Originally Posted by Cylinderheadguy (Post 4559154)

I'm still here. Apparently several of the posts were deleted after a phone call to the frustrated poster. It didn't appear to be doing anyone any good with the back and forth. I will say there is always more to every story. Our position has always been to communicate with our customers. We have been open for business in Chicago for 72 years. I don't suppose we are going anywhere. We have been producing heads in both New Zealand and Queensland Australia since 1999. We have seen several players come and go. Our primary business for over 70 years has been production engine builders and OEM engine builders. That is what has kept us thriving in an up and down market. This head has been worked over by some of the best in the business. We do our best to follow their leads and advice. Again, if you discover any issue that you don't like or that you do like, we are available and interested.

Originally Posted by MILD THUNDER (Post 4559098)

Im not understanding clearly on the chain of events. You purchased the heads bare, assembled them, ran them, had oil pressure issues, pulled engine, then found issues with the heads? Am I understanding that correctly?

When you say you had the seats "recut" , was this before they were installed ? You earlier said the seats had to be REPLACED, was that before or after?

The 1200 dollars spent on them, was that soley in machine work?

The few friends I have that have purchased and used these heads, I strongly suggested getting them checked out and assembled by a professional cylinder head shop. Actually that goes for any brand head. There have been plenty of issues with out of the box name brand heads as well. Its no different than assembling a bottom end. You cant just order up a block from dart, and just hope the clearances/tolerances are good to go. Even a brand new dart/merlin block needs a bunch of machine work before its ready for assembly.

As far as cost, last time i looked, a pair of Dart CNC 335 MARINE heads, with inconel valves , anodizing, and assembled, was just under $5,000 a pair. And even then, i would still want to check them out before bolting them on.

Originally Posted by veloc410 (Post 4588713)

The heads were machined before install . Once you get the seats right. You won't. Have enough material left o n seats to replace guides and do touch up. Must take a close look at guides first. Just press them out and install new then do valve job. Myh guides were not true. Looked like they were cut after they were pressed in . Center hole not parallel or concentric with O.D of bushing. Just don't touch the seats unless you inspect guides first . Yes the heads perform very well, no doubt. Nice heavy castings too. They need to be gone through first thing. . My problem came after i had guide wear most likely from temperature issues . Pushed the original guides out then not enough material on seats because location changed. Had to press new seats in. So probably need new bushings right out of the box. They must remachine guides after they are pressed in . The fixture is not true to guide hole so sizing reamer is out of square to guide hole when it goes through. That is why the valves don't seat from get go. These heads will kick ass but they need machining first. Again I had valve job done first.

And last time I discuss this topic on this thread. Pete

---

---

Originally Posted by MILD THUNDER (Post 4412828)

I know some of you were interested in the Engine Quest heads, so, I'll share what I have found so far.

Good castings out of the box, which I had mentioned in the other thread that got shut down. One of the main reasons I bought these heads, was their low initial cost, which would allow me to have a cylinder head specialist, spend some time on them setting them up for my engines. What guide clearances I wanted, what springs, spring setups, what valves, and so on. Having read a ton about them over on Yellowbullet, and Speedtalk, and a few other forums, the consensus seemed to be, that they are a good head out of the box, but a really nice head, if you spend some time working on them. My cylinder head guy, hadn't used these heads yet, so he was interested in seeing how they performed out of the box. Once he saw the out of the box flow numbers, he got really curious to see what some work would do for them. I pretty much told him, "do what you do, and give me the bill". His thoughts were, lets do a really nice valve job, blend things in, port the chambers, adjust the throat diameters, and go from there. Which he did. He flowed them, and while the results were still very good after all that, he felt the exhaust flow could have been improved a little, so he went into the exhaust bowls a bit, and saw some measurable gains. Anyhow, here's where we are for flow numbers. Mind you, intake ports are pretty much untouched at this point, other then the throat. I think we are going to call them good and assemble.

