Custom vs Factory Quality of Motors?
 

Hello Folks - been a while as I have been saving up to get my motors replaced in the old Harley.

Had an interesting conversation with a gent recently who basically said that a new motor from the factory will outlast a rebuild because:

-Robots are doing the the measuring
-Robots are doing the machining
-Robots are doing the assembly
-Repetition has removed inaccuracies

....And the quality is much higher over-all since there is no human error or "wiggle" factor in the over-all build.

This might be a stupid question but is he right? For someone looking for 500 HP out of a big block marine engine - am I better off just buying factory new?

Factory new Vs. rebuilt will almost always last longer. BUT, that is also considering you are going to have to punch the old block out at least .030 over. As the block ages, and you bore it out, it's not going to be as strong. Plus, you'll have an array of parts from different vendors etc that you piece together. The factory spends a lot of R&D time getting their engines to the best setup.

Now, dollar for dollar the rebuild is simply more economical. If you get the right builder, it's going to last anyway, etc.

It depends on who is doing the work. A top builder is going to be able to hold to closer tolerances than any automated process, if he knows his stuff. His experience will allow him to identify issues he sees- something a robot is incapable of.

As far as the block aging, 20 years ago, we used to dig for the GM tall deck 427 truck blocks. They had been thermally cycled so many times they were more stable.

The only place that can sell you a new, never used motor is GM. Last time I looked, their highly automated production processes still aren't capable of turning out a flawless, issue-free product. That's not to say they don't build a good, solid, reliable product. There's just no guarantee it's always going to be 100% perfect. Ultimately it will be assembled by a human. With a custom motor, you get to pick that exact person based on record & reputation.

good comments guys - keep them coming

I like going with a quality builder and having something a little different than most. That being said, you have to be sure that they know what they are doing and will stand behind their product.

Wrong. GM's engine factorys aren't populated with robots. Engines are still built by people. Sure there's a lot of automated processes and fancy tools, but there's still people on the line putting things together. I'm sure no robot would draw a smilie on the rear cam cover :D

The "perception" that a rebuild or custom motor doesn't last as long as "factory new" is because most custom motors have the sh!t run out of 'em...of course they're gonna wear out sooner. As for rebuilds, you get what you pay for. Buy a Jasper, don't expect someone with 20yrs of experience to have put it together. Use someone that's been building all sorts of engines for 20yrs, use it the same as a "factory original" engine, and I bet it will last just as long if not longer.

I was thinking the same. I can't imagine a engine being assembled by a robot..Does anyone know who assembles engines on a production line with machinery? I am curious to see the process..any video?

The quality comes with the details! Anybody, machine or robot can build a motor. It's not who built it!, its how its built!
I think that the factories have gotten much better at building high quality high performance engines than they did in the past due mostly to better machining practices, higher and better materials technology and the greater demands of extended warranties in the vehicle applications.
Believe me when I say I see a lot of factory performance engines that would never pass our inspection process let alone leave the shipping dock!
However that said, even GM, Ford , Chrysler and the Imports have special engine assembly operations to manufacture and assemble their best perfromance engine offerings. In these operations a great deal of personal individual care and training goes into "Getting it Right" . ie; Hand Built!
I know there are years of engine offerings from the great marine engine endurance builders, that when compared to standard engine production are light years ahead in building a long lasting engine package when you compare the moderate horsepower 425 to 550HPHP engines to the factory produced packages!
You will spend more for privatly built quality marine engines but from the "Good Guys" than you will for most factory engines but that's because it's small limited hand built pieces and some much better aftermarket specialty parts coupled with the personal attention each motor receives.

My bised two cents from an engine builder!

Regards,
Ray @ Raylar

If money wasn't an object, I'd take the new one everytime. At least you get a warranty with it. If it's a Merc, there are a ton of places that will recognize the warranty, where if you get a custom built engine from across country, they may very well honor it, but you might have to ship it to them to decide whether it's a build issue or not.

Jmho

Without speaking directly as to how any particular client(s)assemble an engine, basically all of the manufacturers utilize a combination of robotic processes, automation-both dedicated & flexible, as well as people.

Of course they're not assembled by robots. I figured that went without saying.

The parts are all made on automated machinery so things like boring, honing, rod sizing are not hand processes. Then, parts are "batched". They group things like pistons and rods into similarly-sized groups for assembly. They aren't machining-to-fit or precision balancing anything.

Also, you need to define "rebuilt" That usually means installing all new parts into a used block. If you're grinding a crank and resizing the rods on a beat-to-death motor, your odds of success are certainly lessened.

Chris brought up a good point about balancing. I have built many, many pairs of engines with the exact same parts. I may have only had one or two pairs that had exactly the same bobweight. GM does not weigh each rotating assembly and balance each individually. They use an average bobweight. I think their acceptable range is like 20-25 grams out of balance. I'm sorry but that is not good enough for me.
Now, this may not cause you a problem in a 450-500 hp, 5000-5200 rpm engine, but I am not willing to take that chance. It's not financially feasible for them to balance each and every one by hand and they have a certain percent of failures figured in. Now I'm not bashing GM, they do a great job at what they do. They just build a LOT of engines and can only give each so much time.
So, I am a little partial to a custom built engine.:D
Eddie

Ray, I sorta agree, and not.

