Go Back  Offshoreonly.com > Technical > General Q & A
low compression 548 dyno testing has begun!! >

low compression 548 dyno testing has begun!!

Notices

low compression 548 dyno testing has begun!!

Old 03-28-2017 | 06:51 AM
  #231  
articfriends's Avatar
Thread Starter
Platinum Member
20 Year Member
Platinum Member
 
Joined: Jun 2004
Posts: 7,317
Likes: 1,037
From: frankenmuth michigan
Default

Originally Posted by ezstriper
thats sounds about right, we tried one of those big ones accel was selling and could not get the boat to idle, same one gimme fuel has I'm pretty sure, talked to accel and they had issues and discontinued them. PS Smitty, know you are busy...but damn how long before you call me back ??????????
Ill give you a call later, totally forgot
articfriends is offline  
Reply
Old 03-28-2017 | 06:55 AM
  #232  
Registered
 
Joined: Oct 2010
Posts: 922
Likes: 128
From: Hemlock, MI
Default

Originally Posted by ezstriper
thats sounds about right, we tried one of those big ones accel was selling and could not get the boat to idle, same one gimme fuel has I'm pretty sure, talked to accel and they had issues and discontinued them. PS Smitty, know you are busy...but damn how long before you call me back ??????????
I do have one but it had IAC on it. I was able to get it to idle. did need some fine tuning (more than my skills allow) but would still fire right up and idle at 900 rpm. Was controlled with Holley HP ECU that had a bunch of idle stabilization controls however.
Gimme Fuel is offline  
Reply
Old 03-28-2017 | 08:29 AM
  #233  
Registered
20 Year Member
 
Joined: Jan 2006
Posts: 3,599
Likes: 1,168
From: taxachusetts
Default

Originally Posted by articfriends
Funny thing is found the 69.9 in several tines i had, frank found same number and a michigan guy found same number, the return number was like 65c, some stock tunes its turned off, some tunes its set at 98/99 c, now most boat stats are actually at 140 degrees? Not sure if thats true as ive never looked hard but strange there are 3 tunes in 3 different areas with THAT number!
means all the base tunes came from the same spot.had you gotten a base tune from me,,you'd never would have had that problem,,I turn most of the safeties off.
you'd have loved the 1 problem I used to have.run fine,run fast,jump a wave and come off plane,,motor would die,,no spark,,change module out,,fire back up.took alot of modules and looking at the tune to find it..seems some one gave me a base tune that came from TC w/ the dwell tables cranked up.more than double.changed the table to something more normal and never a problem again.
nothing better than laying on the engines in an already azz heavy boat playing w/ 5.5mm screws all the while the boat is rocking.got really efficient at changing them.
sutphen 30 is offline  
Reply
Old 03-28-2017 | 09:05 AM
  #234  
articfriends's Avatar
Thread Starter
Platinum Member
20 Year Member
Platinum Member
 
Joined: Jun 2004
Posts: 7,317
Likes: 1,037
From: frankenmuth michigan
Default

Originally Posted by sutphen 30
means all the base tunes came from the same spot.had you gotten a base tune from me,,you'd never would have had that problem,,I turn most of the safeties off.
you'd have loved the 1 problem I used to have.run fine,run fast,jump a wave and come off plane,,motor would die,,no spark,,change module out,,fire back up.took alot of modules and looking at the tune to find it..seems some one gave me a base tune that came from TC w/ the dwell tables cranked up.more than double.changed the table to something more normal and never a problem again.
nothing better than laying on the engines in an already azz heavy boat playing w/ 5.5mm screws all the while the boat is rocking.got really efficient at changing them.
What do you set your dwell at, i found a few years ago when dynoing my pontiac w mefi 4 that motor would pull 5800 w stock module then break up, it would pull 6000 w dui module then break up, started lowering dwell to take load off module and it turned 7000 rpms no problem. Mefi4 has a better dwell table if i remember right too. I turn all safetys off most time too, i just missed the high ect causes rpm reduction, thanks, Smitty
articfriends is offline  
Reply
Old 03-28-2017 | 09:17 AM
  #235  
Registered
20 Year Member
 
Joined: Jan 2006
Posts: 3,599
Likes: 1,168
From: taxachusetts
Default

Originally Posted by articfriends
What do you set your dwell at, i found a few years ago when dynoing my pontiac w mefi 4 that motor would pull 5800 w stock module then break up, it would pull 6000 w dui module then break up, started lowering dwell to take load off module and it turned 7000 rpms no problem. Mefi4 has a better dwell table if i remember right too. I turn all safetys off most time too, i just missed the high ect causes rpm reduction, thanks, Smitty
I'd have to look but its down around stockish levels now,I also have a rotor that has fan blades on the bottom,,guess merc knew that had heating issues w/ the module at sustained rpm.
sutphen 30 is offline  
Reply
Old 03-28-2017 | 10:27 AM
  #236  
articfriends's Avatar
Thread Starter
Platinum Member
20 Year Member
Platinum Member
 
