Timing belt - Rock auto kit quality

[esprit888]

So Timing belt off no problem, amazingly she still had the original 29 year old timing belt AND auxiliary belts on her. The aux belts were cracking but the timing belt looked good, at first glance. Magnifying glass showed what looked like the start of separation on one tooth with strands starting to fray (see pic) I should mention she only has 42,000 miles and has never been stored outdoors, that being said if you want to see what not driving does to your water pump see below(original OEM pump, 42,000 miles) Use it or loose it!
Now like a lot of owners i always change the idler and tensioner bearings at the same time as the pump and belt (which was leaking at the weep hole) The kit arrived from Rock auto a while ago and i should have checked it more carefully. The water pump casting is fine, but the idler pulley is not polished like the OEM parts or the dayco kit tensioner pulley. I've bought these from Rock Auto before but haven't come across this, has anyone received the same style of non-polished idler pulley? I'm tempted to re-install the old idler but as it sat for a while i'm concerned about possible corrosion. Anyone have any input?

[Simon_P]

A really good example of OEM vs aftermarket parts. The original items are not service items, so designed to last the life of the car. The aftermarket ones you bought on price. That's not to say that they are bad, just that if you are going to charge them every belt change they don't need to be as good.
Similarly your observations are what is known as Perceived Quality - It looks better. There is a good chance that it is, but you would need to have an objective measure of say belt wear or noise.

The water pump is a good illustration of what happens if you don't change the coolant every 2 years.

[esprit888]

Simon, to clarify i recently re-purchased this car having sold it in 2006. I am under no illusions as to the quality of the aftermarket idler (made in Korea, no brand name) versus the OEM GKN made in Japan. This is my 5th or 6th M100 belt change, all previous parts ordered from Rock Auto came polished, but this is the first time i've received one that isn't, my question was has anyone else received the same idler. I have subsequently researched the options and 50% are not polished (such as SKF TBP89007, GATES T42001) whilst others are, leading me to believe its not something that has been missed in 'quality' control. I agree that the idler/tensioner are not originally designed to be replaced at every belt change, likewise the water pump, its typically a case of 'while i'm in there' and in my case i note some leakage at the weep hole due no doubt to sitting and as you say lack of timely coolant changes. The Denso water pump has a cast impeller vs the OEM Aisin steel one making 24 month coolant changes even more prudent.

[dapinky]

I have to admit that whenever I change the belt, I tend to change the rest of the stuff (unless I PERSONALLY know that it was done last time - or at least in the last 2 changes.... I won't rely on a paper receipt).

I have always used the DAYCO belt/tensioner/idler kit and it has always been a polished item - I have also used Gates belts, but they are not usually polished!

However, when it comes to waterpumps, I have used all sorts (dependent on what ships from the same warehouse at the time of order), and have had some with cast impellers, some with 'bent steel' ones etc.

When I changed mine recently the item on it was an OE (Aisin) one, so I assume that the tensioner/idler were also OE..... which is where my opening statement went 'wrong', as I only changed the belt last time, despite having only a receipt to say that the rest were done a couple of years prior to my purchase....

....but as the work was receipted as being done at a Lotus garage, they may well use Aisin parts as a matter of course - certainly the waterpump was in remarkably good condition with no rust/scale deposits on the impeller.

The pulleys were another story though (so I believe that they were the 1991 items) - although they looked okay, and spun quite freely, they were exhibiting an amount of play which indicated some wear inside..... which isn't really a surprise after 140K miles!

