Tightening rocker stand bolts on 912 356 engines

For you flat four Porsche 912 fanatics

Moderators: Miggs, KS

Post Reply
Super90speedshop
DDK Seasoned Poster
Posts: 29
Joined: Tue Oct 14, 2014 6:57 pm

Tightening rocker stand bolts on 912 356 engines

Post by Super90speedshop »

Just reassembling my 356 motor. The cylinder head bolts themselves are torqued to 22ibft. These special head bolt fixings are critically lengthen so as not to tear the oil sealing ring that's on them. The three rocker stand bolts then fasten into three of these special flanged cylinder head main fixings. But the specified fixing torque for the rocker stand bolts is 36ibft so you are tightening them at 36ibft into cylinder head bolts which are torqued at only 22ibft. Surely this will tend then to over-torque the main cylinder head bolts. Just wondered if anybody had been struck by the same observation and if they had come up with any reconciliation??? Phil Sewell. Super90speedshop, mid Wales
1957 356A T1. RHD coupe
1958 356A T2 LHD coupe
1962 356B T6 LHD coupe
1965 356SC, LHD coupe
1967 912 LHD coupe
1969 911E LHD Targa
1977 911SC LHD coupe
1981 930 Turbo LHD coupe
1998 993 Carrera 4S coupe
1971 914 1.7 LHD
dcraigmyle
DDK above all
Posts: 192
Joined: Sun May 10, 2009 10:49 am
Location: Wimborne - Dorset
Contact:

Re: Tightening rocker stand bolts on 912 356 engines

Post by dcraigmyle »

I thought they were torqued to 15lb?

http://porsche356enginebuild.blogspot.c ... ckers.html
Ashley James
Put a fork in me, I'm done!
Posts: 1654
Joined: Tue Jul 12, 2016 3:30 pm
Location: Near Stroud, Glos. UK
Contact:

Re: Tightening rocker stand bolts on 912 356 engines

Post by Ashley James »

36ft/lbs is correct and it works, honest guv.
dcraigmyle
DDK above all
Posts: 192
Joined: Sun May 10, 2009 10:49 am
Location: Wimborne - Dorset
Contact:

Re: Tightening rocker stand bolts on 912 356 engines

Post by dcraigmyle »

Here is the Harry Pellow list.
He says 29lbs
Sorry I was thinking of the rocker nuts when i said 15!

NUT or BOLT Size Ft-Lbs
Axle Nuts 36mm ATF 398
Cam Gear Bolts 14mm ATF 18
Cam Plug Nuts 8mm 15-18
Carburetor Mounting Nuts 8mm/12mm ATF 15
Case Acorn Nuts - Copper Washers 15mm ATF 22
Case Acorn Nuts - Beveled Washers 15mm ATF 29
Case Perimeter Nuts 13-14mm ATF 15-18
Connecting Rod Nuts 14mm ATF 33
Crankshaft Pulley Bolt 30mm ATF -
Engine Mounting Bolts & Nuts 17mm ATF -
Engine Sheet Metal - Horizontal Surfaces 6mm cheesehead screws -
Engine Sheet Metal - Vertical Surfaces 6mm bolts -
Exhaust Pipe (muffler) 8mm/12mm ATF (brass) 15
Exhaust Rocker 8mm/13mm ATF 15
Flywheel Nut 36mm ATF (1 7/16") 350
Fuel Pump Nuts 12-13mm ATF 15
Fuel Pump Bolts 8mm/13mm ATF 15
Generator Pulley Nut 36mm ATF -
Generator Stand Nuts 8mm/14mm ATF 15-18
Generator to Cooling Fan Nut 36mm ATF 72
Head Bolts 10mm Allen 22-25
Heater Box Nuts 8mm/12mm ATF 15-18
Intake Manifold Bolts 8mm/13mm ATF 15-18
Intake Manifold Nuts 8mm/13mm ATF 15-18
Intake Rocker 8mm/13mm ATF (thin) 15-18
Lug Nuts - 94
Muffler Clamp Nuts 14mm ATF 18
Oil Cooler Nuts & Bolts - Old 6mm/10mm ATF -
Oil Cooler Nuts & Bolts - New 8mm/12-13mm ATF 15
Oil Filter Can Bracket 6mm/10mm ATF -
Oil Filter Can Strap Bolt 14mm ATF 15
Oil Filler Can Bolts & Nuts 6mm/10mm ATF -
Oil Pump Nuts 6mm 10
Pressure Plate Bolts(to 1963) 8mm/6mm Allen head 15-18
Pressure Plate Bolts(1963 on) 8mm/13mm ATF 15-18
Pulley Shroud Bolts short 6mm -
Radius Arm to the axle tube flange 12mm ATF 65-72
Rocker Stand Mounts (Cast Iron) 17mm ATF 29
Rocker Stand Mounts (Aluminum) 15mm ATF 29
Solex Air Cleaner Bolts 10mm ATF -
Third Piece Nuts 8mm/12mm ATF 15
Wheel Bearing Cover 10mm ATF (10G) 40-43.5
Primary Sources & Additional Information
Mike Smith
DDK rules my life!
Posts: 1243
Joined: Wed Apr 06, 2005 12:37 am
Location: Billericay, Essex
Contact:

Re: Tightening rocker stand bolts on 912 356 engines

Post by Mike Smith »

IF the Threads are free IN the Head bolts and the Rocker Stand Bolts are not damaged there will be no turning moment on the Head bolts

i.e. The head bolts will not have any tendency to turn
Mike at P.R.S.
www.prs356.com
Post Reply