Head Removal/Replacement

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James Bricken

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I did a quick search with negative results.

I'm new to this forum so let me explain my situation. I'm a mechanic but I don't work on American cars. I have taken on this project as a favor to an existing customer.

The car in question a 2002 Liberty with a 3.7 V6. What has happened is that a rocker jumped off the lifter and got smashed by the cam lobe and broke the lifter seat (#2 intake).

First question is: can we expect any other damage; to the piston etc? The valve appears OK but owner says leak down test indicates intake valve not sealing.

The second issue is: like I said I have never worked on this motor. Is there anything I should know before taking the head off; like locking the chain tensioners or something? Can I just pull the head or do I have to take the front off the motor? Are any special tools required that I may not have? THe plan is to just replace the one head, but I may replace all the lifters if that is deemed a good idea.

Can I get a quick rundown procedure for removing the head?

Thanks for your time and assistance.

james
 

James Bricken

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You work at a shop that doesn't have All Data? Weird.


No, I own a shop and I don't pay for that data because I would never use it. Like I said: I don't (normally) work on American cars. For the cars I do work on I have about $15,000 worth of factory manuals.
 

TwoBobsKJ

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Welcome to the forum! (welcome)

The challenge with removing the heads is keeping everything in the intake system correctly timed/aligned. This is an interference motor so the cams and crank need to stay in time so valves don't hit pistons and so it will run once back together. There is a pretty easy way to keep it all in time using the timing marks on the cam sprockets and the harmonic balancer.

Here is a link to the Factory Service Manual section on cylinder head removal and installation. Hope this provides most of what you're needing. If not, just post a reply and I'll see what I can do to get the info to you.

Bob
 

James Bricken

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Welcome to the forum! (welcome)

The challenge with removing the heads is keeping everything in the intake system correctly timed/aligned. This is an interference motor so the cams and crank need to stay in time so valves don't hit pistons and so it will run once back together. There is a pretty easy way to keep it all in time using the timing marks on the cam sprockets and the harmonic balancer.

Here is a link to the Factory Service Manual section on cylinder head removal and installation. Hope this provides most of what you're needing. If not, just post a reply and I'll see what I can do to get the info to you.

Bob

Thanks for your input. The owner gave me his Chiltons manual, but what I'm really looking for is those tips, tricks, and gotchas from people who have BTDT. Right now I'm trying to procure the tools to remove the harmonic balancer. The book says to use a chain wrench to hold the pulley but nobody in town town sells such a tool. I hate to do it but I may just have to jam a pry bar into the flex plate.

TTFN
james
 

James Bricken

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OK, I got the head off (dropped valve seat). Here is what I learned today: THe crank bolt will come off with an impact (22mm), without holding the pulley. You need a special Chrysler puller to get the harmonic balancer off; Autozone has them to loan (or buy for $75). THe pin spanner is not needed. You do have to take the belt tensioner off because there is a bolt behind it. If your only doing the passenger side head you don't need to take the power steering pump off. THe lower chain guide pivots (in the head) on a T40 torx bolt that is very tight. A Craftsman T40 tool (3/8 drive) will just fit; A Lisle T40 will not. Do not use a tamper proof t40 :)

I hope this helps somebody else who might happen across this thread.

The owner is securing a new head; This one is not repairable. SO any recommendations on other things to do while I'm in there? I was thinking maybe replace the chain rails. They look OK but I know on some cars they tend to fall apart over time (I think this car has 100k+ miles). WHat about gaskets? Do I need a full gasket set, or should I buy them individually? Is Autozone stuff good enough, or would you insist on factory parts?

TTFN
james
 

ThunderbirdJunkie

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Thanks for your input. The owner gave me his Chiltons manual, but what I'm really looking for is those tips, tricks, and gotchas from people who have BTDT. Right now I'm trying to procure the tools to remove the harmonic balancer. The book says to use a chain wrench to hold the pulley but nobody in town town sells such a tool. I hate to do it but I may just have to jam a pry bar into the flex plate.

TTFN
james

A bit late, but OTC makes a good chain wrench. ThunderbirdJunkie hates to recommend a visit to the tool truck, but Snap Off, Marco, ********, etc should have one.

Sent from my DROID RAZR HD using Tapatalk 2
 

TwoBobsKJ

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OK, I got the head off (dropped valve seat). Here is what I learned today: THe crank bolt will come off with an impact (22mm), without holding the pulley. You need a special Chrysler puller to get the harmonic balancer off; Autozone has them to loan (or buy for $75). THe pin spanner is not needed. You do have to take the belt tensioner off because there is a bolt behind it. If your only doing the passenger side head you don't need to take the power steering pump off. THe lower chain guide pivots (in the head) on a T40 torx bolt that is very tight. A Craftsman T40 tool (3/8 drive) will just fit; A Lisle T40 will not. Do not use a tamper proof t40 :)

I hope this helps somebody else who might happen across this thread.