My prior heads were the 308 Darts, and were flowed on the same bench, same fixture, as the EQ heads, and the 345 Iron Eagles (icdedppl's heads). I havent totaled up what I have in them so far, but obviously cylinder head guys don't work for free, especially when it comes to working with iron. When I get some times, I will tally up my costs per pair when ready to bolt on. I think these would make a really nice head for those running saltwater. Heck, even freshwater took its toll on my old aluminum darts. These are the 320cc versions. Also avail in 360cc. FWIW, my darts were originally 308 heads, but had a little work, and actually measured 319cc at the port. The Darts made 804HP at 6200 on my 468's with 7psi boost. I plan to redyno with new heads.

Originally Posted by Panther (Post 4433762)

Congrats. I'd imagine they sound a little more snappy. I think we might be heading to the dyno next week.

In the meantime, been working on a 598" refresh and go. Found all kinds of unexpected issues from the original builder but I've addressed them all. There were only 100 or so hours on it. It's a shame... I expect it will make 850 hp when all said and done. Not EQ heads but Big Brodie O 351's.
Attachment 554820Attachment 554821

Originally Posted by hogie roll (Post 4734397)

How did these turn out? Cam and intake?

Originally Posted by Panther (Post 4779172)

Hoagie Roll, the engines turned out great. The boat ran great as well and picked up over 10 mph from the stock MPI's. With regards to the heads, I was less than impressed. In hindsight, I don't think I would use them again, live and learn.

Upon completion of last season the engines had 300 hours on them and were due for a top end rebuild. I tore the engines down a few weeks ago and serviced the heads and found the following;
1. All 16 exhaust seats had to be replaced. The seats were not hardened and the valves sunk.
2. All 32 guides needed to be replaced. Apparently they had guides from the factory that are better served for Titanium valves. They were also originally honed from 5/16 to 11/32.
3. Had one broken exhaust valve spring which could just be age.
4. Had to replace 3 intake seats
5. Had to replace two inake valves.
6. Had to replace two exhaust valves.

All in all for 300 hours the heads were shot and needed a total rebuild. Not at all what I would expect from a set of brand new heads. The cam was mild (Crane 268741) and not hard on valvetrain. The owner was very hard on the boat but in general, I think the combo of unhardened seats and the wrong valve guides installed from the factory made these heads have excessive wear. Luckilly there wasn't a failure. Mind you, I bought the heads bare. All Manley valves were used and Comp Springs/Retainers/Locks.

Regardless, it's all been freshened and going back together as we speak. He'll be good for another 300hrs of hard running! I'm not on here much so I don't read messages. It's better to get me on Facebook if you have any questions; https://www.facebook.com/FUMarine

Frank
https://cimg7.ibsrv.net/gimg/www.off...f6f0a701d0.jpg

Originally Posted by hogie roll (Post 4779549)

Thats disappointing, nice head on paper. Did you know they have a harder seat option?

Originally Posted by Tartilla (Post 4874111)

Or just go Promaxx 317...for $750 ea bare? Again....seat issues.

I have 088s now, and want to get away from the poor ex ports...a lot to ask to scavenge a blower fed 454.

Originally Posted by KAAMA (Post 4874372)

So, are you suggesting that the aluminum ProMaxx 317cc heads have seat issues as well???

Also, justt so you know, I have been in JimV's shop and have seen what Jim Valayko can do on the GM cast iron exhaust ports...even from 20 years ago...he might be worth a phone call.

Originally Posted by Tartilla (Post 4892296)

These are essentially the same castings as Floteks.

Originally Posted by Rookie (Post 4892348)

I don't believe they are essentially the same casting. The Flowtek's have lazy exhaust ports compared to the Promaxx. The 317 is closer to an AFR 315 on the back to back flow bench racing I have seen on Super Flow 600's.

Originally Posted by Tartilla (Post 4892367)

Eric does some vids on the castings. Apparently they come from the same foundry and castings.

They'll be different in how they get seats and valve jobs etc. That may be where you get the exhaust variation.

Pretty sure the Floteks did pretty well on ex flow. He doesn't use a pipe.

I was leaning to Flotek because of their powdered seats. But if they need 2.30 valves, then I have to re-think that. I have virgin 454 bores.

I'm all ears on the Flotek ex port issue. I have 088 BBC heads, so a SBC ex port would be an improvement.