How to: - Rear Timing Chain Tensioner Replacement | Page 7 | Ford Explorer Forums - Serious Explorations

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How to: Rear Timing Chain Tensioner Replacement

Prefix for threads which are instructional.
Just so I understand you. So I cannot simply remove the cam with potentially bad threads and replace it with a brand new part from ford because every head is specially machined to match the specific cam?

I suspect that at the factory cam journals are measured and the heads are bored to match with specified clearances. It's a similar process to the way the factory measures and categorizes pistons and then matches them to cylinder bores. I'm not aware of any forum member replacing just a camshaft. I just remembered that Super Six Motorsports sells custom high lift reground cams so maybe its not as much an issue as I thought. The safe way to remove and install the camshaft is after removing the cam followers which requires a special valve compressor tool.
VlvSprngCmprsr.jpg

I purchased an inexpensive one ($150?) that has "shoes" for the SOHC V6 & V8 and the DOHC V8. Removing the cam followers eliminates the valve spring pressure on the cam lobes. The camshaft bearing caps are easily broken when tightening if the followers are in place. If a bearing cap is broken then another head must be purchased because there are no bearing inserts.

Why would i need a used head, because it comes with a matching cam?

Yes.
 






I contacted Tom at Siper Six Motorsports this morning. What a great guy! I told him right from the get go that I was not interested in performance parts and he spent 25 min on the phone with me discussing my current situation.
He says that if the bolt is slipping its some sort of friction issue. "If its spinning, it's not torquing"
He recommended removing the bolt, chasing the threads, lubing all mating surfaces and trying again.
In the worst case scenario that something strips, he recommended getting a new cam from Ford. He says that the cam is not matched to the head but the caps are so take care not to switch them.

I hope to tackle this late tonight.
Thanks for the input @Tech By Trade and @2000StreetRod and wish me luck.
 












Thanks for the report. Its good to know that the bearing caps are the issue and not the heads. Is it possible that the camshaft holding tool is allowing the cam to rotate and you think the bolt is slipping?

It took me a bit longer to get the motor back out and get back to work on this. I used a pipe cleaner on the inside of the cam threads and put just a hint of oil between the bolt head and washer. Went in easy and felt good when torqued to 62 ft lbs. Motor is now back in and the project continues.

On another note, I just realized today that one of the connectors on the new tranny's harness is different. It appears I may have picked up a 5r55w when i should have gotten a 5r55s. Hopefully I can make this work or the project is going to get much more expensive.
 






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