The owner is securing a new head; This one is not repairable. SO any recommendations on other things to do while I'm in there? I was thinking maybe replace the chain rails. They look OK but I know on some cars they tend to fall apart over time (I think this car has 100k+ miles). WHat about gaskets? Do I need a full gasket set, or should I buy them individually? Is Autozone stuff good enough, or would you insist on factory parts?

TTFN
james

Sorry I didn't see your post sooner...

The chain guides, etc. are a lifetime system and shouldn't need replaced or repaired. Just double-check that the springs in the hydraulic tensioners are pushing the plunger out smoothly - no spongy feeling to them.

I ordered the gaskets I needed rather than buying a full set. The timing cover gasket kit comes with the front main seal as well as the the smaller gaskets around the inlet and outlet galleys and around the water pump. Just pick up the valve cover and head gaskets for the side you're working on and you should be good to go

Bob
 

James Bricken

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Sorry I didn't see your post sooner...

The chain guides, etc. are a lifetime system and shouldn't need replaced or repaired. Just double-check that the springs in the hydraulic tensioners are pushing the plunger out smoothly - no spongy feeling to them.

I ordered the gaskets I needed rather than buying a full set. The timing cover gasket kit comes with the front main seal as well as the the smaller gaskets around the inlet and outlet galleys and around the water pump. Just pick up the valve cover and head gaskets for the side you're working on and you should be good to go

Bob


Thanks Bob. THe owner is getting a head from some place in Florida. Suppose to include all the gaskets Etc, ready to bolt on. I'll let ya'll know when I get started on it again.
 

James Bricken

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OK, I'm back at this. Got the head on, went to put the chain guides on and they basically fell apart in my had. Dealer only sells them in a kit for $450. Any ideas?
 

James Bricken

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Get the kit; it was clearly needed anyway.

Sent from ThunderbirdJunkie's mind via satellites

As it turns out you can order the chain guides from AZ or pep boys. That takes about a week and there is some confusion on their web site as to which part is which part. Turns out the local NAPA warehouse had them in stock.
 

James Bricken

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So here is the deal now: I got the car back together. Started it and it was throwing a code indicating bad MAP. Yep, MAP broken. Replaced MAP now its showing code 1297 which basically means the MAP and the TPS are not on the same page. Vacuum leak? None that I can detect. I did read where somebody suggested that a cracked breather hose could do this. Really; even though its unmetered air?
 

ThunderbirdJunkie

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Stupid question.
Why would anybody only replace one tensioner/guide?

If it fell apart in your hand, the others are likely not far behind, and you already have the chain out anyway.
 

James Bricken

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Stupid question.
Why would anybody only replace one tensioner/guide?

If it fell apart in your hand, the others are likely not far behind, and you already have the chain out anyway.

Not my idea. THe owner said he didn't want to have the other side replaced as well. I think he's planning on selling it in the next year. The other guides will probably be OK as long as they stay in position.
 

James Bricken

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OK, problem solved. Turns out the new MAP sensor we got was defective. WHen I checked the MAP reading from the scanner it was reading 37.8 Barometric pressure. On earth it should only be around 29. I also put a vacuum to the sensor with no change. The new sensor read 29.8 static and changed to about 4 when I put a vacuum to it. You can also test this on the motor with a scan tool. It should be about 29 without the motor running, and should decrease with the motor running, and the greater the throttle is opened (unless you have the world biggest vacuum leak, in which case the car wouldn't run).
 
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James Bricken

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Stupid question.
Why would anybody only replace one tensioner/guide?

If it fell apart in your hand, the others are likely not far behind, and you already have the chain out anyway.

For further clarification: These guides have a plastic ramp on them that slides into the metal frame and a lock tab that holds it in place. In my case it was only the lock tab that broke off allowing the plastic part to fall off the metal part. But, there is a secondary system that will keep the plastic in place, as long as the chain is moving in the correct direction (which is why they tell you not rotate the motor backwards). Even though the plastic was fragile, I probably could have JB welded it in place and it would have made another 100k miles. But since it was already off, and somebody else's car and money, I decided to put new parts on. That way if it fails I can't be held to blame.
 

eddiekimberly

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I know this thread is old but, as far as the harmonic balancer puller, is the Chrysler one necessary or will the standard $20 have the proper adaptors?
 

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