Question:
Should a needed 1/2" clockwise rotation (facing the cam) over the previous timing position be a concern after a valve job?

I recently had my head milled and valve job done. Before I removed the head I first put finger nail polish on the single notch (TDC) of the flywheel and then again on the center notch on the 3 timing notches in series (no paint remained and this was too dirty to see). (See 4-16 SM.) I placed the back of a hacksaw blade across the 2 timing wheels and all the marks lined up (I can't see the guides because I can't get a straight-on view.) All looked like it should, TDC mark on the pointer and all 4 timing wheel marks in-line. I then loosened the tension-er bolt, pulled some slack in the belt by pressing in on the belt toward the driver side and then slightly tightened the tension-er back. This allowed me to slip the belt off the cam wheels with no problem.

Now after all the work is done, and I followed the guide which says to loosen the tension-er and rotate the engine counterclockwise, hold the crankshaft steady there and tighten the tension-er. (Note I did not replace the belt because the previous person who worked on the car left the valves out of adjustment, burning them up but the belt is coincidentally new.)

Now during the assembly I was not comfortable with how tight the belt was, it seemed like it has more slop in it than when I removed it before. I did the adjustment a second time and got the same results, the back of a hacksaw blade shows the 2 wheel marks all 4 in a straight line and the pointer on the crankshaft pulley is pointing to the single notch (NOT the 3 notch timing marks). I had to work quite a while to get all 3 lined up again, and the 2 pulleys now appear to be in line with the SINGLE notch on the crankshaft pulley, which is lined up per spec.

Well my issues now are:
- timing belt had a bit of a slight hump between the 2 camshaft pulleys after install (not rubber band tight like when I removed it) and it just doesn't seem as tight as it was when I removed the head
- distributor had to be rotated 1/2" from mark where previous timing mark was to get on the center of 3 timing mark
- engine has a surge now that it did not have before (idle - 2500RPM)

While it was apart I cleaned the IACV with brake cleaner as suggested here as well as cleaning out a very filthy intake manifold also using the cleaner. I did not remove any injectors but removed the intake as a whole assembly after removing the head, and replaced the head in the reverse order. While the intake was off I got tons of residue off the inside of the manifold using brake cleaner.

The check engine light is still on, I am assuming from the Cylinder 3 & 4 misfire codes that first indicated a valve was burning up never got cleared, but I do need to see what is up, and that's my next step after I resolve the timing belt issue. I pulled the valve cover off this morning and am trying to figure out how to resolve these issues.

That's all the info I have. Does anyone have an idea on the belt tightness, the distributor needing a 1/2" clockwise on the rebuilt head, or the slight engine surge at all speeds from idle - 2500RPM? The distributor is now very near being at the extreme travel point (clockwise) of its available adjustment span.

Thanks to anyone who can help in advance!

 

the belt is too loose. did you tighten the belt with the bottom end at tdc? or did you loosen the tensioner, turn it 3 teeth, and then retightened the tensioner? with a hump in the belt that serious, it would not line back up when you go to recheck everything at TDC.

although it is possible, though unlikely that the belt has stretched.

 

Well I removed the valve cover and all the engine belts in order to re-adjust the timing belt tension-er. I discovered that the tension-er must be tightened while the engine is slowly being rotated. You cannot stop turning the crankshaft (at least on this car) or backlash occurs whereby the timing belt becomes too loose. So as one person is slowly rotating the crankshaft counter clockwise another person (or super long arm) should be tightening the tension-er bolt. Once I saw that the timing belt was back tight like before I started the job, I went to work to double check the valve adjustment. I found shockingly that 6 of them had already gone a 1/4 turn too tight just since taking a 5 mile test drive (yesterday the engine was run - not today - it is cold for work today). I made adjustments and rotated the crankshaft two more times, checking that they stayed in adjustment. They did.

While I had the intake resonator box off, I noticed that the control wire for the IAC was not attached due to either forgetting to re-attach it or not properly snapping the connector onto it.

I then replaced the valve cover and checked timing. After I tightened the timing belt, the distributor went back to "near dead center" on the adjustment path (counter clockwise from where it has shown good with the belt loose when I checked it yesterday).

All is well and the engine runs very smoothly and has great performance now. There is no more surging and everything sounds good.

Thanks to those who commented on this question and also thanks to those who have published guides here that helped me get through the valve job - you're the greatest!

 

you don't tighten the tensioner while spinning the motor over. you get it to tdc, turn the motor over 3 crank teeth, then tighten. it is clearly outlined in the manual.

glad to see you got it all worked out though.