Offshoreonly.com - Who has had issues with afr heads??

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You need to start building simpler sh!t lol

Quote:

Originally Posted by Unlimited jd (Post 4310274)

You need to start building simpler sh!t lol

My Father always told me I needed to get my head examined.

Mine always said: if you can't afford double of what ever you are building, don't build it.

Mine told me to find something worthwhile to throw my money at. That, and "turn those damned lights off and close the front door, we don't want to air condition the whole neighborhood." It seems that I'm starting to sound just like him these days. ;)

You can make the argument on lifter to bore clearance that is being made on valve guide clearance. At the end of the day, you can have variances stack up and work against you when you are assembling an engine. Add to that the fact that many of us are running higher valve lifts, higher spring pressures, and spinning the motors faster, and it becomes much more crucial to check ALL the clearances before we drop a motor in a boat. I wish I had checked my guide clearances, because it would dispel one more nagging worry when I run the boat. Maybe I worry too much - I need to make the wife drive and sit back and drink beer.

As Black Baja reported, there are probably tens of thousands of these heads running out there without issues. But machine tolerances can vary, and occasionally you can have the perfect storm of factors that result in an unfortunate situation like Full Force had happen to him. We probably need to wait for all the facts to be revealed before we jump to conclusions about issues with AFR heads.

Bring your heads to 10 different head machinists and see what they report back for valve guide clearances. Most reports will not agree with each other.

Quote:

Originally Posted by SB (Post 4310296)

Bring your heads to 10 different head machinists and see what they report back for valve guide clearances. Most reports will not agree with each other.

Especially when dealing with .0001 measurements. The same guy could use the same tool on the same guide two different days and come up with different measurements. That's where experience comes into play. Knowing your tools and the affect temperature has on things plays a big part in being successful.

I think operating temperature has a lot to do with some of these problems

Quote:

Originally Posted by Black Baja (Post 4310271)

I have to ask. If "Every" installed set of AFR's had to have the guides opened up. Just exactly was the out of the box clearance? And if you open them up what are they being opened up to? I ask out of curiosity not to start an argument. When we measure 2 intake and 2 exhaust we got .0018 across the board. We re-checked this measurement a bunch of times even re-calibrated the gauge cause it didn't seem right to us that they all came up the same. At this point I asked the guy that built my friends motor with new out of the box Brodix heads of he measured the guide clearance. He said most of them were .0013 but a few got up to .0017. He left them what they were from Brodix and explained to me he likes to see them under .0015 and thought the AFR's were a little on the loose side.

Mercs heads all come in between .0021 and .0023.

Quote:

Originally Posted by Precision (Post 4310371)

Mercs heads all come in between .0021 and .0023.

What heads are we talking? Thanks