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Discussion Starter #1 (Edited)
reman or-3421 - or-3423 ??? Difference in spray angle??
new ?? ??



reman or-3587 - or-3589 ??? Difference in spray angle??
new 7w-7041 - 7w7043 ???


Anybody ever matched a mechanical injector to an electronic injector piston bowl?

What would be better, a spray pattern that is to tight, or to wide? Would to tight be catastrophic to the piston crown as it would be spraying on the crown about halfway down the slope. Or would it be better to have a slightly wider spray and have to time the pump so the swirl is backward (starting at the outer edge and swirling toward the center of the crown).
 

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The other guy
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3,936 Posts
reman or-3421 - or-3423 ??? Difference in spray angle??
new ?? ??



reman or-3587 - or-3589 ??? Difference in spray angle??
new 7w-7041 - 7w7043 ???


Anybody ever matched a mechanical injector to an electronic injector piston bowl?

What would be better, a spray pattern that is to tight, or to wide? Would to tight be catastrophic to the piston crown as it would be spraying on the crown about halfway down the slope. Or would it be better to have a slightly wider spray and have to time the pump so the swirl is backward (starting at the outer edge and swirling toward the center of the crown).
3421's: more fuel tighter pattern for 14.5/1 pistons @ 24* timing.
3423's: less fuel wider pattern for 15.2/1 pistons @ 18* timing.
Yep used 3421's in electronic. Steel bowl and better crown fueling regardless of spray angle do to hi comp bowl swirl on steel pistons. Time to whatever "haney" says for your goals (or whomever)...
 

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The other guy
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Oh. Read the rest. ALWAYS spray down topside of tip AT 1/3 TO 1/2 DOWN. IT WILL NOT SWIRL BACKWARDS like a mini motor or stocker. Look at the spray trail on existing piston crowns.

EDIT: And use 3421's and not the new Stelite tips as you need to blow the tips out for fuel gain as you drive. Specially if you use a Sigma sted of Cat...
 

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Tony can correct me, but I believe that any piston that matches the 8785 nozzle is a direct match to a 3421. I came across a few when I was looking at 08 parts and saw a few that changed nozzles to match fuel system, but not pistons.
 

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The other guy
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Tony can correct me, but I believe that any piston that matches the 8785 nozzle is a direct match to a 3421. I came across a few when I was looking at 08 parts and saw a few that changed nozzles to match fuel system, but not pistons.
Yesser yesser, BUT, depends of course on advanced timing from original ECM load, hence ask what the current timing is, tho who cares cause ya know timing is bumped hence the "match to bowl". Sssooo, correct as always :clap
 

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Discussion Starter #6
3421's: more fuel tighter pattern for 14.5/1 pistons @ 24* timing.
3423's: less fuel wider pattern for 15.2/1 pistons @ 18* timing.
Yep used 3421's in electronic. Steel bowl and better crown fueling regardless of spray angle do to hi comp bowl swirl on steel pistons. Time to whatever "haney" says for your goals (or whomever)...
When the 3421's are driven by a 5888 ("c") pump, should the fuel be turned down a turn or so to compensate for the higher pop pressure? Or is it the injectors that determine the pop pressure?
 

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The other guy
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When the 3421's are driven by a 5888 ("c") pump, should the fuel be turned down a turn or so to compensate for the higher pop pressure? Or is it the injectors that determine the pop pressure?
Fuel to injectors (both) make pop pressure but final pressure on a pop nozzle is always the nozzle. The 5888 is a longer duration cam with less lift on a dual scroll plunger. Doesn't work well on a mechanical with B nozzles, but in your case, max it for fuel and get the added bennies of the longer duration stroke. It's a pump. It'll only give out what your foot gives it. Set low idle and drive it like ya stole it :happydance
 

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I have a 8PN with a 55698-005-396450 pump that 4 different shops have worked on. I'm sure it has the correct pistons but it has a head off of a 4MG. It came with OR-8290 nozzles but someone has put OR-3421 in it, will this work or do I need 8290's? I just bought it as is.
 
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