572 crate engine problems

[cook1]

We have ran two 572 gm crate engines and both engines have had the same problem. After about 15 hrs the both broke a valve. These engines were ran out of the crate and set with 32 deg timing. Was just wondering if anyone else has tried them yet.

[canuck1]

Originally posted by cook1
We have ran two 572 gm crate engines and both engines have had the same problem. After about 15 hrs the both broke a valve. These engines were ran out of the crate and set with 32 deg timing. Was just wondering if anyone else has tried them yet.
Make that 3.5. saw one do the same on the weekend and heard about another last week

[cstraub]

When you get them apart, if you can post some pictures of the valves we may be able to diagnose what happened. Hyd. roller seat pressure for street engines is not enough for marine due to the consistantly higher rpm. If I were to purchase crate engines for marine transplantation, I would make sure the seat pressure on the springs is in the 140 to 150# range.
Chris

[superdave013]

Originally posted by cook1
We have ran two 572 gm crate engines and both engines have had the same problem. After about 15 hrs the both broke a valve. These engines were ran out of the crate and set with 32 deg timing. Was just wondering if anyone else has tried them yet.
Does GM stand behind them with any kind of warrenty?

[OMEGA_BUBBLE_JET]

Originally posted by superdave013
Does GM stand behind them with any kind of warrenty?
not if it goes into a boat!:eek: I asked the same question a couple weeks ago and someone posted the warrantee info and specifically mentioned no marine use. I would think if you went to a dealer they would be able to do something though:confused:
Omega

[flat broke]

What kind of exhaust was being used in the boats that toasted the valves?
Chris

[Craig]

Was it an exhaust valve that broke? The motors probably don't come with Inconel exhaust valves, probably one reason they say "no marine use" :(

[230Stingray]

I have one in my boat but I changed cams to a Crane 741 I have 20+ hours on mine now with no problems

[cook1]

This one had kodiak marine manifolds, I guess gm is giving him a complete new engine. He is still concerned because he has herd of some other ones having the same problem.

[230Stingray]

If he was running those manifolds without a cam change I can almost guarantee you that water reversion thru the exhaust caused the problem. The duration on the stock 572 cam is not sutable for marine use. There are others here on the forum that probably can agree with me on this that this cam will cause problems in a wet exhaust motor
Intake .632
Exhaust .632
Duration 254/264 @ .050
LSA 108'
Thats great news if GM will warranty these!

[TX19]

I don't know about others agreeing about the camshaft being wrong, but my cams specs are similar but not on a 572. Specifications are as follows:
duration @ .050 = 258 / 268
lift @ 1.73 RR = .635 / .645
lobe centers 110 @ cam
This is in a 514 BBF / Dominator jet with water jacketed exhaust.
I am on the fourth season and have had no problems.
It may not work for everyone, but it works well for me.

[Dave C]

I used to run a cam that was bigger in wet exhaust and had no problems. Although they were over-the-transom exhaust.:D
This is interesting. I wonder if they have cheap-arse GM valves in them?

[230Stingray]

I hope these are isolated situations. The motors appear to be built using quality componants. I would think they used decent valves also. I ran a ZZ502 for 4 years with no valve problems what so ever. I think the cam thing all depends on how far down the exhaust manifold tail pipes that water is introduced.

[rmbuilder]

The Zz 572 problems stem directly from reversion issues when used in marine applications. The factory cam is unsuitable for use with wet exhaust. The 620 HP version (hyd roller) ships with the following cams specs:
316*/326* @ .004”
254*/264* @ .050
.632/ .632
112* LSA
This nets 97* overlap @ .004 and 35* @ .050
Using one of Cranes most aggressive marine profiles (139741) as a comparison the cause of the problem is clear.
296*/304* @ .004
234*/242* @ .050
.610/ .632
112* LSA
This nets 76* overlap @ .004 and 14* @ .050
The Zz 572 cam has a full 21* more overlap @ both ratings than the 741.
The exhaust valve failures experienced are the result of running at mid to high rpm levels for periods of time, then backing out of the throttle. When the engine returns to idle the (relatively) cold water reverts onto a still very hot exhaust valve causing a fracture at the stem/head area.

