I've been hearing horror stories of how guys are tearing up valve seats in AFR heads on BBC's. From my research AFR, brodix, and Edelbrock all use a hardened ductile iron for the seats. I know there's other better materials for all out race motors, but if all these companies are building their heads with them, are they good for the average 600hp build?

Good info for you.,


http://www.offshoreonly.com/forums/g...-material.html

Just left a high performance engine trade show. Talked to a few companies, dart , durabond, and yes, valve seat material is a factor for offshore marine engines.

Brodix, afr, and edelbrocks bread and butter, is not marine .

600hp, or 700hp, or 800hp, still has high egt temperatures. There is validity to using a better valve seat material. Even low HP oem stock automotive engines, are now using powdered metal and other various materials that are designed to last a couple hundred thousand miles without exhaust valves leaking like crazy.

Dart rep told me they will install tucker seats in your heads if you wish, when ordering a custom set of heads.

I learned about the seat thing just after having all the port work done to my heads a few months ago, I have AFR and did not opt to change them because I had already spent the money, I have found a few possible issues that would allow seats to get beat up and corrected that, so my personal test will be at refresh time to see how they held up, I do have some local friends with AFR that have had them for years with no issues, so I am chancing it... if I was to start over I would have changed the seats, so if you are in the process just do it....

the guys who run to little of ignition timing will really beat those ductile iron seats.

Mike, I was doing some fooling around last week datalogging some stuff on my 454 dually. I had a pcm tune done a few years back on it. I noticed that it has 20 deg of timing programmed into it at wot. But was getting 6 deg of retard from the knock sensors, when i floored it from 50mph to 85mph. So only 14 deg.

Doing some research, it appears that GMs stock timing map, was actually only 12 degrees at wot! No wonder why stock they are slugs. They do have inconel valves in those engines and sintered ex valve seats.

I plan to run the rest of the 87 octane out, and fill with 93, and repeat to see if i am still going to get any knock retard. I was reading up on some stuff on the car forums, and some guys have seen knock retard go away, after the installation of headers and good exhaust. Which kinda makes sense to me .

I still cant believe that thing has such little timing in it. I can actually feel it lay down when it pulls timing. From 0-60, i dont get any knock retard. Maybe because the acceleration rate is much quicker thru the rpms, than from 50mph to 85mph . The silly cam they put in these things prob doesnt help either.