Engine vibration 1HD-T

[Dave2000]

I saw something like this way back many years ago, the vibration was more pronounced as the engine was a four cylinder, coincidently it was a Toyota.

Run great at higher revolutions badly at idle, it was a carb engine so no injector, no air leaks etc, valve clearances good, compressions perfect.

Drove me around the bend and decided to pull the head because it gave all the sounds of a leaking valve.....it was!

Over the years the carbon build up around one of the valve stems was SLOWING the valve down from closing.

If you turned the engine by hand or cranked you could not hear any problems and the gauge showed all was well however, at idle speeds the valve was closing enough to miss the piston but not fast enough to seal the cylinder, only seen this once in more years than I care to remember under the bonnet. Whilst not showing up on hand cranking as yours does, this could be attributed to the diesel engine being higher in compression?

I see you mentioning a broken ring but that would be a very rare occurrence, over revving an old engine with a wear ridge at the top of the cylinder allowing the piston/rod/crank assembly to 'stretch' could cause the top ring to break but you do not sound as though you are a 'thrasher'. Ring failures tend to be attributed to poor assembly and tend to show up within the first few thousand miles with crankcase compression, more so if the crack was in line with the lower ring gap.

Many may of heard an 'ol boy' pootling around the town for years on end and never having an engine problem, the car has ultra low miles (but many hours of running) and gets sold on to a 'boy racer' who by 'bad luck' destroys the engine within a few days of purchasing, seen it oh so many times.

So don't stress about the rings......just yet, fingers crossed for a choked valve stem, or sticking valve.

regards

Dave

 

[StarCruiser]

Hmmm. Thanks Dave for the reassurance, however, what you describe may well have happened, possibly twice. I do drive with a heavy foot, but with the auto box, the engine is generally held in check. I have however started to use the truck off road and, in low range, rev it harder on some slopes. Also I was the first user after it was grey imported from Japan at 9 yrs old and 90,000 Km which kind of suggested it had been pootled around Fukushima all its life (I always wondered why it glowed in the dark). It was so sluggish, it must have been coked up to the gunwales. A month of my heavy foot and it was a different truck. Do I think it got a wear ridge in that time or recently, I doubt it very much, and the BEBs were as near perfect as they could be when I changed them, no appreciable wear. So I dont suspect there to have been a ring break as you describe, at least I hope not.

Now the coked valve stem I have seen before on my Smart. I don't think it affected the running but when I rebuilt the engine it was obviously sticky with carbon so it did cross my mind with this one. Question is, what to do? My first thought is one of the new chemical/fuel replacement engine cleans, but I cannot see this cleaning a valve stem, I'll have to look into it. However this is jumping the gun, I still need to find exactly the source of this Darth Vader breathing.

I videoed the crank case compression, which doesn't seem excessive but I have nothing to compare to. I put my thumb over for ten seconds each time then let go.

https://vimeo.com/135222772

This is just after start up.

https://vimeo.com/135222891

This after it's been running 5 minutes

https://vimeo.com/135223007

And finally, the exhaust, which is, in fact showing the vibration quite well, as is the pump linkage in the second video. I couldn't see any smoking at all.

I guess after a compression test, the next thing is to drop the exhaust manifold and turn the engine over to see where the Darth Vader sound is coming from and check for excessive carbon on the valve stem. I'm pretty sure it's not an inlet valve as the inlet manifold didn't give any sign of the Darth Vaders directly, it was more internal while I was checking the valve gaps.

Thing is, would clearing the carbon actually solve this or would (if indeed it turns out to be a non sealing valve) it have pitted the valve seat? I guess it's head off time if it's a sticking valve. [emoji20][emoji20][emoji20]

 

[Dave2000]

Your import, running poor with low miles and a good thrash does fit the bill but, I doubt there would be a ridge at such low km's. But, just out of curiosity, did the engine vibration just pop up after a thrashing? If a valve does not close quick enough, it 'may' have got clipped, just enough to bend it ever so slightly, this would prevent it sealing correctly, the symptoms would remain constant for awhile until the valve seat started to burn/erode. Also, I cannot find a conclusion about the harmonic damper question I posed earlier in the thread, did it get checked?

Assuming I have simply missed it then on to the sticky valves/Darth Vader sounds, having purchased a bottle of anything similar to 'Redex', you need to squirt it neat onto the valves stems when they are open.

Manifolds pulled away, engine rotated until number one valves open (overlap if possible?), leave for awhile (hour) and then rotate to number two and so on, pausing for an hour or so for the gear to do it's job. A laborious job and only a few bolts from pulling the head. DO NOT be tempted to scrap at it with a screwdriver, lumps can fall away and get jammed in between the valve and seat. Years ago we used to pour it (Redex) slowly down the carburettors, bit at a time keeping the engine running. finally we threw loads down so it was enough to stall the engine, knowing full well that all the plugs/valves were covered. then remove the plugs and squirt some down the plug holes. Leave it overnight, new plugs the following morning and start the engine, just pray your mum/neighbours never had any washing out!! Left valves/combustion chamber nice and shiny, engines idle and run generally better.

Can't do that with your diesel as the risk of hydraulic lock damage is IMO too great, so a part strip of the upper components?

If you pull the head at least you can have all the valves pulled check for straightness, lap and put back in, in the long run this may be the better option.

Also, beg/steal/borrow a bore scope with screen, the tiny camera will allow you to check the bore for a score line, something a cracked ring always leaves behind, the gases get behind the ring forcing it outwards and tighter against the bore, any ring damage will be very apparent.

