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How to remove/install camshaft on SOHC V6?

Vette76

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02 XLT 4.0L & 97 XLT 5.0L
My timing chain saga just took a turn that I didn't expect...

Although I'll explain it in much greater detail later so as to help someone else avoid my fate, I ended up stripping the threads inside the right hand camshaft that receives the camshaft sprocket retaining bolt (it was due to a nuance with the timining tool on the camshaft that I didn't realize).

I'm now wondering if there is anyway to simply take off the RH camshaft or is this the absolute kiss of death? The only procdedure I seem to be able to find here is to how to replace the entire head. I've never worked on a SOHC engine so every step here on these camshafts is new ground.

So can you replace a camshaft on these things or is the only way to get a new camshaft is replace the entire head with the camshaft insalled in it? If you can replace a camshaft, is this something doable by an average wrench turner or do you have to have crazy level skills?

If someone could help me on this I'd be extremely grateful. I think the 'large lady' is starting to warm up her voice :)
 



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no cam bearing inserts

As I recall the standard procedure for removing the camshaft is to first remove the rocker arms which requires a special tool. This eliminates the valve spring pressure on the camshaft lobes. I have removed and reinstalled both camshafts on my engine without removing the rocker arms but the process is risky. If not done extremely carefully the camshaft bearing caps may break. Unfortunately, the camshaft bearing caps and head do not have bearing inserts like those implemented on crankshaft bearings. I doubt it is possible to purchase a camshaft with oversize journals and machine the head and bearing caps to match. If the head, caps and camshaft journals are not within spec then a new head may have to be purchased.
 






camshaft journal to bearing clearance

I just checked my workshop manual CD and confirmed that the camshaft roller followers are supposed to be removed before removing the camshaft timing chain tensioner and the camshaft bearing caps. The bearing cap bolt loosening and tightening order is shown below.
Rear
8 6
2 4
3 1
5 7
Front
The bearing caps should be reinstalled in their original positions so keep track of each position and orientation.
The specified camshaft journal to bearing clearance is 0.002 to 0.004 inches with a service maximum of 0.006 inches.

The bearing cap next to the camshaft sprocket acts as a thrust bearing. If you don't remove the rocker arms first then it is extremely important when tightening the bearing caps to keep the axis of the camshaft parallel to the bearing seats in the head. Otherwise, the camshaft can bind at the thrust bearing and a cap can break as it is tightened. One member has already broken a camshaft bearing cap attempting to remove the camshaft without first removing the rocker arms.
 






Thanks Dale! It looks like I'm going to get pretty familiar with how to take the camshaft followers and main caps off. At this point, I'd be happy to salvage the time and money I've got into this and with my luck, I would probably break the last bearing cap :)

Would you have any idea if a regular valve compression tool would work on this engine? Ford seems to have a way with selling very expensive tools to fix just about anything that needs to be fixed.

Thanks.
 






special tool required

. . .
Would you have any idea if a regular valve compression tool would work on this engine? Ford seems to have a way with selling very expensive tools to fix just about anything that needs to be fixed.

Thanks.

A special tool (Rotunda 303-381 or OTC T97T-6565-A) is required in order to compress the valve springs. It fits under the camshaft and pivots about it when compressing the valves. It might be possible to make an equivalent. The tool costs about $200.
Rotunda_SPX_303-581_LG.jpg
 






Thanks again Dale!

I've been researching this all morning and I found a couple of cross referenced tools that "supposedly" work on the SOHC V6 for this application. One is the OTC 7928 and the other is from Trick Flow Specialities; TFS-90518.

http://www.bizrate.com/automotive-repair-tools/oid121091179.html

Not sure if they really are replacements for the Ford OEM tool but for the TFS version at $39.95, I might take my chances and see what happens.

When you remove the rocker arms from up top while the head is still on, I'm trying to understand why nothing then falls down into the cylinder? I can't remember the exact design of the head (although I'm only 20 feet from my garage right now :) ) but I'm trying to figure out if replacing the camshaft while the head is still on is as easy as unbolting the rocker arm retaining nuts (and not having to worry about anything as a result of doing that) and then unbolting the camshaft bearing caps. God, I hope so!

Is the camshaft journal to bearing clearance actually individually measured once each bearing cap is bolted back on, or does the specified torque that needs to be put on each of the bearing cap bolts provide for the "right" amount of clearance? These overhead cam engines are a whole different animal then I've ever dealt with.

Thanks for the help!
 






Modular V8 valve spring compressor

I doubt that those valve spring compressors for Ford's modular V8 will work on the Cologne SOHC V6. If they did, it would probably be advertised as such.

The valve spring only has to be compressed enough to relieve the pressure on the rocker arm so it can be removed. The keeper on the valve stem is not removed so nothing falls into the head.

cam1.jpg
 






measuring camshaft bearing clearance

The rocker arm or camshaft roller follower is not bolted in. It is kept in position by the valve stem and hydraulic lash adjuster. Some members have removed their valve cover and found the rocker arm laying loose in the head after having popped out of position.

The procedure to check the bearing clearance is to:
Remove the rocker arm
Remove the hydraulic/spring timing chain tensioner
Revome the camshaft bearing caps
Remove the camshaft
Install the replacement camshaft
Insert plastigage on each bearing journal
Install bearing caps and torque to spec
Remove bearing caps and measure plastigage

Is the bore for the camshaft sprocket retaining bolt completely stripped out? I wonder if it could be repaired by a machine shop. It would probably require drilling, pressing in an insert, drilling the insert and then tapping with left hand threads. That doesn't sound very likely but it might be worth looking into. There should be used camshafts available on engines that have suffered chiming chain slip and were not economically repairable but then there's the risk of not meeting the clearance spec. I know that cjmedina has a set of camshafts that he purchased just to get a replacement bearing cap. You might PM him asking about the condition of the lobes and the journals. He's the member that broke one of the caps while trying to install them with the rocker arms in place. Actually, I have removed and installed both camshafts twice without removing the rocker arms but as I said it is a risky process even when done very carefully.
 






Thank you so much for your help Dale! This information was EXACTLY what I was looking for!

I feel pretty confident with this information I now have the complete picture of what I need to do, down to the last detail, to get this thing done. Changing out the camshaft was a real twist in this whole process.

The measuring of the tolerances between the bearing cap and the camshaft journal was not described anywhere either in writing or on the internet. On behalf of others that have to go this route, I thank you and salute you!

Thank you!
 






I used the OTC Tools 7928 Ford Valve Spring Compressor 4.6 5.4 Liter by driving out the roll pin and using an grade 5 or better bolt to fit the hole.

Put the spring half of the tool on the valve retainer, put the cam potion under the cam and over the spring section and join with the bolt.

Saved me plenty of money...
 






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