To Crate or not to Crate
 

I've got a mid 90's Formula 382 with carbed 502s standard 415hp. At a point where I have to either rebuild or replace one. I have seen several Crate engines around the web but after reading posts on OSO not sure about reliability of GM's contractors assembling them. Good or bad would like to get some input.

Mercruiser black motors are all gm marine series engines. So they would of come assembled by gm. Just make sure it is thier marine motor and you should be ok as long as you understand it is a stock replacement and not a hp unit.

If you are not looking to upgrade power, there is nothing wrong with GM crate power.

Yep, and the latest Gen VI 502's have been dyno'ing between 445-465hp depending on induction and exhaust. That's on 87 octane. Nothin wrong with that.

If they are Merc 502's then they are 390hp. IMO, its probably more cost effective to rebuild what you have.

Thought about boring the old block to 540 to bring it up around 550hp. Which brings up another question. If i did only one side this season am I going to see a lot of issues with 550hp on one side of the boat and 100 horses less on the other?

I would go this route as well, not even to 540, make them 509's with stout parts and you'll be miles ahead. might even be able to reuse your crank. with the right cam/head combo you could easily have more hp and great reliabilty.

the new crate engines you see listed all over are NOT assembled by GM, they have a outsourced place doing the assembly...and the quality is shaky, bought 2 had a bad experiance with one and after doing research some others have as well...have a good machine/engine shop redo what you have...

+ 2. 509's. Your drives will hate you going to 540's.

Is that power meassured by the SAE J1349 Standard that Merc, Volvo and Ilmor uses or the genrous SAE J607 Standard many custom builders use? If the latter they would be between 425-440 hp SAE J1349. The reason why I'm bringing it up, is just to make the hp comparisons equal.

I went from 454/330 old on one side to 540 hp on the other side for 5 years (until the other 454 quit), only difference was throttling, had to make sure rpms matched, not throttle levers. The throttle on the new was about 1/2 position of the old at exact rpms.

That would drive me crazy, like one clean sock and one dirty sock.:party-smiley-004:

J607 is pretty old, I think most guys would be using J1349 as the accepted standard these days. There's lots of other correction factors too. My numbers are from standard J1349 with a weather station, and the correction factor on my dyno is usually around 1.02 or less so there's not much there anyway. The engines are also fully rigged, running all accessories and full wet exhaust.

Not really so bad, if the dirty sock is just a little bit dirty, but the dirty sock is like stepping into a bucket of poop so you got no choice but to change it. I could have rebuilt of both at the time, but I chose to significantly up the anti on them such that what I put into the new engine would have paid for rebuilding both old engines to stock level power.

So that would mean all the 8.2 Mag and 8.2 Mag HO are not assembled by GM?

The new Mercruiser/Mercury 8.2Mag and 8.2HO engines are Mercury buillt product from what I understand and are built in Fondulac. I had heard that Mercury was subcontracting the short blocks though and I have not been able to confirm that. In any event they are not assembled by the subcontractors that are now doing the GM crate engine programs and apparently their are several different firms doing this work.
Maybe someone here on OSO can check their Mercury sources and confirm this.

Best Regards,
Ray @ Raylar

So, the new 8.2s are technically "hand assembled" by Mercury instead of being purchased as a short block?

i have heard of people with a 318 dodge on one side and 454 on the other. of course, this was in a sportfish that only had to outrun the fish. but if you keep it geared and propped the same both sides, no issues. you could probably do a little cable adjusting for lever pos at cruise.

I purchased 2 two years ago and took them apart to change cams to RMBUILDER cams. Every bolt inside and outside had different colors of permenant marker. All main bolts had a green slash, rods a red slash and so on.

Crate motors or Mercs?

i would rebuild what you have,4.500 bore makes it a 509,go with edelbrock marine aluminum heads,hp 500 efi hyd roller cam,and 9.5 to 10 to 1 compression,850 holley with single plane intake,and enjoy 575 reliable hp.i have done several like this,you get a lot of bang for the buck.

The paint marks during assembly and torque checks does not necessarily mean they were assembled by Merc, as many engine assembly shops use this method of confirming all bolts are torqued and rechecked prior to finish. It's a good sign of a careful shop procedure and one that indicates a good torque system and check was done on the various bolts and nuts. I have opened Merc Racing engines that did not have this check markings in them and I have opened some that did.

Best Regards,
Ray @ Raylar

Price the Merlin Crate 509's from Teague. They are a nice piece at a good price. They got a bad rap for some problem years ago, but Bob said they are straight up now. 575hp.

There is a local shop that advertises and sells the GM crate 500hp 502. Intake to oilpan with Edlebrock aluminum heads. They advertise these engines as marine replacement engines.
So, do these engines have Inconnel exhaust valves?

The Inconel exhaust valve need and usage is good subject for a whole new thread to explain the "when and where" needs for Inconel exhaust valves!
I think I will get one going here soon as I have some somewhat non-conformingviews of the need for Inconel exhaust valves or such in normally aspirated marine performance uses?? I will see if we can gain some educational and informed clarity on these beliefs?

Best Regards,
Ray @ Raylar

I always felt that, Mercury would not have spent the money for these exhaust vakves in (I think) all of their big-block applications unless they were needed for a long life engine.