Timing Question

[bgold87]

I'm in the process of restoring my first DSM. Car had low compression (around 110) so I figured I might as well rebuild the engine. So I got it pulled and started tearing it down and noticed what looks to me like my timing is way off. Spun the engine 6 times and got the cam gears lined up. Well, dowels are are 12 oclock, but there's no lines to line up except what was painted on. Check the attached pics, the oil pump and cam gears match, but the plate behind crank sprocket is off and so is balance shaft.

Is it possible for the plate behind sprocket to be wrong? I don't see any marks on the actual sprocket.

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[NOSLO2PT0]

Timing is off on crank plate

 

[pauleyman]

So you're just getting started and haven't taken anything apart? If so that explains a lot. Belt likely slipped.

 

[AWD-Tony]

What Pauley said. Get it timed correctly and do a leakdown test for each cylinder. Then you can decide the next step, a tbelt service or a rebuild.

 

[DSMPT]

Wrong valve timing. You have had valves widely open at the compression stroke, that's probably the reason why you have low compression. In a worst case scenario, you may have slightly bent the valves already.

 

[Red Rider]

... Belt likely slipped.

What conditions would lead to the timing belt slipping? I had that happen twice on a new belt and tensioner. Then the belt snapped.

 

[DSMPT]

What conditions would lead to the timing belt slipping? I had that happen twice on a new belt and tensioner. Then the belt snapped.

When you don't have enough tension on the timing belt, it would slip/skip.

 

[Vegas Smith]

Is it possible for the plate behind sprocket to be wrong?

Not really. You can have it backwards though but I think it rubs the timing belt or something when you do that. There is only one tooth/key that the sprocket/plate fits onto.

 

[bgold87]

So you're just getting started and haven't taken anything apart? If so that explains a lot. Belt likely slipped.

Yea, I had to replace fuel lines and several other things just to get it to the point of being able to run. Once I started it it ran terrible and sounded like it had rod knock and that's when I decided it was time to go through the motor and just see what condition it's in. I have fresh head ready and will probably go ahead with a rebuild since the motor is already out.

Thanks for the input!

 

[bgold87]

Got the head off and found this.

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[97egl]

Looks like the exhaust valves kissed the pistons. To determine which ones are bent you can do a water test. With the exhaust cam out pour water down each of the exhaust ports and mark the ones that leak. If you just get a slow drip those ones are probably fine. The bent ones water will pour out of.

Buy new valves. Lap them in and you should be back in business.

 

[bgold87]

Looks like the exhaust valves kissed the pistons. To determine which ones are bent you can do a water test. With the exhaust cam out pour water down each of the exhaust ports and mark the ones that leak. If you just get a slow drip those ones are probably fine. The bent ones water will pour out of.

Buy new valves. Lap them in and you should be back in business.

Any concern to the marks on the piston?

 

[97egl]

I wouldn't worry about them. You may want to take a dremel and clean up a couple of the worse gouges. The thin sharp edges can cause hot spots which promote detonation but the pistons should physically be fine. I've seen valves hammered into the stock pistons on these engines but I myself have never seen one crack. The minimal "damage" to yours will be fine. I bet 1/2 the guys on here running stock pistons have valve marks in theirs from broken belts or previous owners attempting to replace the timing belt on their own.

 

[bgold87]

Decide to pull pan off and found this bearing.

Guess rebuild it is

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[DSMPT]

Any concern to the marks on the piston?

The marks on piston top wouldn't be a big problem if you would remove the sharpe edge to smoothen. Just don't forget to inspect ring lands when you remove the pistons.
A similar case in the link below.
https://www.dsmtuners.com/threads/can-i-use-these-pistons.532075/