[DogHouse]

Originally posted by cook1
This one had kodiak marine manifolds, I guess gm is giving him a complete new engine. He is still concerned because he has herd of some other ones having the same problem.
Sounds like it's time to replace those Kodiaks with some nice Stainless Marine Gen III manifolds and jacketed tailpipes or similar. I run that setup on a 598 with 256/262 @.050, 114 l/c, .730/.700 lift, and have no water getting back into the motor at all. You might even pick up some HP with the better flowing manifolds.
Before I switched to these manifolds, I was running some headers that were leaking significant amounts of water back into the engine. I'm surprised (and lucky!) that I didn't have a failure. :eek!: I guess Dart uses some good quality valves.
-brian

[RedRocket]

Kodiaks are DRY manifolds are they not?

[DogHouse]

Originally posted by RedRocket
Kodiaks are DRY manifolds are they not?
Yes, but they are short and have short risers, so when the water dumps into the exhaust stream it's not very far away from the exhaust ports. Other systems can be configured to dump the water much further downstream. With full jacketed tailpipes, you can even have it dump at the very end, beyond the transom.
-brian

[Dave C]

I used a cam like this for years and years with over the transom wet exhaust (Bassett) and NEVER had a problem.
But I used good stainless valves.
Wonder what the difference is?
Originally posted by rmbuilder
The Zz 572 problems stem directly from reversion issues when used in marine applications. The factory cam is unsuitable for use with wet exhaust. The 620 HP version (hyd roller) ships with the following cams specs:
316*/326* @ .004”
254*/264* @ .050
.632/ .632
112* LSA
This nets 97* overlap @ .004 and 35* @ .050

[flat broke]

The difference would be that as you came off the gas with the injected headers the water flow was cut off ,whereas with the Kodiaks the water would keep on pumping and with overlap at idle, and an increase of H2O volume in the system from being on the gas, you'd have a lot of water dumping into the exhaust while the motor is coming back into a state where overlap is causing reversion. This was the main reason I initialy asked what exhaust was in use in the failed motors.
Could probably get away with the cam if he switched to a system that introduced the water into the exhaust stream much further down the pipe. He can get some custom lightnings with long collectors done up, or custom lightnings with long collectors and reduced water option, or go to a different setup like some CMIs or Stainless Marines with the long riser/pip option that drops the water back into the exhuast a long way from the motor.
When we're putting these things together, we have to remember to look at the whole enchilada and not just a bad ass engine.
Chris

[RumRunner]

The problem is the exhaust valves are not inconel. These are really good engines, but will require the exhaust valves changed for marine applications.

[rmbuilder]

Essentially there are two factors involved in the equation. The given, which is the camshaft, has more than enough overlap that it will revert water if in fact the water is introduced within a certain proximity of the exhaust port. The variable is the exhaust manifold used. The point at which the water is introduced will determine whether or not the engine will fail. Inconel exhaust valves, while necessary to sustain the prolonged temp increase associated with marine applications, do nothing to deter the effects of reversion.

[Party Cat]

if you are gonna run a cam like the '741 crane or bigger...you will need a good exhaust manifold....I put a 509 in my boat last year....initially with the Dana Marine cast manifold with their cast risers....per Dana...I should have had no problems with reversion....well $3k later on a brand new motor, and a set of their Stainless risers (water is introduced further down the pipe) the boat runs great....I sucked water enough water into the motor on initial start up and tuning in a test tank with not a good enough exhaust to screw things up....the reversion may not have caused the problem....but is definatly an issue with a cam like a '741 or bigger....
PC

[Infomaniac]

I am able to sell the Deluxe ZZ-572 for the same price as Scoggins Dickey 12,900.00 or long block only for 12,000.00
Disassemble and increase all of the necessary clearances, add inconel exhaust valves, severe duty intake valves, Isky's latest greatest hydraulic roller lifters. Isky premium Cryo treated valve springs set up at 150# on the seat. Crane 741 cam (or cam of choice). Marine head gaskets. Oil pump prep. Moly ring set, $1,900.00 plus shipping once (me to you) and exchange of removed parts.

