Adjusting rod bearings

[ursus]

This series of posts recalls an erstwhile Fordbarn exposition on the same subject by Mike "Miracle Motors" Flanagan. If anything, he was entertaining. Flanagan rhapsodized about his father's use of a "sounding hammer" to test for the fit of bearings while still mounted to the crankshaft. He claimed that, with a brass hammer and a trained ear, one could quickly determine which of the rod bearings would need to be taken up. That he was an adherent of the foil method must have indicated that he never developed the trained ear necessary for the sounding hammer method.

Personally, I have only too much experience with the sound of loose rods, albeit at road speed. I wonder if anybody uses a "sounding hammer" as a test of lost motion?

Otherwise, I cannot fault the logic behind the oiled paper method. The description makes sense to me, although it still requires some experience regarding the appearance of the paper. There may well be more uniformity in phone book paper Down Under than the Plastigage sold here.

[Patrick L.]

Herm,

You're cheatin' ! You get to use an engine stand. [ smiley face ]

Nice pictures

[BILL WILLIAMSON]

Has ANYONE ever tried to use a QUALITY dial indicator, mounted on a MAGNETIC base, to check bearing clearances, while everything is still bolted up, intact? Just "thinking"!
Bill W.

[H. L. Chauvin]

In response to Mr. Herm's very kind reply #21, (LOL), I went to (2) parts stores.

The young guy at parts store No. 1 never heard of Plastigage & commented he did not have any.

The older gray haired gentleman asked what in the World was I working on & said he cannot remember the last time someone asked for Plastigage; however, he found some in his 150 degree hot, non-air-conditioned metal building attic, covered with dust which was almost hard enough to use for connecting rod shims -- the white paper that accompanied it was even a pale yellow.

Store no.2 had Plastigage stored in an air-conditioned area & did not look like Christopher Columbus used it to adjust the bearings on his Santa Maria anchor winch in 1492.

Never thought about trying oil on the hard & dry ancient Plastigage from store No. 1. LOL

[Marshall57]

Originally Posted by RonC

plastigauge works good. For some reason the supplier catalogs don't mention you have to heat the shims first to peel. To split the peelable shims apart, lightly
warm them with a propane / map gas torch. Don't over heat them to much just enough for them to come apart. The shims can then be easily split apart.

Thank you for that bit of info, I have used up all my cuss words and still not been able to get the darn things to split where I wanted them.
Does anyone have a trick to doing the rear main when it is in the car?
Maybe a special tool to use. I can't seem to reach the bolts unless the engine is out of the car. Also I used the tin foil method and it worked really well.

[SAJ]

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Bill, I put a magnetic dti on the crank next to the middle main and applied a hydraulic jack next to it and measured 0.0015 inch vertical movement. The crank was in the car, bearing cap still buttoned on and fully oiled. I also measured end float at 0.003 with the dti. When I removed the motor for reboring and got it upside down in an engine stand with plastigauge in the bearing it also measured 0.0015. I had thought the oil would disguise the true clearance since feeling a bearing is more accurate when dry in my experience. But plastigauge squshes the oil out ok so I guess a jack can too. End float with a feeler gauge was accurate at .003 too.
I will use the same dti on the next engine I get the sump off of in the car and check the result again.
SAJ in NZ

[Patrick L.]

Originally Posted by Marshall57

Thank you for that bit of info, I have used up all my cuss words and still not been able to get the darn things to split where I wanted them.
Does anyone have a trick to doing the rear main when it is in the car?
Maybe a special tool to use. I can't seem to reach the bolts unless the engine is out of the car. Also I used the tin foil method and it worked really well.

Reply #2.

[Tom Wesenberg]

SAJ, did you pry the center of the crankshaft down, as well as push up? My thinking is the heavy flywheel might be causing the center main to flex in an upward position as installed in the car.

[SAJ]

Tom, that is an excellent point. I cannot recall exactly what I did, but I tested at several points of rotation, looking for ovality in the journal. After taking the crank out I found it was bent 0.006 inch in the centre, and I straightened it in a press after advice from J & M machine, Joe K and others on this forum (maybe you too?). I certainly levered it back and forth and did think about the flywheel weight pivoting the middle main up on the rear cap.
I remain to be convinced it is a good test, but will use it again before taking caps off.
The upper middle babbit has been broken in pieces on a couple of engines I looked at. In both cases the bits slowly slid round the crank and fell out onto my face after I took the middle cap off. One can never be sure about this upper babbit without complete dismantling, which adds a lot of work that may turn out unnecessary.
Having written this and going over it in my mind again, I did lever the middle of the crank down and saw some movement on the DTI in that direction. I took the total movement up and down as the clearance.
Thanks again for raising an important point.
Congratulations on your astounding 15000 posts record. You are always so polite too. I have been guilty of posting some silly questions and answers too, but escaped abrasive replies. I suspect no one reads my posts because they are too long!
For example, recently I pointed out that the turn flashers light between the beeps on the flasher can, not on the beeps (talking about the beeper connected to the "P" terminal on the can). Then , to my horror, I found it was the opposite case on my roadster - the lights were on when the beeper was sounding. So My wife's Tudor and my roadster are different and opposite yet have the same turn signal apparatus. No one picked me up, but I bet you noticed it.
SAJ in NZ

[colin1928]

Wow I must be weird I pull the engine remove the crank and measure with both inside and outside micrometers
I sometimes double check with plastiguage but only on cranks and bearings that have been check for roundness and tape with a micrometer
Colin

[Marshall57]

Originally Posted by Patrick L.

Reply #2.

Time to make that tool, I think there was a picture of just such a tool pictured some time ago... Thanks