Go Back  Offshoreonly.com > Technical > General Q & A
Another dyno session, 454 w bm 420 megablower >

Another dyno session, 454 w bm 420 megablower

Like Tree24Likes

Another dyno session, 454 w bm 420 megablower

Reply

Old 08-09-2018, 06:34 AM
  #11
Registered
Thread Starter
iTrader: (1)
 
articfriends's Avatar
 
Join Date: Jun 2004
Location: Frankenmuth
My Boat: EX 99 MPH 272 Baja owner, 1999 Scarab 33 AVS NOW
Posts: 6,330
Default

Originally Posted by endeavour32 View Post
I was hoping that my estimate on power for these motors was close, looks like it was. Glad this is going to work out well for the buyer, and thanks for posting the dyno results!
I'm glad to see it too, put a new starter ring gear on block side of flywheel, got him a hp Iong snout coupling, swapped pulleys and brackets around until he had power steering.
Im surprised that it kept pulling so high w stock 525sc cam, talking to eddie young he was too. Mike do you think its possible all 3 motors had bigger cams put in at one point? It wasnt neccesarily done climbing at 5900, i just didnt want to see how high it would rev before something bad happened!
articfriends is offline  
Reply With Quote
Old 08-11-2018, 09:50 AM
  #12
Registered
iTrader: (3)
 
Join Date: Jul 2004
Location: chicago
My Boat: 38 Fountain
Posts: 11,288
Default

Good stuff! Love seeing the 454's make some power.

its possible the engine pulled higher because of the larger blower. The 177's start giving up in the upper rpm. Most dyno pulls with them show the boost starting to drop off at higher rpm.

stock flat tappet cam is a 228/236 114lsa .530/.551. Timing event wise, IO=5 IC=43
EO=57 EC=-1

in comparison, a 500efi cam is
230/236 114lsa .598/.610
IO=6 IC=44
EC=57 EC=-1

valve timing at .050 is close.

seat durations differ a bunch though

Stock flat tappet 298/306
500 efi roller 292/298

advertises rpm range in cranes catalog

stock flat tappet 525sc cam 2800-6600rpm
500efi roller 2000-5800

roller setups are nice, but for what they cost , might make someone rethink the gains vs cost. Theres plenty of oils on the market with lots of zinc. Theres lifters with edm holes and or oiling grooves cut in the body to help prevent issues. Roller lifters these days arent without issue either.

A billet roller cam, some good lifters, beefy pushrods, easy to spend 1500 bucks or more. Where as a flat tappet can be in the 300 dollar range. Flat tappets also dont need big spring pressures to control that massive roller lifter from ski jumping over the nose . Just had this convo with a buddy who has a pair of stock 420's in his 30ft velocity Last weekend. Engines run great. Eventually he wants to refresh. Tight budget. Sounds like hes leaning towards sticking with flat tappet setups, a pair of eq or dart iron heads to replace the tired oe heads, and continuing to boat.
MILD THUNDER is offline  
Reply With Quote
Old 08-11-2018, 02:14 PM
  #13
Registered
Thread Starter
iTrader: (1)
 
articfriends's Avatar
 
Join Date: Jun 2004
Location: Frankenmuth
My Boat: EX 99 MPH 272 Baja owner, 1999 Scarab 33 AVS NOW
Posts: 6,330
Default

Originally Posted by MILD THUNDER View Post
Good stuff! Love seeing the 454's make some power.

its possible the engine pulled higher because of the larger blower. The 177's start giving up in the upper rpm. Most dyno pulls with them show the boost starting to drop off at higher rpm.

stock flat tappet cam is a 228/236 114lsa .530/.551. Timing event wise, IO=5 IC=43
EO=57 EC=-1

in comparison, a 500efi cam is
230/236 114lsa .598/.610
IO=6 IC=44
EC=57 EC=-1

valve timing at .050 is close.

seat durations differ a bunch though

Stock flat tappet 298/306
500 efi roller 292/298

advertises rpm range in cranes catalog

stock flat tappet 525sc cam 2800-6600rpm
500efi roller 2000-5800

roller setups are nice, but for what they cost , might make someone rethink the gains vs cost. Theres plenty of oils on the market with lots of zinc. Theres lifters with edm holes and or oiling grooves cut in the body to help prevent issues. Roller lifters these days arent without issue either.

A billet roller cam, some good lifters, beefy pushrods, easy to spend 1500 bucks or more. Where as a flat tappet can be in the 300 dollar range. Flat tappets also dont need big spring pressures to control that massive roller lifter from ski jumping over the nose . Just had this convo with a buddy who has a pair of stock 420's in his 30ft velocity Last weekend. Engines run great. Eventually he wants to refresh. Tight budget. Sounds like hes leaning towards sticking with flat tappet setups, a pair of eq or dart iron heads to replace the tired oe heads, and continuing to boat.
From his expereince Eddie young seemed to think maybe this motor had more cam in it than everyone thinks ,not from power it made but from rpms , history is kinda sketchy so not 100% cam WAS a 525 sc fwiw, Smitty
articfriends is offline  
Reply With Quote
Old 08-12-2018, 07:36 PM
  #14
Registered
iTrader: (4)
 
Rookie's Avatar
 
Join Date: Jan 2003
Location: Grand Rapids, MI
My Boat: 37 Active Thunder, 30 Scarab Panther, 34 Wellcraft Gran Sport
Posts: 4,313
Default

Crane calls usable range for that cam out to 5800 RPM's.

Glad you're having fun with the dyno.
articfriends likes this.
Rookie is offline  
Reply With Quote
Old 08-12-2018, 11:35 PM
  #15
Registered
iTrader: (3)
 
Join Date: Jul 2004
Location: chicago
My Boat: 38 Fountain
Posts: 11,288
Default

MILD THUNDER is offline  
Reply With Quote
Old 08-12-2018, 11:37 PM
  #16
Registered
iTrader: (3)
 
Join Date: Jul 2004
Location: chicago
My Boat: 38 Fountain
Posts: 11,288
Default

Im running a 236/245 114 LSA hyd roller, seat duration is slightly less than the stock 525sc flat tappet. Installed at 110icl, power was still climbing at 6200, but fizzling off. Next dyno session, installed on 114 icl, pulled to 6500rpm, never saw it nose over
articfriends, SB and Gimme Fuel like this.
MILD THUNDER is offline  
Reply With Quote

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


OSO Sponsor
OSO Advertiser
OSO Advertiser
OSO Advertiser