Enforcer30

I know this thread is out there, but the only one I found was hijacked and never really seen a answer. I guess I have two questions: What is reallistic? Can these fire breathing 1,000-1,200hp engines survive for 200 hrs? Can they get by with a top end refreshining or do you tear them all the way down for a complete overhaul? I know there are alot of good respected builders out there i.e. Teague, Chief, Sterling, Merc, ect. I don't want this to get into a builder bashing (thats what happened to the last one), but is there one that stands out among them? Thanks, Barry

Young Performance

I wouldn't say that one builder really stands out from the rest. There are several of us that can make 1000 hp last for 200-300 hours, or more. I have a pair of my 925 efi's (970 hp) that are just shy of 300 hours. They have never been touched, other than oil changes. We are not rebuilding them this year, so they will go another summer. They will be well over 300 hours after this summer, when we may or may not rebuild them.
My 1200/1400 has gone as long as 125 hours, set at 1400 hp. I was concerned about the valvetrain. We did a complete rebuild. At that point, everything looked great and it certainly could have gone longer. The valve springs had lost about 10#. I did a complete rebuild, since I was in that far. That just makes sense to me. Do it all while it is out and half torn down. I would really love to push one to see just how long it would go.
Like I said, I'm sure there are quite a few other builders with similar results and longevity, or possibly more. A lot has to do with the valvetrain. Merc uses a solid roller in both the 850 and 1075. I don't know why they do it, but it will not last as long as a comparable hyd. roller. Not to mention the hyd. roller is pretty much maintenance free. I would say that is a big reason why they want that engine rebuilt at around 75 hours. The hyd. camshaft and lifter technology has advanced quite a bit in the last few years so that larger, more aggressive cams and lifters, that stand up to higher spring pressures and longevity, can be used to extend the effective life of a big hp engine.
I don't think you can go wrong with a well known Marine engine builder. There are no super top secret methods to get 1000 hp to last over 200 hours. It just takes good parts, good assembly methods, and good tuning. Good luck.
Eddie

2112

So Am I hearing your correctly Eddie, The Hydraulic roller is more responsible for longevity than say... Valve train Geometry? Or with all other things being equal, The Hydraulic rollers add lifespan?

Who's Hydraulic rollers do you like? I am just about to embark upon a new set of motors using solid Red Zones. My Ford Geometry is hard on the roller end of the lifters.

I always thought solid gave more power with the same cam? Does Hydraulic need more oil flow through the lifter galley?


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Young Performance

[QUOTE=2112;3042253]So Am I hearing your correctly Eddie, The Hydraulic roller is more responsible for longevity than say... Valve train Geometry?

No. If the geometry isn't correct, then no valvetrain will live.

Or with all other things being equal, The Hydraulic rollers add lifespan?
Yes, that is what I am saying. The hyd. rollers do not need the spring pressures that the solids do. And, they just have a longer lifespan. I am constantly hearing of guys with solids loosing lifters because of a broken axle, etc.


Who's Hydraulic rollers do you like? I am just about to embark upon a new set of motors using solid Red Zones. My Ford Geometry is hard on the roller end of the lifters.

Morels.

I always thought solid gave more power with the same cam? Does Hydraulic need more oil flow through the lifter galley?[Quote]

A solid roller must be approx. 8-10 deg of duration larger than a hyd roller to be comparable.
The solids have the potential to make more power mainly because you can get so much more aggressive with both duration and lift. You can have a very steep ramp on both opening and closing. You have higher spring pressures to keep the lifter on the cam and to stop the valve from bouncing on the seat.
The hyd doesn't neccessarily need more oil flow, but you can not run oil restrictors.

Eddie

2112

So the cam grind needs to be specific for Hydraulic? It isn't as simple as using hydraulic rollers on a solid roller cam?

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Young Performance

The cams that I use are Hyd. specific cams. You can use a solid grind with hyd. roller lifters. You just have to watch the opening and closing rate. You can have a faster opening and closing rate (steeper ramp) with a solid than you can with a hyd. cam, so you have to be careful. The higher the spring pressure, the more aggresive the cam can be. Obviously, there will be a point at which you overpower the lifters. The newer lifters can take way more spring pressures than anything in the past could. Some hyd. setups are now approaching solid spring pressures. They still can't match a solids spring pressure, but they are getting close.
Eddie

mittens

so what about a set of factory 525? will they last like a good old 454? 1000-1400 hours?

Griff

More like 500hrs before they should be replaced. On 525EFI's I would probably do top end refreshes around 300hrs with new lifters. Its cheap insurance.

mittens

what make them need to be worked over in comparison?

and what motors is the best you can go with out having to redo them every few hundered?

496's should be fine for over 1000 hours.

jeffswav

The 525's, 500 MPI, 500HP carb and most custom motors with performance cams need to have the valvesprings replaced more often. Most builders recomend you change the springs in the 200 hour range. Merc racing used Crane springs in there erlier engines, later they switched to Comp springs. I am not sure of the cuttoff years. I use the Isky endurance series spring that will last much longer than most others. The 454mag, 502mag, 496 mag HO, all have mild cams and do not require spring changes so often.