S70 Bent valves or no bent valves ?

gojoaddict · Post by **gojoaddict** » 08 Oct 2009, 18:03

Long read I know but needed.
I started my S70 for about 5 seconds after removing and replacing the timing belt and of course the cams moved so I removed the valve train cover so the cams would float freely and I then aligned the crank and cam gear timing marks to their perspective place between the 2 notched teeth on the crank gear and at the angle 2 0clock and 10 Oclock positions on the cam marks to timing plate, the car when started kind of rumbled like it wasn't correct so I immediately shut it off and got on this forum and almost everyone said I probably bent some valves. So off with the head and wondered what I would see when I turned it over, well I saw nothing out of the ordinary, the valves all look fine, seated nicely and I see no metal to metal marks on the tops of any of the pistons or on any of the valve edges SO could they still be bent ?
And for a side note, even though I aligned the marks crank and cam properly and then started it for 5 seconds I worry about the valves because I made a previous post about how this engine IS at TDC for piston #1 when the marks are aligned (with the cam marks at the 20clock and 10-oclock positions) and odder the plastic timing cover has a single notch at 12 oclock above intake cam and a red dot at 12oclock above the exhaust cam. So could someone have somehow set this vehicle up AT TDC and with the cam marks not at the angled positions but at 12 oclock?? I know this was a long read but I hope someone can see why I am confused and would appreciate any help on this matter.. gojo

ignatz · Post by **ignatz** » 09 Oct 2009, 18:03

After I replaced the t-belt and tensioner on my 98 t5, the car stumbled, idled a little rough, and threw a code. (check engine light). I too only ran it for 5 seconds or so. I thought somehow I got the belt on wrong, but everything lined up right. It was a misfire code and I just cleared it with my code reader. I started it up again and its been perfect since. Smooth and quiet. That was 15-20,000 miles ago.
I heard a guy start a Mitsubishi after a t-belt change with the belt on wrong. The devils zylophone for 1 second!
Was your "rumble" a misfire like mine or a sound like Dr. Deaths zylophone?

gojoaddict · Post by **gojoaddict** » 09 Oct 2009, 22:47

I t was more of a rumble when I started it not a death rattle, I heard no clunking or anything that sounded like metal to metal and as said after checking the valves are seated nice and the usual carbon buildup coating on the piston tops and valves is still in place and there appeared to be no contact between the two. I guess my concern is that no one can tell me how far from tdc the #1 piston will be when the crank mark is aligned, a tiny bit or like an inch down from tdc. I also think I should set the engine up just as it calls for in the manual as I did it before and started it and had no valve damage, so maybe something else made the engine rumble (just didn't sound like it was breathing right when running) the engine kind of rocked back and forth a little . I may have been off by one tooth when I did it the first time as I aligned the crank to the one tooth with a notch and didn't notice the next tooth also had a notch so I should have aligned to the valley between the two notched teeth, would one tooth off cause the engine rumbling?

ignatz · Post by **ignatz** » 10 Oct 2009, 04:59

When I first started mine up it too slightly shook and stumbled. I don't know if somehow my computer had to get aquainted with my new timing belt before it would run right.
What I would do if I was'nt comfortable with the timing marks is confirm TDC and the relationship of the cams.
I'd pull all the plugs (makes turning the engine over easier) and pull the valve cover to observe the cams. By manually turning over untill #1 piston comes 100% straight up on its firing stroke and seeing that the cams are allowing the valves to close equally.
A stick shift car is easy to just put in 4th or 5th and push back and forth to rotate the engine, automatic cars will need someone turning the crank with a wrench. You can carefully place a rod down #1 plug hole when the piston is close to the top of it's stroke and by going past TDC and back the other way untill your comfortable that that piston is all the way up....your crank mark should coinside and be correct.
If your up on #1 firing, those cams will be in a position allowing the valves to be closed. At this position, this is where you need to observe that everything looks equal. I would also want to see if at TDC #1 position that another cylinder's cams are "overlapping" equally. That means at TDC #1....another cylinder's cams are pushing down the valves equally. You would have to rock the engine back and forth to see this also.
I should say that normal cars have the timing marks coinsiding with TDC. I don't know if Volvo has random marks for setting up the timing belt.
Do you feel comfortable with this?.....at this point its worth a look.