Quote:
Originally Posted by SAJ
Thanks for the replies folks. Crank came out today and babbit in block on front and middle is toast too. The middle is crazed all over and fell out in pieces. To me it looks like a lead-content babbit, due to the crazing and dullish colour. I will check it for lead if I get time later out of curiosity.
The photos play tricks and you cannot feel or see any wear on the cam lobes- just the staining at present. There are two dark stripes on the heel of two of the cams which is peculiar, since there should be no contact here unless there was no clearance at some time. Pic attached
Due to the quality of the centre and front babbiting, I feel we cannot trust the rear main either, although it looks re-usable at present.
Unfortunately I don't feel there is a reliable bearing pourer near us in NZ, so we will go for a full line-bore and shell mains, leaving the current standard oiling system and full flow filter as fitted.
The owner was using Penrite 30W/70 oil and at room temperature working on the oily engine is like working in maple syrup!
The owner drives at 45 mph everywhere, with accidental exciting digressions to 50 down hills when not paying attention! It is a 1930 Cabriolet. I hope he doesn't read this!
I agree that lugging is far more harmful than running easy.
Diagnosis of the failure was interesting, since no one except the owner thought there was a problem when hearing it run and driving it. So I sped up the idle, pulled the spark right down and messed up the mixture with the air screw until the car had a jerky, staccato idle and then, wow, the knocking really started unmistakably. A listening tube under the sump put the rattle at the rear main, but it was sound travelling from the middle bearing, in fact. A mechanics stethoscope with rigid prong magnified tappets etc but not the knock. Shorting plugs made no difference, and retarding it smoothed the idle so the clanging was reduced anyway.
It was a buggered engine still running like a good'un!
The shiny marks on the rear babbit may be chatter marks, but don't look typical of chatter to me. Maybe James could identify, but unfortunately, by the time I got to my workshop today, a team of three had the whole engine down (See pic) and parts put away so I only got the two more pics.
Crank journals are all 1.60005 to 1.6001. I bet there are no shells this size!
Thanks for the replies
SAJ in NZ
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The crank will have to be turned to use insert bearings, there are no .025 under shells. I don't like the way the oil groove is done on the rear. It should NEVER run to the front of the bearing and out the thrust. This is an attempt to keep the rear main from leaking. It will sometimes keep it from leaking when stopped but, it will leak BAD when running. This is because, crankcase pressures will find this path and use it to force the oil out the rear tube and possibly cause starvation and excess wear. I have had 2 engines in the last 2 months with the same problem as this that were bad jobs with inferior babbitt composition, both were repaired by pouring and boring with new Ford composition babbitt the way ford did it. One had the slinger cut off and a crappy modern seal that leaked, BAD. I replaced the slinger and got rid of this seal AND the leak.
As for running over 45 MPH, I wouldn't have a car that wouldn't run over that for at least the day. I don't change out of second till I hit 35 and that is every time I drive my car. This engine was built 5 years ago and is done as Ford built them. The motor has never given a minutes trouble and does not leak except for a quarter size spot overnight when I drive it long distances. I pulled the engine last spring to freshen the paint and while it was out I decided to check the bearings since, I had to pull the pan for paint anyway. There was absolutely no wear or damage to the mains or rods after 12,000 miles. The mains actually looked just like they did when I closed it up after the rebuild.
I say "drive 'em like you stole 'em". You'll be much happier in the end. JMHO
Another thing I noticed in your last picture, and just my opinion. Ever hear that "too many cooks will spoil the porridge"?