solid, roller or hydraulic?
10-03-2003, 09:48 AM
#1
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solid, roller or hydraulic?
Guys,
My 540's have been nothing short of a nightmare eating cams and spitting out lifters like chicklets...
We started with hydraulic lifters and the valvetrain just will not stay together...my mechanic is using ultradyne camshafts and crane hyd lifters. I dunno what the lift and duration is, but my question is this:
What is the best cam configuration with a tall deck 540, team g manifold and holley 1050 dominator carb? Do we go with solid or roller and what should the lift/duration be?
I think we've already decided that hydraulic is not a good choice here...
My 540's have been nothing short of a nightmare eating cams and spitting out lifters like chicklets...
We started with hydraulic lifters and the valvetrain just will not stay together...my mechanic is using ultradyne camshafts and crane hyd lifters. I dunno what the lift and duration is, but my question is this:
What is the best cam configuration with a tall deck 540, team g manifold and holley 1050 dominator carb? Do we go with solid or roller and what should the lift/duration be?
I think we've already decided that hydraulic is not a good choice here...
10-03-2003, 10:23 AM
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Ultradyne has some wild profiles. It would help to know what you have. I'm using Crane 651 hyd roller, merlin heads, merlin intake, 1050. Runs great, idles good at 800 rpm. No plug fouling or wierd problems. From what people here say the secret to making these valve trains live is keep rpms down below 5600 and check and replace springs and lifters often
10-03-2003, 10:49 AM
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If you've had a series of cam/lifter/valvetrain failures, I would attempt to try to find the source of the problem before making the assumption that you need to go to a solid roller setup. Specifically, what is failing? Assuming that you are using high-quality parts designed for the intended use, which it sounds like you are, I would make sure you don't have geometry, coil bind, interference, or oil pressure/volume issues first.
If you know the flow specs for your heads/intake, it will give you a good idea of what you're valve lift and intensity should be. Duration is more related to the target operating rpm range, engine displacement, static compression and fuel quality, and exhaust system design.
If you know the flow specs for your heads/intake, it will give you a good idea of what you're valve lift and intensity should be. Duration is more related to the target operating rpm range, engine displacement, static compression and fuel quality, and exhaust system design.
Last edited by Monty; 10-03-2003 at 10:51 AM.
10-03-2003, 10:58 AM
#4
Most (it not all) Merc performance are using hyd. rollers clear down the the 454 Mag. A straight Hyd cam will not work in your situation. I wiped a lobe off 2 different cams in my 454 Mag EFI (hyd cam). I found that later models Merc upgraded to a hyd. roller. The profile is very subjective to type of operation, HP, dependability and life. Call the CAM manufacturer directly for suggestions. Crane was very helpful and knowledgeable for me. They said they did not have a better cam than what I already had for my requirements.
Soilds can be a maintence nightmare for the common boater. The lash on the rockers will need to be adjusted every few weekends. This assumes to can get your valve covers off easily and you know what your doing.
Soilds can be a maintence nightmare for the common boater. The lash on the rockers will need to be adjusted every few weekends. This assumes to can get your valve covers off easily and you know what your doing.
Last edited by bajalion; 10-03-2003 at 11:02 AM.
10-03-2003, 11:16 AM
#5
If you are wiping out flat tappet cams ,when the block is at the machinist have the lifter bores checked for squareness to the crankshaft centerline .Poorly machined lifter bores are common and a lot of engine builders bush the lifter bores with bronze bushings.
Rob
Rob
10-03-2003, 11:16 AM
#6
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MOnty,
Admittedly I am not a mechanic, but I know enough to make me dangerous...therefore, I'd like to know more...
can you elaborate on:
"geometry, coil bind, interference, or oil pressure/volume issues"
Oil pressure has always been good, at around 75lbs running and not below 50 at idle...
I've never run th boat above 5K...more to follw as i get info...
Admittedly I am not a mechanic, but I know enough to make me dangerous...therefore, I'd like to know more...
can you elaborate on:
"geometry, coil bind, interference, or oil pressure/volume issues"
Oil pressure has always been good, at around 75lbs running and not below 50 at idle...
I've never run th boat above 5K...more to follw as i get info...
Last edited by Sean; 10-03-2003 at 11:20 AM.
