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87glhs232
05-20-2006, 11:20 PM
I've had a slight knock at first start up. A few revolutions of the motor only... maybe 3-5. Once the oil pressure starts to rise it's gone for the day. Since I have the motor out and the pan off...should I bother with new bearings? The motor only has 2k on it. Is it something to really be worried about?

The S is Silent
05-21-2006, 12:17 AM
You might as well put in new rod bearings. They only cost $25, and it will never be easier than it is now. At least pull them off and check the clearances with plastigage.

GLHSKEN
05-21-2006, 09:11 AM
^^ doesn't hurt to plastigauge it. As long as things are out takes about an extrra hour to check. Worth the time.

87glhs232
05-21-2006, 09:43 AM
Roger that. I'll get some as soon as the parts stores open this morning. I just pulled #4 cap and measured....1.948.... it's been turned .020 :eek:. That bearing had a nice streak and something embedded in it.

GLHSKEN
05-21-2006, 10:13 AM
That's a hefty turn... Have a spare crank??

87glhs232
05-21-2006, 10:19 AM
That's a hefty turn... Have a spare crank??

Yep. 2 of them. Unknown condition as there still in short blocks. I can live with it. I'm not going to push it hard this year. After it's back on the road I'll be starting on a forged assembly and a 555 or 568 hybrid. Thats next springs installation.

GLHSKEN
05-21-2006, 11:03 AM
:thumb: I've found that my best engines ever were junkyard specials.

87glhs232
05-21-2006, 11:06 AM
:thumb: I've found that my best engines ever were junkyard specials.
Funny how that works :p

87glhs232
05-21-2006, 07:38 PM
I found a small burr on the #4 rod journal. I miked the journal in 5 positions to make sure it was round...which it is. Then I inspected the burr area with a high power magnifying glass. Sure enough there was a slight dent/gouge and an even smaller raised burr. I took 1000 grit paper on a known straight/flat stock of wood (ebony) and VERY lightly touched the area. Followed that up with a scotch bright buffing. Thoroughly cleaned it up and miked it again. No change in diameter. I miked right on the questionable area and it is right on with the rest of the journal. I inspected it again with the magnifying glass and the burr is gone...but there is still a slight dent. I don't think it will cause a problem...and I am putting new Clevite 77's in.
Comments?

The S is Silent
05-21-2006, 07:57 PM
Aren't you glad you checked ;)

I don't know if the dent will allow the oil pressure to bleed out on that rod. The clearances might be too large in that spot, but you can put it back together and see. How deep is the dent? have you mic'ed it in that spot?

87glhs232
05-21-2006, 08:13 PM
It's too small to get the tip of the mike in. Can't get a depth. I just miked the red plastigauge I bought today and it was .018. Comparing the plastigauge to the dent it's about .025 in diameter and maybe .005 deep. It's just off center on the journal and about 1/2 inch from the oil hole.
I miked the jourmal diameter right on the spot after touch up, and it's right on with the rest of the journal.
I'll have to wait for new bearings to arrive. I live in a major metro area and NO ONE has bearing for this. Some times it sucks living in TD no mans land. Oh well....I have no rust!

The S is Silent
05-21-2006, 09:36 PM
I don't think it'll be a problem then. I didn't have a problem getting bearings for mine. I ended up going with Sealed Power bearings. I hope they are good.

mech1nxh
05-21-2006, 11:54 PM
I don't think it'll be a problem then


^ +1, just as a caution check taper on the journals too...
as GLHSKEN mentioned .020 is a heavy grind...

87glhs232
05-22-2006, 12:36 AM
^ +1, just as a caution check taper on the journals too...
as GLHSKEN mentioned .020 is a heavy grind...

Remarkably even.

DUGZSHELBY
05-31-2006, 11:34 PM
A bad oil filter with a falty check valve "anti drainback valve" will cause a loud knock from the oil pump on first startup. Had a few "frams" that did this. Sounds just like a rod.

87glhs232
06-01-2006, 02:03 AM
A bad oil filter with a falty check valve "anti drainback valve" will cause a loud knock from the oil pump on first startup. Had a few "frams" that did this. Sounds just like a rod.
Good idea...though this has persisted through a couple Mobil 1's and a K&N. I'll never use a 'sham' filter.:p