Shark_Week

what am i missing? where is this located in head? any photos or illustrations

Vilhuer

Parts 39-44.

jon928se

Hard part - remove cam covers.

Easy part and to add some clarity to Errka's WSM pic (which looks likie the NR valve is down the centre of Cyl4 spark plug.

Standing at the front of the 928 looking to the rear cylinders 1-2-3-4 are on the left and there is a NR valve to the rear and left of cylinderNo.4. Part No. 44 which is an internal hex(use an allen key I think 2mm but possibly 2.5mm) grub screw screws through the side of the head just above cyl4 exhaust port into the side of part No.42 to lock it in place (in the WSM it looks llike it screws into the top of part 44 - it doesn't it goes in from the outside of the cylider head to locate a groove in the side of part 42).

The other NR valve is in the 5-8 cyl head. This head is identical to the cyl 1-4 head but is just rotated through 180 degrees so the valve is forwards of cyl5 and to the right (near the ABS pump)

Undo the grub screw and pulll the valve cover (part 42) out with a magnet ?? I seem to recall you can screw an M6 bolt into the top of them to pull them out. renew the O ring (part 43) ensure the ball is clean and the ball seat (part 39) is securely staked into the head and reassemble.

Shark_Week

ok got it, i looked at that illustration several times too. duh

BC

What were the symptoms that led you to the control valves?

Shark_Week

cleaning heads and just wanted to check them for condition. thanks for the heads up vilhuer/jon928se
had my dent puller ready to go and just didn't get that set screw on the side. thank god i asked before hammering on the head. whew

Mrmerlin

when you inspect the valve make sure that the part number 39 is in fact secured to the head, if it slides it should be cleaned and green loctited into place then stake the edges so it wont move.
If it does move it can slide up with the oil pressure and block off the feed port to the cams/lifter and the cams will soon seize and take out the belt

Shark_Week

will double check that they are secure. thanks

aaddpp

I pulled my check valves today. Drivers sides was fairly dry (a coating of oil), the passenger side hole (where the check valve sits) was full of oil that did not drain when the plug was pulled. It did however drain once the ball was pulled (with a magnet). First question, which one of these is normal? Second, what is the best way to make sure part number 39 is secure with the tight quarters and a need to preserve the smooth surface. For starters, I used a magnet, but nothing budged.

Thanks,
Dave

P.S. The passenger side head had partially lost the lower rear galley plug - which might be what was causing the lifter sound I could hear. Since I found the plug out (thanks Sean!) all rear plastic plugs have been replaced with pins (thanks Roger!), and I have also changed the rear cam seals.

Shark_Week

the pros will set you straight, but what i did was put a strong magnet on it and it did not budge. i then took a piece of phenolic to the lathe and made a punch to fit the hole. i tapped #39/seat to make sure it was completely seated into head.

Mrmerlin

adding a drop or two of green loctite to the seats wouldnt hurt ,rinse them with some brake cleaner then blow dry with compressed air,
then drop the green.
Put some assembly lube on the spring and the ball,
use Dow Corning 111 for the O ring lube,
blue loctite for the set screw

aaddpp

That sounds like a good idea.

Thanks for the tip. Just picked up some DC111 so its time to put it to some good use. Any idea how #39 seats in the hole? Is it like a bearing race in the hub where its a tight fit, and you work it down with guided force, and its held in place by fiction and pressure? If so, the green loctite goes on the the top of #39 (i.e. what you see when you look down the hole) to hopefully seep down the sides of #39 and hold it in place?

Many Thanks,
Dave

jon928se

Yes like a bearing race - tight ish hopefully but sometimes they aren't and come back out causing no oil flow to the heads and seized cams. If 39 has come out p,ut the green locktite in the hole that 39 goes into before you press 39 back in.

I can't recall if Green L is the sort that will migrate capilary style into thin voids - if it is it won't do any harm to put some around the top of 39 if your 39 is still firmly seated.

aaddpp

Jon, thanks for the confirmation. Will check out the bits, and hopefully its a cake walk b/c this is the last item before the cam covers go back on. If only my work / family schedule would cooperate

Thanks,
Dave

atb

Isn't there a mod to use the 944 part for faster bleed down?