preemptive SOHC chain/guide replacement

[jvogel]

I have a '97 Sport with the 4.0L SOHC and 115K mi.

For the first 100K miles I had the rattle-on-startup, but never had a problem (Ford convinced me it was not harmful). About a year ago Ford replaced the chain tensioner(s?) for free and the rattle went away.

Because of the high miles, resale value is almost nothing. However, the car runs strong and is still very useful. I'd like to put some money into it and keep it for a while.

Cam chain and/or guide failure seems to be the biggest problem with the SOHC so far. I'm concerned about wear on the chain and guide during the rattle years with the malfunctioning tensioner.

Has anyone done a preemptive cam chain/guide replacement? I know the back requires pulling the engine, but does the front? Is the back cam chain as big a problem? I think(?) they only replaced the front tensioner to cure the noise.

Any other weak spots to watch out for with this engine?

Thanks!

 

[procyon]

Front (LH) chain guide replacement can be done with the engine still in the vehicle. Rear (RH) replacement cannot.

Performing this procedure requires about 6 special tools to properly set the timing of the camshafts. Even with the tools, it is a tricky process for any 1st timer. You would be better off finding a tech who has done it a bunch of times instead of forking over all the dough for the tools.

BTW, the chain guide failures are pretty much isolated to the front guide. This is what ONP 01M01 is for. 00M12 is for some intake gaskets and the timing chain tensioners which are on the outside of the head.