There is no question that quality comes with the details.

But I think the 'who builds it' is paramount: its not the company who builds it, it the actual person.

Specifically: If Bob or Norm Teague personally built a motor for me, no problem. If some employee of theirs built the motor, I would feel far more confident if I had done it myself. FAR MORE. And I really don't know what I am doing.

I work on spacecraft. If anything is wrong, we lose the mission. There are literally millions of analysis done, decisions made, tests done, and anywhere in there can be the thing that kills the bird, or rover. Its not the logo, its the weakest link. I've got people with unbelievable experience and academic credentials that I've had to can, or I've forced out, because they just can't sustain the level of perfection under pressure required. Its those individuals, not the logo on the building, that screwed up, or that enabled the success.

With a big giant faceless company like GM, you really are just playing the odds. Most of the time, maybe the vast majority of the time, you'll win. If they were not pretty darn good, they would have gone broke long ago: a billion pissed off customers will kill the biggest company. Or you'd think so, anyway, but Microsoft is still with us :rolleyes:

But the thing is, engines really are not complicated. The most worn piece of junk will run. But paying attention to the details, and building on experience and wisdom, will probably result in a better engine for you.

And experience is not enhanced by doing the same thing a million times over. Its enhanced by experimentation -- by trying things a little different, and paying attention and tracking what works and what does not.

Bob Teague and Paul Pfaff are two who do this: they build and run and fix a lot of different engines for a lot of decades -- engines they built, and engines others built. They learn!

Does a guy on an assembly line who simply builds engines all day, and never fix ones screwed up by someone else, does he ever get any wisdom?

Does a production line run to meet quarterly reports for Wall Street pay attention to, say, how putting the alternator under the power steering pump causes the alternator to fry when the power steering pump leaks?

Experienced custom builders are the way to go, in my opinion.

Just as a data point, Yanmar's 3.3L 4 cylinder diesels built in Japan are nearly 100% automated. I did not see the factory first hand, but two engineers I used to work with did. They said it was amazing to see the engines being put together by robots. That also includes and sealant, gaskets, etc. Torques were all by DC torque wrenchs - very precise and accurate.

I have no direct knowlege but would assume many automotive manufacturers, especially those in Japan, are nearly 100% automated.

If you visit gmperformance.com they show their production line where the engines are assembled. One guy, one engine.

It has probably already been said but in the lower hp ranges, I don't know if a builder can compete $ wise with some of the crate packages, if he is using new parts. I think I'll get agreement, majority of GM problems are valvetrain oriented. In higher hp configs I think this is where the builder can really add proven value. Personally I would rather have a custom built anything vs factory but I am willing to pay the difference for the value received....unlike John Doe.

http://boatingtodaytv.com/feature/lastweek.asp Hope this helps.:drink:

Last I knew Merc charges big money for one of their engines. You can have the same amount of HP from custom engine building shop for much less than what Merc charges. (How much does Merc charge for one of their 1075's? I understand Merc builds their own higher echlon hi-perf engines and Merc may have the lower echlon engines (short and long blocks) pre-assembled from GM. I'd rather have my engines built by someone who knows what the heck they're doing and not give all the deceptive smooth talk as they con your hard earned green backs out of your wallet.

Ha...and finding a shop that knows what the heck they're doing when it comes to hi-perf offshore engines and how they deal with you as a business can be another whole challenge in itself! Hope it goes well for you.

If you have something to add that might educate us, please add it. If not, why waste all of our time with your barbs?

Well said. Probably a good word for it is "Blueprinting". I have been told that .001" can make a difference in the survival or disaster of an engine. Taking all the slop out of a mass produced factory engine and have it built/fitted within a certain set of specs by a competent engine builder is what I would prefer to do.

A thousandth too small on exhaust valve clearance can turn your $30,000 motor into a pile of virtually worthless scrap metal in about 3 seconds.

Where did I said they were Marine engines? Oh, I didn't...

Someone above questioned whether or not anyone was building engines without human hands on them. I offered a data point nothing more nothing less. And I'm 100% sure they knew exactly what plant the were in and what product they were looking at.

Again guys,, good stuff. But I'm getting more confused by the minute.
My problem. Getting new 525's from merc. for about $21,000+- (at least that's what I hear I can get them) or custom/semi custom new built motors. The custom motors would be from a 540 block and about 560+ HP and $18,000 (no headers)
Which way to go ? :mad: I might post a question thread on this.

As we have spoke on the phone, You are trying to compare a Mustang to a Ferrari . The right builder is either going to make you a happy camper or not.

Thanks, and I understand, but here's the problem.
Custom motors... location.. warranty.. rigging and aligning drives,, bu.. t more HP. unique etc.
Merc. less HP but no other issues. $'s are close.

Good thread and great info as usual guys - thanks

Seems like - if all you want is reliable 450-500HP that runs on pump gas a set of factory new 502s with decent exhaust and maybe a little head work will get you there....reliably. Add in some oversized coolers, oversized oil pans, synthetic oil, and closed cooling and you can get 500 hours between refreshes.
Does that sum it up for 500HPs?

Now if you want more HP - gotta go custom