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More problems after 0012m upper/lower manafold gasket, Tentioner kit fix

Nothing I would recommend, doing this job without the correct tools could result in major engine damage, as you now know. Why are you still trying to put it back together with a damaged head?

Bob

I'm probably going to get it back in timing with the cracked Cap and check for compression. If the head is OK except for the Cap then I found this for sale on Ebay:

http://cgi.ebay.com/ebaymotors/2001...r_Truck_Parts_Accessories?hash=item335a92735e


I then could replace with one of the caps that have good clearance by checking with Plasigauge.

The guy in the engine shop was wrong. The clearance is not .0008 but between .002 and .004. A lot more clearance.


What do you think?


Cliff
 



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Buy now!

I'm probably going to get it back in timing with the cracked Cap and check for compression. If the head is OK except for the Cap then I found this for sale on Ebay:

http://cgi.ebay.com/ebaymotors/2001...r_Truck_Parts_Accessories?hash=item335a92735e


I then could replace with one of the caps that have good clearance by checking with Plasigauge. Or I can go ahead and buy and mail you a cap when I get it. Let me know.

The guy in the engine shop was wrong. The clearance is not .0008 but between .002 and .004. A lot more clearance.


What do you think?


Cliff

I say buy it now! If you don't, I may buy it just for a possible regrind to change my duration and overlap.
 






Ok

So you think it's a good idea? I can check for proper clearance with plastgage.

I can't see not finding a good fit.


Cliff
 






I'll buy it and send you a cap

So you think it's a good idea? I can check for proper clearance with plastgage.

I can't see not finding a good fit.


Cliff

If you like, I'll buy it now and mail you a cap as soon as I get the whole package.
 






OOOOP's I just bought it

I just need the caps.

I will send you the cams since I don't need them.


Cliff
 












Oh well.......Thanks for the thought.

With my luck the head has bent valves.

I will send you the cams.



Cliff
 






contact the seller to split the shipment

Oh well.......Thanks for the thought.

With my luck the head has bent valves.

I will send you the cams.

Cliff

Try contacting the seller and ask that the cams be shipped to me and the caps be shipped to you. I'll e-mail you mailing address.
 






You cant do that.

I just need the caps.

I will send you the cams since I don't need them.


Cliff

You CAN NOT mix and match BEARING CAPS, PERIOD!

Clearance tolerance assumes you put back on the cap that was machined to fit back on.

You can not even switch around the caps from the same engine.

camcaps-vi.jpg


DONT EVEN TRY IT!!!!

That guy on fleBay is selling scrap metal, I can zoom in and see that the lobe chamfer is completely worn away. Its scrap metal. He got all he could for the castings and is now selling some scrap metal. He turned the cam in a position so its hard to tell its shot, but it is, its scrap metal.

His picture I enhanced.
crapcam-vi.jpg


This is a good cam, you can see the correct unworn chamfer.
cam6-vi.jpg


What he is selling is not even as good as a bad cam. This cam is no longer usable.

cam7a-vi.jpg


Your biggest problem is I can not find any place on this planet that sells over-sized cam bearings for a 4.0L SOHC. So if you put used mismatched bearing caps on the head and find someone to machine it back to round, you will need to have custom bearing made for it.

The Head must be replaced..... End of story..


Sorry to have to be the one to tell you all this, but that's just the way it is. Please do not cause additional damage to that engine trying something this wrong. I don't even want to get into what it will do.


Sorry again for being the bearer of bad news.
Bob


Edit: Dont you also find it strange that he has been trying to sell that for four years?
 






Caution when tightening bearing cap bolts!

Nothing I would recommend, doing this job without the correct tools could result in major engine damage, as you now know. Why are you still trying to put it back together with a damaged head?

Bob

I investigated further into how a camshaft bearing cap might break when tightening the bolts. I found that the bearing caps must be square with the head mating surface or the caps may bind. If the cap bolts are tightened with the cap off-square the cap may break. This failure can occur any time that the other three caps are removed or loose and a valve spring is compressed placing pressure on the camshaft. The valve spring pressure attempts to lift the camshaft but if the timing chain tensioner is in place one end of the camshaft is held down by the chain. The result is that the camshaft axis is at an angle to the head instead of parallel to the head. When a camshaft cap is tightened it attempts to seat on the journal which is at an angle to its seat on the block. As the cap is tightened the cap can bind and break from the stress.

The situation is most likely to occur with the right camshaft when it is in the correct position for timing. At this position the #2 cylinder valve springs are both significantly compressed placing a lot of pressure on the camshaft.

In most situations it is good practice to torque something long uniformly and in steps. In the case of the right camshaft I believe the risk of distorting the cam due to non-uniform torquing is much less than the risk of breaking a cap. I suggest that hand pressure be applied to the front end of the cam to compress the cylinder #2 springs as much as possible using the leverage of the camshaft length. Then the second from the front cap should be positioned with the other hand and its bolts carefully tightened. Repeat the hand pressure process for the third from the front cap and then return to the second from the front cap. The bolts on a particular cap should be tightened progressively so that the cap gaps stay comparable.
 






Perhaps that is why the service manual says to install the followers last.

followerslast-vi.jpg
 






I believe so

Perhaps that is why the service manual says to install the followers last. . .

When I first saw that I wondered about it and decided the step was unneccessary. From what I have just learned I suspect that is why the step is there. Using the timing tool set to time the camshafts eliminates the need to remove the camshaft bearing caps.
 






