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Jphoenix13

cam belt tensioner bearing?

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I installed a new blue cam belt and tensioner from JAE 6 months back and the engine just started developing this bearing noise. I removed all of the v-belts, so only the cam belt is running in the video. I suspect the tensioner bearing, but could it be something else?

 

http://www.jimphoenix.com/wp-content/uploads/2014/07/IMG_1192.mov

 

Next step - unless someone suggests something easier - is to remove the tensioner bearing.

Edited by Jphoenix13

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Tough to tell from video.  Could be bearing. 

 

But to me the noise sounds a bit more like intake noise.  You get that sort of noise when one of the lines into the intake manifold pops off or splits.

 

1)You have the hose and check valve from the charcoal canister to the intake manifold port up front, near the thermostat. 

2)The Tee and hose from the intake manifold to the fuel pressure regulator, under the chargecooler box.

3)Same Tee to a check valve to the crankcase breather above the clutch housing.

4)the port for the MAP sensor under the fuel pressure regulator.

 

Check those ports for cracks (they are all plastic) and check the hoses and one way valves.

 

I had a bad one way check valve (brand new) that was amplifying the sound from the intake and trumpeting that sound back through the crankcase and the air filter/intake box.  It was super loud and annoying!


Did you have any other work done recently, like replacing the head gasket or having the head machined?


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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That's interesting Travis, I'm going to do more investigating. It really sounds like v-belt npoise, but they are not the problem. It doesn't start immediately either, only after it warms up just a bit, within 3 minutes of starting, but remains until the engine is completely cold.

 

I have a new bearing coming from JAE (and a new AC belt - got frustrated and cut it off since I didn't want to remove the crank pulley - yet). I'll remove the cam tensioner bearing tonight and check it out, but I find it hard to believe it's failed with only 4000 miles since new.

 

No other work done since the cam belt, etc. I did 4k miles ago - been driving it trouble-free for months.

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I took a good look at the lines to the manifold, etc. but they are all in excellent condition, so under I went and popped the tensioner off.

 

The bearing is very rough, still turns OK, but definite ratching internally and it sounds like it has no lube internally, very dry sounding. New one on the way from JAE.

 

I did this math this afternoon, this bearing has 2800 miles on it since I installed it along with the blue belt, etc. Actually, as long as I'm not removing the belt, getting the tensioner off is not bad. No need to drain the coolant, etc. - just have to deal with the v-belts, but I have recent practice at that and it's always easier second time around.

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I thought I had read somewhere that there was a batch of underlubricated bearings on sale. Could have been wheel bearing but something tells me it was the tensioner bearings.

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I received a LKG bearing once, rather than the SKF...  I didn't like the feel of it and sent it back due to a funny noise.  That noise turned out to be that the machinist who surfaced my head, made it tapered, and the belt was trying to run off the front of the engine... :(


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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Interesting. We just went through a possibly similar experience in our shop. We installed an engine we had rebuilt in an '89 Esprit and upon start-up everything appeared just fine. After we logged about 40 or so miles on the car it developed an incredibly loud high-pitched squeal. We immediately suspected belt noise and one by one took off all the accessory belts. With just the cam belt (a Gates "blue" belt from JAE) it squealed just the same. We finally took both the tensioner and blue belt off the car and replaced the tensioner and installed a stock Gates "black belt" on the car. Problem solved. That day the customer drove the car back to Louisiana and had no problems at all. He took the blue belt with him, but we still have the tensioner in the shop. It feels fine if you rotate it by hand - feels exactly like you would expect a new one to feel. I have not subjected it to and high rpm testing to see if if squeals when it gets wound up to a couple of thousand rpm but I plan to do that when I get some time. The car now has over 700 miles on it and no re-occurrence of any problem. 

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Many people say that the blue belt squeals at the "correct" tension for the old black belt.  The blue belt being "stronger" and therefore made of stiffer construction, probably requires a different tension than the old black belt...  Especially when measure acoustically. IMO


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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Yes, the blue belt whines at "the correct tension" and is very sensitive to the "perfect tension". I managed to get the blue belt adjusted to 106 db (or mhz or whatever I'm measuring with my phone) and it's perfect, no whine until it gets nice and warm, then just a hint of a whine.

 

The "bearing noise" I started hearing a couple of days ago was not the same as blue belt whine. It may have sounded similar to v-belt noise, I initially suspected alternator bearing, but after pulling the v-belts, the only thing left was the cam tensioner bearing. The roughness I felt in the bearing disappated after pressing out the center mount, very strange. Both bearing ID's (old and new) mic out the same down to half a thousandths, but the new bearing definitely pressed on harder for some reason.

 

The old bearing I'm comparing it to has at least 20k miles on it and feels very smooth with some low rolling resistance. The new bearing has less rolling resistance and I can hear the rollers indicating no grease left. With the center mount removed, I can feel slight roughness (ratcheting) especially if I side-load the bearing a little. I tried spinning it up with my drill, but the drill makes more noise than the bearing.

