Crankshaft oilway plug and main bearing groove?

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jon8christine
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Your car is a: 1976 Fiat 124 Spider
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Crankshaft oilway plug and main bearing groove?

Post by jon8christine »

Finally have my engine parts back from the machine shop (6 months later) and most of the parts to start rebuilding my 1976 1800 engine. When I pulled it apart all five main bearings had grooves in them

https://drive.google.com/file/d/1ryKWN8 ... p=drivesdk

The new set I got from Vicks all have the groove except one set that doesn't and they're a bit wider. Reading in the Guy Croft manual it looks like that one goes in the middle, and the journal is a bit wider... Just wanted to double check on here that this is correct.

https://drive.google.com/file/d/1fGLfW5 ... p=drivesdk

Last question is on the crankshaft I got back from the shop. It's my first time working with a crankshaft, but aren't the oilway galleys supposed to have plugs (bungs) in them. They look like 10x1.0mm threads. Noone seems to have them in stock specifically. Do I just buy 10mmx1.0 set screws and put them in with a little pipe tape?

https://drive.google.com/file/d/1rpiCDE ... p=drivesdk

Thanks again
Nut124
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Joined: Wed Oct 25, 2017 6:39 pm
Your car is a: 1978 124 Spider 1800

Re: Crankshaft oilway plug and main bearing groove?

Post by Nut124 »

Yes, the set w/o grooves goes in the middle.

If your crank has threaded oil galleys, then it is likely a later mod, not factory. Mine had little sheet metal plugs. The threading is a GC recommendation, which I considered and tried but was scared off by the hardness of the steel, worried about breaking a tap in the hole. I think the threaded plugs make the next crank job easier. No other benefit.

Yes, find the matching allen head set or grub screws and secure w locktite. I would add a few light dimples with a center punch to make sure they cannot back out, cause a disaster.

I radiused the crank oil holes per GC book. Ideally, you should have done this before the crank went to the shop. I used a dremel with a diamond dust oval bit.

Did you have the rotating assy spin balanced? I highly recommend it. Rods, crank, FW and the clutch. Cost for me was about $150. I had this done after I reinstalled the plugs.
18Fiatsandcounting
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Your car is a: 1969 and 1971 124 spiders
Location: San Francisco Bay Area

Re: Crankshaft oilway plug and main bearing groove?

Post by 18Fiatsandcounting »

In addition to the advice from Nut124 above, I'd take a look at the middle journal on the crankshaft. As he noted, the middle bearing is wider and does not have the grooves, and since the engine had an incorrect middle bearing, it might be a good idea to double check. I doubt there's any issue, but sometimes I get paranoid about these things.

-Bryan
jon8christine
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Your car is a: 1976 Fiat 124 Spider
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Re: Crankshaft oilway plug and main bearing groove?

Post by jon8christine »

I called the machinist and he apologized for not putting the plugs in. He had tapped them as they were flat plugs that he didn't have and then didn't put them back in after the cleaning. He didn't recommend a spin balance, so after a quick trip to the shop we're ready for assembly again. At least to the point where I need the 40-80 cams which may be back in stock in September.
Nut124
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Joined: Wed Oct 25, 2017 6:39 pm
Your car is a: 1978 124 Spider 1800

Re: Crankshaft oilway plug and main bearing groove?

Post by Nut124 »

jon8christine wrote:I called the machinist and he apologized for not putting the plugs in. He had tapped them as they were flat plugs that he didn't have and then didn't put them back in after the cleaning. He didn't recommend a spin balance, so after a quick trip to the shop we're ready for assembly again. At least to the point where I need the 40-80 cams which may be back in stock in September.
What was his rationale for not needing spin balance? If you are putting in cams, that means 6500-7000rpm to get anything useful out of the cams.
jon8christine
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Your car is a: 1976 Fiat 124 Spider
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Re: Crankshaft oilway plug and main bearing groove?

Post by jon8christine »

The center crank journal looked fine, and all five plastigaged at .002, which is good. He said since the crank was previously balanced and the plugs are all in the same two planes it would be fine. He was also busy and probably didn't want to do it (may have taken another six months).

The axial runout (end float) is out of spec, however. He had to touch-up the thrust faces and now I have .013 runout. Spec in my Haynes manual is .012 max and I can't find oversized thrust washers. Think I'll be ok?
jon8christine
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Your car is a: 1976 Fiat 124 Spider
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Re: Crankshaft oilway plug and main bearing groove?

Post by jon8christine »

I called Mark Allison and he still had a set of oversized thrust washers so that should get it back in spec, even though a call to the machinist said it would be fine.
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