I recently purchased a 97' 960 Wagon with the 2.9L DOHC 24 Valve 6 Cylinder. It was a no start, with a broken timing belt. I purchased a rebuilt cylinder head as almost every valve in the old head was bent. I installed the new head with the camshafts from the original cylinder head. I easily found the timing marks on the cam sprokets and aligned them with the plastic timing cover. I found the notch on the engine block, but the mark on the crankshaft does not put cyl. #1 at TDC. I went ahead and installed the belt. I tried to turn the engine over by hand slowly, and it would go so far and stop. Clearly there was interference with a valve. I took the belt off, realigned the cams, and using a dial indicator, brought cylinder #1 up to TDC. I reinstalled the belt, turned it over by hand and there was no interference. I tried to start the car, but it would only turn over and not run. It sounded like it was going to start but didn't. A quick look at the plugs and they looked fuel fouled. I cleaned them and tried again. Same result. I performed a compression test and have close to 180psi in all 6 cylinders. I have spark, checked with a spark tester. (i only checked one cyl.) I have injection pulse. (checked with a noid light). And I have RPM signal to the PCM, checked with a scan tool. I took a lab scope and scoped the cam sensor. I have a square wave on one wire, 12v on another and 12 volts on another. This is my first Volvo project so I am stumped. Any help would be greatly appreciated.

 

I'm not that technical but are you getting proper fuel pressure? You should like you are way ahead of me.

You can also try unpluging the MAF and see what happens.

 

If you have fuel and valve timing right (which it seems you might) you need to look at spark.
Even if your valve timing was way off, ignition would still cause backfires etc.

Regards, Andrew.

 

When the crankshaft is on it's mark, #1 is NOT TDC.

The way is suppose to work is, when the cranks is on it's mark then all pistons will be down enough to allow the valves cams to rotate without interference.

What might be happening is you are not really lined up correctly when you think you are. The trickiest part, are those cam wheel marks, there are a couple different markings on them and sometimes people will read the wrong ones.

Were the cam gears ever taken off the cams? Are the cams installed correctly, ie., exhaust, intake?

After your install and hand rotating, did you line up everything again as a last check?

Glad you did the hand rotation test first, when you did it, did you hear compression thru the spark plug holes?

DanR '94 964 349,000 miles (115,000 on the new engine)

 

Perhaps I am confused as to where the crank is to be lined up. I have yet to find a definitive mark in the crank pulley. The first time I put the belt on #1 was NOT at TDC and when I tried to turn it over by hand it would not turn over, the valves would contact the pistons. That's when I used a dial indicator to bring #1 to TDC. At TDC #1, when I turned it over by hand I made 2 full crankshaft revolutions by hand and lined the marks up again before trying to start the engine. It sounds good during cranking, normal and even sounds like it wants to start. It's like the ignition timing is retarded. I have yet to find a good picture of what the crankshaft timing marks are supposed to look like. AllData has a great pic of the cams, but a lousy pic of the crank timing marks. The sprokets were never taken off of the camshafts and I marked the intake cam gear with the letter "I" and the exhaust cam gear with the letter "E" before I removed the original cylinder head just to be sure that I didnt mix them up. As far as timing marks on the cam gears, I only find one mark on each gear. I have seen pictures on other forums where it looks like the intake gear has a series of marks. Mine does not look like that. It has one notch on the intake gear and one notch on the exhaust gear. I was going to include a picture, but I don't know how to include them in the thread. Thanks in advance for any input.

 

See if this helps.

The photo is lacking the serpentine belt pulley, the face where the arrow is goes up against the engine block.

DanR

 

The marks on the gears, my engine has a set of very very light notches and a set of small, etched triangles, my first t belt change, I first used the triangles because they were most prominent, that was wrong and then discovered the actual notches. They have since been painted for all ensuing belt changes.

Good luck.

I have a drawing from a volvo engine manual, but it is too large to post here.

DanR

 

Here are my instructions if it matters or helps:
http://www.atthetipwebs.com/technolo...iming_belt.htm

 

Thanks to everyone for all of the feedback especially rspi! I'm going to apply what I've read, and I will post the results within a couple of days. Thanks again for your time and input, hope I can repay the favor sometime!