JaayTeee

not to keep "beating a dead horse"
yes i have experience the"pain and
suffering" of this problem, as well as
a broken lifter, luckily the warranty
"gods" were good to me,
i reallyhave to wonder if the risers are a
real big factor to this, mine wern't replaced!
merc discontinued p/n 818499a1,
was used on hp465 and 500 bulldog
packages, i don't have the cam spec's
pertaining to lobe centers and overlap,
but, just listening to the idle characteristics
of these two engines, i would expect these
to also have "reversion" issues, yes i know
these are flat tappet motors, and the
hp465 was never equipped with oil
cooler thermostats.
i have about 100 hrs. since this disaster
and had to remove a manifold to fix a oil
line leak, removed valve cover, did see
some condensation underneath valve cover
but no rust on springs, no broken inner
springs, this was after a month of no
useage, these things live around humidity
so i can see some condensation would be
normal.
engines were 98' vintage, a freinds 99'
did the same thing, a friends 96' with
300 plus hours still running, eyeballed
these springs, none appear broken as
did mine, enough about my problems,
here are the questions:
nobody is "complaining" about broken
valve springs on 465's and bulldogs with
these risers.
why are some of the "older" hp500s
not having this problem?
sound like to me, the valve springs,
not the risers are the real culprit.
just a something to think about..
j.t.


oh by the way, summit racing now
lists the crane retainers, p/n 99961-16
now, i believe for $ 65, they already list
the comp cams 929-16 springs,
i'm planning to do the above mentioned
96' soon, time can't be on it's side!

paradigm shift

My vote is on the springs. Why did they change the spring part # if there was no problem. That is just me. Springs and new retainers are pretty cheap insurance that is for sure. Couple $$$ vs couple $$$$ depending.

Raypanic

I was told by my engine builder that he is having the best luck with ISKY springs on the HP500 FYI

US1 Fountain

iTrader: (1)

I have the HP465. Never had a spring problem.
This is because it was a flat tappit cam, not a roller cam like the newer carbed HP500's which had this problem. These motors use different springs. Crane no longer makes the spring that was prone to breaking. Do a 'search' by Scott, on HP500 springs. He had the same issues.

I was also told by Fountain and Crane (supplier of the cam) that reversion was a problem with that cam, which is why my boat did not come with silent choice. The HP465 cam had 25* of overlap with 240/250 @ .050 duration. My motor still showed signs of reversion, even with the straight thru hull Merc/Gil exhaust. I changed over to a roller cam when I installed silent choice. No reversion at all now. I don't see how the risers would have anything to do with spring breakage. They can be prone to reversion if to short. Condensation is common when operated in colder water. Even if you run long enough to heat the oil up and boil out the water, once you idle long enough such as loading on trailer, the oil will cool down enough to form condensation. I added the oil t-stat unit that is on the HP500's last year for extra protection.

JaayTeee

i guess my point is, if there is reversion,
there is suppose to be " rust"
the rust on the springs are suppose to
part of the problem, on the flat tappet cams,
with less aggressive duty cycles, you
don't here about any spring breakage.
i know about the revised spring and retainer
setup for hp500, that sound like the REAL
answer.
if the springs are going to rust, there going to
rust, yes the valve springs are different
between flat and roller tappet engines,
but if the flat tappet cam equipped engines
spring are rusting, why aren't they breaking ?

Lee

iTrader: (4)

Replace them with Isky P#8005-SP

Scott

I don't think rust has a thing to do with the springs breaking. It seems as thought the seat pressures were way too high with the old springs and the new Crane replacement. Go with the Comp Cams or Isky springs and you will be fine!
BTW I had No rust in my motors when the springs and lifters failed just a lot of shredded metal!!!!!!

paradigm shift

BTW I had No rust in my motors when the springs and lifters failed just a lot of shredded metal!!!!!! [/B][/QUOTE]

Been there done that. Sounds you never forget!! Not with a 500hp though.

Mr Gadgets

Years ago, I had a 365 Magnum, so did my buddy. He propped his to run max 4900/5000. I propped mine to run 5200/5300.. end result was I broke valve springs he didnt. Merc told me not to run past the 5k mark on the tach. I figured 200 rpm wouldnt hurt anything.. WRONG>. The springs allowed the valve to bounce shut at the higher rpm.. causing the springs to break.. I upgraded to a better spring and life was good!! Just a thought.. from the past, not sure if it applys here..

Good luck..

Dick