850 sounding like a diesel

iancam33 · Post by **iancam33** » 22 Jan 2012, 19:10

I just got done with a long project of replacing a exhaust valve and finally got the motor all put together on my first volvo , its a 1995 volvo 850 glt wagon with 130,000 miles on it. The engine is very clean, now when it starts up and you open the hood the engine kind of sounds like its a diesel, but it drives smooth and sounds good when your in the car, also when you accelerate it makes a weird kind of noise like a bunch of chains hitting each other and then it goes away once you arent accelerating anymore .
Any suggestions of what it might be ?
Thank you!

Post by **jblackburn** » 22 Jan 2012, 19:42

Either your timing is slightly off (a mark or two), or you just need to drive it more. In my case, it was both.

Mine sounded like this after I'd just got through changing a timing belt - there was no oil pressure building up for a good 10 min of run-time up top. As I took it out and got the RPM up, it quieted down to normal.

Before:

After:

Post by **rspi** » 22 Jan 2012, 20:12

It's either knocking or ticking. Knocking is usually the lower end, ticking is usually up top. Double check timing marks, hopefully is till smooth out.

iancam33 · Post by **iancam33** » 22 Jan 2012, 21:51

Its more of a ticking, but yeah after doing all that work I had to red do the timing belt so it is most likely that the timing is off by a couple of notches, How would do i fix the timing?

Post by **jblackburn** » 22 Jan 2012, 21:54

Double check all timing marks!!!

iancam33 · Post by **iancam33** » 22 Jan 2012, 22:19

Before all of this I just replaced a cracked exhaust valve, and had to take the cams off and timing belt, when we got it all back together the first start up the timing belt jumped off because the timing belt tensioner wasnt tensioned all the way, so we had to re- time it and tried to get all the marks in the right spot but now it sounds like a diesel but not as severe as those videos of yours it sounds a little more like the second one with a little ticking noise and when you accelerate it sounds like a chain is dragging on the ground or something but only when you accelerate anyways Im worried that when i started it up the first time after doing all that work and when the timing belt jumped off do you think its possible that we damaged a piston or a valve ? I cranked it about three times on the first ?
So the question is possible for a piston to hit the valves when the timing is off on a volvo engine ?
Also when adjusting the timing belt witch way am I going Advancing it or retarding the spark ?

Post by **jblackburn** » 23 Jan 2012, 00:01

It is absolutely possible for the valves and pistons to meet if you are more than 2 notches off on the timing gears. If you fear that, run a compression test or feel for a misfire while driving.

How did you re align everything when you put the gears and belt back on? The crankshaft pulley has a timing mark, and hopefully you marked the cams or something before reinstalling them. There are marks on the gears that line up to the valleys on the timing belt cover in a "V" as well.