[Lee]

I'm building a motor for a guy, he got a set of the Black Friday SpeedMaster heads. I finished bolting the heads on yesterday, and thought I would share some of my observations.

1. One head went on smoothly. The other, however, I could feel tension on the head bolts. I ran the bolts up/down a few times, and the tension diminished, but I decided to pull the head back off and take a look. I had chased ALL the threads and thoroughly cleaned afterwards, so I knew that was not the problem.

It was hard to photograph, but the first picture shows what I found. I suspect the head must have shifted while they were drilling the head bolt passages. With the head off, you could see where the bolt threads had cut into the side of the passage. The "clocking" of the contact was consistent on all the holes, and one side of the head had more contact than the other.

The 2nd picture shows the rat-tail file I used to remove the contacted areas. I did several test fits, continuing until I eliminated all the contact. The first picture was actually from the 3rd or 4th test fit, and you can see the area below that had been previously file - as I removed one contact area, another would appear upstream. By the end, I could thread all the bolts down flush with just my fingers.

2. I used the CompCams push rod guide plates, along with 2.100" ARP rocker studs. SOME of the studs pairs would thread-in nicely, but most would be tight. I suspect there is a few thousandths of an inch of variance in how they drilled the stud holes.

The 3rd picture shows my solution. A 29/64th's drill bit took just a teensy bit of material out of the openings of the guide plates. I'd give the drill bit just a tad of side-to-side wallowing after breaking through. After this, I could thread the rocker studs into place by hand.



As for how the heads work, that will be awhile before we can determine. The owner is having work done to the car itself, and it will be several months before the motor is installed.

[74Grandville]

Are you going to put a threaded plug in place of the freeze plug that is between the rocker studs? i'm thinking it would need to be an aluminum plug vs steel. i'm wonder your throughts on this.

[Lee]

Originally Posted by 74Grandville

Are you going to put a threaded plug in place of the freeze plug that is between the rocker studs? i'm thinking it would need to be an aluminum plug vs steel. i'm wonder your throughts on this.

I've been looking at those plugs! It WOULD be bad, if one of them blew out...

Dang it, I guess I'll be popping them out and threading.

[Nobuddy]

Did you try that head on the cylinder bank where the other head fit OK? Sounds more like dowel pin alignment problem.

[steve25]

I sure would replace those top side pressed in plugs with small pipe plugs, or have you customer sign off on keeping them in the heads!

[PontiacJim1959]

Originally Posted by Nobuddy

Did you try that head on the cylinder bank where the other head fit OK? Sounds more like dowel pin alignment problem.

Good point.

[DiamondJim]

How’s the porosity if the heads? Made in China?

[GoatZillaRacing]

Originally Posted by DiamondJim

How’s the porosity if the heads? Made in China?

Excellent castings. I've never seen any porosity and I guarantee you that 've seen more of these heads than anyone else.

[mgarblik]

Originally Posted by Lee

I'm building a motor for a guy, he got a set of the Black Friday SpeedMaster heads. I finished bolting the heads on yesterday, and thought I would share some of my observations.

1. One head went on smoothly. The other, however, I could feel tension on the head bolts. I ran the bolts up/down a few times, and the tension diminished, but I decided to pull the head back off and take a look. I had chased ALL the threads and thoroughly cleaned afterwards, so I knew that was not the problem.

It was hard to photograph, but the first picture shows what I found. I suspect the head must have shifted while they were drilling the head bolt passages. With the head off, you could see where the bolt threads had cut into the side of the passage. The "clocking" of the contact was consistent on all the holes, and one side of the head had more contact than the other.

The 2nd picture shows the rat-tail file I used to remove the contacted areas. I did several test fits, continuing until I eliminated all the contact. The first picture was actually from the 3rd or 4th test fit, and you can see the area below that had been previously file - as I removed one contact area, another would appear upstream. By the end, I could thread all the bolts down flush with just my fingers.

2. I used the CompCams push rod guide plates, along with 2.100" ARP rocker studs. SOME of the studs pairs would thread-in nicely, but most would be tight. I suspect there is a few thousandths of an inch of variance in how they drilled the stud holes.

The 3rd picture shows my solution. A 29/64th's drill bit took just a teensy bit of material out of the openings of the guide plates. I'd give the drill bit just a tad of side-to-side wallowing after breaking through. After this, I could thread the rocker studs into place by hand.



As for how the heads work, that will be awhile before we can determine. The owner is having work done to the car itself, and it will be several months before the motor is installed.

That was a good catch seeing and feeling some interference between the studs and the casting. If you look at any OE aluminum head, especially if being installed on an iron block, the holes in the head MUST NOT be constrained. The factory bolts are intentionally undercut to provide clearance and movement as the aluminum head grows at double the rate of the iron block it's attached to. If the studs constrain the movement, something has to give up. 9 out of 10 times, it's the head gasket. So, I am in no position to complain or bash any brand of aftermarket head, but I know the holes need to be in the right place and be large enough to allow growth. If not, file or drill them to gain clearance.

[PAUL K]

Originally Posted by GoatZillaRacing

Excellent castings. I've never seen any porosity and I guarantee you that 've seen more of these heads than anyone else.

So is it a dowel pin location issue or a bolt hole issue?

[Nobuddy]

Originally Posted by PAUL K

So is it a dowel pin location issue or a bolt hole issue?

Hard to say if the OP did not investigate the fit issue.

[PAUL K]

Originally Posted by Nobuddy

Hard to say if the OP did not investigate the fit issue.

A lot of times the problems repeat themselves.... I doubt they have had issues with both.

[Skip Fix]

I've had a number of aftermarket heads that were just too tight on the dowels, either from maybe the block being off or the hole in the head drilled a little off. Test fit some High Ports recently that was the case. Had a similar deal with some E head round ports on a different block.

[67Fbird]

I would think if the dowel - to - bolt hole alignment is THAT far off it will show up in the pushrod holes as well.

[Skip Fix]

I have seen some head bolts the threads seemed to cock them at a slight angle also.

[P@blo]

Well if the reputation gets too bad they can just change the name again and hope they get it right. Time will tell.

[Formulajones]

Originally Posted by P@blo

Well if the reputation gets too bad they can just change the name again and hope they get it right. Time will tell.

LOL