 

Jim

Edited by Jphoenix13

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The noise we experienced was higher pitched and much louder than what I am hearing on the clip posted here. Of the five people present four were experienced Lotus or auto mechanics. There was a split of opinions on whether it was bearing noise or belt noise but it was unanimous  that it was not whine - way too loud and "squeally". Much more akin to a failing roller bearing running dry..We did several tension adjustments and they had no effect on the noise. The only thing that worked was the new belt/tensioner install. Since we were under some time pressure to get the car on the road we decided to swap them both simultaneiously. So we can't yet say definitively which it was. 

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The iphone audio is not very good, and the bearing noise just started and in the course of a short trip, it got progressively worse, so I expect if I let it go for a couple more trips to work and back, it would be squealing pretty well, certainly was not getting better and started shortly after driving the car for a few minutes, as if the bearing was heating up quickly. I'll know in a couple days when I get the new one in. Thew good news is I'm sending it back to JAE for a credit - and it's much easier to change than the belt.

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Installed the new cam tensioner bearing, quiet as a church mouse now. The old bearing was definitely the problem. The new bearing (yellow seal) from JAE is very different from the old bearing - it is a german bearing, the one I took out has no markings except a part number laser-etched into the side of the carrier.

post-15426-0-19753800-1405047295.jpg

Edited by Jphoenix13

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Interesting thread.

 

Today I pressed the cam belt tensioner bearing on the insert and the new bearing feels as rough as a badger's arse! Consistently notchy is the best way to describe it. I pressed it in the correct way, using a socket to support the inner part. Not sure if I want to fit it on my car. I've read on SKF's website that bearings can feel this way when new due to the lubricants they use (link to PDF) but I'm not totally convinced.

 

I had some surface pitting on the old bearing, perhaps corrosion from sitting so long, a sticker on it or whatever. New bearing on the left, old on the right.

 

cam_tensioner_bearing_01.jpg

 

 


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Well, as I mentioned, we had two bearings fail - one immediately on install - squealed horribly and we went through the whole protocol of removing all the accessory belts, etc. Replaced it with a new (but identically sourced/same batch) tensioner/ That tensioner started to squeal after about 1000 miles of driving. We switched to German-made Flennor bearing and so far no problems. I strongly suspect that the failed bearings (which had no manufacturing identification on them) came from some third-world source and were either improperly lubed, improperly sealed, or improperly machined. 

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As an engine builder I have been aware of this issue for some time. 

There is a batch of bearings being supplied which have little or no

lubrication inside, this can not be seen because of the seals. 

These bearing do tend to be cheaper, so as in all things you get what you pay for..

The only advise i could give to all is,  always by the best possible product available.

I know cost will be an issue with some but the quality manufactured parts as

opposed to the after market, will always work out cheaper in the long run...   

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As an engine builder I have been aware of this issue for some time. 

There is a batch of bearings being supplied which have little or no

lubrication inside, this can not be seen because of the seals. 

These bearing do tend to be cheaper, so as in all things you get what you pay for..

 

But why, a dollop of grease is hardly going to significantly affect the price?  :question:


Cheers,

John W

http://jonwatkins.co.uk

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The replacement bearing is marked exactly as the original; made by SKF and part number 414871A. 

 

Still not happy about putting this in the car to then (potentially) have to replace it in 1,000 or 10,000 miles. I'll contact SJ's to see about a replacement.

 

Apart from the one Jim showed a picture of above, are there any other quality replacements?


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We had a second tensioner bearing fail. We installed it in a customers car after the first bearing failed immediately (high pitched squeal). We replaced the squealing bearing with a second new bearing we had in the shop. Problem solved. However the customer called back and after about 1000 miles the squeal returned. By this time he had returned to his home, about 700 miles from our shop. We had ordered a new German-made Flennor bearing and sent it to him. He was able to find a local shop to replace the tensioner and that solved the problem. Both of the failed bearings came from the same batch (we had purchased both at the same time). They were unmarked as to manufacturer or origin. We had bought them from our usual supplier. They had blue plastic seals on the races. We suspect they were cheap copies, possibly Chinese in origin. This is a serious issue and I urge all of you to do whatever you can to make certain the bearings you are purchasing are good - not that there is any simple test to determine that! I will stick with Flennor German-made bearings in the future,

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Hi Guys

 

Going to bring this one back up as I can't find the Flennor bearing anywhere. Does anyone have the SKF part number or can they confirm that the bearings sold by SJS or PNM currently aren't the defective ones?

 

Cheers

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Got mine from Lotusbits.

Asked the question about sourcing and Mike was relatively scathing about the alternative. Assured me that the ones they sell are good stock. Not on yet though, so cant confirm running...

I did, however, drop in to collect it en-route as their comms are nororiously inconsistent :-)

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