Bushcrusher

Bushcrusher

Active Member
Hi guys, cand some one please help me decide what the noise could be? I've trawled the usual places and I belive it to be the hydraulic lifiters (well one or two of them) the ticking is there from the moment you start .it doesn't dissappear when hot and increases ticking when engine revs.
She is a 1998 3.9 v8 and goes like a train even with this annoying tick.
I belive it should replace all the lifters and Rods and even the cam shafts.
Would this be a reasonable thing to do? I ASK this as there are some articles about the piston slides that are put in under extreme pressure drop due to poor tooling (age related and never really calibrated )SO you would be opening up a can of worms.
So please guys what would you think is best?
Dave
 
If the ticking is like a machine gun when the engine is under load, you could have a blown exhaust manifold to Y pipe gasket something I had once.
Or if a lighter tick that could be an iffy injector, just remove the electrical connection from the suspect and if it’s now quiet that’s the faulty one, agin something which I had, but a double or treble shot of Redex in the fuel sorted that out.
Only if your engine has ever overheated the there is a possibility of the bore liner slipping which understand ticks when the engine is up to temp.





Sent from my iPad on a train
 
Liner movement will sound like a metallic TAP, starting as the engine begins to warm up (or at running temp. depending on how new the problem is) & the noise will be at piston speed.
You don't say if you are running LPG, if so & the problem is recent switch over to petrol whilst driving & see if the sound diminishes.
 
What is the oil like?

Does the tapping noise disappear as the engine speed increases?

As said by Discool it could be a blown exhaust manifold Y gasket..
 
Possible causes as above.
I've had the downpipe to Y-piece one and the exhaust manifold gasket blowing one - the latter after a top end overhaul incl cam & followers so I wasn't happy with the rapid tapping noise shortly after initial start-up! I did suspect the manifolds as they were badly pitted & I should have refaced them before refitting. (Double S tubular sports manifold)

Other likely cause is worn cam & followers. You have one camshaft & 16 followers. These must be replaced all together as they wear together.
Usually worth doing the timing chain & its sprockets whilst you're at it plus stripping a cleaning the rockers, amazing how much crud builds up. Pushrods were fine on mine.

What oil are you using?
 
Last edited:
Hi guys, it is a lpg the oil in use is 20w-50 mineral oil. The noise is constant from very cold start up and when engine up to temp. It increases when revs increase and never goes away, I must admit when I switch over to lpg it's not so tinny sounding.
I agree with ratae regarding the other things to change whilst the top half of Engine is off.
She sounds bloody lovely when idling (still ticking but not so loud) and heads turn (yes I'm a tart) and then the ticking cuts in! Gutting
 
I change my oil every 6000 miles , some say to soon but I was like this with my nitrous busa drag bike
It's the engines lube and needs to be tip top as do the other oils and lubes especially after going swimming
 
Go with the easy stuff first. Discool is probably right.
If you had cam/follower issues I would have thought you would know about it as performance would be poor.
Slipped liner is a possibility but check exhaust first, hopefully you'll find it is just a bust gasket, easy fix but if on manifold can be a bit of a fiddle especially if the studs are tight or snap when you undo them.

You might also consider a compression test if you really think it is valve train related; vacuum gauge checks might also give you a clue.
 
Hi Kev, good to hear from you m8, I have a pressure guage soil will check for sure. So what should I do 1st not counting pressure test as I will do that as a matter of fact.
I mean would it benefit me stripping down the top half of Engine and check ever thing over or am I making a load of work for myself? I've always been one to do everything by the book with engines, brakes and gearboxes
 
If it's happened over a long period of time in your ownership or was well worn when you bought it you might not notice a reduction of performance in something that has the aerodynamics of a garden shed. I certainly noticed an improvement after replacing the cam.

I agree with your oil change frequency & the oil type. FWIW I use a 15/40 mineral.

Exhaust gaskets would - hopefully - be the easiest check assuming it all comes undone. Look for black marks on the gaskets & head & manifold faces. Don't forget that if you use the individual gaskets they can go on in different ways but only one is correct.

