Was this after your 45 minute WOT run from the post in the Fountain Owners page? One of my friends ran an entire poker run WOT on a pair of carbed HP500's in a 35 Fountain and literally beat the valves right out of the heads (or more appropriately right into the heads)! Those engines only had 35 hours on them. That might have contributed to your seat failures.

I guarantee the ones that fell out were the ones they replaced. I'd be raising hell with them on this. I had one drop and it f*cked the whole engine up.

new intakes,new exhaust manifolds on my boat...

i wished i knew which were the old / new seats to compare...

maybe they used cheap seats for cars or something..

Maybe not the proper press fit on the new seats.

Steve,
There is no real difference btween the seats for "cars" and those for marine use. At least not if you use a high quality seat manufacturer. If I remember correctly from the last set of those heads I did, the seats are an unusual size and material. I think I had to special order them. Your shop might have cut the heads for a larger seat instead, which is perfectly acceptable and done all the time.

A lot of the manufacturers are starting to use powdered metal seats and they are available in the aftermarket. I am not comfortable with them yet and will not use them. Ford had some problems with them in some of thier engines with the seats shattering into pieces Also, like someone else mentioned, if the seat was not installed with enough press fit, it can come loose too. Too much press fit can cause problems also, stressing things.

Hope it didn't do too much damage.

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

ok..here are the news :

both motors running on 91 octane ,full tanks the day before...
both motors had the same head jobs...a few seats on each head...same shop.
the starboard motor compression was taken today.exactly 170 all over...all identical. not one has damage to a valve or seat. i never did put the heads back to the original motors..we mixed them up not knowing which head came from what motor...
the star motor is perfect still after running the same amount of time as the port side...same fuel,same everything..

now the port motor, on both heads, seats came apart....both heads ! the other motor, zip !

the port motor was smoking a little when being started...running rich...carb was leaking some fuel we noticed...

that is the only diff. with both motors...one running very rich.

i always checked the temp,pressure,oil temp.etc.... was very carefull the during those rides since we put all back together....

why does on motor with the same valve job/seats stay perfect and the other fall apart on both heads ?

damages:

cylinder liners all scratched up with the metal pieces..
lots of metal punched into the piston top...
for sure valved bent...
heads have minor damage...

tell me that one seat fell out, or one on each head ...but at least 2 on each head ?

and the other motor is perfect as it had gotten the same tratment ?

i am sure the running rich had to go with it ??? can it ?

hell, i am lost of ideas here !

Running rich won't do that. Sorry to hear about your troubles.

StevemamanFountain, you never answered this question...

Two valves on each side of motor sounds like a two plain mainfold.This means four of the eight are conected threw the manifold and use the same fuel supplied threw the carb.This means one problemmore than likley starting at the carb.make sure the carb is working.With a two plain manifold,the fuel is spread evenly threw the engine,Half of the carb feeds 4 cyclinders and the other half feeds the rest.If you have a total of 4 cyclinder bad,your problem is fueling,probably lean.also when if only one seat fell,once it breaks it can travel to the other three threw the manifold and distroy those cyclinders aswell.Like I said before,ive had this happen and it was a lean condition. Check and see if the four cyclinders are connected together by the manifold!

no ,not after that run... the i went out for another run after that...maybe 25 minutes at the most..not pushing it that bad... upon reentry at the marina at idle, after 5 minutes at idle... knock knock !