HP500 valvesprings
 

Looking at a 99 353, with HP500 EFIs, which years had the bad valve springs or was it carbed engines only.

So Mike, is it true that the carb motors that were still available 1st half of the '99 model year are uneffected? I'm shopping also ,and have had this valvespring issue in my head. Thanks, Randy

I wouldn't let the valve springs stop you from looking at any boat. Just prepare to change them over if need be.

If you call Mercury Racing and ask them about the valvetrains on the 500's, both carb and EFI they will tell you to replace springs at 200 hours.

Rod

I have a freind who just replaced valve springs in his 2000 500 EFI's due to breakage. Not sure of the hours but it does appear that this is a weak spot for the motor.

I've got late '95 vintage HP500's with a bit over 200 hours. They were running fine, but I figured better safe than sorry and winter is the time to do it.

I'm doing the first motor now. I wanted to check the head gaskets as well since I've been told that the stock Merc part was a bit weak. So far I've found the head gaskets leaking very slightly between cylinder 1 & 3, 3 & 5, and 4 & 6. I'm having the springs replaced and set-up by an expert this week. I'll let you know if I have any that are broken.:rolleyes:

Then comes motor number two... :crazy: :crazy:

Good luck!

Jeff

jbraurer makes a good point. Have a leak down test done on the boat first. Valve springs are easy to replace.

The article in Powerboat said 99 and earlier HP500 carb motors had the valve spring issue. In late 99, Mercury changed to a different spring which resolved the issue. Powerboat article last Summer said there was a technical bulletin on it, but my Mercury guy in Northern Va couldn't find it.

I could have sworn it was too strong valve springs causing the roller lifters to break that was the problem, not valve springs breaking. I thought Scott would have jumped in by now, he went through all that problem.

TARHEEL YOUR RIGHT ON ALL COUNTS ,,,USE 929 COMP SPRINGS
THATS WHAT WE'VE USED AND THEY STAY IN THERE !!

I think some of you are missing the real issue here.....

Both 500's run fairly high lift cams and the springs need to be replaced at 200 hours as preventative maintenance, not beause of warranty issues. If you call Mercury about recalls or service bulletins, they are going to tell you NO, there are none. If you ask them about specific recommendations on HP 500 valvetrains, you will get told to replace the springs at 200 hours. Those that choose to run them past those hours are on borrowed time and when one fails and you float a valve and pop the head off and now its costs 6-8k instead of $1,000.00, its not because Mercury put sh$t parts in, its because you didn't follow recommended preventative maintenance. Guys, do yourself a favor - Replace them.

Rod

From model year 2000 on, both the carb version and the efi version utilize the same spring. Its part # 24-845617A1, so yes it is the same spring.

The issue isn't because its a bad spring, the issue is cycle duty (distance compressed (% of free length) and pressure) load. Even if we built you an engine with the best springs we could find, I would tell you that at 200 hours they would need replaced. This really comes from the spring manufacturers themselves.

Typically the more HP you make, the more spring pressure it takes. Another part of the problem is that the install height needs to remain pretty much the same which means that the spring coils get bigger and will actually be able to compress less without increasing fatigue.

Hope this all helps.

Rod

The last four posts are correct answers to the question including the part number 929 COMP SPRINGS.

The confusion sets in from the springs they used to use prior to late 99 and 2000 on the carb 500's. The seat pressure was way to high causing premature valve trane component failures. When I say prematuer were talking around 140 hours or so seemed to be the majic number. If you ask Merc why they changed the part number they will tell you that they wanted to have one part number for all three motors (carb,efi +bulldog). I say they should of been held liable but never pushed it with them since my springs and lifters broke right out of warranty I had no case. Crane still offers a replacement spring but I found out from the head people that the pressures were still too high and I think Merc is also now changed over to the Comp Spring.
Just my opinion from my research that I was forced into!!!
BTW I 100% agree with the 200 hour replacement and all of the reasons why i'ts the logical thing to do they are way too cheap compared to pieces parts going through the motor and tearing everything up!! little needle bearings can cause a mess!!! I'm not guessing I know.

