Cam troubles, is it common? Are there upgrades?

[Sport1998]

My 98 sport sohc knocks like crazy when I first start up. Im at 120k miles right now. My mechanic said when the car is shut off the oil drains down into the pan and doesnt hold the oil up at the cam at all, therefor the clunking noise at startup. Is this due to bad seals or gaskets? Ive also heard another Explorer sport on Campus start up on campus and he had the same knock, my mechanic said it wasnt uncommon among the 4.0 sohc.

Is this a common problem and what is the fix for it? New cam? New seals or gaskets?

Also are there any aftermarket cams that I could look into if I was going to tear the motor apart to fix the problem. Why fix the stocker if I have the chance to upgrade.

Thanks in advance.

 

[HappyGilmore]

how long does it do it for? my 94 ohv does it for about 2 seconds then stops if its sat over night or for a long time. if its for like a minute then id think youd have a problem. i could be wrong but it sounds like what your mechanic said is right. anyone else want to chime in?, i could be wrong.

 

[Blee1099]

Are you sure its the cams? It could be related to the tensioners.. Every SOHC motor I've listened to was somewhat noisy.

 

[IAmTodd]

God forib, you've posted in the wrong forum. Some one do something before the world falls apart!!!

 

[HappyGilmore]

haha your right. i didnt catch that, iamtodd.

 

[CDW6212R]

I have a 99 SOHC which I just went through the work on. There is a tensioner on each head, which can wear out. They are removeable from the outside.

The real problem is that the 96-01 models have cam chain cassettes(chain, two sprockets, and plastic lined bracket) which have been known to come apart. There is also a check valve which may not be in the early models, which holds oil in the front tensioner.

The rear chain cassette is less likely to fail, I have been told. The recall is over I believe. The fix is to replace the front cassette, the two tensioners, and add the check valve. The front tensioner, check valve, and gaskets come in a TSB kit, which is what the factory repair installed.

I also changed my Jackshaft chain, the main crankshaft to jackshaft chain. It wasn't very expensive, and simple to change with everything else apart.

The hard part is getting the special tools to set the timing. The tools hold the crank and cam still, to allow the adjustment to be made. Someone else here paid $180 for those tools new, and sold them on Ebay for $160.

Do note that when doing the work, DO NOT loosen the bolt on the jackshaft or either cam, until the crank is at top dead center, and the tools installed. Any of those three bolts will allow the cams to rotate far out of time. Good luck,
Don