cclouis

Well, despite being real careful, I got 1 tooth off on the front Cam sprocket on my 2004 TL while replacing the timing belt. So when the crank is at TDC, the rear cam sprocket is at TDC, but the front is 1 click right of TDC.

Before we realized this, we got it started, and noticed it ran like crap. Idled real bad, knocked a lot at low RPM's and stalled a couple times. We thought it might be the crank position reset for the computer that had to be done and went through that process, driving it through the neighborhood. Finally drove it home and double checked and found the error.

So, my question is, anyone think I did damage? It didn't sound bad at higher RPM's, and I drove it for somewhere between 20 and 30 miles. It certainly knocked and i heard valve clicking, but it ran enough to drive home. (It won't be moving again til it's fixed). See pic attached. It is the front cam while everything else is at TDC. Anyone know if I might have harmed some valves? Thanks, I'd love to hear from anyone who is a mechanical wiz or has made this error before.

imj0257

iTrader: (1)

Try asking majofo. He replaced his timing belt himself so i am gonna take a guess that he might be able to help you out if hes not high or drunk or in a food coma

cclouis

Yea, I read through his step by step on it. It was real helpful. Should have read that part about turning the engine and re-checking TDC on everything a second time.

I hate cars

One tooth off may or may not have done damage. I would re-time it and check compression on that bank of cylinders.

cclouis

Well, I'll be lining up the cam right and then see how it runs obviously. If it's right and not running well I'll probably assume I dinged some valves. Only other thing I thought of was the crank sensor got some coolant on it when we pulled the water pump.

cclouis

Update. After fixing the misalignment, it sounds and runs fine. Seems that there was no damage, but man...... 1 gear tooth out on a cam and it sounds like a diesel.

Gostridr

glad its better! I will take your advice as I hope to do this soon. Thanks for letting us know what happens!

I hate cars

Glad everything is ok. This is the reason I used to laugh in the old days on here when people would say the car would run ok if you were 1 or 2 teeth off.

Turbonut

iTrader: (1)

Still do, Adjustable cam gear:
http://www.american-pi.com/corvair/html/adjcamgear.html

professor48

I did the same thing on my previous car, an 05 Toyota Solara V6. The car ran great but the "Check Engine" light came on. I checked with my brother, a professional mechanic, who checked with a friend of his who works at Lexus (same engine as Toyota). It seems it's a common mistake; the rear cam moves one tooth. There is an inexpensive plastic alignment tool which locks the cams in proper position. In a few years, when I have to do the timing belt on my 08 TL, I'll buy the tool. Having to redo a timing belt once is enough. Glad all worked out for you. Hy

I hate cars

You can get the cam phase off just a little on a dohc engine and it will run ok but not the overall cam timing. One tooth off on a sohc engine means it will barely run if at all.

Adjustable cam sprockets are usually used for cam phasing adjustments which many cars do electronically now anyway. They can be useful with aftermarket cams that might need to be degreed in and cams that are made to be run advanced or retarded but take one of these adjustable cam gears, retard it 12 degrees on the stock TL cams and see if you can make it out of the parking lot.

Turbonut

iTrader: (1)

I certainly wasn't referring to the TL, just complementing the statement you made about changing cam timing, and yes, I've degreed in more cams than I care to remenber.

cclouis

Funny, the rear cam is the one that is tough to keep in place but the front is the one I got misaligned. This is because we followed the official Acura instructions and tightened the idler pulley after the new belt was on thus pulling the front cam while taking out the slack on that side. Follow the step by step mojofo put up. It's much better. And for gods sake don't break to go rent a 200 ft lb torque wrench and forget to check it after its all tightened.

I hate cars

I know, it was more in reference to the Solara above.

As a 17 yr old I retarded the cam timing in my friend's Porsche 944 by one tooth to try and get more power. The results were not very good. I could tell you about the time I installed the cam in my GN with a hangover and used the wrong marks. Bent the intake valves and got a backfire through the intake that was so bad it broke part of the compressor wheel and a weld on the intercooler.

Majofo

I need pop in here more often.. who knows what wild rumors have been spread already.

surlynkid

iTrader: (1)

one tooth will do no damage. as you saw you are running way off your desired TDC mark. divide 360 by number of teeth, and you are off by that much. correct it and you will be good to go. toyota put these sweet markings on their belt that make it idiot proof to mess up on their V6 motors. it makes it worth paying for the OEM belt. match marks to dots, and you are good to go. i was off one tooth on a VW years ago, and it was fine after I corrected it.

i_love_cars

iTrader: (1)

glad everything turned out.

I had the same issue when I did my timing belt - was 1 tooth off initially, turned the car on and then I turned it off 2 seconds later as it sounded awful and I immediately knew I got lazy on my double-check of the tooth alignment lol

Re-did the install with all teeth aligning and 2 hours later the car was running just fine.

I think with 1 misaligned tooth your risk of damage is low as long as you don't drive the car or put the RPM's up before you fix the issue.

Majofo

I hate cars

Mechanical clearance is mechanical clearance. If it does no damage at idle, it will do no damage while driving. In 1 second at idle, the valves have opened and closed 6 times and the pistons have come into close proximity 12 times. Rod stretch shouldn't be a factor so if it does no damage at idle, you're good.

There are other damages that can occur from extended driving with the timing off but not valve to piston damage.

surlynkid

iTrader: (1)

interference fit motors typically have timing chains although there are some exceptions. you are right though. if it runs for 2 seconds without the valves hitting the pistons, it will run for 20 minutes.

cclouis

Well, with the gear off 1 tooth, I drove it around the neighborhood doing the crank position sensor pattern learn proceedure, (which involved running it up to 5000 RPM in low gear) and then I drove it 20 miles home from friends garage.

After fixing it right it sounds same as always. Certainly, based on how it sounded and failed to hold an RPM, other things could get screwed up. I figure intakes, sensors, etc would eventually suffer with valves open and closed at the wrong time.