ICDEDPPL

I paged Tim, there used to be a guy on here that used to tell all his customers that his heads were built by AFR to his specs including larger clearances but he was a liar, stock heads stock clearances, he cost a lot of people a lot of money.
Also any place that assembled all that and didn`t mention this I would definitely not go back to. Find a reputable builder that knows marine.
I had a guy build me motors , set the piston to wall clerance too tight and they lasted 2 months.
The story I heard from BBWWT about your dyno place is pretty bad.

ICDEDPPL

Also sorry man but theres something to be said about stock engines.

Full Force

Ok no bashing bs here but here's the facts, no head is bolt on ready for marine use, always always always build them for your application, had I listened to that advice from a buddy and not someone else a world of hell would have never happened, my afr had .0010-0012 clearances, with a lot of metal transfer bronze to valve, I will look for a pic, that combined with a slightly tight lifter bore (another clearance I asked about and was told was fine) created a very expensive failure in less then a hour. I took care of them issues and had new cams ground, along with proper upgrades springs... my supplies springs were upgraded for marine, yet when o personally talked to pac they were a "street car hot rod spring" I might even have that email still..

take or don't take my info but many guys here can say this was my situation, some hate me for posting the culprit so save that bs that's years ago...

that being said after them issues fixed the engines are currently still going rock solid after my boat and sold them to a guy in a 38 scarab for 6 seasons now

SABER28

curious, whats your beef with them? dealt with them dozens of times for almost 40 years, never had a problem and always more than helpful. they built my current 557's and they have been flawless for 4 years.

Full Force

Out of the box heads?

Full Force

Ahhhh memories lol 🤦🏽🤦🏽🤦🏽 simply, build own heads call it a day.

Full Force

PQ290Enticer

Good morning everyone, So I'm not sure I was clear about this and maybe BBYSTWY misunderstood too. Performance Engineering in Jenison only performed the dyno and final tuning for me. They did NOT build the engines. I spoke with them yesterday and he said that they always check clearances in the heads before install. My original guy did not. Could be because I supplied everything, I don't know and at this point it's water under the bridge. I am not going back there. Moving on.
Whether Performance Engineering feels bad for me or maybe it's regular pricing, he gave me a number I can live with to straighten out the heads. I believe that the "consensus" is .002 clearance on the valve guides(?) and then up the spring pressure to low to mid 400's? With the springs, I don't want to be the guy that "trips over a dime to pick up a nickel" but is this "pressure" something that can be achieved with a shim? Maybe a shim moves the "bind" number? There was a lot of math earlier in this post and I think the existing open ht pressure of 340 was just barely acceptable in my application? I think it figured out to be 336 required? The website says out of the box their springs are good for a bigger cam than I currently am using.

PQ290Enticer

Are these clearance problems only associated with aluminum heads? Only with AFR heads? I went aluminum because they are supposed to make more power, obviously the weight reduction is a good thing and well the "cool factor". ICDEDPPL, you mentioned that there's something to be said for stock power. I agree however stock sucks. Of course this dilemma I'm in sucks too but... I never looked at buying stock marine engines at all. The prices from Mercury are ridiculous. Maybe I could \ should have looked around but clearly I'm the guy who puts the cart in front of the horse. I always thought Mercury just bought a bunch of truck engines complete, swapped the water pump out and sent them out the door. Does Mercury just order parts and marinize and assemble their engines? I believe that 100% on the big stuff but 7.4's?

Full Force

I set clearances at .002, zero issues after, every marine head should be custom built to your specifications that also goes for valve springs. You can't just use a general pressure you need to get with the cam manufacturer and use what they tell you and set up that way.