2000 LC Amazon 4.7 V8 LPG engine noise

[Anjam]

Hi All,
New to forum so please be gentle with me. I have a year 2000 Amazon with a Tartarini LPG system fitted. The LPG system was fitted in 2007 whereas I bought the car a few weeks ago. Starts a drives perfectly but it has a strange noise coming from the engine bay when revving the engine. The noise can only be described as a harsh ticking, you do not notice it in the car unless you have the windows down and at low speeds. It's more prominent at lower revs, it may be that the engine notice drowns the ticking at higher revs but it is present. Also seems less noticeable after a run.

I have lifted the bonnet and the noise appears to come from the passenger side of the engine bay. I have just driving the LC 300 miles with no problems, no smoke, no over heating, oil pressure seems fine.

The only other time I have heard a similar sound is when I had a car with a leaking exhaust manifold collar.

I am going to take it a local garage to get it checked but any pointers would be highly recommended.

Thanks in advance!

 

[Gav Peter]

An expert on these matters will be along in a moment Anjam but I think that it could be that the exhaust headers are cracked/cracking as you surmise - I'm led to beleive that this is not uncommon on the V8's...

 

[Jon Wildsmith]

Most likely to be a cracked manifold which as Gav mentioned is known to sometimes happen on these motors if the simple things like loose nuts or joints are eliminated. I think some people have welded the cracks with some success. I replaced mine with some pacemaker headers from australia before they had chance to crack but that's not a cheap or simple solution.

 

[BRE Fabrications LTD]

The ticking noise could be your LPG injectors. I know mine tick loud enough to hear them at idle. Check to see if you still hear the ticking when running on petrol. Worth a shot before taking it to a garage...

 

[Dark Dude]

At long last, I NOW know what the pacemakers are. Thanks Jon. Are there any viable alternatives to Pacemakers which doesn't cost the earth?

John

The Dark Dude.

 

[Jon Wildsmith]

Are there any viable alternatives to Pacemakers which doesn't cost the earth?

Having the originals repaired or buying some second hand ones are the only 'cheap' options. You have to modify the exhaust to fit Pacemakers, they're not a simple swap in but with a bit of welding they can be spliced in without changing the whole system. I got mine through Julian at Overland Cruisers.

 

[Anjam]

Thanks everyone for responding. Glad I have found such an active forum.

I have switched over on to Petrol and noticed the same ticking noise so I think we can rule out the LPG injectors.

Do the manifolds crack from anywhere in particular? I could have a go at crawling under the car to see if I can see any signs of escaping fumes.

I know I am probably jumping the gun here but I have been looking around for some secondhand replacements but there are not many available, anyone have any sources I could try?

Finally I am in Berkshire, anyone know of an LC guru within a reasonable radius who could help repair. My local mechanic is very good but does not see many Land Cruisers and even fewer petrol ones. I have used Coxon Toyota in Henley and they seem to be a very helpful family run dealership but I simply cannot afford dealer rates at the moment.

A

 

[Jon Wildsmith]

AFAIK they usually crack between the pipe and flange but viewing access is very restricted plus heat shields that will be rusted on so chances of you seeing the crack with the manifold still fitted are slim I'm afraid TBH getting them off this first time will be a pretty big PITA, even just getting the heat shields off could be a challenge as there's inevitably going to be corrosion of the nuts and access is very limited. It took a respected exhaust specialist who must have seen it all before most of a day to get mine off and that with me letting them cut bits off that were in the way because I wouldn't be reusing them. I hope I'm over stating the PITA factor and you end up wondering what the guys I used were playing at but expect some touble all the same.

 

[Anjam]

Thanks Jon. I will get my local mechanic to give it the once over and diagnose and then have a think about where to get it done. I can't hear the noise when I am driving so not bothering me too much but I assume it can't be good long term for my mpg?

Thanks for your help so far. I have other niggles which i would like some help with but I will start separate threads to keep things tidy.

A

 

[pugwash]

If you can hear the noise at stationary, one tip for finding the exact source is to get a metre length of hose pipe, stick one end in your ear and use the other as a stethoscope- you can absolutely pinpoint where things are coming from like this- its very effective.

 

[Anjam]

My mechanic has some cool tools for that. He has some wireless sensors that can be attached to engine/transmission/suspension etc and you hear the sound through headphones in the car. We used them a few times to locate some suspension knocking in my wife's car.

 

[Anjam]

Any idea how much a used manifold would cost?

 

[Jon Wildsmith]

I never priced them up so can't help you with that but I would think they'll be pretty hard to find and would plan on welding your existing ones as even if you find some you don't know how long till they also crack?

 

[Singhabeer]

Ive just had the the heads off mine [1999 v8 with LPG] while replacing the exhaust valves and whilst stripping it all down i couldnt see a way of getting the manifolds off the heads without taking the heads off . Im sure im wrong but i just couldnt see or get any thing in there to do it. its easy on the bench though.
There was one on Ebay recently with the same problem being 'sold as seen'. I PRESUMED THIS WAS WHY IT WAS GOING CHEAP.

 

[Dark Dude]

Well, it's a trip to Burgess Hill, then.....

JC

The Dark Dude