timing chain slipped when not at TDC

krautviper48

New Member

Apr 20, 2012

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Apr 20, 2012

#1

• Apr 20, 2012

• #1

Hey everyone! im new to stangnet but i have a big problem.

so to give you some background, i took off the RHS timing chain when the crank was at TDC but the cam timing marker wasnt in a position where it was touching the chain on the sproket, so i counted teeth and tried matching it to the stright part on the LHS. so i thought i had everything right. went to go do a test hand turn on the crank to see if i got any interference but i didnt put the tensioner back in and low and behold i slipped a couple teeth when i was 180 off from TDC, what can i do now?

thanks in advance!

 

N8Dogg98

15 Year Member

Apr 4, 2005

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Apr 20, 2012

#2

• Apr 20, 2012

• #2

There are numerous write ups on this particular topic. I'd start by positioning the engine in "safe" mode. This means the crank key is 90* to the passenger side. Then you can spin the cams in the head to get the dot in the correct location and you'll know that you aren't messing anything up. You really should not have turned the cam while the engine was at TDC. If a piston was at TDC while you were turning the cam it could potentially have contacted and bent an intake valve. Again, get the engine in "safe" mode and then turn the cam to get the timing mark in the correct location. Here is a write up on how to do this:

http://www.modularheadshop.com/Articles/cam installation.htm

 

krautviper48

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Apr 20, 2012

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Apr 20, 2012

#3

• Apr 20, 2012

• #3

Thanks N8Dogg98!

I thought TDC was safe mode guess i was way wrong on that one... Right now the key is at about 4 o'clock so if i need to get it to 9 o'clock Im just worried that if i go anymore that i might hit a valve.

 

J

james98GT

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Apr 20, 2012

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Apr 20, 2012

#4

• Apr 20, 2012

• #4

You'll not bend a valve just turning it by hand if a valve hits a piston.

 

N8Dogg98

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Apr 20, 2012

#5

• Apr 20, 2012

• #5

james98GT said:

You'll not bend a valve just turning it by hand if a valve hits a piston.

Click to expand...

False. There is so much tension from the valve springs the cams don't actually spin freely with the cam caps installed. Instead they turn some of the way then the force of the springs snaps them into a new position. You can easily damage a valve by turning a cam by hand.

 

usaf_branham

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Oct 30, 2008

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Apr 20, 2012

#6

• Apr 20, 2012

• #6

N8Dogg98 said:

False. There is so much tension from the valve springs the cams don't actually spin freely with the cam caps installed. Instead they turn some of the way then the force of the springs snaps them into a new position. You can easily damage a valve by turning a cam by hand.

Click to expand...

yup. if your that concerned about it, remove the cam caps and cams, set the crank at safe mode, reinstall the cams and cam caps then time it... have a friend handy to hold the cams in position, it will make life a lil easier.

or, if you are not worried about screwing something up, pop the followers out, gently position the cams, and gently position the crank to safemode, time it, then pry the followers back in place.... (i highly do not recommend this).

check out MHS's article on timing the 4.6

 

krautviper48

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Apr 20, 2012

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Apr 21, 2012

#7

• Apr 21, 2012

• #7

Hey everyone,

So just to update, i was lucky and got it to safe mode being careful, did the chain reset and started it up and it runs perfect. the main lesson learned, is dont try and do this job in one day in the parking lot of your apartment complex when its 95 degrees out... you tend to make mistakes. but thanks everyone for your help!

 

N8Dogg98

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Apr 4, 2005

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Apr 22, 2012

#8

• Apr 22, 2012

• #8

Glad to hear it worked out