AFR heads

[jagbucket]

machinist found that the seats were .004 out on the exhaust side which he said was normal for aftermarket heads. So the utube warnings are valid even tho afr's are supposed to be able to install out of the box it would have ran but not as well as possible just a fyi

 

[nvrstuk]

So what is exactly .004" "out". Could you explain? Thx..

 

[pcf_mark]

I hope that is not valve seat concentricity. If so that is not very good for performance or valve / seat life. Sometimes you need new guides, sometimes you need to re-grind the seats. Not cheap either way.

 

[Broncobowsher]

Off- center?
Out of round?
Too deep?
Variance between cylinders?

Please explain what is "out"

 

[Bronco Junkie]

Seems like the valve is not seating all the way?

 

[Broncobowsher]

Everyone is still trying to guess what the OP's problem was...

 

[jagbucket]

out of center from the guides all taken care of now by a regrind of the seat and not that expensive. machinist has the heads to check for just this sort of problem . the reason i posted was not how to fix this,already done, but to warn others not to trust run out of the box advertising even afr cnc beauties

 

[markw]

Jag, thank you for posting this. Never checked my AFR heads, didn't even think to do so. I will in the future though.

 

[fordguy]

sounds like poor quality control. if they cant check tolerances when they assemble and call it ready to run.............if it said assembled but not ready to run, yeah. no doubt afr heads flow good, but that is dissappointing to me.

 

[jagbucket]

yes i didnt expect any problem with them and mostly sent heads in with the block to mock up for gasket thickness.

 

[Broncobowsher]

Single data point. Anyone ever check any other heads? What is the allowable tolerance?

Even with the above statement I would have ZERO issues opening a box of AFR heads, bolting them on, and beating on the engine to no end.

I still see this as the engine builder who will only build things his way, nobody else can do it good enough.

 

[Local Boy]

For whatever its worth...

This post got me thinking.... Maybe it was my heads????? Hmmmm....

My last motor was a bored, stroked, and blown 331, from DSS racing...It had AFR heads. That motor under-performed at just under 400 Hp....I was shooting for over 500 Hp at the time.... It was just a nightmare because of the huge disappointment... All testing pointed to the heads...But I was in denial... No way AFR heads could be bad...right? I tried everything, ran it to the edge ..... no improvement...Then I rebuilt the heads, new valves, new springs and related parts...nothing.... Just could not figure out what was wrong...

Ended up destroying the motor ...running it on the edge like that... Basically gave the heads away after that .... had such a bad experience ...that I won't use AFR for my stuff...

To be clear, I 'm not saying that it was definitely the heads.... I can't be certain, as I did not have an experienced machinist check the specs on the heads...again perhaps because of denial.... plus, so many variables to consider...but, I have my suspicions... I just can't afford such an expensive boat anchor ever again...

I've always wondered about those heads... Hmmmmm???

I still shake my head in disgust when I think about that motor....

Again, not bashing AFR...just sharing my experiences...and still maintain my suspicions...

Aloha

 

[jagbucket]

there's a real excitable guy on utube that says we should only buy bare heads and have a local shop machine and assemble with quality parts. Demonstrates on a pair of darts but says all aftermarkets are the same and even if you spend up to 3k for the head you will still have Chinese brittle valves. the rational is that in the end you spend the same but have a good set of heads

 

[Local Boy]

That's interesting ... about the valves...

I rebuilt the heads because my machinist told me that the valves and springs were just regular "off the shelf" variety... and looked poor in quality....

I was beyond upset when I heard that!

Fortunately.... I'm very happy with the Kasse P-38's... : )

Good Luck with your build...

Aloha

 

[nvrstuk]

Very interesting for sure-

I installed Trick Flow 205 CNC ported heads on my stroker 8 years back. I always pour paint reducer or alcohol into each combustion chamber to see if the heads seat before I install... I'm guessing you would have needed a garden hose to supply enough liquid with the OP's example... HOWEVER...

3 days ago a buddy that I helped spec out a complete new top end on an existing 408 block started his "new" engine up and within a minute heard a loud KNOCK...I was 3,000 miles away but he said I should have heard it where I was!

Ended up being small chunks of aluminum from either the brand new AFR heads or the new Trick FLow uppper/lower...only alum he had anywhere close to that end of the shop...One of these two manufacturers left some casting chunks in and it should have wipe out a piston/cylinder and a valve but didn't get any of them...

Just tossing this out there...new stuff needs to be checked...he was lucky and he knows it...he never could have proved it wasn't his fault.

 

[jagbucket]

checked on the shops progress and asked again about the heads " was out in the squarness of the seat to the guide " , not concentric to the guide as i had originally said but needed attention . should have block and heads back next week

 

[Letsgocrawling]

machinist found that the seats were .004 out on the exhaust side which he said was normal for aftermarket heads. So the utube warnings are valid even tho afr's are supposed to be able to install out of the box it would have ran but not as well as possible just a fyi

Not strange at all but good paying attention to detail by your engine builder for sure. Any real good builder does this, just because it's new out of the box doesn't mean it's good to go. Sure the heads will work but it's like for the money this crap costs going the extra mile is worth it not only for performance but for longevity too! FYI my new dart pro 1 cnc deals had the exact issues...valve seat to stem concentricity, from what I remember some holes had as much as .004 total runout but the new valve job cure that.

 

[WheelHorse]

Any aftermarket head should be checked. Edels are/were notorious for having way to thick of an exhaust valve to seat contact and way to thin on the intake and yes, they were also off a bit for contact.