Backside valve adjust problem

KNS · 10-21-2009, 07:27 AM

Having done my valve adjust the traditional way in the past, I thought I'd try the backside method. It is much easier! *But* When I go and rotate through to double check, many of them will let the 003 blade "GO" in when it wouldn't before. I re-adjust to let just the 0025 in and then when I rotate through to double check, the 003 blade slides back in also. It seems I'm turning the adjusting screw tighter and tighter each time to let only the 0025 slide in on my double check.

This is frustrating to say the least. I know I'm not adjusting them too loose because I always try to slide a 004 blade in and that definitely won't go. I've probably gone through at least five times. I'm not new to valve adjustments (I probably did a them hundred times on my old VW). I saw an older post with someone who had the exact same problem but didn't see a resolution.

Anyone...?

john walker's workshop · 10-21-2009, 07:38 AM

the resolution is to do it the normal way with a .004.

Formerly Steve Wilkinson · 10-21-2009, 08:09 AM

I'd suspected as much. Thank you, John.

T77911S · 10-21-2009, 08:13 AM

i ran into the same thing. went back to the 004. i set the 004 so it is very tight, i can still net it in and out, but very snug. i rotate the engine several times when done them check them all again.

KNS · 10-21-2009, 08:25 AM

Well, when I re-check with the traditional feeler gauge at the valve/foot (the exhaust side anyway) the measurement is correct. I think the backside method is actually more precise and you can really get to splitting hairs (IMHO). In any case, my valves are in closer tolerance now than they have been for the last several thousand miles so I'm done.

MrScott · 10-21-2009, 09:24 AM

I had the same issue with consistency using the backside method; on re-check some were too loose, some were too tight. My guess was the standard method forces the elephant's foot to seat properly where the backside method does not.

john walker's workshop · 10-21-2009, 09:48 AM

what do you want? ballpark or right on? with a go/no go, i see ballpark, close but no cigar. maybe it's correct (.004) on one or two, but probably not all. that's the way i see it, but that's just my 2 cents.

T77911S · 10-21-2009, 10:06 AM

so jw, how do you do it, the valves that is. do you think the swivel feet on the adjusting screw could be causing the the inconsistancies?
i have had some that the feeler would be snug, but when i removed it and tried to put it back in, it would only go half way.

john walker's workshop · 10-21-2009, 10:29 AM

you develop a feel for it over time. if you can slip it in or out, it's still a hair too loose. if the gauge wrinkles or won't go in, or you can't get it out after adjustment, it's obviously too tight. if you can get it in 1/2 way and with 2 or 3 light twists get it in the rest of the way and out again with 2 or 3 light twists, it's correct. the gauge holder should be held lightly in your fingers. the blade should only be as long as the swivel foot is wide. too long and it bows or you have trouble getting it down next to the valve stem.

burgermeister · burgermeister's Garage

I've found for the backside method that it is necessary to move the rocker arm by hand so it is tight against the valve. There is enough stiction in the rocker that if it isn't tight to the valve, the feeler gage can't always push it out of the way.

I seem to have trouble getting the .004 in to check the clearance myself, so I use the backside method to see which valves need adjusting ... I then use the .004 to adjust, and the backside method to verify. It's slow, but it allows this retarded left handed monkey diseased moron to do his own valves ...

bazar01 · bazar01's Garage

Quote:

Originally Posted by KNS

This is frustrating to say the least. I know I'm not adjusting them too loose because I always try to slide a 004 blade in and that definitely won't go. I've probably gone through at least five times. I'm not new to valve adjustments (I probably did a them hundred times on my old VW). I saw an older post with someone who had the exact same problem but didn't see a resolution.

Anyone...?

I also experienced the same thing when I did my 964 using the backside method.
003 will go in but 004 will not. I just left it at that.
0.003" x 1.4 = 0.0042" anyway and still within spec.
Even if it's 0.0035" it is still within limits of +/- 0.002"
And at least i know I am not on the lower limit which is bad.

KNS · 03:08 PM

bazar,

That's pretty much what I figured and left a few that way, I went through several times so I know none are too loose or too tight.

Got everything buttoned up and went for a drive. The good news is that a loud "Tick Tick Tick" when the engine was warm is gone now.

I may have a different problem that I'm not sure is valve adjustment related... While cruising near a low wall and accelerating from about 3000 to 4200 RPM and then rapidly letting off the throttle, I would hear *small* backfires, almost like a metallic popping, not loud but there. To be honest, I never made a habit of driving this way so I'm not 100% certain it wasn't there before, I was simply trying to listen for sounds under different conditions. The car drives normally otherwise.

Can this be something from my adjustment, if so please describe.

On another note, I pulled the plugs (not during the valve adjustment) and they all looked good. All the lower head studs are secure.

Thanks

burgermeister · burgermeister's Garage

A .001" difference in valve clearance will not change the way the engine runs, so the backfires are not related to the valve adjustment.

KNS · 07:37 AM

burgermeister,

Thanks for the reply, that's reassuring, The little popping, backfires off throttle are puzzling me though.

T77911S · 10-22-2009, 09:13 AM

Quote:

Originally Posted by john walker's workshop

you develop a feel for it over time. if you can slip it in or out, it's still a hair too loose. if the gauge wrinkles or won't go in, or you can't get it out after adjustment, it's obviously too tight. if you can get it in 1/2 way and with 2 or 3 light twists get it in the rest of the way and out again with 2 or 3 light twists, it's correct. the gauge holder should be held lightly in your fingers. the blade should only be as long as the swivel foot is wide. too long and it bows or you have trouble getting it down next to the valve stem.

that is what i shoot for. i have to work it to get it in and out, a little begging never hurts