Joined: Jun 2004
Posts: 7,317
Likes: 1,037
From: frankenmuth michigan
Default

I dont have it in front of me but it seems like a mefi3 from stock tune has 10.5 in each dwell box top to bottom, a 502rj tune goes from 12 at idle to like 3.8 but table is set up a little different too, i took that down to 1.8 or 2.2 to get it to rev 7000 and not over heat module if i remember right
articfriends is offline  
Reply
Old 03-30-2017 | 12:12 AM
  #237  
articfriends's Avatar
Thread Starter
Platinum Member
20 Year Member
Platinum Member
 
Joined: Jun 2004
Posts: 7,317
Likes: 1,037
From: frankenmuth michigan
Default

More info, back to POS Canton oil pan, hate it, pos junk. I mentioned previously it was real touchy, canton 10 qt 364 power pan. First got motor running with it a month or two ago, oil press twitched from 80 down to between 35 to 50 and back above 6000 to 6600, that put a little metal in filter from scuffing the bearings slightly. Pulled AFR heads off at that point, opened up drain back holes, was better but still twitched down around 60 to 70 and back. When had intake off swapping it carefully punched holes in valley screens, yes, i have ran them in many engines and never caused a problem. After that oil pressure twitched to 72- 75 from 80 above 6200. Canton told me on phone pan uses 9 qts of oil plus filter, running 2 qt filter. Added a extra quart and a half, oil pressure pretty steady at wot, when your running a 10 quart pan it shouldn't be sucking air the minute its a 1/2 a quart low or not exactly full. Fast forward, changed oil the other day on dyno, put 2 quarts in for filter, 9 in pan just to see if it was my imagination, first pull problem was back added 1 more quart of oil, goes away, sure, it should be full but again, when you have a large pan you should have a little safety cushion from extra capacity. I ran a hardin 14 qt on this before with 12 quarts in pan, never did anything funny, i think trap doors and pouches are keeping oil away from pickup, its NOT going in my boat THIS way, maybe gut them out and just add dismond lovered windage trays, ive yet to find someone running these.

Last edited by articfriends; 03-30-2017 at 12:15 AM.
articfriends is offline  
Reply
Old 03-30-2017 | 05:58 AM
  #238  
Registered
20 Year Member
 
Joined: Jan 2006
Posts: 3,599
Likes: 1,168
From: taxachusetts
Default

I had good luck w/ the milodon windage tray.screen version.
sutphen 30 is offline  
Reply
Old 03-30-2017 | 07:15 AM
  #239  
SB
Registered
20 Year Member
 
Joined: Nov 2004
Posts: 14,104
Likes: 3,692
From: On A Dirt Floor
Default

Sounds like a trap door issue. Trap doors essentially make two or more (depending on # of doors) sumps when closed and if they come close to almost sealing. I wonder if the engine being stationary and relatively level (as being on dyno) is keeping doors from opening, and thus the sump the oil pump see's is a whole lot smaller than it would see without the doors or different designed doors.

You having to add that much oil makes me wonder about this.

Interesting.
SB is offline  
Reply
Old 03-30-2017 | 07:26 AM
  #240  
SB
Registered
20 Year Member
 
Joined: Nov 2004
Posts: 14,104
Likes: 3,692
From: On A Dirt Floor
Default

Originally Posted by articfriends
More info, back to POS Canton oil pan, hate it, pos junk. I mentioned previously it was real touchy, canton 10 qt 364 power pan. was back added 1 more quart of oil, goes away, sure, it should be full but again, when you have a large pan you should have a little safety cushion from extra capacity. I ran a hardin 14 qt on this before with 12 quarts in pan, never did anything funny, i think trap doors and pouches are keeping oil away from pickup, its NOT going in my boat THIS way, maybe gut them out and just add dismond lovered windage trays, ive yet to find someone running these.
18-364 - BBC REAR SUMP MARINE POWER PAN (18-364)
Construction
* Six Trap Door Baffles
* Oil Recovery Pouch
* Crank Scraper
* Bolt In Slosh Baffle
* Built In Louvered Windage Tray
* Three 1/2" NPT Bungs
* Provision For our Pan Mounted Dipstick
* Powder Coating & Brass Plugs For Corrosion
Protection
This pan requires our 18-365 pickup.
SB is offline  
Reply

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.