Jack I Brooks wrote:
>
> Sol'ers
>
> I am about to order the new shells for my engine and have few
> questions/comments to bounce off y'all (yeah, New Jersey now, but North
> Carolina for a few years) before I start replacing main and big end
> shells.
>
> 1. One big end journal has very light scoring around a narrow band in
> line with the oil hole. It is more of a light scratching, probably from
> a grain of sand or dirt. It is felt, very lightly, with a fingernail.
> The engine is still in the car. Rather than letting the new bearing get
> scratched from this existing damage, I was contemplating lightly using a
> fine wetstone to smooth out the raised sections of the scratch. Will I
> create more damage than exists? Has anyone ever dealt with very light
> scoring like this? Any suggestions other than pulling the engine and
> have it ground?
>
> 2. For general info, since my engine is fairly tight at the front and
> rear seals, and the center main was plastigaged at 0.003", I am currently
> planning to replace the shells on the big end bearings, the thrust
> washers and the center main only. I am concerned about maintaining the
> integrity of the oil seals after replacing the front and rear main
> shells, when I really don't think they are horribly worn. I know 0.003"
> is the allowable wear limit, but I don't have the time to pull the engine
> this year. Also, with an insurance stipulation limiting my annual
> driving to 2,500 miles, it should be some time before I add a lot of wear
> to the bearings. In my opinion, the center main should wear the most,
> so if it is only 0.003" then the others should be better. Any
> suggestions or commentary from your vast experience would be appreciated.
>
> Thanks.
>
> BTW - If this message comes through as only a header please let me know.
> (Sarcasm)
>
> Jack Brooks
> Hillsdale, New Jersey
> 1960 TR3-A TS69032L
> 1974 Norton Commando Roadster
I replaced my big end bearings (or at least, those in my TR3A!) several
years ago when I first got it. I found major scoring on the #1 crank
journal, which I cleaned up with a stone. The car has been running fine
since, although the oil pressure has been getting lower recently... I
did this as a temporary expedient, just to keep the car running for a
few more miles, knowing that the engine requires a complete rebuild. Of
course, the optimal approach would be to pull the engine and do it
right.
An interesting note is that I also found a substantial piece of metal
embedded in the shell from #1. After examining it, I decided that it
was a piece of the timing chain tensioner that evidently passed through
the oil pump, through the crank oilway and then got stuck in the #1
journal. I've never checked the tensioner to see if I really have one
(I found other pieces in the sump), but I suspect I don't. Again, I
never bothered to replace it because the engine runs happily and I
intended to pull the engine and fix it properly. This all occurred six
or seven years ago and I'll let you guess if I have actually rebuilt the
engine yet!! Needless to say, I very seldom take the car on long trips.
After replacing the big end shells and the oil pump rotor (also
danmaged), my oil pressure went from 20 when hot to 50 psi. Now its
down to about 40 psi, so maybe it is time to rent the engine hoist...
|