Roy928tt

As above, wouldn't be to stressed about all of this, clearly an issue on one bank, most likely cam timing. Otherwise numbers are fine, and a whole lot of life left in the motor.

Where abouts are you?

DeWolf

Cam timing is off. 5-8 is almost spot on with timing mark. Coming up just before the mark. Maybe 1mm. Bank 1-4 is almost 3/4 off the mark. I rotated the engine several times to verify and all came up the same.
Symptoms are a misfiring/poor running. Like it's running on seven cylinders. I have replaced all the plugs, leads, rotors and caps and put on a new maf. Still misfiring. Doesn't blow any smoke and no strange smells from the exhaust.
It's a 5.0 manual RHD. I believe one of thirty made so I want to rescue it if I can but short on budget atm.
Gotta say I'm new to doing this stuff myself and the info and minds on this board are a Godsend. Cheers guys.

Roy928tt

Hmmm I wonder about a sticky or faulty injector, I recently was messing around chasing a miss in an Alfa V6 and that was what it came down to. Plenty of comp. powerfull spark, but no fuel going in meant it wouldn't fire on that cylinder...... the clue was the dry spark plug..

FredR

Not sure what you mean by 3/4 but presume you mean relative to a full tooth and if so that is not good. This leaves two possibilities [I suspect] either the adjustment has completely slipped or the belt is one tooth out.

The cam wheels have 48 teeth and each tooth represents 15 degrees of crank rotation. Thus one tooth out of adjustment defers 15 crank degrees of timing.

The adjusters permit in the region of 10 crank degrees either way before the limit is reached. To better understand what is going on suggest you remove the top inspection cover from the 1/4 bank and rotate the engine forwards until you are on TDC number 1 cylinder. At this point you can take a look at exactly where the timing is relative to the marks. Remove the rotor arm [the pick up should be pointing in the 3.00 direction if at number 1] and take a look at where the rotor arm screw threads are in relation to the slots. If the threads are at one extreme of the slot you should be able to improve matters crudely by moving the cam relative to the sprocket so that the threaded hole is roughly in the middle of the adjustment range. If the hole is already centrally positioned then chances are the belt is one tooth out.

Best thing you can do at this moment in time is get hold of a 32Vr cam timing tool [see liftbars.com] or be prepared to do the cam timing as per WSM procedure that will require removal of the cam covers and needs appropriate dial gauge kit.

Cam timing is a doddle with the 32VR kit [and Bumpstick kit] and not too expensive either. Use of this kit assumes that the cams are accurately finished and "zero" when cam timing is correct. There has been debate about this all I can say is that my cams were timed using the WSM method and when I got the 32VR kit it showed spot on results. Adjustments thereafter are very easy indeed.

Perhaps you can take some pics to show the cam wheel head on view when the motor is at No 1 TDC. You should also verify that the cam belt is tensioned correctly before doing any adjustments- many of us use the Kempf tool to do this rather than the [very expensive] factory tension tool [ideal].

If the belt is off by a compete tooth then it is pretty much the same procedure as replacing the timing belt completely unless someone knows better.

Finally if you have something like a misfire you may do well to ensure that all the injectors are known to be working correctly. To do this thoroughly they need to be removed and sent to a shop with a test bench that usually has the ultrasonic cleaning capability- my experience with Bosch injectors is that they need a clean every ten years or 100k km[?].

Trust the above helpful

Rgds

Fred

DeWolf

Thanks Fred. I see that on 1-4 bank the screw threads are on the outer limits and 5-8 bank are pretty much centered.

GlenL

On the 1-4 cam there look to be bolt head marks and the threads aren't aligned with them. I'd make that adjustment and re-try the cmpresion test although there's no replacement for timing the cams correctly.

Before loosening the cam bolt, put the three small bolts back in.

I don't see the sprocket marks for that side, which would be nice.

Crumpler

Dewolf, interesting thread, I'm following. So this must have been a progression from the injector check thread from the other day. Glad you pursued it, good diagnostic approach and regards.

