Tall valve covers will not clear ac bracket?
 

my new engine (455 in a '67 Goat) will have a roller cam and roller rockers which will require a taller valve cover. I'm told the taller covers will not allow the ac bracket and compressor to be mounted . Hopefully I can fabricate something that will resove this potential problem. Any one else run into this?
Here's a pic of the stock install with factory valve covers.

Harland Sharps fit under the stock valve covers.

Stud girdles need tall valve covers. Roller rockers do not. Choose your polylocks to fit the OEM valve cover.

I have the Comp Ultra Gold rockers and locks. I'm using stock valve covers with Butler 3/8" gaskets. The rockers clear fine but I don't have AC so not sure if the AC bracket will clear. It's basically 3/16" taller than a standard gasket.

He's looking to see if anyone has run taller valve covers and running into interference problems with the ac brackets......I run tall covers but no a/c so I can't comment

I would absolutely expect tall valve covers to interfere with the A/C compressor mounting.

The point is, he doesn't need tall valve covers if he's careful about installing the right parts under them.

Think you are out of luck retaining the bracket with the 3" covers and even the 2-1/2" would require spacers. You could fab up a new bracket that was tall enough to clear the valve cover. I'll probably get yelled at but I would just leave it off. Pontiac was worried about 100,000 mile reliability but the compressor has multiple mounting points without the top bracket. I count four mounting points without the top bracket that more than triangulates the mounting. Think the swing of the compressor will also be slightly reduced with the tall cover.

I just double the valve cover gaskets to raise the stock covers slightly that way all the stock stuff bolts in.

Ive done this with harland rollers and crower rollers and works every time.

When I first installed a pair of M/T valve covers on my stock engine years ago, the upper rear compressor bracket hit the top of the cover. Two 3/4" spacers and Ionger bolts let me raise that bracket vertically to clear the cover without impacting the swing of the compressor very much at all. On my current rebuild though, I had the same issue with Comp roller rockers. The Polyloks were too high and hit the M/T covers. I had to add the 3/8" spacer from Butler along with the second gasket to clear.

And that's when the $1650 headache started. The upper brackets for the compressor no longer cleared and it was evident there would not be enough swing left in the adjustment arc to adequately tighten the drive belt with a fabricated bracket. So a CVF serpentine kit was installed that included a new compressor, power steering pump and 100 amp alternator. (Needless to say, now I've got a brand new 1970 Saginaw power steering pump and reservoir and new Autozone alternator to sell, as well as all the original A/C brackets and compressor)

Everything was cool until the twin snorkel air cleaner housing would not sit low enough for the hood to close. The front snorkel hit the A/C compressor and the driver's side snorkel was hitting the hood brace on the side of the scoop opening. The snorkels are being shaved off the housing now to bring the air cleaner housing and scoop down.

Lowest valvetrain is the Crower stainless rockers and the Crower short polylocks. The valvetrain can clear with the standard valve cover gasket, but it's close enough that subsequent tightening over the life of the gasket might compress it enough to cause interference. I use the thick gasket and start off with a little over a 1/4" of clearance. Results also depend on the travel of the rocker and I'm usually at around .580" valve lift on most of the cams installed. Photo is '67 engine bay with the thick gasket, stock covers, and the brace in place with a few washers painted black between brace and manifold.

My 72cc (and previously 87cc) E-heads with 1.5 Crower rockers and .390" net lobe lift works with the 1/4" thick Fel-Pro 'ram air' gasket and '67-up valve covers. Before the Crowers, I had Harland Sharps and those needed the pushrod end chamfered a bit to clear the valve cover.

I tried those 3/8" thick gaskets and the set I had were porous and always seeped oil. The Fel-Pro 1/4" ones are fine and have just enough clearance.

And, yes, I have an A6 compressor too. This is in a '66 GTO.

Shorter polylocks would have saved you heaps of problems, and lots of money.

Absolutely. I didn't know they were available when I got the engine back from the rebuilder with the valve covers off. :-ohwell: But the serpentine drive is pretty sharp. :cool2:

Dump the A6 compressor they weigh a ton, are old technology and rob 50 HP when you turn the AC on. You can put on a new compressor weighs less than half of the A6 doesn't need the bracket in the rear runs more efficient and doesn't rob much HP. And yes you can still run R12 with the new compressors as long as you use the correct compressor oil.