Final thought, using the expensive fuel like BP Ultimate or whatever may work if the problem is a sticky valve, it would be a slow process but thinking of your pocket it may be an easier route?

regards

Dave

 

[StarCruiser]

Thanks Dave for that detailed post and the Redex trick. I can get hold of a borescope but will need to see if it will go down through the heater plug holes.

That's another thing that's been nagging in the back of my mind that sometimes older heater plugs have been known to break off. Easily checked I know.

I'm not sure when this came on as I think it was over a short period of time rather than immediately after something I could pin it on.

Truth is I have only really this past weekend had a chance to start looking into it. If the harmonic balancer is in effect a dual mass type pulley at the front of the engine, then this is solid as a rock as I was turning the engine over by hand with this over the weekend. I will give it a good look over as much as I can manage anyway.

I know I've got a list of things to work through, I'm just short on time at the moment.

I suppose I could do a leak test once I have the exhaust manifold off by squirting a small amount of liquid into the valve seat at fully closed and see if it disappears then blow it out the heater plug hole.

Plenty to do and I will do it, when the time is there, mountings and external stuff first.

 

[StarCruiser]

Ok Dave, felt bad, went out and showed my pulley the iPhone camera.



The rubber between the parts is complete and, well, rubbery I guess. Not hard, not soft either, but what you'd expect trying to push your finger nail in. Firm I would say.

I guess that rules that one out?

 

[Dave2000]

The harmonic balancer is best tested by levering from behind with a plate to protect the engine front and a big screwdriver, you are trying to move the very outer rim that drives the fan belts, this is bonded to the inner part held by the big bolt. In worse case scenarios they can come off doing all sorts of damage. I would paint a white line right across the diameter of the front of the pulley, fan and shroud removed, then get a timing light attached to your spark ignition car parked next to yours and point it at the pulley as you rev the engine up and down, if the line distorts i.e. the outer and inner pieces are moving ever so slightly out of phase you have found your problem. This is quite a problem on the petrol 80's, have heard of it on an 80 but cannot recall seeing it on the diesel? In the back of the old grey matter I seem to recall a 4x4 but do not thing it was a LC, damn getting old!

regards

Dave

 

[Dave2000]

The rubber compound is way to hard to test like that, check out my last post to do a proper test. I might add the upper left of that rubber bond does not look as tight as the lower left. Could be an OI but you can never tell from a pic, also the lower left shows the width of the bond being narrower, again another OI?

regards

Dave

 

[StarCruiser]

Ok, I'll try that. The pulley seems to have two parts, a double grooved pulley with a single grooved bolted on. As the single one is what is seen on the photo. The twin probably has the same setup I guess and is not easily accessible. So, I probably need to remove the front pulley and check the rear one the way you describe.

 

[Dave2000]

Cannot remember mate, we need some help here guys with a picture or diagram?

Off to bed now as a long day tomorrow, and a late party to attend.

I will check in on Wednesday to see if anyone has come up with anything.

regards

Dave

 

[StarCruiser]

Ok, thanks Dave.

 

[Shayne]

My trucks booked in to DATSC tomorrow so they can disconnect the fuel tank and run the engine on cleaner for a couple of hours . I think i'm chasing ghosts myself so i don't really expect to see a result but i thought i would mention it as a possible alternative to Dave's redex solution .

 

[StarCruiser]

Thanks Shayne, I'll be interested to hear how that works out.

 

[Shayne]

As i said i don't expect results , i think it might be the bonnet itself that i'm picking up on but i have a 50% hearing loss in both ears and a number of tones i cannot hear at all so i tend to sort of feel it if that makes sense . I've tried to fathom how they run a car on cleaner and i can only imagine them putting a full bottle of injector cleaner in a gallon can with some expensive diesel ?

 

[StarCruiser]

I saw it on TV where a machine is connected in place of the fuel lines with two cans of…stuff (liquid, gas whatever fuel cleaner) on the top. The engine is run for some time and is supposedly cleaned at the end of it though I don't know how you tell without an exhaust analyser. It showed exhaust gas analysis before and after and it was better.

 

[Towpack]

I saw it on TV where a machine is connected in place of the fuel lines with two cans of…stuff (liquid, gas whatever fuel cleaner) on the top. The engine is run for some time and is supposedly cleaned at the end of it though I don't know how you tell without an exhaust analyser. It showed exhaust gas analysis before and after and it was better.

Are you thinking of this?https://www.youtube.com/watch?v=wiViPKIoG68

Don't know if there's anything similar for diesels though.

 

[StarCruiser]

That's the one!! [emoji4]

 

[Towpack]

Don't know if there's anything similar for diesels though.

Well, it's looks like the same treatment is ​available for diesels! https://www.youtube.com/watch?v=o5elcmhpLyA

 

[frank rabbets]

Oily carbon may be cleaned but if the engine has had a normal life hard carbon cannot be removed without stripping the engine. It's so hard it needs a HSS cutter to remove it, or banging with a metal bar to chip it off.

 

[Shayne]

I have my doubts too Frank but i've just been given a lift home from the garage by a minimum wage employee there and he confirmed they use some sort of chemical . I'm still skeptical but i figure limescale is the same left long enough it takes a hammer to remove it but a long enough soak in the right chemicals will dissolve it . Can't hurt anyway but it would be nice to see a before and after pic of engine internals .

 

[StarCruiser]

A 'How do I know it's done any good' type question might be of use when you pick it up Shayne.