Thanks for the tip guys.....great information.

RPM is right on the money, That is the same story I got out of Mecury Racing. I just changed mine @ 234hrs, not a big deal. Look at the price tag of doing it the hard way. By the way Comp springs for $140 and took me start to finish 5hrs, 2000 500hp carb.

had to replace mine. Only 5 sets of springs were still in tact. Here's what I fished out of the oil pan. About 300 hours best I can figure.

FOR WHAT IT'S WORTH I RAN WILDTHING OVER 150 HOURS LAST YEAR ON NEW SPRINGS. 1 SPRING WAS BROKE IN ONE HEAD. MOST OF MY RUN TIME IS W.O.T. IN POKER RUNS.IT'S NOT WORTH THE RISK.REPLACE THEM THEIR CHEEP COMPAIRED TO A MOTOR.

Great thread, I am at 178hrs on 2001 efi. Guess I will start looking around to get them replaced?:rolleyes: So what is a fair price to have them replaced, $500-1000???

Will

My understanding of the problem was only inherent to the carb 500hp motors. The problem stems from a combination of the cam profile and the earlier Merc/Gil exhaust risers. First issue is that the cam ( I believe ) is ground on a 110 degree LSA. This is too tight of an angle for most marine applications with wet exhaust, they are more prone to reversion on the overlap cycle ( intake & exhaust valve open at the same time). Reversion only happens at Idle .Second issue is the design of the earlier Merc/Gil exhaust risers, they are fairly short. When combined together, at idle the engine would experience some reversion , pulling in a slight amount of water through the exhaust, just enough to create some moisture in the oil. This moisture would make it's way onto the valve springs and over time ( about 200hrs ) would rust them causing them to fatigue and fail. There was also a defect in Crane's factory springs. Once this problem was discovered, Merc has changed the riser design on later model 500hp's, making the pipes "swoop" up higher, this makes them slightly longer before water is introduced into the exhaust stream. They have also changed to the Comp Cams springs. The 500EFI motor has CMI exhaust, a different cam profile and the Comp. springs, so it's not an issue. It wasn't spring pressure that caused the failure, hydraulic rollers run very low spring pressure( about 135-145lbs. on the seat ) this is the same range of pressure that an average perf. hyd. flat tappet cam would run. Solid rollers run high spring pressures because they have much more aggressive profiles and are capable of higher RPM's. It was a combination of design flaws that caused the problem, But you can still change springs every 200hrs, ..... if you want. That's just my long winded .02 cents! Thanks guys!!

Mike, 1,000-1,100 rpms idle are too high, slamming your Bravo drive in gear at that rpm is hard on the cone clutch and gears. ( even XR's) If you keep your idle at around 800 you'll be fine with the newer style pipes. 500-600 too low . Frank.

Yes it was spring pressure!!! I measured mine at 180+lbs:eek:

No rust just broken parts:rolleyes:

This is fact from my own motors and also many others!!

One more thing I do have the new risers and had no signs of reversion. I now run a different cam and springs:rolleyes:

Back to the EFI motors, none of the above has anything to do with them other than the advise given to change them at 200 hours.

I give up.:confused:

Rod

Guys, I'll post spring info tomorrow.

Scott, sounds like an unnesessary amount of pressure for a hydraulic roller, but still not an excessive amount to break springs, unless mismatched pressure vs. coil diameter size. Most likely a defect in Crane's manufacturing process. These cams are not that big compared to what is available. What type of new cam did you install and what do the specs read on the card ? what kind of spring pressure is recomended ( on the seat)? Frank.

Here is a link to the HP500 carb cam spec.Cam Card

The OLD style springs had too much pressure per MERC + CRANE. This was harmful to the whole valve trane including but not always the springs. Crane made a announcement a couple of years back about there new anti Harmonic spring that they still suggest and use in the card above. Harmonics were tearing up the valve tranes and it didn't have to be at WOT it could be 3000rpm it just depended on the springs. Yes there could of been a inner coil VS outer mismatch or it could of been the two different metals (don't know don't care) all I know for sure was the Harmonics created by these springs do to there HIGH seat pressures and bad engineering made the recipe for a lot of broken valve tranes.

