500hp Valve Springs ????
 

Have 96, 35' Fountain with 500 hp's. 200 hours. Was told I should immediately replace valve springs and exhaust valves. Anyone have info on what I should put in for springs, valves, retainers..etc. Thanks in advance!

You definately should put Inconel valves in the exhaust side. I believe Manley is the brand most commonly used. I'm not sure what springs are correct for your application, but they are due for replacing @ 200 hours. I have two sets of new Comp 929 springs if they will work for you. I'm sure someone here will know exactly what you need.

I would not worry about replacing the exhaust valves until after a leak down test. It is the springs that the problems around 200hrs.

I beleive Isky makes a nice set that are actually coated,and the valves just need to be checked,pretty hard to screw up an Inconel valve unless theres water intrusion or valve guide scoring!

I thought Merc used inconel exhaust valves as part of the stock HP500.

Thanks guys for your help! I appreciate the input. I think I'll do a leak down test and go from there.

I would change the spring regardless of what the leak-down test shows. The Comp springs mentioned above are a great choice over the Crane springs. Isky has a line of springs (a lot more money) that are supposedly one of the best available.

The Merc HP500 uses Inconel exhaust valves and has had some reversion issues (risers) from that era.

With that said we have a friend in the area that had the springs changed and ran the engines with well over 500+ run hard trouble free hours:cool:

The springs are a "maintenance item" as far as I'm concerned! You will probably see a slight increase in performance as well.
As far as going any further, I would do the leak & a compression check and if all looks good, run it!!
I have had very good success with Comp valve train parts, best performance for the $$.

P.S. Chuck is that you??

RedDog382:

I'm at the 200 hour mark on my HP500 as well. Might be interested in your springs if I can confirm those are the right springs and the price is right. Drop me a note as to what you want for a set. Also, just curious, how did you come to have two new sets of springs?

Mike
[email protected]

Boatnick,

I just did mine with Comp 929 springs. My lesson learned was because its a double spring, you have to use the lever-type spring compressor. I originally bought the spring compressor which has jaws that engage the spring and screw clamp to compress it. The jaws weren'y deep enough to grab and compress the inner spring.

Don't forget, you need the spark plug adapter to hook up to an air hose...so you can keep the valve shut while you're changing the spring.

I put new new Crane valve locks and retainers in as well. You need 3/8" valve locks for the 500. Got everything from Summit.

Pulling the exhaust was the worst part of the job. I don't think you can get the valve covers off without doing so.

Bill

Tarheel,
Have you ever heard of the method of inserting small rope inside spark plug hole and turning motor over (by hand of course) therefore keeping valve in place while removing springs?

Sound like madness or genius???

Thanks,
Boatnick

Yes TomR its me....
know any knowledgable, enthusiastic volunteers that I can assist with my "maintenance items"?

Is this "spring maintenance" at 200 hours still necessary on the newer 2002 - HP 500 EFI's??

Splash,

I asked this question to the factory reps (2) at this years Lauderdale show. The reply was a confident 400-500 hours, with "normal" but well maintained usage. My dealer says the same. However, if you search this forum (of which I have quickly learned to respect) there is a general consensus that with the stress the high performance springs are under, both at rest and during usage, change them out. I would be interested in feedback from the forum, of those that have NOT had problems approaching 500 hours.

That's a GREAT question! How many out there have had NO problems and are well above the 200 hour mark??

A good question indeed, BUT the only problem is when you do have a problem you've likely already beat a lifter out of the motor, destroyed a cam, and not to mention all the "foreign material" thats floated throughout the motor and gone through the bearings.

An even better question might be, what year did Merc change over the valve springs, what "exact" spring did they change too, and why?

My 2000 500efi's w 155 hrs are getting changed out regardless this winter, and while I'm at it I plan to put on a set of Cometic head gaskets. Merc uses OE junk, and I personally know people who have had problems with them.

I would be glad to help you!:)

Actually, Thats sounds like a great idea! That way you eliminate the chance the motor will spin over from the air pressure if not exactly on TDC.

Valve spring life has so many variables it’s difficult to put a cycle value on them. Because they are affected by heat, RPM (even one “zing” can remove a substantial portion out of spring life), and profile, the degradation curve is not linear and varies greatly from application to application. I would suggest that you remove your springs (all or a good sampling), have them checked

http://www.precisionmeasure.com/valve6.htm

for current values at seat pressure and open pressure, compare that to new spec and see if you are within tolerance. Even if you do replace all your springs, these figures will give you baseline references for future fatigue evaluation and alert you to other potential valve train problems. Check springs for discoloration and/or cracks regularly.
Bob

RM Builder,

WOW, nothings easy huh! All the stories about the stock 496's and 502 mags, with 1000 hours, go to the "blue" motors, and buy problems. All for 3-4 m.p.h.

Biggest problem is finding competent shops to do the work. (Maryland/Del area)

I used the rope in the cylinder method to do my small block chevy. It takes about 8-10 feet of the 5/16" clothes line to fill up the cylinder if you happen to start at the bottom and then I rocked the car make sure it was filled.

It worked perfectly BUT I am definitely going to use the air method on the '02 500 EFI next spring. I have 275 hours on them and they haven't broke yet. My buddy messed up both his carb HP500's with only 100 hours on them.

Good luck!