I investigated further into how a camshaft bearing cap might break when tightening the bolts. I found that the bearing caps must be square with the head mating surface or the caps may bind. If the cap bolts are tightened with the cap off-square the cap may break. This failure can occur any time that the other three caps are removed or loose and a valve spring is compressed placing pressure on the camshaft. The valve spring pressure attempts to lift the camshaft but if the timing chain tensioner is in place one end of the camshaft is held down by the chain. The result is that the camshaft axis is at an angle to the head instead of parallel to the head. When a camshaft cap is tightened it attempts to seat on the journal which is at an angle to its seat on the block. As the cap is tightened the cap can bind and break from the stress.

The situation is most likely to occur with the right camshaft when it is in the correct position for timing. At this position the #2 cylinder valve springs are both significantly compressed placing a lot of pressure on the camshaft.

In most situations it is good practice to torque something long uniformly and in steps. In the case of the right camshaft I believe the risk of distorting the cam due to non-uniform torquing is much less than the risk of breaking a cap. I suggest that hand pressure be applied to the front end of the cam to compress the cylinder #2 springs as much as possible using the leverage of the camshaft length. Then the second from the front cap should be positioned with the other hand and its bolts carefully tightened. Repeat the hand pressure process for the third from the front cap and then return to the second from the front cap. The bolts on a particular cap should be tightened progressively so that the cap gaps stay comparable.


I'm pretty sure this is what happened in my case.

When I loosened the Caps I did so in the sequence of front to back, rather then the normal torque sequence of middle on out. This may of caused the Cam to lift so that it ended up not parallel to the head but tipped higher in the front then the back due to the fact that the chain and sprocket is holding the back down. However I'm not sure this made a differance.

I was VERY careful putting the caps back on, trying to keep them square to the head. I also finger tightened all of them before starting the torque sequence. Then, I torqued them in the correct sequence of middle on out, in steps!

Before the cap cracked, all the bolts were NOT fully torqued, however, the value was close to 25 In/lb but, I believe less then 35 in/lb.

When I left the back cap to torque the front cap, I thought it was strange that the bolt felt to be bottomed out, like they were completely torqued, yet I wasn't finished with the others! When I turned just a little more, this is when I heard the click and saw the crack in the cap!

It is my opinion, that the cam did not start square to head and during torquing put uneven upward pressure on each cap, specially the front. So I probably over torqued the front cap accidentally with my beam style torque wrench. I have a 1/4" drive click style from Harbor fright on order.

One other thing.....I still think this vehicle is jinxed,...... and I still don't know how the cam jumped timing!



Cliff
 






What Now?

Well I was going to start torquing down the right cam after I found a set of Caps which I hope to find a good fit.

I will then use Plastgage to find the front cap replacement. The spec is .002 to .004 of clearance.

When I started to do this project I noticed that the cam is not sitting down on the stanchions...By A lot!!!!

See Photo:

ftp://cj136.gotdns.com/files/Explorer/DSCN8473.JPG

The Cam is tipped up at an angle from back to front. The back journal is down on the stanchion.

Also the rear guide can be moved up and down about 1/4" or so. I don't know if this is normal or that it is because the cam is lower in the back.

See Photo:

ftp://cj136.gotdns.com/files/Explorer/DSCN8475.JPG


How do I now get the cam down on all the stanchions so I can safely torque them?



Cliff
 






Found Rocker laying head

I didn't notice this before........

I can't move the cam now yet I could before the front cap broke.

I don't see what holding it

Now I saw the back rocker on the #3 cylinder was laying in the head. You can see the nick and there is one on the side of the journal but not on the rolling surface.

ftp://cj136.gotdns.com/files/Explorer/DSCN8479.JPG


Can I remove the cam without pulling the head?




Cliff
 






You should not install the cam without first removing all the followers. Also the chain sprocket should be removed first.

You can not use caps that were machined to another head.
Close only counts in hand grenades and horse shoes.

This just simply will not work. They are machine bored together, no two are exactly alike.
 






I found the instructions how to remove the head and I found that there is a tool to remove the Sprocket.

CamRemoval.PNG
Tool.PNG
 






Guide fractures?

. . . Also the rear guide can be moved up and down about 1/4" or so. I don't know if this is normal or that it is because the cam is lower in the back. . . .
Cliff

The only thing that keeps the traction side of the guide assembly in place is a bolt that passes thru the pivot/bushing at the bottom of the assembly and the positioning bolt with a flange at the top. The bushing is larger in diameter than the bolt and allows a little movement. If you're saying that the guide moves up and down 1/4 inch that seems a little excessive. If you're saying that the guide moves side to side 1/4 inch that's about right. The groove in the top is larger than the flange on the positioning bolt that fits in the groove.

There is another reason for concern. The closeup photo you posted identifies possible fractures in the rear guide. I've marked the possible fractures with red arrows in the photo below.
RtGuide.jpg

I suggest you investigate further and try to determine if these are actually fractures or are seams from the mold that formed the guide. If they are fractures then the guide could fail at any time because there is no metal on that side to support it. That was my complaint about the "improved" guides.
 









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Can't see it cracked

It looks like molding marks.

The guide moves up and down. I did not notice it loose before. I'm assuming it may be because the cam is tipped down slightly in the back. I don't know why the cam is not turning though.

I need to loosen the cam.

DSCN8336.JPG
 






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