I am installing new valve springs, retainers, and locks in my AFR 190s. The springs are the ones designed to work with my new Comp stick and I am using tit. retainers and 10* super locks. As if any of that really matters to what I have encountered.

I finished one head completely, setting installed height and installing the new springs. On the first exhaust valve on the second head the valve did not want to come out of the guide. AFR heads, like most heads, use bronze valve guides. I went ahead and took apart the corresonding intake and that valve came right out. I then took that intake valve and stuck it down the exhaust guide. It would smoothly slide in the guide, however you could hear a scraping sound that it does not make in its own guide. The exhaust valve would not want to go into the intake guide and I did not force it.

Just to reiterate, I really had to force the exhaust valve OUT of the guide, I first tapped it down so I could get a hold of it, then I had to twist it to make it come out.

I next put the valves into my drill press to see if it was bent and I did not notice any excessive play. I set up a dial indicator and measured less than .001" of run out. I measured the stem with a mic and it is the correct size, 11/32. I have not finished disassembling the head because I am tired and now a little pissed at AFR. Honestly, I have had more trouble with these heads than any other head I have ever had.

Oh, if you look down the guides with a light, you can see a some scoring in the exhaust guide, the intake looks very smooth and even.

What do you all think, bad valve guide? Possibly a bad valve that took out the guide?

I will continue disassembly tomorrow and hopefully none of the others will be like that.

Well, let me know what you think.

I can't get to a machine shop until Friday at the soonest.

 

The keepers can cause a bit of a lip to form on the edge of the top groove. That may be what you felt and heard.

As with anything, you should have suspected something the moment you had trouble. The best thing to do is
STOP!!! and take a look at what's going on, not pull out the BFH.

Something as small as a grit of sand can cause that problem. You should clean the valve, then clean the valve, and when you're done with that, clean the valve.

Then you check it with your finger tip to feel for any imperfections. If you feel anything, find out what it is. If it's a lip (sharp edge protruding out), grab a fine file and gently smooth it out.

Have the machine shop check out the guide and see how bad it is. I doubt it's horrible, but it does stink since you just bought them.

 

I did all that. My last resort was to force it out. I didn't really have a choice, it had to come out not matter what. The heads have very little mileage on them.

I know what you mean about keepers causing a lip cause rocker arms can cause the tip to mushroom after lots of miles. Nothing like that, the valve seems fine to me. Nothing obvious and it measures out okay.

Oh well, its only money!!! I must say I am disappointed in these heads.

 

i'd say you have, or had, a burr on the top of the valve and it scored or marked the guide when you forced it out. take a fine file and dress the end of the valve a little and it should fall right out.

 

The valve wouldn't move easily from the moment I removed the valvespring. With all the others, after I removed the valve spring compressor, the valves were only held in place by the seals. They had almost no resistance. This one didn't want to move without persuasion...

I don't know, I am going to call around tomorrow and see what the deal is.

Thanks for the replies...

 

I took it to my machinist today. He does great work and builds lots of comp. engines and does amazing head work. Well, he said what you guys said about the a burr. I couldn't see anything, but he dressed it up and cleaned the guide. The valve slipped right in!!!

Thanks again for the advice, ya'll were right!!!