The rope method works great, and you can do it with considerably less rope if you feed the rope into the cylinder with the piston approaching TDC and then continue gently turning over the motor (by hand) until it won't turn.
The piston and rope are now holding the valves closed! ;)

Cigarette 30
Not easy, but worth it. Valve springs are a “read” component, similar to a spark plug, in that they contain a great deal of information relating to the operating condition of your engine. Not only are they responsible for returning the valves to their seats, they need to keep them there; a difficult task compounded by aggressive ramping and (in some cases) forced induction. In the process they are required to dampen and stabilize the harmonics created by the valve train and dissipate the resulting thermal buildup. Many engine failures have been blamed on soft cam cores or defective rollers, when the problem has been valve train instability due to improper spring rates. Monitoring your springs for degradation is cheap insurance against “the big one”.
Bob

Once you've made the changeout on springs do you have to do this every 200 hours or do the aftermarket spring hold up better for more hours??

RM Builder,

Could you recommend a shop (in the Maryland area)that would be half as knowledgeable as you appear. (no I am not being sarcastic) I currently have 160 hours, do it now or at 200? I would be happy to pay travel expenses to have the work done here, and the perk of an extra couple of days for relaxation. Also, hate to be greedy, could you please check the current tread regarding the vapor lock kit with any recommendations.

Thanks

JDNCA1, what are Cometic head gaskets, never heard of them.

Ron,
Cometic gaskets were recommended by Dean Nickerson and several other knowledgeable builders in this area,
http://www.spottsperformance.com/com...head%20gaskets

see www.cometic.com

Only way to go on a blower motor or if you want extra assurance.

When we have to change valve springs while the heads are still on the motor, either in a car or boat. We made a fitting with spark plug thread and a air hose fitting, Thread it in then plug your air hose in it, for us that puts 200+ psi into the cylinder, the psi holds the valve up for you, then you can change the springs and whatever else you need done :)

Traviss, US 1 Fountain,

You can get the fitting at any auto parts place that sells special automotive tools. The same company that made the spring compressor also makes the spark plug air fitting. I was using around around 125# pressure, and it would hold the valve shut regardless of where the piston was. Since you have to set the lash after you change springs anyway, I wasn't too concerned about being exactly at TDC...just wanted both valves shut.

Cig 30,

I met with the Mercury Rep when he was at my local Mercury parts shop. He said if I had been airing the boat out while wide open, then I should change them out at 200 Hrs. Since I pretty well baby mine, I changed them at the end of the season at 270 hrs. No springs were broken, showed signs of corrosion or other wise. Rather than test the old springs, I opted to change them out and replace the locks. That should cover the springs until the engines need to be overhauled.

Bill

Any opinions on doing the lifters as well while doing the springs? Have heard it is a must and also that just springs is more than adequate? not trying to start a debate just needing info since I need to do this in the spring.

If you keep up with the springs then the lifters should not become a problem. I don't plan on changing mine. If you find broken springs then the lifters need to be changed out in my opinion.

??

Cig30,

there are a lot of knowledgable performance minds in your area...

to get a good lead on the best.. try giving Ray Barton Racing Engines a call in Reading, PA... they build some of the best engines running in NHRA Stock and Superstock... Hemi's are their forte' (they assemble the mopar available hemi's also) but they also do a mighty fine job with BBC and SBC's. They can probably either do it or surely point you in the correct direction.

Then there is the BBC guru pat musi and numerous others right there under your nose...

Btw, we set the NHRA Superstock SS/IA class record last month in alabama with a new Barton SBC @ 9.79 - 133 mph... We were a ligitimate 70 lbs heavy and gave up almost a tenth in the 60 on that run and it went lean on the top end... she'll be a 9.50's car when the suspension gets sorted out a bit more... :)

Merry Christmas

Jamie

Jamie,
Congratulations. National records, especially in SS, are very hard to come by!
Happy Holidays,
Bob

For a data point, I have 1998 500HP's in a 32' AT. I changed springs at 380 hours, two inner springs were broken. I went back with Crane springs and now have 500 hours with no spring or lifter problems. The springs I got from Crane were not the same springs as were installed. Something about a harmonic that broke the springs at hard running at ~4000 rpm. I had a valve job done at the time and replaced the head gaskets. The newer 500EFI's were said to not have this problem due to the different springs. Call Crane or Comp Cams for more info.

Tom Gurley
Thunderstruck

???

400-500hrs. I'd still check them for sag @200 hrs then every 100hrs after.

You might try Bay Performance on the Northeast River in Md. I have talked to Norm there several times and he seems quite knowledgable. He is also mercuiser certified and specializes in perf boats.

Dave

Blue Thunder,

Thanks for the lead. I would think that as much as everyone references the spring replacement as "good maintenance", more dealers/shops could step up with recommendations and even a standard quote, detailing the different options (ie: quality of replacement parts).

A dream world I guess, but it would be so much easier if this subject could be answered as such;

1) In the owners manual along with the other dealer recommended service @ 100-200-300 hours etc.

1a) Funny how Merc. doesn't mention it.

2) 10 hours x 90.00 per hours + parts @ 900.00 (example) total $1,800 - better springs + $1,000 more.

3) Bring your boat in Thursday morning, pick it up Friday night.

And if there was a Santa, a good mechanic to go TO the boat, perform the service, and send a bill for his/services, and go boating!

Glenns,
A lifter check is advisable while you are changing out your springs. Visually check the roller wheel for burnishing or abnormalities. Then take each roller and run it across the surface of polished granite (or a similar hard, dense, smooth surface). The action of the wheel must be perfectly smooth. If not discard and replace the lifter.
Cigarette 30,
I did not see your engine package in previous posts. Let me know Ill get you some information.
Bob