Possible argument for removing the heads & checking the heads are flat & valves/seats/springs if you're that close.
Much discussion about hgs & I went with the Elring composites & as mine had the 3rd row of headbolts I left those out.
 
I'm going to do what my gut feeling is and that's strip it down and check it all. I will do what ratae also suggested as i will have the top half off and would seem daft not too.I will of course do the other checks suggested by classic Kev and discool before going into full mode landy owner (doing it yourself )
 
Bushcrusher said:
Hi guys, it is a lpg the oil in use is 20w-50 mineral oil. The noise is constant from very cold start up and when engine up to temp. It increases when revs increase and never goes away, I must admit when I switch over to lpg it's not so tinny sounding.

Switch over TO lpg or FROM (back to petrol)?
The reason I ask is that combustion chamber temps. are higher with gas & sometimes running on petrol (cooler C.C temp.) will quieten the noise down, if the fault is indeed liner slippage … the fact that the noise is there from 'very cold' leads me to doubt it.
Click to expand...
 
I've no first hand experience of liner problems, but from what I have read, there are usually other problems too, such as exhaust gases getting into the coolant, or coolant getting into the bores.
Have you checked all the spark plugs are in in tight and the compression washers are in good condition? A loose plug will certainly make a tapping sound and not affect performance. Don't ask how I know this!
 
Ha! There's always one! Fortunately it's not an interesting story, got home one day and heard what sounded like a dead tappet (bmw straight 6). Took the coils off each of the plugs and noticed one was extremely loose!
 
Bushcrusher said:
Hi norseman, can you explain more please
Click to expand...

Further to my post #3. The steel cylinder liners are just pressed into the alloy block & the slightest crack in the block loosens the 'grip' on the liner & the piston (still a close fit inside due to the piston rings) drags the loosened liner up & down in the block, hence the 'tap' when it strikes the underside of the head. This is why the noise is at piston speed, not valve gear which runs at half crankshaft speed. Also when the block is cold the liner is still held in place, but as the engine warms the alloy block expands & looses it's grip on the liner allowing it to move.
This is however a worse case scenario & I suggest you check through all the items posted by the experienced guys on here.
 
Bushcrusher said:
Hi Kev, good to hear from you m8, I have a pressure guage soil will check for sure. So what should I do 1st not counting pressure test as I will do that as a matter of fact.
I mean would it benefit me stripping down the top half of Engine and check ever thing over or am I making a load of work for myself? I've always been one to do everything by the book with engines, brakes and gearboxes
Click to expand...

Stripping the top end is just making work at this point because you don't know if it is actually necessary. Really you need to either crawl under it with the engine running and then check for exhaust leaks or if you have access to a ramp get it up in the air. You could also try listening to the engine with a long screwdriver or use a proper mechanics stethoscope. Place your listening instrument of choice at different positions and listen, you should hopefully be able to narrow down where the tapping noise is coming from.

If doing compression test, do wet and dry tests. This can help indicate if a problem could be related to valve train. Similarly, vacuum testing can be an aid to diagnosis.

As already suggested, do check the plugs are firmly in their ports.

If you decide for your own reasons to strip the top end, make sure you order parts and gaskets first and allow 2 days to do it, you really don't want/need to rush. You should take the opportunity to look at all the followers and so far as you can see, look at the cam lobes. Hopefully all will be O.K. You should also remove and lap the valves and check for any sloppy valve guides and replace the stem seals. Absolutely make sure if you do take the top off that you thoroughly clean the ram housing and plenum and check the throttle disc, clean the idle air control valve (stepper). If you go a stage further and pop the timing case off you can remove and inspect the cam and oil pump and oil pressure switch and if the crank front seal needs done it is easy to do with the cover off. However, you also need to drop the sump if going the whole hog. When putting it all back together make sure all the gaskets are properly seated and that you use a good quality gasket sealer.

HTH good luck.
 
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