[431andy]

Hi folks,

I'm a relative newbie to LEC and in process of gathering parts. Thanks to all the useful advice on here I've ordered a Dayco timing belt kit from Rockauto. One question, for those in the know, there was a second Dayco kit listed with all the same parts but including '3 pre assembly seals'? (see attached pic) This kit wasn't available (out of stock) so I didn't buy it and couldn't fathom what these seals are for, despite researching. I just want to make sure I have everything I need for my mechanic to complete the timing belt change. To confirm, I bought the kit (as attached) but without the three O ring looking seals with lubricant. I couldn't see them on SJ but maybe they usually come with the idler/pully components? Can anyone confirm that I don't/do need these three O ring looking seals, as they dont seem to be within the kit I purchased? Many thanks Andy W

[Brit-Car-Nut]

I am assuming they are the seals for the two camshafts and the crankshaft.

Changing them is more of a personal decision. Everyone has their own preference if they should be changed when the belt is changed but it is good to have them available if you need them.

Once the front of the engine is exposed, you (or your mechanic) will "know" if you need any of them. They are probably available quickly at your local DIY store: 1991 Isuzu Impulse Turbo is a more common listing and they are the same as the M100

[431andy]

I am assuming they are the seals for the two camshafts and the crankshaft.

Changing them is more of a personal decision. Everyone has their own preference if they should be changed when the belt is changed but it is good to have them available if you need them.

Once the front of the engine is exposed, you (or your mechanic) will "know" if you need any of them. They are probably available quickly at your local DIY store: 1991 Isuzu Impulse Turbo is a more common listing and they are the same as the M100

Of course -thanks I should have realised that they weren't O rings but seals for cam / crankshaft. Didn't make the connection with these and a timing belt change! It's s relief that I don't necessarily need them for the timing belt change. Now that Ibe seen Toby's you tube vid, I feel confident enough to attempt it myself. It was done before I bought the car so hopefully I can get the bolt undone!! Do you recommend replacing the power steering belt at sams time?

[Rambo]

I usually do as it's fairly cheap and easy to do but I don't think it's considered essential

[dapinky]

Andy,

The cam/crank seals have never been changed on my car (they were on my old one, but only because I changed the HG so disturbed them anyway) - my thinking is that unless the cams are lifted from the head, they will remain 'sealed' until they wear out! That said, if yours are weeping at all, then they are easy to change at the same time as the other work, and are cheap enough to buy. There is nowt magic about them, and they are a 'standard' size part used in other applications so shouldn't be hard to get locally.

The PAS belt is a matter of choice (I change mine while I'm there) - but the Altenator belt is well worth looking at - It is a real pain to get at, and has to come off anyway, so I always recommend changing it.........

....... Geoff recommends using a Citroen belt for the Altenator (because they are common and cheap in the UK!) - 4PK698........ but I got one from Rock Auto at 27.4" (696mm). Both are "better" than the Lotus OE part because they allow the Altenator to be slightly further from the engine block, but without hitting the bulkhead, so it is easier to get to the adjustment bolts for fitting it!

viewtopic.php?f=29&t=20153&p=358634&hilit=citroen+belt#p358634

[Simon_P]

The cam/crank seals have never been changed on my car

I've never seen any that need changing. I did mine for the engine rebuild and at 100k they looked fine.

easy to change at the same time as the other work

Like an engine rebuild or HGF otherwise there is a crankshaft up the middle of one, and the others are behind the pulleys, under the cam cover, with camshafts in the middle stuck in with sealant.

[dapinky]

easy to change at the same time as the other work

Like an engine rebuild or HGF otherwise there is a crankshaft up the middle of one, and the others are behind the pulleys, under the cam cover, with camshafts in the middle stuck in with sealant.

Quite right! - what I really meant was if you DO find that they are weeping, then you are already in a situation where they can be got at and changed (with extra work!), but you would be unable to see any leakage without getting the plastic covers and big pulley off anyway.

Either way - I wouldn't worry about it - as Simon says, they never need changing (unless Sods Law applies). I did mine when doing HG, and still have a set on the shelf which I bought years ago for an impending engine rebuild (which has been on the cards for nearly 10 years, but I'm still waiting on a new oil pump to become available.... I have everything else)

[431andy]

Thanks everyone, really helpful!
Andy