10-03-2003, 11:41 AM
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Sean,
I was just suggesting that you attempt to find the cause of your problems before you go through another set of cams/lifters, etc or change to a solid roller. There's got to be a reason you are breaking parts. They are either unsuitable for what you are trying to do, or somethings not set up correctly. Proper valvetrain setup is often a trial and error process, and since you ahve a tall-deck block, the geometry is different than a standard deck height block. You will need longer pushrods, and the proper length typically needs to be determined with an adjustable pushrod length checking tool.
I've got nothing against solid rollers, I run one in my twin turbo Corvette street car. They can be made very reliable, with minimal maintenance, when set up correctly. Due to the lifters ability to handle very intense lobe profiles, they almost always offer a performance advantage over other cam/lifter types. however, the benefit isn't typically realized until higher rpms, beyond the normal operating range of most pleasure boats in many cases. With good lifters (I use Jesel), and a rigid valvetrain, valve lash adjustments will not be required as often. Many cam companies offer "street" rollers which utilize relatively tight valve lash and feature lobe ramps which aren't as hard on the valvetrain as teh more agressive race oriented solid rollers are.
When I mentioned "geometry, coil bind, interference, or oil pressure/volume issues", I was just suggesting that you check the obvious stuff first. Valvetrain geometry is an inclusive term which includes the rockers contact path with the valve stem, as well as the valve, rocker, psuhrod, and lifter relationships. As you are aware, BBC heads have compound valve angles, if the pushrod/valve stem length, and rocker height aren't right, there are side loads imposed that greatly increase wear and negatively impact relaibility and durability. Coil bind means that the individual coils of the valve spring come in contact with each other before or at maximum valve lift. BAsically, the valve is too short or installed too short and the sping becomes "solid" hwile the rocker is still trying to compress it. Bend pushrods are typically the result. Interference can come from many areas, the rocker can contact the retainer, the pushrods can contact the cylinder head, etc. I mentioned oil pressure/oil volume because hydraulic lifters require sufficient oil pressure and voume for proper operation. It is fairly common to restrict oil flow to the top end and valvetrain on high performance engines, although this should never be done when hydraulic lifters are used.
If you could be mor specific about what your problems are, what parts are failing, you can more easily pinpoint what the problem might be.
I was just suggesting that you attempt to find the cause of your problems before you go through another set of cams/lifters, etc or change to a solid roller. There's got to be a reason you are breaking parts. They are either unsuitable for what you are trying to do, or somethings not set up correctly. Proper valvetrain setup is often a trial and error process, and since you ahve a tall-deck block, the geometry is different than a standard deck height block. You will need longer pushrods, and the proper length typically needs to be determined with an adjustable pushrod length checking tool.
I've got nothing against solid rollers, I run one in my twin turbo Corvette street car. They can be made very reliable, with minimal maintenance, when set up correctly. Due to the lifters ability to handle very intense lobe profiles, they almost always offer a performance advantage over other cam/lifter types. however, the benefit isn't typically realized until higher rpms, beyond the normal operating range of most pleasure boats in many cases. With good lifters (I use Jesel), and a rigid valvetrain, valve lash adjustments will not be required as often. Many cam companies offer "street" rollers which utilize relatively tight valve lash and feature lobe ramps which aren't as hard on the valvetrain as teh more agressive race oriented solid rollers are.
When I mentioned "geometry, coil bind, interference, or oil pressure/volume issues", I was just suggesting that you check the obvious stuff first. Valvetrain geometry is an inclusive term which includes the rockers contact path with the valve stem, as well as the valve, rocker, psuhrod, and lifter relationships. As you are aware, BBC heads have compound valve angles, if the pushrod/valve stem length, and rocker height aren't right, there are side loads imposed that greatly increase wear and negatively impact relaibility and durability. Coil bind means that the individual coils of the valve spring come in contact with each other before or at maximum valve lift. BAsically, the valve is too short or installed too short and the sping becomes "solid" hwile the rocker is still trying to compress it. Bend pushrods are typically the result. Interference can come from many areas, the rocker can contact the retainer, the pushrods can contact the cylinder head, etc. I mentioned oil pressure/oil volume because hydraulic lifters require sufficient oil pressure and voume for proper operation. It is fairly common to restrict oil flow to the top end and valvetrain on high performance engines, although this should never be done when hydraulic lifters are used.
If you could be mor specific about what your problems are, what parts are failing, you can more easily pinpoint what the problem might be.