[cstraub]

I'll chime in on Bobs comment about inconel. An exhaust valve that is running at 1300 degrees and has 160 degree water come in on it. . . doesn't matter what material it is. . .it will break.
I have worked for 3 valvetrain companies over the years while in this industry. I have learned a great deal about materials and marketing BS. A 21-2N or a 21-4N stainless valve can be solution treated with chemicals to increase yield and tensile to match better materials. Nothing will survive a dose of cold water.
Crate engines are great, just do as Info says and have them "marineized" by a Marine guy.
Chris

[Dave C]

BINGO.... hence the use of CMI's that dump the water at the end after the down turn . I forgot about that, I gotta remember that!
Thanks.
Originally posted by flat broke
The difference would be that as you came off the gas with the injected headers the water flow was cut off ,whereas with the Kodiaks the water would keep on pumping and with overlap at idle, and an increase of H2O volume in the system from being on the gas, you'd have a lot of water dumping into the exhaust while the motor is coming back into a state where overlap is causing reversion. This was the main reason I initialy asked what exhaust was in use in the failed motors.
Could probably get away with the cam if he switched to a system that introduced the water into the exhaust stream much further down the pipe. He can get some custom lightnings with long collectors done up, or custom lightnings with long collectors and reduced water option, or go to a different setup like some CMIs or Stainless Marines with the long riser/pip option that drops the water back into the exhuast a long way from the motor.
When we're putting these things together, we have to remember to look at the whole enchilada and not just a bad ass engine.
Chris

[Dave C]

Thats pretty good right there.!
Re increase necessary clearances.... care to be more specific? I'm thinking valve lash, ring clearance.
Originally posted by Infomaniac
I am able to sell the Deluxe ZZ-572 for the same price as Scoggins Dickey 12,900.00 or long block only for 12,000.00
Disassemble and increase all of the necessary clearances, add inconel exhaust valves, severe duty intake valves, Isky's latest greatest hydraulic roller lifters. Isky premium Cryo treated valve springs set up at 150# on the seat. Crane 741 cam (or cam of choice). Marine head gaskets. Oil pump prep. Moly ring set, $1,900.00 plus shipping once (me to you) and exchange of removed parts.

[Infomaniac]

More complex than that.
An extra .0015 - .002 piston to cyl wall clearance with torque plate
ring end gap per ring mfg marine specs.
.003 main and .0025 rod bearing clearance
lifter bore and valve guides honed on condition.
rotating assembly checked for proper balance.
block off the Gen VI filter bypass located in the block.
brass freeze plugs

[Dave C]

I was always wondering about this. Do you have to order the pistons with additional clearance? or are they machined.
inquiring laymen's minds are dying to know!
Thanks for the "info" as usual.
Originally posted by Infomaniac
An extra .0015 - .002 piston to cyl wall clearance with torque plate
ring end gap per ring mfg marine specs.
.

[Infomaniac]

That extra clearance is standard for a marine hot piston - cold block application.
You just have the cylinder honed to .0XX" larger than the piston diameter. Depending on what brand and material the piston is made from.

[Dave C]

that makes perfect sense.... I think I need some more coffee

[CustomCruiser]

I know someone running twin 572 crate motors in his 28' Daytona. Nothing was modified on the engines except for a larger oil pan and accessories. He's running IMCO Powerflow Plus, dry all way to the tips. So far no problems.
Info - the clearances you described make sense, particularly when using a crossover without a thermostat. Have you discovered any of the stock rotating assemblies being out of balance so far?

[230Stingray]

I have 20+ hours on mine now. I replaced the stock cam with the Crane 741 and used a Cloyes hexadjust timing set to set the intake valve center line to 112' Not sure how much horspower was lost going to the shorter duration cam, but I knew I could not run the stock cam. I'm running thru a set of Gil manifolds with low hatch clearance risers. Pulled the exhaust manifolds off after the first run to remove the valve covers to re torque the heads. No visable sign of moisture in the exhaust ports. I decided on the 741 after talking with Partycat and Dennis Moore a couple of times over the winter. It seems to be a great cam with good idle characteristics. I would recommend it.

[Taylorman]

If i may suggest a good electric water shutoff valve that closes at about 2000 rpms to prevent water reversion. I have been using one for a couple months and have to say its much better than a Bassett t valve. A handfull of guys on the boards are now using them and all seem to be happy with how they work.

[Party Cat]

Originally posted by 230Stingray
I have 20+ hours on mine now. I replaced the stock cam with the Crane 741 and used a Cloyes hexadjust timing set to set the intake valve center line to 112' Not sure how much horspower was lost going to the shorter duration cam, but I knew I could not run the stock cam. I'm running thru a set of Gil manifolds with low hatch clearance risers. Pulled the exhaust manifolds off after the first run to remove the valve covers to re torque the heads. No visable sign of moisture in the exhaust ports. I decided on the 741 after talking with Partycat and Dennis Moore a couple of times over the winter. It seems to be a great cam with good idle characteristics. I would recommend it.
With the '741, Gen VI 509, Dart Pro 1 heads, Edelbrock AirGap Intake, Dana cast manifolds w/Stainless risers, single Holley and MSD Marine Ignition.....I dyno'd 628/652...I'm reall happy with the engine setup....now to get the props set.....

