problem with aftermarket cylinder heads.
10-17-2015, 08:59 PM
#121
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Thread Starter
I don't think your theory applies in the high perofrmance offshore world.
People love to brag about their toys. Powerboat owners especially like to impress. Exaggerating how many hours they run in a season, how fast thier boat goes, how long they can get a bravo drive to last, etc. But in reality they are anchored at the sand bar, lost a race to a slower boat then their claimed top speed, all while having the bravo blues. Why would the same not apply to engines?
There's plenty of proof to say that there is a problem, I think the more accurate question is, how much reliability and piece of mind will I gain for the money?
Sure some can bolt on heads without precision setup. Not everyone needs shaft rockers or piston oilers either. But when it comes to Marine High Performance Engines what's the best bang for the buck while trying to achieve ones goals?
IMO spending a few hundred on double checking and setting up heads is priceless compared to other "upgrades" that may be recommended.
People love to brag about their toys. Powerboat owners especially like to impress. Exaggerating how many hours they run in a season, how fast thier boat goes, how long they can get a bravo drive to last, etc. But in reality they are anchored at the sand bar, lost a race to a slower boat then their claimed top speed, all while having the bravo blues. Why would the same not apply to engines?
There's plenty of proof to say that there is a problem, I think the more accurate question is, how much reliability and piece of mind will I gain for the money?
Sure some can bolt on heads without precision setup. Not everyone needs shaft rockers or piston oilers either. But when it comes to Marine High Performance Engines what's the best bang for the buck while trying to achieve ones goals?
IMO spending a few hundred on double checking and setting up heads is priceless compared to other "upgrades" that may be recommended.
10-17-2015, 11:10 PM
#122
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10-21-2015, 04:29 PM
#123
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Thread Starter
ok,i had a set of afr 315 cnc heads that were bought from bob madera checked for valve to guide clearance and got the report today.all intakes ,0015&.0016.all exhaust .0018.these were checked at a very reputable shop that specializes in cylinder heads.these heads were ordered for a 1000 hp supercharged marine engine.just thought i would post my findings.
10-21-2015, 06:46 PM
#124
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I will have a set of Raylar 496 heads next week, I plan to verify installed height and guide clearance before installing them. I'll report the findings, not that there is a big market for them here, but it will at least give a point of reference.
10-21-2015, 07:09 PM
#125
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Hey DM - ah forget it, you have closed cooling.
10-21-2015, 08:18 PM
#127
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Platinum Member
Had one set of brodix heads 2PR that I had to mill all of the jesel stands where the shaft goes through them like .014 from side to side a real pain in the ass. The roller was not flat on the valve. This was 10yrs ago. Intake and exhaust.
10-21-2015, 10:45 PM
#128
Platinum Member
Platinum Member
When i switched from merlins vrs to afr 315 CNC's with a bob madera cam i picked up 200+ hp, later on with a bigger yet cam and those heads with one size smaller blower pulley picked up another 165 hp, very happy and no, did NOT need to open valve guides up even though i boat in "great lakes" water !
10-22-2015, 09:14 PM
#129
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I almost hate to think of all the heads I have flowed and ported as well as intakes. Bottom line Brodex and Canfield no matter what stage on my bench flowed + or - 5% of there advertised data and had the least amount of machining issues etc and best valve train components stock.
10-22-2015, 11:26 PM
#130
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Join Date: Oct 2000
Location: Spicewood, Texas USA
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I'll throw in my 2 cents worth. I've built about 30 engines using aftermarket cylinder heads. Also have bought a few sets of AFRs from Bob Madera. Never had any problem with the AFRs. Most of these were in the 600 HP range with a few being 900-1000 I've used various Edelbrock BBC and SBC heads with the only problem being the exhaust ports sealing with cast aluminum manifolds. A set of SBC Procomps that were customer supplied required a lot of clearancing to get the pushrods to fit. The biggest problem I ever had was with a set of Dart 325's. There was casting flaw that caused a water port to leak into the valley. That was very difficult to find. Dart claimed to have never heard of such a problem. The fix was to weld the port and resurface the heads.
Bob Lloyd
Edit: I forgot to mention the Raylar 496 heads that developed cracks and leaked water. Had 3 sets of those.
Bob Lloyd
Edit: I forgot to mention the Raylar 496 heads that developed cracks and leaked water. Had 3 sets of those.
Last edited by bobl; 10-22-2015 at 11:34 PM.
