Virgin valve adjustment - engine not turning

tedder · tedder's Garage

I am at the first stage of doing my first valve adjustment and I am already confused (typical). Turning the fan nut is not turning the engine, the belt is slipping.

Its in neutral, the belt was new < 1000 miles ago when I put on the rebuilt alternator, it has 5 shims on the outside (I tightened it from 3-5 to see if that would help it move then engine).

I can (and probably will) move the last shim but doubt that will do it. I am trying to decide whether to pull the spark plugs now or not. Bentley manual says no, 101 projects and Hayes say yes, archives of this form are mixed.

Before I pull the plugs to ease compression is there anything else I should try? Would it be better to remove the plugs or just loosen them to break the seal?

Ted

john walker's workshop · 09:01 AM

push in on the right side of the belt with your right hand while turning the nut with a ratchet. removing or loosening plugs can cause carbon to get trapped between a valve and seat, which would make you think the gap is excessive, which you would adjust to what you think is correct, then when the carbon blew out upon starting, the gap would be too small.

911Rich · 09:09 AM

You can pull the plugs to effortlessly turn the engine... You can turn the engine by the crank pulley (bolt)...although more effort/turns. Never had a problem adjusting valves with plugs off...my experience

livi · 03-09-2008, 09:10 AM

+1 on Sir John Walker.

tedder · tedder's Garage

Thank you Sir John, pushing on the right side of the belt did the trick perfectly. In my mechanical ignorance (fwiw I only have 2 engineering degrees) I had tried pushing on the belt on the LEFT side to no avail before I posted here.

Seems I only need to tighten the belt near the top of a compression, the rest of the time the engine will turn without pushing on the (right) side of the belt. I had just had the bad luck to start out in that position I guess.

Thanks again for the help,

Ted

Gunter · Gunter's Garage

+1 JW re: carbon.
Leave the plugs in for Valve-adjust and squeeze the belt for turning.
For the folks who remove plugs:
There is a lot of dirt in the hole that can fall into the cylinder.
Before pulling the plugs, blow the hole out with compressed air wearing safety glasses.

911Rich · 03-09-2008, 11:24 AM

Blowing out spark plugs before removing them is just good common sense (on any motor for that matter). As far as valve adjustments you should always clean & blow out the area before even removing the covers...these are all basics.
oh and...don't forget to disconnect the battery neg terminal and discharge the A/C

j/k

safe · safe's Garage

IMO, if you can turn over the engine by the fan nut, your belt is to tight!

Don Ivey · 03-09-2008, 01:52 PM

Question: I'm on my first valve adjust too, and am curious if I can remove the valve covers first, before removing sparkplugs? I've always removed plugs first on other engines, but just wanted to check. Thanks,

Don Ivey
'87 Carrera

dshepp806 · dshepp806's Garage

just no need to remove the plugs....my 2 cents. If you absolutely feel the need to do so, be damned sure you blow out the spark plug area, wipe, then blow again. I'm pretty anal about keeping ANYTHING from going inside the engine,..as someone mentioned, it's pretty gunky down there,..lots of opportunity to get something where it shouldn't be.....

Best,

MOMO3.2 · 03-09-2008, 02:34 PM

Don:

The valve covers come off without removing the spark plugs.

Just in case either of you are feeling any anxiety about your first valve adjust, there is no reason to stress. It all works out as long as you take your time, double check your gaps, and make sure you tighten the tappet adjust nuts (ask me how I know).

The next time you adjust your valves, the time will be cut in half. It gets faster, easier, and less mysterious every time you do it.

Mike
"5x survivor of 911 valve adjusts"

Don Ivey · 03-10-2008, 04:34 AM

Thanks for the info. I feel better just knowing you guys are here.

Don Ivey
'87 Carrera

shbop · 03-10-2008, 06:32 AM

Use caution when pulling all the plugs before turning the motor. These motors expose the exhaust valve and seat to any debris (carbon) that would fall when removing the spark-plug. It only takes a little bit to land on the seat and the integrity of the seal is degraded. Just went through this performing a leak-down.

Don Ivey · 03-11-2008, 05:13 AM

A couple of things have come up, and maybe ya'll could help me. I wonder if the large group of wires that go into the area on the left side of the engine, where the four fuses, and relays reside, can be unplugged and moved out of the way for doing intake valves. Also, is the heat shield on the catalytic converter necessary? What does it protect, and will I harm anything by removing it? Thanks,

Don Ivey
'87 Carrera

safe · safe's Garage

Sure, you can unplug the 14-pin connector to get a little more space.

I don't have any catalytic converter so I can't really comment on that, but in general they get very hot and you want as little heat as possible heating the engine and its oil.

Gunter · Gunter's Garage

Don:
Can you post a picture?
There is never enough room to do valves.

A/C compressor is in the way, etc...........
If you unplug any electrical connections, use dielectric grease when you re-connect.
You can try removing the heat shield temporarily but you'll find the bolts pretty rusty.

joecrum · 03-11-2008, 08:59 AM

I had the same issue with the belt slipping after I had moved the shims. The trick is to turn the ENGINE over to force the belt radially out of the pulley groove. Even though you moved the shims out, the belt will not move out of it's 'loose' position by turning the fan. If you bump the starter a couple times it will force the belt to ride towards the outside of the pulley and thus tightening.

I hope this makes sense. I think it is from Wayne's 101.