How can I track down odd noise?

[JimSuperSix]

After the usual cylinder head saga I've been treating my surf very carefully, but recently it's started making a strange noise at idle when cold - it's difficult to describe, not a squeak, not a thump, but more a sort of "aggressive-chirping"?

It's pretty loud for about 1 minute when the engine is really cold (first thing in the morning) - the truck idles at 700rpm but even the act of moving it backwards using the engine's torque (no throttle and at about 800-900rpm) decreases the noise significantly, and when you pull away (1000rpm +) it vanishes.

After about a minute at idle, or a few hundred meters driving (slowly) it is perfectly quiet again, and remains that way until the next cold start.

I fitted a new Stevo cylinder head + new water pump + cambelt, but not cambelt tensioners I don't think, unless Stevo supplies them as standard with his kit of bits (I can't remember if that was the case, it was last year) Also had new drive belts x 3. No air-con.

The thing that worries me is if it's a tensioner pulley on the way out, or something likely to damage the engine if it breaks. If it's an item that "fails-safe" (injector pump or something) I'm happy to wait until it goes.

How can I track it down? It doesn't last long enough to diagnose, and under the bonnet the noise is impossible to pin-point, but a friend seemed to think it was located on the passenger side of the engine-bay.

HELP PLEASE!!! I'm completely paranoid about it breaking!!
Are there any Surf-specialists around Newcastle that I could have listen to it?
thanks
James

[Gazbo]

I aint too hot on the surfs set up yet? But could just be lifters/tappets?

[Sancho]

I am absolutely no expert on these things, but mine used to merrily chirp away too. When I broke down in France, the noise changed from chirping to a kind of tortured squealing.

Anyway, one visit to TonyN and a new head later, it's gone. Tony said the crankshaft pulley was knackered. That might be worth checking because my head had already been replaced once, a couple of years ago and it probably got damaged then.

I think there's some threads kicking around with 'harmonic balancer' in. That seems to be the name for the bit of rubber that was broken in mine, rather than some kind of space laser.

[JimSuperSix]

Hmm, well I've had a new head from Stevo on it about a year ago, so I don't want to damage it.

Sancho, I can't quite understand what your post means - do you mean the crankshaft pulley failed and was that the cause of damage to the head, or do you mean that you think your crankshaft pulley was damaged when the head was replaced?

How can I check the condition of the crankshaft pulley? I assume we're talking about the large pulley that sits just behind the rad and drives the alternator - I can't see how that failing can do anything other than cause the alternator to stop working...?

[Sancho]

I just saw a big round thing.....

I don't know anything about engines, but piecing together the little bits of evidence and knowledge that I have, it goes something like:

1. Surf comes from Japan with cracked head.
2. Bloke who owns surf before me gets cracked head replaced by trained monkeys.
3. Trained monkeys put new head on but smash up cambelt cover, damage pulley and god knows what else.
4. Knackered pulley stops water pump from turning perfectly, but it still works a bit.
5. Owner has some overheating issues, probably cracking the head a little bit, but all seems fine.
5. Bloke sells surf to me with receipt for head replacement and apparent clean bill of health.
6. I drive surf up french mountain after 600 mile non stop journey with five people and all their stuff in.
7. Slipping pulley / not-turning-very-much water pump / big mountain makes engine overheat big time and crack the head some more.
8. I fill surf back up with water, cracked head pressurises cooling system, water flies everywhere, everything now toasted.
9. Nice man tows surf to England.
10. TonyN fixes it for me and tries to explain the above in small words.

Like I say, I don't know anything. Search the forum for 'harmonic balancer' - just a guess on my part. To answer your question, I think it was damaged when the head was first replaced and its failure meant the head had to replaced again. I believe it drives the water pump.

[JimSuperSix]

Great, thanks Sancho. I removed the pulley carefully when I did the head but I'm sure someone had been at it before I bought it (prob. because it overheated) and judging by the nice imprint of the fan in the back of the rad and the fact that 4 head bolts were loose (!) I suspect they probably weren't being that careful, so they probably just yanked the pulley off with a crowbar.

I don't recall the pulley driving the waterpump though, but I'll have to check.
[edit: doh, of course it does...]

I've searched for harmonic balancer and found the thread about glueing the pulleys back together, but I can't find any info on how to check for an impending failure - can anyone tell me how I can test the pulley?

thanks
James

[Pauleds]

It's the bottom pulley on the engine.
Mine has just been replaced and the symptoms were EXACTLY the same.
The pulley has a rubber cush in it which is bonded to the metal of the pulley itself. The bonding perishes causing the pulley to move in and out and catch on the bottom of the cam cover causing the chirping.
As soon as you up the revs it all pulls back into line and stops chirping.
I got mine all done for £350 and it's a different motor now.

[marky]

The Rubber bit is called the HARMONIC BALANCER it cushions the 2 piece crank pulley wheel.

[JimSuperSix]

£350!!! Was that including labour charges?? Can I buy a new pulley cheaper somewhere? [edit: just found Roughtrax do them for £100 - much better!]

I need to be sure that's the problem before I spend that much - is there a definitive way of telling?

The other thread mentions superglueing the thing back together, as recommended by Tony (so I assume that's a sensible cure), which sounds like a nice cheap option to me....

What I don't understand is why it goes quiet after about a minute at idle, surely slop in the rubber would mean it rubs the cam cover all the time?

[Pauleds]

It moves in and out if you watch it very carefully meaning the chirping is intermittent.
I got the pulley from Milners for £115 ish and my mechanic fitted it for me, i forgot he also did me some rear shoes , that's why it was a bit pricey. Probably looking at more like £250 all in.
Maybe glueing it would work but i cant see me trusting it somehow, but i'm no expert.

[Gazbo]

Wooow, i am going to have to put my prices up!!

[JimSuperSix]

do you sell pulleys then?

[Gazbo]

Soz mate, no? But the labour rate Pauleds paid is nuts!!

[Gazbo]

Ahh, a fellow geordie then?

[JimSuperSix]

Ahh, a fellow geordie then?

Nope, sorry - I'm from the South really, just that it's much much nicer up here than in the Midlands.