Question on the 1965/1966 BBC Oil Pan(Center Bolt)

[Larry E.]

Just want to verify what is in the 5th Edition of the 66 Corvette judging guide. It says that the 66 Big Block
engines had the center bolt in the the Oil Pan and Timing Cover. Is this correct? Also was this the only years
this happened? Seems like a good idea. Maybe Joe Lucia can shed some light on this. Any idea's if the current crate engines have this feature? Thanks>Larry

[Keith B.]

Re: Question on the 1965/1966 BBC Oil Pan(Center Bolt)

65- 66 BB only. I think its the same 1/4-20 bolt used on the oil pan rails

[Joe L.]

Re: Question on the 1965/1966 BBC Oil Pan(Center Bolt)

Just want to verify what is in the 5th Edition of the 66 Corvette judging guide. It says that the 66 Big Block
engines had the center bolt in the the Oil Pan and Timing Cover. Is this correct? Also was this the only years
this happened? Seems like a good idea. Maybe Joe Lucia can shed some light on this. Any idea's if the current crate engines have this feature? Thanks>Larry

Larry------

The only big block engines that used the center bolt from oil pan to the timing cover were the 1965-66. It's possible that very early 1967's may have also used it IF any were originally built using engines with 3869942 blocks. The change to blocks with dowel pin locating provisions for the timing cover obviated the need for the bolt, at least in the mind of GM engineers.

No crate engines built in the last 50+ years have had provisions for the bolt. In addition, no timing covers sold in the last 50 years have had the hole and weld-nut for the bolt. The hole also disappeared from oil pans about 50 years ago but, of course, can easily be added.

The bolt used was GM #3856691, the same as used for the corner bolts for the oil pan. This was a 1/4-20 X 5/8" bolt with captured split lockwasher and phosphate finish.

[Leif A.]

Re: Question on the 1965/1966 BBC Oil Pan(Center Bolt)

Larry------

The only big block engines that used the center bolt from oil pan to the timing cover were the 1965-66. It's possible that very early 1967's may have also used it IF any were originally built using engines with 3869942 blocks. The change to blocks with dowel pin locating provisions for the timing cover obviated the need for the bolt, at least in the mind of GM engineers.

No crate engines built in the last 50+ years have had provisions for the bolt. In addition, no timing covers sold in the last 50 years have had the hole and weld-nut for the bolt. The hole also disappeared from oil pans about 50 years ago but, of course, can easily be added.

The bolt used was GM #3856691, the same as used for the corner bolts for the oil pan. This was a 1/4-20 X 5/8" bolt with captured split lockwasher and phosphate finish.

Joe,
Out of curiosity, is this the timing chain cover you are talking about?

https://www.parts123.com/parts123/yb.dll?parta~dyndetail~Z5Z5Z50000370a~Z5Z5Z5AAEZZ~P65.00~~~~S5T10IER6076203412015j~Z5Z5Z5~Z5Z5Z50000370a

[Joe L.]

Re: Question on the 1965/1966 BBC Oil Pan(Center Bolt)

Joe,
Out of curiosity, is this the timing chain cover you are talking about?

https://www.parts123.com/parts123/yb...Z5Z5Z50000370a

Leif-------


This is the 67+ cover. It has dowel pin holes and does not have provisions for the center bolt. The 65-66 cover has no dowel pin holes and does have the hole and weld nut for the center bolt.

[Leif A.]

Re: Question on the 1965/1966 BBC Oil Pan(Center Bolt)

Leif-------


This is the 67+ cover. It has dowel pin holes and does not have provisions for the center bolt. The 65-66 cover has no dowel pin holes and does have the hole and weld nut for the center bolt.

Thank you Joe