TOP DEAD CENTER 3.8 TIMING BELT QUESTION ASAP

[2to4wheels]

Hey everyone, got my Gen 3 torn down tonight and will be pulling the belt off first thing in the morning. Took me about 3.5 hrs to get to the belt. I just want to verify that TDC Piston 1 is when all 3 marks (cams, and crank) are aligned. When I rotate the engine and just the cams line up but the crank isn't, obviously another piston is at top but not #1 I am guessing. Obviously, can't test with spark plugs since they don't come out without the intake manifold off which I really don't feel like doing.

Thanks.

 

[PA_JERO]

Line up all all three marks, crank, and both cams and you are all set. Remove belt, and one of the cams, can't remember which one will want spin forward or back though, so watch your fingers. Use a 17mm wrench on the cam sprocket bolt to spin it back as you go to put the new belt on.

 

[nckwltn]

Passenger side will want to spin... It's a lot of force, but can be balanced right on the timing mark.

 

[PA_JERO]

Passenger side will want to spin... It's a lot of force, but can be balanced right on the timing mark.

This is true, just be careful when you slide the new belt on if you let that cam balance on the mark.

 

[normal_dave]

When the crankshaft is at TDC, it should line up like this:

With the crankshaft at TDC, and both cams at their respective marks, (V-notch in valve cover), then you are at #1 TDC.

Here's a timing mark diagram for the 3.5L (same for 3.8 I believe)

(photos from a post at justanswer.com)

 

[nckwltn]

If found that if you turn the crank gear back (counter clockwise) 1/2 tooth or so, when you get everything set and rotate the engine clockwise, that 1/2 tooth will pull in any slack between the crank gear and the cam gear on the drivers side.

 

[2to4wheels]

thanks for the help! I'll post a more detailed story in the 3.8 Timing Belt thread but second time was a charm! Got it all back together and fired it up and, oh crap, a little bit of a tick that wasn't there before. This was at 8pm last night. Tore it all down to fine the crank was off by 1 tooth so marked it with a yellow crayon so I could clearly see it and we had it back together and running properly by midnight. The second key turn was the most anxious point of the weekend.

 

[The Viper]

thanks for the help! I'll post a more detailed story in the 3.8 Timing Belt thread but second time was a charm! Got it all back together and fired it up and, oh crap, a little bit of a tick that wasn't there before. This was at 8pm last night. Tore it all down to fine the crank was off by 1 tooth so marked it with a yellow crayon so I could clearly see it and we had it back together and running properly by midnight. The second key turn was the most anxious point of the weekend.

I have to finally do mine in the next month...would love to hear your experience, and any tips you might have learned.

 

[PA_JERO]

thanks for the help! I'll post a more detailed story in the 3.8 Timing Belt thread but second time was a charm! Got it all back together and fired it up and, oh crap, a little bit of a tick that wasn't there before. This was at 8pm last night. Tore it all down to fine the crank was off by 1 tooth so marked it with a yellow crayon so I could clearly see it and we had it back together and running properly by midnight. The second key turn was the most anxious point of the weekend.

Hopefully that wasn't your valves being clearanced.

Just a though for those doing there's in the future. Once you have your new belt on and tensioner PROPERLY set. Crank the motor around a few times by hand to make sure the belt has set in to the right place. Make sure all timing marks line back up before reassembling.