[superdave013]

Party Cat, what did you do with those CMI's you got from me?

[Party Cat]

Originally posted by superdave013
Party Cat, what did you do with those CMI's you got from me?
They're sitting in my garage.....ya wanna buy em back :D :D

[superdave013]

no but I bet they would be easy to sell.

[Party Cat]

yah....but I've been lazy and they're just sitting there...
any takers ???? :)

[Jordy]

Originally posted by Party Cat
yah....but I've been lazy and they're just sitting there...
any takers ???? :)
Do ya have any pics ya lazy focker? :D

[Dave C]

hows the idle with that cam?

[TIMINATOR]

A crate motor is SOMEONE ELSES idea of a one size fits all solution. Why anyone would buy a crate motor thats not the correct application, then pay an expert to modify it and void the warrenty is beyond me! But then again we are custom engine builders and build what you need the first time. We have also done a lot of repair/ upgrades to crate engines too. The weak link is the exhaust valves and clearances as info mentioned. I run a Comp roller 278/282 @ .050 .714/.680 and have no reversion problems, its been in the boat for 2 1/2 years so I would know by now. The next time somebody asks about crate VS custom motors I will refer them to this thread! Driving style/load and many other factors determine whether you get lucky with a crate motor or not. The operative word here is LUCKY! TIMINATOR

[230Stingray]

Timinator, what exhaust are you running with that big cam. Doesnt this whole valve breaking issue in your opinion really come down to exhaust manifold choices? I'm sure you are correct on the driving style and load conditions making a difference on longevity. But I think that comes into play with whoever puts the motor together. So for right now, call me 5th year lucky:)

[Trouble Maker]

Info.
Why is there two bypass valves in the block? One for the filter bypass and one for the system pressure? Is the filter bypass the one right there on the top? I have a Gen V...should I block off the filter bypass? If so, with what?
Thanks in advance..
Originally posted by Infomaniac
More complex than that.
An extra .0015 - .002 piston to cyl wall clearance with torque plate
ring end gap per ring mfg marine specs.
.003 main and .0025 rod bearing clearance
lifter bore and valve guides honed on condition.
rotating assembly checked for proper balance.
block off the Gen VI filter bypass located in the block.
brass freeze plugs

[Infomaniac]

Don't block anything off just because I say that I do.
If you want to block off the filter bypass, it is the one right there next to where the filter screws on. A drive in plug fits I have heard. I tap the hole with a 1/2 NPT tap. Engine must be torn down naturally.
GM makes a higher pressure bypass that folks use in lieu of blocking it off.

[Trouble Maker]

Info
Reason I ask is because I just fried my motor due to an "oil heat/filter/cooling" problem. Only thing I found wrong when taking the engine out was that the lines where going to the remote filter the wrong direction. After teardown...looks like things just got real hot..tore all the main bearings up...oil smells burnt.
If oil was going through the filter backwards...you think that would create enough back pressure to open up that filter bypass? Thus the oil wouldn't be getting cooled or filtered... It happened after a 30 minute run between 4-5k when I notice the oil pressure dropping off slowly at first then dropped to zero pretty quickly.
That may be a good idea to just put in a higher pressure bypass valve...that, and hook the F%^king hoses up correctly... Engine was just put in about 15 hours ago after a winter rebuild...hard to believe that just mixing up a couple of hoses around can ruin the whole deal.
Also, what is the normal pressure bypass valve to use. When I took them out there wasn't any part numbers on them...it's a Gen V 454 block...originally started as a 525SC...still has the original GM high volume pump.
Thanks again...

[Trouble Maker]

TTT

[Infomaniac]

Gary The GM part # for the 30lb bypass valve is 25161284. It is used in the 6.5L Diesel.
Ron

[Trouble Maker]

Thanks Info....

[230Stingray]

Interesting little piece of editorial in the new Hot Boat Magazine by Bob Brown about these motors. Don't know what he really knows about engine building and he doesn't elaborate on his qualifications but he sees potential in these motors.

[230Stingray]

I met Bob at a dealer meeting several years ago. Seems like a great guy. I was just happy to see someone like that say something good about these 572's I have 30 hours on mine now and no problems.