harmonic balancer pulley bolts

[Jack B.]

I'm installing the crank pulley on my 1965 fuel injected car. The 3 bolts had no head markings that I could discern. I would appreciate if someone could give me the correct head marking. Mine is a November 1964 production.
Paragon offers bolts with head marking "E", "S", "LE" and "TR".
Should they be grade 5 or 8?
Also, need correct head markings on the bolts connecting the fan to water pump.
Thanks

[Scott S.]

Re: harmonic balancer pulley bolts

I'm installing the crank pulley on my 1965 fuel injected car. The 3 bolts had no head markings that I could discern. I would appreciate if someone could give me the correct head marking. Mine is a November 1964 production.
Paragon offers bolts with head marking "E", "S", "LE" and "TR".
Should they be grade 5 or 8?

Jack,

The L84 Non-Illustrated Parts section (UPC L84, Sheet 2) shows the same Bolt (GM #181629) called out as used with the L76 (UPC L76, Sheet 2). It is also the same bolt part number as was used on my 1967 L79 at the crank pulley location. Part number 181629 is listed in the Standard Parts Catalog as being 3/8-24 x 5/8", Grade 5, Cadmium plated.

Mine had been changed at some point, so I can't help with the headmarks.

[Scott S.]

Re: harmonic balancer pulley bolts

Also, need correct head markings on the bolts connecting the fan to water pump.
Thanks

If I understand correctly, the fan blade attaches to the fan clutch by studs, and the fan clutch hub then attaches to the water pump with four bolts (GM #186634), shown on UPC 6-A3. If the L84 engine uses the same GM 186634 bolt at this location (I did not see anything saying otherwise), it is also the same bolt used on my L79.

My originals are 5/16-24 x 1”, confirmed by the 67 P&A (Gr. 8.900) and the Standard Parts Catalog. Grade 8, Cad-plated. The headmark is "A S".

Hopefully someone with a fuel injected '65 will be able to confirm, or correct me if I am in error

[Jack B.]

Re: harmonic balancer pulley bolts

Thanks for the info Scott. I suspect ,but don't know for sure, that the same bolts were used on the different model on the assembly line. Maybe there are some NCRS judges that can help clarify this. Again, I'm looking for the head markings on the crank pulley and water pump pulley bolts.

[Scott S.]

Re: harmonic balancer pulley bolts

Thanks for the info Scott. I suspect ,but don't know for sure, that the same bolts were used on the different model on the assembly line. Maybe there are some NCRS judges that can help clarify this. Again, I'm looking for the head markings on the crank pulley and water pump pulley bolts.

Jack,

There are a few more headmark data points in the following thread, see Post #4. It's about a '66, but same bolt part number as yours: Fan Clutch Bolts

Rich Pasqualone would be able to give you some good info on this subject, I would try him by email if he doesn't see this Thread.

[Timothy B.]

Re: harmonic balancer pulley bolts

The bolts I have for the crankshaft pulley/ damper attachment are RBW with intergral internal tooth lock washer grade 5 approx 5/8" length.

[Rich P.]

Re: harmonic balancer pulley bolts

Crank pully bolts will have RBW, E or GL. They also have an captured internally toothed star washer. 65 fan clutch to water pump hub, I know of 6-7 headmarkings. AS, RSC, RBW, SBC, UR and L8. I'm sure I am forgetting a few. The last original 65 fuel car I restored had L8 bolts on the fan clutch and RBW for the crank pully.

Rich

[Scott S.]

Re: harmonic balancer pulley bolts

The bolts I have for the crankshaft pulley/ damper attachment are RBW with intergral internal tooth lock washer grade 5 approx 5/8" length.

Crank pully bolts will have RBW, E or GL. They also have an captured internally toothed star washer. 65 fan clutch to water pump hub, I know of 6-7 headmarkings. AS, RSC, RBW, SBC, UR and L8. I'm sure I am forgetting a few. The last original 65 fuel car I restored had L8 bolts on the fan clutch and RBW for the crank pully.

Rich

Tim and Rich,

Are we all talking about the same crank shaft pulley bolts here?

The 1967 L79 uses the same crank pulley bolt as Jack's 1965 L84, GM #181629 (see L79-A1 in the '67 AIM, for 1965 see L84, Sheet 2, referencing same bolt p/n used on L76, Sheet 2). This is a different bolt than used on the base engine (6-A3, Item 6, 3784349 Bolt Asm.).

The high performance applications (L84, L76, L79, maybe others I haven't checked yet), use Bolt #181629 for the crankshaft pulley, which is not called out as an "Asm.", and does not appear to use an attached anything. For both 1965 (L84, L76) and 1967 (L79), the assembly manuals show crank pulley bolt 181629 is used in conjunction with the 103321 split-lock washer and the 446212 flat washer.

Are you sure this bolt also had an attached internal tooth washer, or were you referencing the base engine crank pulley bolt?

[Rich P.]

Re: harmonic balancer pulley bolts

Tim and Rich,

Are we all talking about the same crank shaft pulley bolts here?

The 1967 L79 uses the same crank pulley bolt as Jack's 1965 L84, GM #181629 (see L79-A1 in the '67 AIM, for 1965 see L84, Sheet 2, referencing same bolt p/n used on L76, Sheet 2). This is a different bolt than used on the base engine (6-A3, Item 6, 3784349 Bolt Asm.).

The high performance applications (L84, L76, L79, maybe others I haven't checked yet), use Bolt #181629 for the crankshaft pulley, which is not called out as an "Asm.", and does not appear to use an attached anything. For both 1965 (L84, L76) and 1967 (L79), the assembly manuals show crank pulley bolt 181629 is used in conjunction with the 103321 split-lock washer and the 446212 flat washer.

Are you sure this bolt also had an attached internal tooth washer, or were you referencing the base engine crank pulley bolt?

Interesting info from the AIM. This bolt as Tim described it was used on allST. Louis assembled stamped steel crank small block pulleys to 68-69 time frame, when they moved to a seperate bolt and split ring lock washer. Now if you have an add-on crank pully I "believe" it is a different bolt (just a bit longer with a seperate lock washer).

Rich

[Jack B.]

Re: harmonic balancer pulley bolts

Thanks for all the great info guys.
Jack