Hey guys,

Long story short, I've finally gotten the cash together to buy the heads I've been lusting after for so long - but when they arrived, I got a bit of a surprise. It's way too much for me to type out again, but I did put up a webpage that outlines the whole thing.

I'd really be appreciative if I could get some constructive feedback...

Thanks all.

(Mods: I wasn't sure which forum was most appropriate for this, so if it's off-topic, I do apologize.)

 

There is nothing functionally wrong with your heads and I'm sure its part of their casting and locating process. The edges aren't any sharper than the corners of the combustion chamber and if preignition were to ever occur, you'd want it to start where the spark plug is. (aluminum doesn't get red hot) It is common for cnc heads to have areas that aren't touched by the machining process. Frankly I just wouldn't worry anymore about it.

On a side note this is the week of the PRI show in Orlando and a small company may have most of their staff there right now so you may not receive any email reply until next week.

Just my opinion.

 

At first I was going to suggest a casting flaw, but those are very closely the same diameter and depth looks like. It actually doesn't even look like aluminum, like something has been filled in a hole ???

-Shannon

 

Yeah, I saw the same type of "defects" on my AFR 195s. Mine weren't as complete as yours, I could make out an arc to the "chip" but not a complete circle. Maybe we specified different CC volumes and got different machining but have the same underlying point defects? I will resize a picture of what I saw and send it to the email you listed on your page so you can compare...

 

Dont fret, its a data point or reference point for the CNC machines. It's used so the CNC machines have a reference on depth and cut for the chambers. All SBC heads have them from AFR...some clean up better than others. They dont affect the performance or fuctionality of the heads.


Josh

 

Well, given the size & depth of these "reference points" (see below), I have to say that I'm not completely comfortable with these heads. I've gotten photos of other heads with these "reference points", & they're nowhere near the size of these. And it seems a bit illogical for AFR to have put an initial reference point in the middle of a cylinder bowl - it seems much more likely that they'd start from somewhere on the outside of the block of aluminum, where the reference point would be constant from the beginning to the end of the machining process.

I'm going to take them to this morning to a local cylinder head shop that does most of the work for the circle-track cars around here, if they say they're OK, I'll feel a bit better about them.

(Circumference on each is about .280", depth goes from .041" to .057".)

 

OK, latest (and probably last) update - the guys at the cylinder head shop took a look at them, & told me that the 'reference points' were a bit deeper than they'd ever seen before, but that it wouldn't affect the heads' performance in any significant manner. (And yeah, I know that one or two other people said that as well, but I guess I needed to hear it from someone face to face...) I do appreciate everyone's feedback on this.

I also got a rather significant piece of good news regarding these heads, but I need to get a piece of info from the vendor that sold them to me before I say anything...

 

As far as the good news I mentioned above - they're not the standard 100% ported chamber & exhaust with 70% porting on the intake... They're 100% CNC-ported all the way through!!!

 

It would be to your benefit to let a local head porter take look at them. See what hed have to say about those areas in question. If they are significant enough to cause any worry then welding and reshaping of that size shouldnt cost a lot of money. I personally would have them fixed but Im kinda **** about this stuff and even if 100 people told me it wouldnt create any problems Id still get them fixed.

 

Yeah, you're the 2nd person to suggest that to me, and I'm going to be doing that. I was just dreading the thought of maybe having to argue with a vendor, ship the heads back, wait for another (possibly also bad) pair of heads to be shipped back, etc., etc., etc... At least this way, I can deal with it all locally, PLUS I've gotten a "bonus" on these heads that's worth more than what I'll pay to get the "reference points" fixed!

Thanks for the reply.