1G Idler pulley questionable?

[Sbgriffin]

So I'm on the home stretch of my 6 bolt rebuild, and everything has gone fairly smooth (knock on wood). But today I was putting on some of the timing components, when I spotted a possible issue. While cleaning the idler pulley I noticed that it has puked some grease out the back seal. The pulley seems to be in fine shape though, spins very smooth, no roughness. Also I should state I just had replaced all timing components a year ago, with only 3k miles on them. So I was planning on putting all of it back in rotation(get it, ). But seriously, is this normal, or am I better off replacing it again? Also both pulleys are OEM, and my belt is a gates that I'm reusing. Thanks.

 

[We're on Boost]

Man, I don't know but that is disturbing. It doesn't seem right. I have 2 brand new idler wheels right here in my hand that I'm looking at, OEM items I bought from STM. Just for a check, the idler wheel seals are a reddish-brown color and they say "Koyo" and "Japan". Is yours like that?
I'm also looking at a brand new OEM tensioner wheel which has blue seals and it says "NTN" and "Japan". I am just noticing now that the blue seals are slightly wet (oily) on both sides, but this is not puking grease, it is more like just a little oily. But the red ones are dry.

I think I would replace that one if you have any doubts about it, since they are still available genuine OEM and not crazy expensive.

 

[Turbo2g]

I think it will be fine. I have to re-use questionable parts all the time in my field . They always seem to hold up. Ive re-used my own timing pulleys a few times now. And they are even a little loose. If its smooth, you'll be fine.

 

[97gsxIA]

If it is not making any noise, binding, or wobbling and chewing your timing belt, its fine. The oily look vs dry look is simply how the retailer or manufacture packages the pulley. Seal color is ambiguous but typically idler pulleys are brown and tensioners are blue, but idlers can be either... frankly because they are a cheap, simple part.

 

[chrysler kid]

I think it will be fine. I have to re-use questionable parts all the time in my field . They always seem to hold up. Ive re-used my own timing pulleys a few times now. And they are even a little loose. If its smooth, you'll be fine.

Don't cut corners. Replace worn timing components

That's all I'm going to say. . .

 

[Sbgriffin]

So I was mistaken, the tensioner pulley is OEM, the idler pulley is a gates. But both have less than 3k miles on them. And who knows, that grease could have been there all along. I don't really see anyplace on the seal where it had been leaking from, the seal looks mint. But still my guts telling me I probably should get a new OEM unit. I really don't like those what if's in the back of head. The whole point of my rebuild was to sort through all of nagging issues. I think I'll listen to my gut and get one ordered. At least then all my pulleys and my auto tensioner will be OEM, with a like new gates belt. Thanks for all the input. Several things I've learned with our DSM's is, attention to detail, and listen to your gut. Or you might end up being a statistic.
So here's a few progress pics from my build, for any who's interested. Been itching to share with someone, don't have any DSM buddies in my area. Keep in mind I was on a pretty tight budget, but feel like I covered a lot for what I had. Just want a well sorted, reliable car. 300whp is my goal. Thanks again.

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[We're on Boost]

I really don't like those what if's in the back of my head .....

That's how I am too. If I reused it I'd be always wondering if the darn thing is still leaking grease, or if it is defective in some way that caused it to leak grease in the first place. With the engine out of the car it is easy to put a new one on. That's the time to do it.

As far as the idler wheel being a Gates, well, I would expect a Gates part should be a good part. But Gates is not as far as I know an actual ball bearing manufacturer. So the innards of that part are probably made by somebody else, who?? and where?? which makes it a bit of a mystery part. Whereas Koyo and NTN have been world leaders in ball bearing manufacturing for decades. The Koyo idler pulley I'm looking at came in a Mitsubishi Motors box that says "Made in Japan" on the label, and has the MD156604 part number on it. It was $50 from STM.

The engine looks good!

 

[Sbgriffin]

That's how I am too. If I reused it I'd be always wondering if the darn thing is still leaking grease, or if it is defective in some way that caused it to leak grease in the first place. With the engine out of the car it is easy to put a new one on. That's the time to do it.

