How to Idle Down a Blown 454 To limit Outdrive Gear Stress and Turn Large Prop
10-13-2003, 03:11 PM
#11
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Charter Member
Weiand makes the 177 "blower" which is now produced by Holley who also took over B&M.
I am just throwing out a possibility here but, maybe there is no module because your timing is "locked" (no advance).
I run my timing "locked" at 29 degrees.
29 at idle and 29 at full throttle.
I am just throwing out a possibility here but, maybe there is no module because your timing is "locked" (no advance).
I run my timing "locked" at 29 degrees.
29 at idle and 29 at full throttle.
10-13-2003, 03:24 PM
#12
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Charter Member
When used on a V8 engine, the V6 module will give you between 6 and 10 degrees advance.
That information is on page 187 of Dennis Moore's Big Block Chevy Marine Performance book.
That information is on page 187 of Dennis Moore's Big Block Chevy Marine Performance book.
10-13-2003, 03:50 PM
#13
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My 468" has a 250 from the TBS, and a 1095 King Demon on it. Idles at 750 out of gear, 625 out of gear. 30 degrees of timing locked in all the time. Just a matter of tuning the carburetor transfer slots, idle circuitry, and engine timing.
10-13-2003, 06:38 PM
#15
There's some info on this thread:
http://www.offshoreonly.com/forums/s...t=525sc+timing
http://www.offshoreonly.com/forums/s...t=525sc+timing
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10-13-2003, 10:24 PM
#16
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The blower says B&M so It must be the 174 not 177. I added a photo prior to the new carb so maybe some one will recognize the blower model.
Spent some more time digging through the receipts I received from the brokerage service. The camshaft is the Crane 134241 CH-286-2, Engine Builder added a timing offset Bushing kit 10119911, Rotor is #5513524A5. Cap is 55805759A2. If anyone has clues to what the offset bushing kit does or experience with it I am all ears. I probably won't get to hunt for the ignition module until this week end. But I do not recall any wires going into the distrbutor besides coil and spark plug leads.
With the HP500 carb I am not getting any soot and excellent fuel milage compared to the Holley 850 I removed. If I can get the idle worked out suitable I'll be extemely happy with the set up.
The part number for the gasket on the exhaust heads was 084113014116. Anyone know what head this correlates to? Currently I have no real clue at what the ngine compression is. I run 93 octane so if the timing is fixed what is best 28 or 30 degrees?
Spent some more time digging through the receipts I received from the brokerage service. The camshaft is the Crane 134241 CH-286-2, Engine Builder added a timing offset Bushing kit 10119911, Rotor is #5513524A5. Cap is 55805759A2. If anyone has clues to what the offset bushing kit does or experience with it I am all ears. I probably won't get to hunt for the ignition module until this week end. But I do not recall any wires going into the distrbutor besides coil and spark plug leads.
With the HP500 carb I am not getting any soot and excellent fuel milage compared to the Holley 850 I removed. If I can get the idle worked out suitable I'll be extemely happy with the set up.
The part number for the gasket on the exhaust heads was 084113014116. Anyone know what head this correlates to? Currently I have no real clue at what the ngine compression is. I run 93 octane so if the timing is fixed what is best 28 or 30 degrees?
10-13-2003, 10:48 PM
#17
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The ONLY way you can run a distributor with NO WIRES going into it except for the ones on the cap is if the motor has a crank trigger setup. Follow the wires that go to the coil and find what is triggering it.
For weird idling problems, start with the easy stuff. Check your fuel pressure at idle. Should be 5 to 7 pounds. Then with the fuel pump running (if it is mechanical then that means that the motor has to be running) set your float levels both front and back with the screw plugs out of the sides of the bowls.
Then check to see if your motor idles with the throttle plates almost all the way closed OR if they are open more than you'd have expected. If the latter is true, open up the little bypass holes one size in the throttle plates and adjust the butterflys closed more. (now is also a good time to loosen the butterflys front and back with the idle stop all the way out and center the plates on the shaft before retightening.
Then adjust your 4 corner idle screws the same number of turns out until you like the idle...
Let us know how this affects anything.
For weird idling problems, start with the easy stuff. Check your fuel pressure at idle. Should be 5 to 7 pounds. Then with the fuel pump running (if it is mechanical then that means that the motor has to be running) set your float levels both front and back with the screw plugs out of the sides of the bowls.
Then check to see if your motor idles with the throttle plates almost all the way closed OR if they are open more than you'd have expected. If the latter is true, open up the little bypass holes one size in the throttle plates and adjust the butterflys closed more. (now is also a good time to loosen the butterflys front and back with the idle stop all the way out and center the plates on the shaft before retightening.
Then adjust your 4 corner idle screws the same number of turns out until you like the idle...
Let us know how this affects anything.
10-14-2003, 07:44 AM
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I believe the idle slots should be just barely exposed. If more than that is exposed, then you could try drilling a 1/16" hole in the throttle blades. This will help get a little more air into the engine so you can get back into the idle circuit.
The bushing kit is used to degree the cam. They drill the cam sprocket pin hole oversize and put a ecentric bushing in. By turning the bushing they can adjust the cam advance.
The bushing kit is used to degree the cam. They drill the cam sprocket pin hole oversize and put a ecentric bushing in. By turning the bushing they can adjust the cam advance.
10-14-2003, 11:18 AM
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My fuel pump is mechanical. It is only running 3.5 psi fuel pressure at idle 5 at WOT. Have not replaced the fuel water separating filter since buying the boat end of July. The bought went unsued around four years could be junked up now. Did not pay close attention to fuel pressure gage. Brokerage was running boat on fumes so I probably have 14 years of crud in the filter. Will a partially clogged filter cause fuel pressure to lower. I thought it would be other way around obstruction causing increse pressure. But since it is upstream of the ump might not be drawing fuel fast enough. I thought if the bowls have gas idle circuitry should work fine. Or is this not the case. Regardless I'll change the filter to address easiest things first.
