AlfaGTA
Diamond
- Joined
- Dec 13, 2002
- Location
- Benicia California USA
Long shot here. Working on a project and i need data that seemingly no longer exists!
Short version:
Need to line bore engine block main bearing housings.
Original housings have been reworked several times poorly. Original housing size can not be derived from current bores.
Rear main has been welded up to repair previous blow up....(crank failure) Housing is oversize for oversized bore (thicker wall shell)
Specifics:
Engine:3 liter, V 12 BRM Gran Prix purpose built racing engine (circa 1974 type 202 i believe). No factory specs. available.
7 main bearings.
1-6 standard housing bore (as far as i can tell) .0755 wall bearing shell
#7 housing over bore (repair of damage from previous crank failure). .087" wall bearing shell
Have a set of original bearing shells (NOS)
Vandervell.
Shells have numbers, but shell numbers don't relate to anything in any catalogue i can find.
Std housing shells: #5674 .005
Oversize housing shell: L8986/1 .0005
Contacted the shop that supports these engines in the UK and they supplied housing bore info, but the numbers don't work....Bore less shell thickness does not come close to std crank
sizes....
Have in the past when confronted with this sort of problem made test bearing housings and test assembled bearings...
Shells will tend to "pinch in" at the parting line if the bore is too small...Have started underside and incrementally increased the test bore till the shells give even bore...(these shells are not5 tapered on wall).
Looking for a better way at getting the dimensions i need....Perhaps a smart guy method of accurately measuring the real length of the bearing shells, edge to edge so i could calculate the installed
circumference...
Open to ideas.....
Cheers Ross
Short version:
Need to line bore engine block main bearing housings.
Original housings have been reworked several times poorly. Original housing size can not be derived from current bores.
Rear main has been welded up to repair previous blow up....(crank failure) Housing is oversize for oversized bore (thicker wall shell)
Specifics:
Engine:3 liter, V 12 BRM Gran Prix purpose built racing engine (circa 1974 type 202 i believe). No factory specs. available.
7 main bearings.
1-6 standard housing bore (as far as i can tell) .0755 wall bearing shell
#7 housing over bore (repair of damage from previous crank failure). .087" wall bearing shell
Have a set of original bearing shells (NOS)
Vandervell.
Shells have numbers, but shell numbers don't relate to anything in any catalogue i can find.
Std housing shells: #5674 .005
Oversize housing shell: L8986/1 .0005
Contacted the shop that supports these engines in the UK and they supplied housing bore info, but the numbers don't work....Bore less shell thickness does not come close to std crank
sizes....
Have in the past when confronted with this sort of problem made test bearing housings and test assembled bearings...
Shells will tend to "pinch in" at the parting line if the bore is too small...Have started underside and incrementally increased the test bore till the shells give even bore...(these shells are not5 tapered on wall).
Looking for a better way at getting the dimensions i need....Perhaps a smart guy method of accurately measuring the real length of the bearing shells, edge to edge so i could calculate the installed
circumference...
Open to ideas.....
Cheers Ross