Broken timing chain

[Hossexplorer]

I am trying to help a friend with his '97 4.0L SOHC that has broken a timing chain. I found a kit online and the special tool I think, but I have heard these are interference engines. Will there be bent valves or other issues that will have to be fixed beside the chains and cassettes? Can someone who has done this help me? Thanks.

 

[2000StreetRod]

which broken chain?

How did you determine a chain was broken?

Which timing chain is broken: crankshaft to jackshaft; jackshaft to left camshaft; jackshaft to right camshaft; or crankshaft to balance shaft?

The SOHC V6 is an interference engine. I suggest you determine if there is valve damage before purchasing the OTC-6488 timing tool kit and timing chain kit. It may be less expensive to replace the engine rather than repair it.

One way to check for valve damage is to use an inspection camera inserted thru the spark plug hole. Another way is to use an air compressor to pressurize the cylinder when the valves should be closed and check for leaks. A third more labor intensive way is to remove the heads.

Click on the link in my signature to my helpful threads and read about timing chain related issues for more information.

 

[Hossexplorer]

Thanks for the info. A local mechanic told him that the chain was broken, unsure of which one though.

 

[2000StreetRod]

right cassette?

If the right cassette guide assembly is broken then either the engine (preferred) or the transmission will have to be removed to replace the cassette.

If the valves (expensive) are bent a special tool (expensive) must be used to remove the cam followers. The expensive head bolts are torque-to-yield and not reusable. If there is valve damage it may be cheaper to replace the engine with one from a salvage yard.

After market parts prices:

Intake valve: $16
Exhaust valve: $16
Head bolt set: $30 (one head)
Head gasket: $41
Rotunda 303-581 Valve Spring Compressor: $181
OTC-6488 timing tool kit: $210

 

[rocket22]

If your truck is worth less the 1500....

junk it....or buy a used engine. No reason to fix this. Hence the death rattle

 

[koda2000]

junk it....or buy a used engine. No reason to fix this. Hence the death rattle

i junked my SOHC this past May. it just wasn't worth the time or money to fix it. got $430 for it for scrap. as far as i'm concerned the SOHC engine is a POS. V8's are the only way to go.

 

[2000StreetRod]

harsh words

I agree that the SOHC V6/5R55E is not as robust as the OHV V8/4R70W however I enjoy having an engine that easily revs to 6,000 rpm and has five forward speeds. It's a shame that the engine needs to be pulled every 150K to 200K miles and have the camshaft timing components replaced. But then I can remember when my 1970s and 1980s engines needed to be rebuilt every 80K to 100K miles.

 

[koda2000]

I agree that the SOHC V6/5R55E is not as robust as the OHV V8/4R70W however I enjoy having an engine that easily revs to 6,000 rpm and has five forward speeds. It's a shame that the engine needs to be pulled every 150K to 200K miles and have the camshaft timing components replaced. But then I can remember when my 1970s and 1980s engines needed to be rebuilt every 80K to 100K miles.

yeah, i wonder if it's more the engine or oil technology that makes the newer engines last closer to 300,000 miles when engines from the 60's and 70's were lucky to see 100,000. i'm running Mobil 1 in my v8's and expect to see 300k out of them. i was using Motorcraft synthetic blend, but then i saw that Walmart was selling Mobil 1 full synthetic for about the same price, so i switched.