Merc no longer uses the new crane they have changed to Comp (I think) when I ordered the Crane replacement springs (number is on cam card) we tried them in my heads and still had pressures around 168 to 170 lbs sorry but TOO MUCH for my roller valve trane. Sent them back and used the Comp's.

Here is the Spec for my new cams. Notice the RPM range, the #5 module is set for around 5350rpm's so this makes a nice change without going to the 741 which in my opinion would not work well with this ignition setup and also the headwork I had done.
New cam card

Scott -

I've got a set of Crane 896 springs that I checked myself on the test stand. Measured +/- just a few from spec.

If your installed pressure is as high as you say, are you sure you have the height set correctly?

It is always better to use LONGER springs than SHORTER springs when you have a choice. Do you have a shim or can you use +.050 retainers to allow the 896s at a longet installed height?

The pressures on the 896 spring look good to me on paper.

In fact, in looking at the Comp chart, the 92 9spring appears to come out of the same batch, except that the CRANE goes tighter before coilbind...

mcollinstn,

I do not have a answer I saw the readings from the old springs and got a phone call from a trusted Head guy about the 896's.
Sorry but I was already ticked about the Crane spring issues so I changed over to the Comps that were running a lot closer to the specs on the cam card. BTW I purchased these from another source. Not the head builder so there was no financial gain involved. I will only state what my experience has been I am far from an expert but had a lot of hours tied up in trying to get the facts straight.

If you can't get the correct seat pressure at the specified installed hight then you have to either cut the spring pockets a little deeper or go to a longer valve stem , like+.100 longer, or a combo of both. Frank.

So what your saying is that I have to modify the product that the manufacture says will work without modification. We are talking about a proven set up that should not require any changes or machining other than shims. I am talking about one specific motor setup and that’s the 500 carb. With that I am done with this I have no desire to debate my findings or talk about rust breaking a spring:rolleyes: What about all the other components that should break from rusting out or are they immune to the rust! I am talking from logical research and first hand experience not from wives tales.

Sorry I just stopped smoking today and my sarcasm is showing:rolleyes:

I think we can all agree from this thread that it would be wise for all of us to keep a eye on our springs and valve trains and consider a spring change on our setups at the prescribed intervals.

One quick note I have talked to Merc, Crane + HPproffesionals about this numerous times (too many) and Harmonics is always the common answer. Including many articles by Teague and other respected names. With that I throw in the towel. Time to go buy some more Patches:eek: :eek: :D

Not to beat a dead horse, but what did your installed height measure?

And - the agitation and fits are STILL better than continuing to smoke aren't they? I'm not and never been a smoker so I can only offer to be a cheerleader for you. Rah Rah ree - throw em in the trash!

OK......OK.....I think I've got it now......I need to replace my valve springs when I get close to 200 hours on my 500 HP EFI's.......right.....someone tell me is this right:crazy: :confused:

I can do the work myself but am not interested in taking a motor apart that does not need to be.

It is a little unsettling that Merc. would actually recommend valve spring changes at 200 hours on a motor that only produces 1 hp per cubic inch. I built a 289 the produces 310 hp at the flywheel and it has 400 + hours on it (actually more but 24,000 miles at 60 mph is 400 hours). I have had the car for almost 25 years....man am I getting old.

I wonder what GM is saying about their new motor (HP3) with respect to replacing valve springs:eek: :rolleyes:

It's not a matter of HP per cubic inch. It's a matter of HP.

You got 60% more horsepower. You got valves that are 50% heavier and have 25% more lift. You gotta have springs strong enough to control the valve, but it's gotta move 25% further with each lift event.

You also got a marine motor where 200 hours will be comprised of 10 hours idling, 100 hours at 3000rpm, 70 hours at 4,200 rpm, and 20 hours at 5,000 rpm. This is far different than a street car application, even one that sees weekend grudge match duty.

