Start up knock/tap

[96stx]

Fired up the old red 96 today, it has been sitting for a month while I've been away on a job. Started with a rapid tapping/knocking sound, kept at it for a few minutes, volume lessening, I shut it off.

I guess its either a lifter or a bearing. Hopefully a lifter, truck has 180k, pretty well kept up for the last 100k, before that I didn't own it.

Ideas as to how I should proceed.

96 stx

 

[pcollins]

Seeing as this is the 4.0L forum i assume its that such engine. most likely a lifter, those engines and the 2.9 are pretty popular for that.

 

[96stx]

Yes, 4.0 with 5 speed. What can I do to solve problem short of tear down? Deer season is upon me and this is the hunting ride.

Thx,

96 stx

 

[RonD]

You can try adding a high detergent oil or something like Marvel Mystery oil to the oil in crankcase now, then start it up and run it for a bit, 10 minutes may be, see if ticking goes away, i.e. lifter pumps up.
Then change oil.

Knocking is another issue if it is a rod bearing, an exhaust leak can sound similar.
Often disabling the spark on the cylinder with the bad rod bearing will quiet the knock, so you can test one cylinder at a time to see if it is a rod that's making the noise.

 

[brinker88]

The push rods/rockers are what's worn. It's the same thing that's wrong w/ my truck.

Deltacam.com is the best place to get the whole rocker assembly and new hardened pushrods. They charge $180 + $42 core charge.

 

[96stx]

All sound like the solution. Brinker88, have you done ur truck yet with the rocker etc.?

 

[brinker88]

Havent gotten the chance to do it yet, no.

 

[96stx]

poured in the Marvel oil, seemed to change the sound, tapping noise still present, drove up road, got truck warm, tapping still there. What is relative danger of breaking something by driving truck??

Thx,

 

[notaprob]

Often disabling the spark on the cylinder with the bad rod bearing will quiet the knock, so you can test one cylinder at a time to see if it is a rod that's making the noise.

Does that apply to most engines or just push rod?

 

[RonD]

Does that apply to most engines or just push rod?

Connecting rod(piston)

Knocking noise on the connecting rod is loudest on the power stroke when it slaps the crank journal, no spark stops the power stroke but you will still have some knocking from the loose rod bearing.

 

[notaprob]

Connecting rod(piston)

Knocking noise on the connecting rod is loudest on the power stroke when it slaps the crank journal, no spark stops the power stroke but you will still have some knocking from the loose rod bearing.

haha thanks. I just had a brain fart!

 

[96stx]

Good News! Sort of

Well, decided if she blows, she blows. Went for a good long drive. Looks like the ticking, tapping, knocking etc. has gone for a while. Eventually this engine will need rebuilding, are the lifters reusable or should they be replaced?

 

[RonD]

The 4.0 lifters are usually $20-$30 apiece, so $240 to $360 for the set, although I have seen them advertised for $120

They are not hard to take apart, clean then reassemble.

 

[96stx]

Thanks, I guess we've beat this to death. Appreciate all the help, hope I can return the favor.

Fnsane

 

[daniel3507]

All sound like the solution. Brinker88, have you done ur truck yet with the rocker etc.?

I have replaced mine with delta cam and still have a ticking sound.