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Bluesultan
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Top Dead Center and Changing a Head Gasket

How important is it that an engine be at top dead center (number 1 cylinder) when changing the head gasket? It's a 93 Escort with the 1.9L and that's the first of many steps in removing the head. I would think that as long as you keep the crank and head sprocket in the same place, you should be fine just bolting everything else back up. If it's absolutely necessary, what's an easy way to do it without using a dial indicator on the crank, it's a tight engine bay to work with as it is.
Old 04-07-2005, 07:18 PM Bluesultan is offline  
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mhaskell
I am an SBC-lovin' beancounting crackwhore...
 
Quote:
Originally Posted by Bluesultan
How important is it that an engine be at top dead center (number 1 cylinder) when changing the head gasket? It's a 93 Escort with the 1.9L and that's the first of many steps in removing the head. I would think that as long as you keep the crank and head sprocket in the same place, you should be fine just bolting everything else back up. If it's absolutely necessary, what's an easy way to do it without using a dial indicator on the crank, it's a tight engine bay to work with as it is.


Its possible that without being at, or near, TDC one of the other valves could be open. This means that when you removing the timing belt the cam could turn making timing hard to set upon reassembly.
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Old 04-07-2005, 07:26 PM mhaskell is offline  
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Bluesultan
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Do you know of an easy way to set it at TDC? Thanks.
Old 04-07-2005, 07:31 PM Bluesultan is offline  
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mhaskell
I am an SBC-lovin' beancounting crackwhore...
 
Quote:
Originally Posted by Bluesultan
Do you know of an easy way to set it at TDC? Thanks.

Take out the spark plug and place your finger over the hole, wait until you feel pressure build and then stop, this is TDC however it could be on the compression or exhaust stroke. Simply watch the exhaust valve for movement while doing this and if it is stationary then you are at TDC on the compression stroke.
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New England Crew

1999 Ford Lightning
1984 Corvette Z-51
Leaf springs,pushrods, aluminum heads, nitrous and wideband fuel injection for life.

1998 saab, 5 speed, winter beater
Old 04-07-2005, 07:38 PM mhaskell is offline  
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Bluesultan
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Quote:
Originally Posted by mhaskell
Take out the spark plug and place your finger over the hole, wait until you feel pressure build and then stop, this is TDC however it could be on the compression or exhaust stroke. Simply watch the exhaust valve for movement while doing this and if it is stationary then you are at TDC on the compression stroke.

How do I see the valves, should I pull the valve cover off? Thanks for all of your help so far.
Old 04-07-2005, 07:42 PM Bluesultan is offline  
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mhaskell
I am an SBC-lovin' beancounting crackwhore...
 
Quote:
Originally Posted by Bluesultan
How do I see the valves, should I pull the valve cover off? Thanks for all of your help so far.

The valve cover has to come off anyway to remove the head, so might as well take it off at first.
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New England Crew

1999 Ford Lightning
1984 Corvette Z-51
Leaf springs,pushrods, aluminum heads, nitrous and wideband fuel injection for life.

1998 saab, 5 speed, winter beater
Old 04-07-2005, 07:57 PM mhaskell is offline  
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Bluesultan
ungrateful prick
 
Sounds like I have my work cut out for me. Thanks for all of the help.
Old 04-07-2005, 07:59 PM Bluesultan is offline  
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Luder[PAK9]
 
If you're plugging the hole with your finger, you'll only feel pressure build when the piston is on the compression stroke. This is becuase when it is on the exhaust stroke the exhaust valve will be open, releasing any pressure. Of course, like was said, no reason not to double check by watching the valves themselves.
Old 04-07-2005, 08:01 PM Luder[PAK9] is offline  
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godofcheese
 
If it was the exaust stroke, there shouldn't be any pressure since your exaust valve is open. . . . . . or am I not thinking things through. . . .

I would get a helms manual for your car and it will show you how to do this with pictures. I know on mine there are markings you line up.
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Old 04-07-2005, 08:48 PM godofcheese is offline  
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Kckazdude
 
Once you remove the valve cover and timing cover you will be able to see the marks to line everything up TDC. On these motors it is easier to line TDC center than trying to make new marks and hope you get it right. IIRC this is an interference motor.
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Old 04-07-2005, 08:54 PM Kckazdude is offline  
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mhaskell
I am an SBC-lovin' beancounting crackwhore...
 
Quote:
Originally Posted by godofcheese
If it was the exaust stroke, there shouldn't be any pressure since your exaust valve is open. . . . . . or am I not thinking things through. . . .

I would get a helms manual for your car and it will show you how to do this with pictures. I know on mine there are markings you line up.


If the cam is small, with short duration, there is a good chance the exhaust valve will be open after BDC thus pressure will be made for a short time and then released, mimicing TDC on the compression stroke. For a first time mechanic its a good idea to check the valves and not be confused.
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New England Crew

1999 Ford Lightning
1984 Corvette Z-51
Leaf springs,pushrods, aluminum heads, nitrous and wideband fuel injection for life.

1998 saab, 5 speed, winter beater
Old 04-08-2005, 05:41 AM mhaskell is offline  
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godofcheese
 
I think lining up the arrows is alot easier then feeling for pressure.
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Old 04-08-2005, 05:56 AM godofcheese is offline  
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Bluesultan
ungrateful prick
 
It's not an interference motor because the timing belt broke in the past and the pistons/valves did not collide. Thanks for all the tips.
Old 04-08-2005, 06:21 AM Bluesultan is offline  
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punisher
 
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Really doesn't matter at all. Rip the head off, do the gasket and set the timing marks/belt up when you go together with it. You really are just wasting time even worrying about this until reassembly.
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Old 04-08-2005, 11:44 AM punisher is offline  
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Squeezer
 
uh....just line up the fucking timing marks on the cam gears and the pointer on the crank pully before you take off the timing belt.

buy the ford factory service manual since it sounds like you dunno what you are doing.

http://www.helminc.com/helm/Result.a...95UHUSJ6GF5QWC
Old 04-08-2005, 02:47 PM Squeezer is offline  
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