Anyway, trouble is, I cannot get my spring compressor on the #7 exhaust spring.

I cut the compressor down really short so as to get at the #7 intake and #5 exhaust springs under the brake MC, but I cannot get at the #7 exhaust spring under the brake MC mounting plate (this is the valve spring closest to the firewall on the driver's side.)

I tried one of those flat lever style spring compressors but I felt like I was going to break something, even after cutting it down.

Any suggestions?

Andy

Remove brake MC?

I have never messed with a brake MC before, is it basically detach the MC piston rod from the brake pedal, and then unbolt the MC and firewall mounting plate?

I'm assuming you have the stock 944 MC bolted to the cereal bowl. Depending on how much room you need, you may need to just remove the MC from the cereal bowl (two nuts) which could give you a few more inches to work with. Otherwise you may have to remove the cereal bowl from the firewall (4 nuts up under the dash).

Thanks, should be easy.

This whole job has been a lot more work than I figured it would be.

The OP stripped out the threads for one of the plugs so I had an insert installed and I could not get my air compressor adapter to screw into the insert threads. But a plug screwed in no problem. So I hollowed out a sparkplug and screwed & JBWelded an air fitting into the plug and used that to keep the valves up.

Then I couldn't get at the springs under the MC and had to chop the spring compressor down as much as I could to fit under the MC.

And made up a keeper removal tool from a 3/4" plug socket with some magnets stuck inside.

All this only took about 50x longer to do than to describe!

That's was a lot of work to hold the valves up. I just did this job and did it the low tech way by putting the piston at TDC for each pair of valves I was working on. To determine TDC (or close to it), I used a ziptie inserted into the plug hole and turned the crank. Simple and effective.

This will hold both valves closed.
The Indian Rope Trick is known by all good airplane mechanics for freeing stuck valves on aircraft engines.
Remove spark plug, turn engine over by hand until appropriate cylinder is at BDC on the firing stroke, fill cylinder with soft rope by feeding it in the plug hole until cylinder will no longer take rope. Slowly bring that cylinder up to towards TDC, piston will compress the rope and hold the valves shut. Stop moving the piston when a restriction is felt.
If you had a stuck valve it would have been pushed closed by this method. Back piston off and remove rope.

Thanks guys, got that last seal on by moving the MC.

Now I found that my air compressor adapter cross-threaded one of the spark plug holes. The hose on the adapter was about a foot long, so it was a pita to use as much of the hose was bent by the side of the engine bay and put sideways torque on the adapter as I screwed it in. After I did a couple sets of seals, I cut the adapter down to about 6" and added a air compressor fitting so I could get a straight shot into the plug hole.

Anyway...I've been reading about a "back tap" (http://www.amazon.com/Powerbuilt-640811-Back-Tap-Thread-Repair/dp/B0014FGVVW) has anyone used such a thing?

I just replaced my valve stem seals too as I was blowing smoke on decel and my compression/leakdowns were fine.

Found wear in the exhaust valve guides too, so I'll be replacing the heads this offseason with a set of ported 243's.

I have heard of some good uses for rope….but that is one is new! I like it. Putting that in my bag of tricks.

Very clever.  

simon123 wrote:This will hold both valves closed.
The Indian Rope Trick is known by all good airplane mechanics for freeing stuck valves on aircraft engines.
Remove spark plug, turn engine over by hand until appropriate cylinder is at BDC on the firing stroke, fill cylinder with soft rope by feeding it in the plug hole until cylinder will no longer take rope. Slowly bring that cylinder up to towards TDC, piston will compress the rope and hold the valves shut. Stop moving the piston when a restriction is felt.
If you had a stuck valve it would have been pushed closed by this method. Back piston off and remove rope.

The Back Tap worked as advertised, it easily fixed the X-threaded plug hole.