As far as the idler wheel being a Gates, well, I would expect a Gates part should be a good part. But Gates is not as far as I know an actual ball bearing manufacturer. So the innards of that part are probably made by somebody else, who?? and where?? which makes it a bit of a mystery part. Whereas Koyo and NTN have been world leaders in ball bearing manufacturing for decades. The Koyo idler pulley I'm looking at came in a Mitsubishi Motors box that says "Made in Japan" on the label, and has the MD156604 part number on it. It was $50 from STM.

The engine looks good!

Good point, and question. I think just for shits and giggles tomorrow I'll snap a pic of that gates pulley, where the stamped writing is on the back. Maybe we'll all learn something, possible something to avoid. I remember at the time I decided to go with OEM on the tensioner side, gates on the idler pulley. I figured it was less critical on that side, and was about half the price. I've had great luck over the years with gates timing belts, and water pumps. But maybe the pulleys should be avoided, especially if they outsource on the ball bearings from an inferior source. I'll post a pic tomorrow, see what everyone thinks.

 

[Sbgriffin]

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Well unfortunately the idler pulley doesn't have any markings to indicate who manufactures it. Besides the part #, gates, and China. But I really don't see anyplace where the grease leaked from. Plus it sure spins smoothly. Not sure what I should do? Replace it, or send it and check on it in 20k?

 

[We're on Boost]

Yeah it's hard to say. You would only see the problem if it was gross, like torn or cracked rubber. There could be a small problem at the OD of the seal, or even with the lip, that you wouldn't see. There could be a problem with the surface finish of the inner race, the "running surface" that the seal lip runs on. I'm a little disappointed that it's a "no-name" seal.
Sometimes a seal has an internal part that tensions the lip, like a spring. I would have no clue if this one is supposed to have a spring or not, but I'll put up a typical diagram of one of those (from SKF).
If I can get a large resolution picture posted here I'll also post some pics of a new OEM Koyo idler, both sides.

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[chrysler kid]

Replace the idler. Oem tensioner looks great but the idler looks dry rotted

If grease came out it will let dirt and oil back in where the grease use to be.

At 7k rpms under large side tension load do you really think "it spins fine by hand" is an adequate test?

It bothered you enough to make a thread about it, so just replace it.

 

[boostdawd]

Would u like to replace it when the engine is in the car? I would form out the cash and get a new one if this is for your own personal car and reliability is of up most importance.

 

[Sbgriffin]

Yeah it's hard to say. You would only see the problem if it was gross, like torn or cracked rubber. There could be a small problem at the OD of the seal, or even with the lip, that you wouldn't see. There could be a problem with the surface finish of the inner race, the "running surface" that the seal lip runs on. I'm a little disappointed that it's a "no-name" seal.
Sometimes a seal has an internal part that tensions the lip, like a spring. I would have no clue if this one is supposed to have a spring or not, but I'll put up a typical diagram of one of those (from SKF).
If I can get a large resolution picture posted here I'll also post some pics of a new OEM Koyo idler, both sides.

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Yeah I like the way that koyo seal looks compared to the gates. Looks like it seals a lot tighter. And I know you guys are right, I'm ordering one tonight. Not trying to be cheap, but you guys know how much a 4g63 rebuild cost. It definitely starts adding up. But I know I'll sleep much better known its replaced with an OEM unit. It sure does irritate me that the gates pulley has less than 3k miles on it. Makes me lose a little faith in them. Anyway thanks again, I do value all the input.

 

[We're on Boost]

Well I think you can have good confidence in Gates for belts and hoses, which is what Gates is known for.

I usually think that the best thing for parts like this wheel is to get genuine Mitsu OEM parts if available, and get it from a dealer who you have confidence isn’t going to be selling counterfeit parts.

Your hp target range around 300 is a nice sweet spot I think, for these engines. You can do it without horrendous expense and keep pretty close to original reliability. Hope your project goes really well!