PDA

View Full Version : Musta misst that lesson!



Rick Fischer
19th January 2021, 04:58 PM
Hiyas

Installing main bearing caps on ye olde engine. Had a big fail with rear cap and cork seals![bigsad] That is those skinny strip ones in the cap and go between cap and block.

Did follow instructions, even made the special tapering tools so cork would compress in. NUP! The 90 degree ones just sheared off and pushed the other halves out.

For me, big fail! Had to use 3bond red silicone instead.

Had an earlier fail, though didn't think I was particularly complicit, and an advice for young (new) players.

On return from Machine shop crank would not turn with finger tight bolts, and big ends were a wee bit tight. So just took it back. They had a look did what was necessary and LO! it went round. Do recall an earlier Thread where someone else had similar problem

Ummm! We be too used to things just fitting and working. Interchangeabiliy! Yanks had that sorted by mid 1942 as every bit in a Jeep or a Sherman or other weapon was interchangeable with every other like thing. British didn't get it nailed till late 50s or early 60s. Did notice later the bit in the text which talks about selecting appropriate bearing shells. (Is/was a case of "I thought I had")

Mmmmm not really an option 75+ years down the track. Machine shop needed to do a bit of scraping in the bearing shells, they also found that as the shell centres compressed around the Crank the join/split edges would distort and fold/come in. The big end shells needed to be adjusted for end float. Again selective fit if one had a choice.

Cheers

Rick F

Rick Fischer
19th January 2021, 05:31 PM
Hiyas

Installing main bearing caps on ye olde engine. Had a big fail with rear cap and cork seals![bigsad] That is those skinny strip ones in the cap and go between cap and block.

Did follow instructions, even made the special tapering tools so cork would compress in. NUP! The 90 degree ones just sheared off and pushed the other halves out.

For me, big fail! Had to use 3bond red silicone instead.

Had an earlier fail, though didn't think I was particularly complicit, and an advice for young (new) players.

On return from Machine shop crank would not turn with finger tight bolts, and big ends were a wee bit tight. So just took it back. They had a look did what was necessary and LO! it went round. Do recall an earlier Thread where someone else had similar problem

Ummm! We be too used to things just fitting and working. Interchangeabiliy! Yanks had that sorted by mid 1942 as every bit in a Jeep or a Sherman or other weapon was interchangeable with every other like thing. British didn't get it nailed till late 50s or early 60s. Did notice later the bit in the text which talks about selecting appropriate bearing shells. (Is/was a case of "I thought I had")

Mmmmm not really an option 75+ years down the track. Machine shop needed to do a bit of scraping in the bearing shells, they also found that as the shell centres compressed around the Crank the join/split edges would distort and fold/come in. The big end shells needed to be adjusted for end float. Again selective fit if one had a choice.

Cheers

Rick F

JDNSW
19th January 2021, 08:04 PM
An interesting story told to me by a friend of mine who was a mechanic (died thirty years ago). The company he worked for in Roma in the 1950s was asked to overhaul the engine of a RR Phantom 3 V12 owned by a local grazier. They had to send the conrods and caps off to the UK together with detailed shaft journal measurements (after satisfying the manufacturer that they were qualified to do the work). The bits came back, and when the engine was reassembled it was found that the crankshaft would not turn until the big ends were properly torqued - it then turned freely.