Bill Ball

Your second picture (annotated below), cylinders 5-8, shows the belt position clearly with the trough of the gear tooth at the leading edge of the front slot lined up with the notch on the backing plate. PERFECT if the crank is at TDC. So, the belt is installed correctly for 5-8. Your first picture, cylinders 1-4, does not show the top of the gear, so we cannot see how the belt is installed on that gear. Show us that. The fact that the adjustment is skewed to one side leads me to suspect that someone tried to compensate for the belt being on the wrong tooth. Your goal is to have the belt within i/2 tooth of the trough of that tooth at the leading edge of the front slot (or better, the small notch on the back edge of the gear) lining up with the notch on the backing plate. Sometimes it is perfectly aligned, as you show for cylinders 5-8, but the goal is 1/2 tooth or less. The rest is taken care of with the cam adjustment slots.

Bill Ball

You may have some injector or ignition problem if you are running on 7 cylinders, but that would not affect the compression test results. Show us how the belt is installed on the 1-4 cam gear first. If that is wrong, it needs to be repositioned. If correct or corrected, then Ken's tool is needed to check and adjust the cam timing. Repeat compression test. All I can say is that the 928 I worked on had compression results like yours and ran somewhat poorly, feeling like it was possibly only running on 7 cylinders. It had consistent compression numbers and ran much better after we got the belt on correctly and adjusted the cams with Ken's tool.

DeWolf

Ok, so top photo is 5-8. Not exactly on the mark either. Photo 2 is 1-4, not on the mark. Third is the pulley. It doesn't look like it but I can assure you it is dead smack on the 0/T mark.
Given this has been done to the engine I wonder if the actual cams are timed relevant to one another. The valve cover on that side has been off. In fact it has different bolts holding it on.

ramcram

All 86 cars 'down under' are ROW, or what you call 86.5 in the US.

FredR

This is starting to look as though you are a complete tooth out. In your original photo the 1/4 wheel is fully advanced on adjustment [i.e. fully adjusted clockwise as viewed from the front] and clearly it still needs more clockwise adjustment than is possible.

Whether this apparent error explains your symptoms or not remains to be seen- for sure it will not do the motor any good. It will be interesting to see if our friends concur.

Any idea who set it like this? - we need to send the boys round!

For sure you are going to have to time the cams just a question of which method you use.

I also note the comment on this model availability in Australia - for some reason I had it in my decrepit noddle that this model was only marketed in North America. No idea why I have that in there with the rest of the rubbish.


Rgds

Fred

DeWolf

No idea who did it actually. It has a big hole in it's service history from 2001. The last belt change to records was 1996. I think it's been done since then though. The 1996 invoice was from Bruce Buchanan so I would assume it was done properly back then.
The miss I mention is consistent right through the rev range. Gets no better or worse. It has plenty of go given whats going on but you still feel and hear the offbeat running.

Bill Ball

If in your second set of pictures you are now dead on TDC, then it looks like the belt itself is 1/2 tooth or less off, and that is the best you can do. If one side is more than half a tooth off, it should be moved over, but this does not appear to be the case. No adjustment can be made regarding belt position other than moving over a tooth if needed. So, what you need to do is check and adjust the cam timing with either Ken's tool or the WSM procedure. Now, if for some reason the cams were removed in the past, it is possible they were not installed with the correct spacing on the cam chain. I've seen that. But your first task is to time the cams. Easiest is with Ken's tool. If you do the factory method instead, you will get a chance to confirm cam spacing as well.

GlenL

Best method: time the cams.

And I'll posit a theory. (It would be irresponsible not to speculate)

At some time in the past, the belt was put on one tooth off and the cams were re-time in that position. During a subsequent belt replacement, the sprocket was re-aligned correctly but without re-timing the cams.

So me, being a bit slack at times, would do one of two things: re-jump the sprocket one tooth to the right or move the cam adjustment to the old bolt marks. Then I'd get the tools to align the cams and promise myself to do it soon and get to it in a year or two. Oh, and check the compression again and when it came up good smile and go for a drive.

And why isn't Kibort on this?