Big block cam retaining plate?
Thread Starter
Drifting
Joined: May 2001
Posts: 1,651
Likes: 13
From: Holly MI
Big block cam retaining plate?
Can anyone confirm that the 427 used a cam thrust plate on the front of the engine behind the cam sprocket. I have to admit that I didn't document this part of the teardown very well, and I can't find anything in the books. The block has the holes for the fasteners, but this wouldn't be the first time there are holes with no use. Thanks for the help.
Race Director
Joined: Nov 2000
Posts: 11,872
Likes: 12
From: Waterloo ontario Canada
Re: Big block cam retaining plate? (bb69)
MY 454 did not have a cam retaining plate. The flat tappet lifters push the cam towards the back. The roller cams need a button on the front to keep the cam from walking out the front of the block.
Just guessing but I would say no. Some did have the retainer. I like to drill a 1/8th hole in the front of the block to allow oil to lubricate the back of the timming gear to prevent chaffing the block.
Just guessing but I would say no. Some did have the retainer. I like to drill a 1/8th hole in the front of the block to allow oil to lubricate the back of the timming gear to prevent chaffing the block.
Drifting
Joined: Feb 1999
Posts: 1,351
Likes: 3
From: Fremont, CA, USA
Re: Big block cam retaining plate? (bb69)
"bb69"
Mark IV Chevrolet big blocks (65-91) did not use a retaining plate for the camshaft. Gen 5 big blocks did not, either. The Gen 6 big block was designed around the use of a roller camshaft. Therefore, those blocks do have the camshaft retainer (thrust) plate and provisions in the lifter valley for the roller rocker retainers.
The retainer plate is not necessary with any big block equipped with a flat tappet camshaft, regardless of whether it is a Mark IV, Gen 5, or Gen 6. However, it is necessary if a roller camshaft is used. For Mark IV or Gen 5 block, a camshaft thrust button can be used in place of the thrust plate. However, the thrust plate is a better arrangement than a button. To use a thrust plate, the camshaft front journal must also be specially configured.
Mark IV Chevrolet big blocks (65-91) did not use a retaining plate for the camshaft. Gen 5 big blocks did not, either. The Gen 6 big block was designed around the use of a roller camshaft. Therefore, those blocks do have the camshaft retainer (thrust) plate and provisions in the lifter valley for the roller rocker retainers.
The retainer plate is not necessary with any big block equipped with a flat tappet camshaft, regardless of whether it is a Mark IV, Gen 5, or Gen 6. However, it is necessary if a roller camshaft is used. For Mark IV or Gen 5 block, a camshaft thrust button can be used in place of the thrust plate. However, the thrust plate is a better arrangement than a button. To use a thrust plate, the camshaft front journal must also be specially configured.
Thread Starter
Drifting
Joined: May 2001
Posts: 1,651
Likes: 13
From: Holly MI
Re: Big block cam retaining plate? (Joe Lucia)
Thanks for the reply guys. I'm using a Comp Cams flat tappet with slightly more duration than stock. Other than that, everything is stock. I thought I was losing it when I couldn't find the plate. I have several books, and the problem with that is that they use multiple engines in the pictures and descriptions without always mentioning which is which. I hope to finish stuffing the pistons tonight, and then I can put the timing set on.
Thanks :cheers:
Thanks :cheers:
Le Mans Master
Joined: Mar 1999
Posts: 6,744
Likes: 1
From: delmont pa
Cruise-In I Veteran
Cruise-In II Veteran
Re: Big block cam retaining plate? (bb69)
that retaining plate was used on a BB when you used the GM gear drive over the counter cam. this cam was available in the late 60s. a 1/8 hole is much too big for oil flow,.just drill a .032 hole in one of the lifter galley plugs to add oil to the timing chain.:chevy
[Modified by clem zahrobsky, 5:37 PM 10/22/2001]
[Modified by clem zahrobsky, 5:37 PM 10/22/2001]
