[kingkom]

So after putting a 2004 second hand H27A into my 2003 formerly H25A GV and getting a new timing chain, water pump and everything else that goes along with it fitted I did about 4000km and it started making an off time rattling/ticking noise and eventually a very loud rattle that sounded like the chain hitting the inside of the timing cover. Screwdriver stethoscope was loudest at the gap just above the water pump pulley where the two banks join together (or the 2 heads meet). Took it in and was found that the "number 1 idler sprocket" (the one that the chain goes around as it comes down from one cam and goes up to the other) was worn away significantly to the point where it had so much play that it was moving around and caused the tensioner to be all the way out.


You can see where it's actually eaten away the hole in the sprocket and damaged the thread on the bolt as well. I went to Suzistore and they found me an identical looking one complete with bolt, washers etc which had a needle roller bearing instead of a bush like my existing one had - no idea what car/engine it was from but it looks identical except for the bearing so should be fine/ an improvement.
Just wondering if anybody has had this issue before? My H27A has 190xxxkms on it and will have had the timing chain done at some stage before so I'm thinking poor quality sprocket was fitted then? Although this isn't a part that comes with any timing kits so can't say for sure. When my mechanic looked it up it's supposed to be a non serviceable part that lasts the life of the engine - to get another one was ex Japan.
I'm also thinking that since the timing kit was initially put on my horribly abused (by previous owner) H25A which looked inside like it had only had one oil change in 160xxxkms. After the chain was done I did about 50km and it started bucketing smoke from an oil leak at the exhaust valve guides - the gunk was literally holding that motor together - so I cut my losses and bought a H27A with full service history and put all the the basically new timing gear on that. However that sprocket wasn't touched according to my mechanic (non serviceable part) and when the job was done for the first 3000km it was silent so I'm thinking just bad luck and coincidence?
Any ideas?

[fordem]

Some of the aftermarket kits do come with the sprockets, so it is a possibility that that one did - if you used aftermarket - but the mechanic says it wasn't touched, my question is, how long ago was that, and how good is his memory. I work on a lot of equipment, I'll remember the details for maybe a month or so, but beyond that, it's gone forever.

A couple of questions ...

- there may be an oil feed to the sprocket (look to the right of the bolt in the picture), could it be clogged?
- take a closer look at your old sprocket - the picture shows a lip - are you sure that is a bush and not the outer race of the original needle roller bearing?

[kingkom]

Yeah it was about 2 months ago but I know the kit didn't come with that sprocket (came with all the other main ones except this one which is specifically non serviceable apparently) so I have reasonable confidence. Plus my family has been going to the same mechanic for about 30 years so I believe him - he was really surprised because he was initially adamant that the noise couldn't possibly be coming from anything timing related (they have always been extremely thorough, taking a bit of extra time to do the job right which is why we go to them).

Oil feed unlikely to be clogged as engine has excellent servicing however I guess anything is possible. It's getting a flush when it's all back together.
Yeah I see the lip (I've had the sprocket in my hand) apparently there were the remnants of a bush in it. He was also surprised when I rocked up with the second hand sprocket with the bearing saying that's much better since my old one had a bush and he wonders why.

[fordem]

Just so it's clear, I wasn't questioning the mechanics integrity, just his ability to remember.

I took a second look at the picture of the sprocket - it looks very much like a steel sleeve there, and I have never seen a brass or bronze bush with a steel outer sleeve, I'm also curious as to your insistence on the idler being "non-serviceable" - nothing in my documentation suggests that, in fact, the FSM instructs that it be "checked for wear or damage" as they do for all of the sprockets - it also mentions that the #1 idler has a bearing, and the #2 idler has a bush - the #1 idler is the one being discussed.

[kingkom]

Hey. Yeah I had a look at the FSM myself and you're right the number 1 should have the bearing. I think those idlers are meant to be inspected but the timing kit didn't come with them, only with all the other sprockets. I reckon maybe it was on it's way out and the increased tension from all the other new timing stuff tipped it over the edge? I found big strips of metal in the engine oil when I drained it lol. Any way. Went to Suzistore and got a second hand one, all back together now and done about 1000km and the engine is silent and runs perfect. Just an interesting thing I thought I'd put up in case anyone else has this problem in the future. I think the sprocket would have been either the wrong one put on in the past when the timing chain was done by the previous owner or just a cheapie aftermarket with a bush instead of a bearing. Either way all good now.