Metric Mechanic 2900 Sport

[jneumss]

Quick off topic- I’m so glad you posted this comment. I hooked up a vacuum gauge to my engine a couple weeks ago while messing around with it and my gauge has a red/yellow/green zone, my stock i reads in the yellow and I poked and prodded for a WHILE looking for leaks. My engine idles very smooth, starts right up, runs as smooth as I expect so I ignored it in the end but damn if it didn’t bug me for a week or so....

I had exactly the same feeling. I just adjusted the idle and TPS and now it's idling well around 800 rpm.

I also passed emissions.

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[325e '87]

Even a stock m20 has low vacuum compared to other cars (~11).

If the WOT switch in the TPS is malfunctioning, it will never go into the WOT maps, and it will continue to read the o2 (goes in open loop at WOT). But that doesn't explain the idle.

Quick off topic- I’m so glad you posted this comment. I hooked up a vacuum gauge to my engine a couple weeks ago while messing around with it and my gauge has a red/yellow/green zone, my stock i reads in the yellow and I poked and prodded for a WHILE looking for leaks. My engine idles very smooth, starts right up, runs as smooth as I expect so I ignored it in the end but damn if it didn’t bug me for a week or so....

[ForcedFirebird]

Even a stock m20 has low vacuum compared to other cars (~11).

If the WOT switch in the TPS is malfunctioning, it will never go into the WOT maps, and it will continue to read the o2 (goes in open loop at WOT). But that doesn't explain the idle.

[jneumss]

Perhaps the closed position on your throttle body needs to be adjusted? To idle, the engine needs the idle control valve to function, and a very small opening on the throttle body.

Ahhh, yes. I adjusted the TB according to the Bentley using a 0.0015 feeler gauge. However, I did see another method is to unplug the ICV and set the idle to 950 rpm by adjusting the small set screw on the TB.

I'll try this tonight.

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[earthwormjim]

Perhaps the closed position on your throttle body needs to be adjusted? To idle, the engine needs the idle control valve to function, and a very small opening on the throttle body.

[jneumss]

Ok, so I've had the car running and driving for about two months, but have only put about 700 miles on it so far.

I have an issue that I'm battling, I'm running an SSSquid Stage 2 tune and I'm experiencing a hesitation between off idle and 3k rpm. In addition, I have low vacuum at idle ~10inHg and a steady low and slightly rough idle ~650 rpm. Above 3k rpm, the engine runs smooth and pulls hard through 5500rpm.

I also failed Colorado emissions having slightly high NOx. I had an average of 4.6545 and the limit is 4.0000 grams per mile. So it's definitely running a little lean. CO and HC emissions are well below the limits.

Things I have done to troubleshoot:
- smoke tests (no vacuum leaks)
-compression test (all good)
-new O2 sensor
-stomp test (no codes)
-Bentley electrical tests (nothing out of tolerance)
-valve adjustment

The only thing I haven't done is check the timing to ensure I'm not off a tooth or so, but that's my next step. Has anyone else experienced this or have any other ideas of things I could try out?

I found one other thread that had described symptoms like this, but they did not post any resolution and had a completely stock engine. Any other suggestions?


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[jneumss]

Interesting approach for bearings. Shop that made/installed bearings couldn't machine OEM ones or there is some other trick? Just wondering why it was easier to produce those custom ones vs machining OEM units. Final fitting process would be the same (machine to the diameter +.001-.0015" clearance ->press in->final verification and minor honing to maintain the clearance)...no?

Those cylinder bores look super shiny or it's just a pic? Hopefully your new rings will break-in well.

I don't really think there is any advantage to making custom bearings for the intermediate shaft. It was an extremely annoying process trying to get this machinist to work on the OEM bearings. And, in the end, he refused to work on the OEM bearings because they are harder than your typical cam bearing and came from the factory undersized. He was more confident he could make bearings out of bearing stock that was a softer material so that's how it came about. I couldn't believe that I had such a hard time finding a shop to do the install, but literally no one in the Denver area would touch it. I really hope that they work out.

Also, the shiny cylinder walls are a combination of a film of oil and lighting in the pic, they definitely weren't that shiny after being honed.

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[ForcedFirebird]

^^correct. Making custom bearings and installing would be no different than installing OEM.

It's not a difficult task, really, just have to pay attention during the process.

[zaq123]

Since I couldn't find anyone who could machine and install new OEM intermediate shaft bearings, I had some custom bearings made using oil impregnated bronze and were made to mimic the OEM bearings. I haven't seen or heard of anyone doing this before, do I'm praying that they won't give me any issues.

Interesting approach for bearings. Shop that made/installed bearings couldn't machine OEM ones or there is some other trick? Just wondering why it was easier to produce those custom ones vs machining OEM units. Final fitting process would be the same (machine to the diameter +.001-.0015" clearance ->press in->final verification and minor honing to maintain the clearance)...no?

Those cylinder bores look super shiny or it's just a pic? Hopefully your new rings will break-in well.

[jeffnhiscars]

That sure looks a whole lot better :)

[berlow94]

Gold!


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[jneumss]

It's been a long 6 months between buying a house and moving the iX / engine over to my new place in boxes, being busy at work, and finally figuring out my intermediate shaft bearings.

Since I couldn't find anyone who could machine and install new OEM intermediate shaft bearings, I had some custom bearings made using oil impregnated bronze and were made to mimic the OEM bearings. I haven't seen or heard of anyone doing this before, do I'm praying that they won't give me any issues.

With the new bearings installed, I painted the block, took delivery of my new rings, rod bearings, and main bearings and I reassembled the bottom end.

I also found a brand new iX oil pump and waited about 35 days to receive it from Germany.

After building up the bottom end, I switched focus to the head. I replaced the valve stem seals and installed the 274 Bimmerheads Cam, with IE heavy duty rockers/oversized eccentrics.

And finally, over the past two days I reassembled the engine and it's ultimately ready to be installed in the car.

After the new year, I will hopefully have the time to mate the front subframe, engine, trans, TC and install from the bottom up.

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[digger]

send the block to MM get them to do it and they will send it back

[jneumss]

So I haven't gotten anywhere on getting these intermediate shaft bearings replaced. I'm looking for some opinions on another option, would it be possible to just have the intermediate shaft turned down to clear the new bearings?

After a quick internet search I haven't found anyone who has done that. After talking to Jim from MM, I got the feeling that this could be a possibility. He also said in a pinch that he has carefully taken the bearings out of old ETA blocks and installed them into an i block with good success as well. Not sure what to do here, looking for any other recommendations or possible solutions so I can get this thing back on the road.

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[jneumss]

So the machine shop called me today and said everything was done except the intermediate shaft bearings. They said they did not know how they could size and install them. I've called around to several shops in the area and no one seems to want to touch it. I'm not really sure what to do here, I've tried explaining the process to install these bearings and I definitely can't put the engine back together in this condition.

Does anyone know of any places in the Denver area that has done these bearings before?

My other option is that I could send my block down to a shop called Memphis Motor Werks in Memphis that can do the work.

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