Engine 93 Cobra new pedestal RRs reuse bolts?

[fords2fast4u]

With new Crane pedestal mount 1.6 roller rockers on AFR165s, can I reuse the stock 93 cobra rocker arm bolts (from the Crane/Ford 1.72s)?

They appear to be similar length and there’s no free play when mocked up. The bolts that cam with the new Crane RRs appear to be a different thread count than the stock bolts and won’t start in the AFR heads...

Setup: ‘93 302 (126k miles but at some point was refreshed with new rings/bearings by the previous owner who was a BMW mechanic) new TFS1 cam, new FMS roller lifters (HD), stock pushrods (I believe), new crane pedestal mount 1.6 roller rockers, new double
roller timing chain and a new H2O pump.

The car already has AFR165s, TFS track heat intake, 75mm accufab TB, 73mm C&L MAF, 1 5/8” ceramic coated BBK LTs...

What started this new valve train project was a leaking timing chain cover gasket. The car had the stock valvetrain on the AFRs under the TFS intake, so I thought I’d replace the cam / lifters / chain while there. Half way through I thought to get new RRs so as to not push the AFR recommended .550” max lift with the 1.72s so I bought these 1.6s.

Why would Crane make a pedestal mount RR kit with bolts that won’t work on these heads that took the stock SVT hardware fine? My guess is that the kit is for a GT 302 and the Cobras had different bolts on the GT40 heads for the 1.72 RRs.

Has anyone else done this same thing, reusing the 1.72 bolts on new 1.6 RRs?

Lastly, here’s the 1.6RR roller pin wear on the AFR valve stems with the old bolts. It appears all is ok...

 

[fords2fast4u]

Upon further inspection, I do believe the bolts are the same size. The stock bolts do have a taper on the tip to guide them in whereas the new ones do not.

I’ve noticed something at the mouth of each rocker bolt hole, possibly burnt oil or old threadlock? In the pics you can make out the black hard material that’s breaking up and preventing the threads of the new bolts to start. When screwing in the bolts by hand, I can start and screw in the old bolts without issue, tried serval bolts holes. But the new ones lock up as soon as they grab thread and then when I back them out there’s residue of that hard black material acting like gravel in the threads.

I can understand the old bolts starting easier right the taper, but if they are in fact the same thread / size bolt, I don’t see how the stock bolts don’t also exit with pieces of that same junk. Maybe the oil reside on them, or how often they’ve heated up and cooled down?

I don’t want to strip the aluminum, and it feels like I’ll do that if I force the new bolts. Also, I’d rather avoid getting in each bolt hole with dental pics ha (which I did to the bolt hole on the right in one pic). So should I just tap wash hole and oil the new bolts, or just use the old ones?

In the pics, new hardware is on the right. Again, any suggestions are appreciated.

 

[fords2fast4u]

I know I’m tired because I have a two week old, and last night I was feeling pretty dumb thinking that these bolts are the same size, and just some old burnt oil was preventing them from starting. But today, after wire brushing a few holes with a rifle cleaning rod and a cordless drill, and wiring brushing the black anodized bolts to wear down some of the finish, as well as putting oil / assembly line and WD40 on a few, I’m back to thinking these bolts are different sizes.

I’ve only got one new bolt to start and screw in, which gave me hope! But Every other hole seizes on the first thread by hand. Everyone one of the old bolts starts without issue. They’re so close in size that they’re hard to believe they’d be a size off - possibly one is standard and one is metric they’re so close.

Frustrating!

 

[fords2fast4u]

Attempting to measure the bolts didn’t pan out so I used the original bolts. When torquing and shimming the RRs I noticed the stock bolts were coming out scarred as I guess the new pedestals and RRs aren’t as tall as the original (pic below). The new bolts I gave up on using appear to be a hair shorter, but their bolt head is also slightly shorter.

And now my valve covers contact the new Crane 1.6 RRs... fun!

 

[fords2fast4u]

Do you think I should grind the tips of the old bolts as their contact inside the head may affect the torque applied?

I guess this is why stud mount are the preferred style!

 

[giddyup306]

Get the right bolts. I did R&D for an engine building company. My boss said he couldn't get the right head bolts for an engine. Reused old ones as per him. Loads of comebacks. Do it right the first time.