Question 97-4.0 OHC Noise

[Johnshan2]

Hello guys,

Please help! I replaced my engine ( Salvage Engine) and the engine had a timing chain noise. I removed the engine and then the salvage yard replaced both chains and tensioners etc. I now have a ticking noise from the pass side of engine?? The sound is like a lifter noise. It is there all the time(Idle and up). It is not very loud but annoying. It is best heard through the fenderwell with the hood shut. Has anyone ran into this???

Thanks so much for any help!

John

 

[Snowboi]

Have you replaced the spark plugs and wires? You can buy a automotive stethoscope, or buy a foot of heater hose (the heater hose will be alot cheaper), put your ear up to the heater hose, with the engine running, put the heater hose around the block/valve covers/ intake/etc., try to pinpoint where the sound is coming from. It could be the injectors that your hearing.

Edit: Do you mean OHV or SOHC, I'm sure you mean SOHC though.

 

[Johnshan2]

SOHC is the engine.
Defiantly not injectors, it sounds like the old V8's with one rocker out of adjustment. Plugs and wires are good. I will try to pin-point it further, just thought maybe it was a common thing. If I open the hood and listen It is barely audible( Fan etc...) but through the fender-well or under the truck you can hear it very well. Middle of the engine and more to the rear, that's why I questioned the right chain??? I will let you know.
Thanks!

 

[2000StreetRod]

cat heat shields

Sometimes the welds break that hold the catalytic converter heat shields and the shields rattle.

 

[Johnshan2]

It is not a rattle, it is a consistent tap/click noise. But thanks for the suggestion!

 

[Snowboi]

It could be the signs of the timing chain (or tensioner) going out, alot of those engines have somewhat of a major problem with timing chains (I think its the front to be exact). It could be a exhaust leak, or a bad plug (spark plug, or spark plug wire).

 

[2000StreetRod]

tick

I had a similar noise on one cylinder after replacing my timing chain components. I suspected it might be due to loose sludge particles lodged somewhere in the valve train. I drove my Sport normally for a day to make sure it was running fine. The next day I did a WOT pull in first gear to near engine max (6250 rpm) and from then on never heard the "tick" again.

I suggest that you flush the engine (I use Gunk) for 5 minutes at idle after the engine is warmed up and then change the oil and filter.

 

[dimension12]

I would run some cleaner through the fuel system and intake. Sometimes carbon build up on the valves will create a ticking noise. On older vehicles I used to poor cold water down the carb. which is tricky as you need to keep the engine running.

 

[Johnshan2]

Thanks for the reply's

After further listening the sound appears to be coming from the area around #2 cylinder where the exhaust manifold and cylinder head meet. Leading me to believe it could be the trash on a valve thing. One more thing, the noise is much quieter when the engine is cold and louder when completely warm. I will try the cleaner and see what happens.
Let ya know...

 

[2000StreetRod]

gasket leak?

It might be a leak in the exhaust manifold gasket. Listen with a length of flexible hose at the junction of the exhaust manifold and the head.

 

[Johnshan2]

Well guys, I ran the injector cleaner in the fuel system and I also sucked some cleaner into a vacuum hose. There was a lot of white smoke but no change in the noise. I can rule out an exhaust leak as there was no smoke under the hood. Maybe I will pull the valve cover next.
Thanks for the reply's!

 

[Johnshan2]

Removed the valve cover today, I see no issues at all. Timing chain and guides look good. I'm not sure where to go next...

 

[2000StreetRod]

SOHC V6 Timing Chain Inspection & Repair

SOHC V6 Timing Chain Inspection & Repair

Using your fingers try to pull upward the traction side of the right guide where the upper positioning bolt is located as shown below.

If it moves upward more than 1/16 inch then the guide is probably broken at the base near the pivot point.

 

[Johnshan2]

Wow great picture!
The guide doesn't move except the small amount of play at the bolt in the picture. I used a mirror and looked down the guide, it looks good.

Question though; When I first looked at it the tensioner was relaxed and the chain was loose. Is this normal? Isn't their a spring in the tensioner to keep it somewhat tight while the engine is off(No oil pressure)??

Thanks for the help!!

 

[2000StreetRod]

valve spring pressure

The photo credit goes to cjmedina.

You are correct that the right and left tensioners utilize hydraulic and spring pressure. The spring pressure is inadequate to keep the chain taught. Depending on the position of the camshaft depressed valve springs can force the cam to rotate clockwise creating chain slack on the traction side. Normally (when engine is running) the rear jackshaft sprocket pulls the camshaft sprocket via the chain (traction side). The hydraulic/spring tensioner is on the slack side and just takes up slop in the chain to keep it from slipping. If you rotate the crankshaft manually (always clockwise) you should notice the chain cycling between slack and taught depending on the valve spring depressions.

 

[my98nnj]

Did you check that you don't have a lose spark plug?

Had a similar noise in an old XJ12 Jag I had. Wound up being nothing more then a lose spark plug. tap tap tap tap - was the plug moving around each time it fired. I was lucky it didn't blow the threads out.