10-03-2003, 11:43 AM
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If your cam has more lift than your springs will allow you are in coil bind. Your springs become a solid mass and will not compress further. Some thing has to give. Also check pushrod length. The rockers should wipe an area across the center of tip of the valves without coming in contact with the spring retainers. Spring pressure is an issue. A lot of people I talk to think that more pressure is better than not enough. It helps keep the valves from floating. 150-160lbs on the seat,450 open. Just some ideas.
10-03-2003, 01:39 PM
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Guys,
Thanks for all your help and advice. I've got a lot to learn, but spoke with the mechainc and found out a few things...
Blocks are "Bowtie green siamese" blocks---what does that mean?
Rods are Carillo and pisotns are Wiseco. Heads are Merlin cast iron, but that is about all i know about them. Manley severe duty valves are used.
My hydraulic cam was ultradyne 590 lift. it seems we are going to a solid roller Comp cam with a 625 lift. valve springs are also being replaced with 200lb seat pressure when closed.
whadda ya'll think and what else do i need to find out to determine what this setup will do for me? does it sound reliable?
I have a feeling that the pushrods are correct bcause none of them are bent. The old cam lost a lobe and the bottom of one of the lifters was blown out. all parts were found in the valley...
Thanks for all your help and advice. I've got a lot to learn, but spoke with the mechainc and found out a few things...
Blocks are "Bowtie green siamese" blocks---what does that mean?
Rods are Carillo and pisotns are Wiseco. Heads are Merlin cast iron, but that is about all i know about them. Manley severe duty valves are used.
My hydraulic cam was ultradyne 590 lift. it seems we are going to a solid roller Comp cam with a 625 lift. valve springs are also being replaced with 200lb seat pressure when closed.
whadda ya'll think and what else do i need to find out to determine what this setup will do for me? does it sound reliable?
I have a feeling that the pushrods are correct bcause none of them are bent. The old cam lost a lobe and the bottom of one of the lifters was blown out. all parts were found in the valley...
10-03-2003, 02:04 PM
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"Bowtie Green Siamesed" means it's a brand new GM Bowtie block with siamesed cylinders. "Green" means it's brand new and hasn't been seasoned by repeated heat cycles. You'd think an engine block is very rigid, but in actuality the bores and mains will move slightly as the brand new casting is heat cycled through normal use. Obviously these movements are measured in thousandths of an inch, but they can affect piston ring sealing and main bearing wear. It is not uncommon to rehone a "green" block after it's used a bit to accomodate account for the movement.
Siamese means that the water jackets do not completely surround the cylinder. The cylinder walls are solid between the adjacent cylinders and no coolant can pass between them. This greatly increases the rigidity and stability of the bores. In the early days, overheating problems were attributed to this, but it's really not an issue these now.
Bowtie block are GM high-performance blocks sold for racing and high-performance use. They are not production blocks, they have many upgrades such as thicker decks, cylinder walls, splayed maines, blind deck holes, etc. Actually, alot of them are cast and machined by Dart. They are good blocks for high-performance use.
The parts you've listed are generally regarded as high-quality, high-performance, so you should have no problems there.
I'm sure that if you're machinist is competent he has selected the appropriate valvesprings for you cam profile. It's hard to say given teh info provided, you need to know the coil bind and installed height to know for sure.
If you're losing hydraulic roller lifters, the usual cause is either too little or too much spring pressure or insufficient oil supply. There have been manufacturing/material issues with some hydraulic rollers, most notably Comp Cam's Xtreme roller lifters, but those are the exceptions.
Siamese means that the water jackets do not completely surround the cylinder. The cylinder walls are solid between the adjacent cylinders and no coolant can pass between them. This greatly increases the rigidity and stability of the bores. In the early days, overheating problems were attributed to this, but it's really not an issue these now.
Bowtie block are GM high-performance blocks sold for racing and high-performance use. They are not production blocks, they have many upgrades such as thicker decks, cylinder walls, splayed maines, blind deck holes, etc. Actually, alot of them are cast and machined by Dart. They are good blocks for high-performance use.
The parts you've listed are generally regarded as high-quality, high-performance, so you should have no problems there.
I'm sure that if you're machinist is competent he has selected the appropriate valvesprings for you cam profile. It's hard to say given teh info provided, you need to know the coil bind and installed height to know for sure.
If you're losing hydraulic roller lifters, the usual cause is either too little or too much spring pressure or insufficient oil supply. There have been manufacturing/material issues with some hydraulic rollers, most notably Comp Cam's Xtreme roller lifters, but those are the exceptions.