A marine engine at 500 hours equates to a street car at 100,000 miles (I can't remember where I read this - and feel free to quote a better comparison). This means (assuming the above comparison is valid) that a 200 hour performance marine cycle is equivalent to a 40,000 mile auto cycle.

Granted, 40,000 miles is not a severe lifespan for a car valvespring (On the flipside, I went thru several GM 2.8 V-6 motors in less than 30,000 miles each: #1@22k, #2@38k, #3@65k, then I sold it).

I, too, am VERY interested in the HP3 valvespring lifespan.

mcollinstn,

Thanks for the support.:) I am in a seminar this week in Philadelphia I had to give a presentation yesterday and I'm not even sure what I said (hard to stay focused):crazy:
As much as I want to answer your question I can't but can assume they were set at specified heights. The original springs that were way out of whack (no longer offered) were set up by Merc , GM or who ever it was that year! Merc says they build them but I have to wonder just how much they do or if they are built to spec by someone else.
I had decided to have my heads cleaned up and had some exhaust relief done on them so I did not install the new springs. The head guy that I used seems to have a great reputation and I had to put some trust into his work. I would hope they are at spec. I will be checking them this spring and if I find anything strange I'll post it.

With all of the spring talk, are you able to replace the springs with the heads still on the motor. or do the heads need to come off for spring pockets to be machined etc when changing to the new springs? ive changed broken springs on cars many times without pulling heads but always installed factory replacement , just filled the cylinders with air and switched the springs, what about retainers? or you swapping retainers also?
later

Later,

Yeah, unless you got head or valve issues, just air em up and drop new ones on. Can't cut pockets on the motor, since the pocket cutter has a pilot that goes in the valve guide.

I called Merc last fall and asked about when to do springs and the idiot said to run it until it broke, the worst that would happen is I'd break a cam. Not very impressed with their techs.

Shawn

ok so am i getting this correct the comp cam spring is the way to go, correct? is the part number 929 or is there more, two the number, and will my present retainers work i have 98 carb motors.
thanks
Later

P/N: 929-16

Later,

From what I have been told the retainers need to be changed also. They were part of the problem. Have heard Merc. used a GM retainer with the Crane 99895 spring which over stressed the inner spring.

The correct path for the fix is, as stated in other posts, the Comp Cams 929-16 spring @ 1.88" installed hgt. and the Crane 99955 retainer. Valve locks are the same. You could also use the new Crane 99896 spring @ 1.906" installed hgt. however it seems people are prefering the Comp spring.

Mark

HEY JEFF THEN CHANGE YOUR SPRINGS THIS YEAR !!! LEAK DOWN WILL NOT TELL YOU ANYTHING EXCEPT THEIR WORKING NOW WELL ENOUGH TO HOLD THE VALVE CLOSED ,IT CAN'T TELL YOU'VE RUN THE CHIT OUT OF IT AND ITS BEEN CYCLED TO DEATH
MARK THE 929 COMP IS TOUGH AND A VERY GOOD SPRING I'VE USED FOR YEARS ,IF THEY OFFER A COATED VERSION USE IT IT WILL PAY FOR ITSELF ,

AND ALWAYS USE NEW LOCKS AND RETAINERS IF YOU DON'T IT IS LIKE CHANGING OIL AND NOT THE FILTER ,,,CHEAP ,AND JUST PLAIN WRONG

SCOTT YOUR RIGHT ON TARGET :D :D :D

JEFF NOT YELLING ,BUD ITS THE WAY I TYPE ,,,, JUST TRYING TO HELP YOU ! ITS CYCLES NOT JUST HRS. ,,YOU SAID YOU RAN ALONG WAY WOT THAT BUILDS HEAT AND KILLS TENISON OF SPRINGS ,
CHECK SPRINGS WITH SPRING TESTER ,,EVEN A MOROSO HAND HELD ONE ,,,WITH THAT ONE JUST CHECK THE DIFFERENCE FROM SPRING TO SPRING TO SPRING IF THERES ALOT CHANGE THEM -----929SPRINGS ,RET.,LOCK, LESS THAN 150..00 NEW MOTOR ??OH MAN !
BUT ITS YOUR MOTOR ENJOY:D :D