GM 262 4.3 V6 - Timing issues... maybe?
July 19th, 2021, 2:13 PM
#1
GM 262 4.3 V6 - Timing issues... maybe?
Hey guys,
So I'm a long time automotive mechanic, but my niche is European and Asian vehicles, and as ridiculous as it sounds for living in Texas, I've never built an American designed engine. The engine in my boat exploded, and needed a rebuild, so I took up the challenge.
The engine is rebuilt, installed and running, but I need some tuning help. So the boat is a 2009 Sea Ray 185 Sport, and came with a 2009 GM 4.3 V6. I couldn't find a block that matched casting numbers, but I did find a 2002 block in good shape, sent it to the machine shop and had it machined and rebuilt with new bearings, rings, etc etc. I purchased a brand new set of heads (not remanufactured, new production) and installed everything per the manual. I then purchased an Edelbrock Performer intake (for the Vortec heads so it matches) and topped it with an Edelbrock 1409 carburetor. Per Edelbrock, I Installed Edelbrock calibration kit #1485 (which came with new rods and springs) and fired it up.
Now, here comes my stupidity. I've literally never used a timing light before this build, so naturally I bumbled through it, didn't figure it out properly but assumed i'd accomplished what I meant to (because I have nothing if not lots of false bravado.) Come to find out my timing was way off, and apparently I'd used the wrong carb spacer as well. After figuring all this stuff out (and trying to diagnose low power situation) I swapped to the correct carb spacer with four small holes (the spacer is absolutely necessary for the boat - I have to fit a bunch of coolant lines and crap underneath the carb, and the factory carb has at least a 2in spacer built in to accomplish this.) but I still can't figure out a carb popping issue. It seems that when aggressively increasing throttle, it stumbles a bit on its face, pops a little through the carb then seems to pick up power and gets up on plane. The carb pops were enough to melt the air cleaner I had on it originally (although it turns out I was supposed to have a flame arrester, so I guess no big deal...) and have since gotten better, but it's still not gone.
Almost everyone I talk to tells me that carb popping is indicative of incorrect timing - apparently it's less likely to be an incorrectly adjusted carb. I know for 100% fact that the engine is now timed correctly at 10* BTDC (at least according to my harmonic balancer...) but here's the question - the newer block didn't fit the original metal timing cover that came off of the blown engine, so I had to purchase a new 2002 timing cover to fit the block. The harmonic balancer part # is identical between the '02 and the '09, so I find it hard to believe, but is there any way my old balancer/new timing cover don't match correctly, and is putting me out of time?
I've also repeatedly followed the "mean-best" idle speed adjustment instructions from Edelbrock, I've repeatedly adjusted timing to 10*, but the issue is still there.
I guess what I'm asking is, should I just advance the timing to where the engine runs correctly, and forget the timing light? People have said that timing needs will change based on what's bolted to the engine - is it possible that my combination of 2111 performer manifold, the 1409 carb and a 2" spacer requires different timing than the engine did standard? Should I try to resolve my obvious timing inconsistencies, or just adjust the dist. until the engine runs right and makes power and then just ignore whatever was originally the problem? I did put the wrong plugs in at first and have since swapped them to the correct copper plugs. My boat doesn't have any cats or anything to foul up so I guess the worst case scenario for a slightly rich condition would be killing plugs more often than usual which I'm not too worried about, but I've put so many hours into learning about these damn engines (on hard mode too, I have no family in this country and my wife's entire family collectively know less about carbs than I do.) I don't really know where to find a greybeard locally to school me on how the **** to work on carbs, so I guess for now I'm still bumbling through.
I've watched every video on how carbs work and etc etc I can find and I mean I have a basic understanding, but I just have absolutely no experience. Literally, the first time I ever touched a carb was when I bolted this one to my engine.
Looking forward to hearing your advice,
Jon
So I'm a long time automotive mechanic, but my niche is European and Asian vehicles, and as ridiculous as it sounds for living in Texas, I've never built an American designed engine. The engine in my boat exploded, and needed a rebuild, so I took up the challenge.
The engine is rebuilt, installed and running, but I need some tuning help. So the boat is a 2009 Sea Ray 185 Sport, and came with a 2009 GM 4.3 V6. I couldn't find a block that matched casting numbers, but I did find a 2002 block in good shape, sent it to the machine shop and had it machined and rebuilt with new bearings, rings, etc etc. I purchased a brand new set of heads (not remanufactured, new production) and installed everything per the manual. I then purchased an Edelbrock Performer intake (for the Vortec heads so it matches) and topped it with an Edelbrock 1409 carburetor. Per Edelbrock, I Installed Edelbrock calibration kit #1485 (which came with new rods and springs) and fired it up.
Now, here comes my stupidity. I've literally never used a timing light before this build, so naturally I bumbled through it, didn't figure it out properly but assumed i'd accomplished what I meant to (because I have nothing if not lots of false bravado.) Come to find out my timing was way off, and apparently I'd used the wrong carb spacer as well. After figuring all this stuff out (and trying to diagnose low power situation) I swapped to the correct carb spacer with four small holes (the spacer is absolutely necessary for the boat - I have to fit a bunch of coolant lines and crap underneath the carb, and the factory carb has at least a 2in spacer built in to accomplish this.) but I still can't figure out a carb popping issue. It seems that when aggressively increasing throttle, it stumbles a bit on its face, pops a little through the carb then seems to pick up power and gets up on plane. The carb pops were enough to melt the air cleaner I had on it originally (although it turns out I was supposed to have a flame arrester, so I guess no big deal...) and have since gotten better, but it's still not gone.
Almost everyone I talk to tells me that carb popping is indicative of incorrect timing - apparently it's less likely to be an incorrectly adjusted carb. I know for 100% fact that the engine is now timed correctly at 10* BTDC (at least according to my harmonic balancer...) but here's the question - the newer block didn't fit the original metal timing cover that came off of the blown engine, so I had to purchase a new 2002 timing cover to fit the block. The harmonic balancer part # is identical between the '02 and the '09, so I find it hard to believe, but is there any way my old balancer/new timing cover don't match correctly, and is putting me out of time?
I've also repeatedly followed the "mean-best" idle speed adjustment instructions from Edelbrock, I've repeatedly adjusted timing to 10*, but the issue is still there.
I guess what I'm asking is, should I just advance the timing to where the engine runs correctly, and forget the timing light? People have said that timing needs will change based on what's bolted to the engine - is it possible that my combination of 2111 performer manifold, the 1409 carb and a 2" spacer requires different timing than the engine did standard? Should I try to resolve my obvious timing inconsistencies, or just adjust the dist. until the engine runs right and makes power and then just ignore whatever was originally the problem? I did put the wrong plugs in at first and have since swapped them to the correct copper plugs. My boat doesn't have any cats or anything to foul up so I guess the worst case scenario for a slightly rich condition would be killing plugs more often than usual which I'm not too worried about, but I've put so many hours into learning about these damn engines (on hard mode too, I have no family in this country and my wife's entire family collectively know less about carbs than I do.) I don't really know where to find a greybeard locally to school me on how the **** to work on carbs, so I guess for now I'm still bumbling through.
I've watched every video on how carbs work and etc etc I can find and I mean I have a basic understanding, but I just have absolutely no experience. Literally, the first time I ever touched a carb was when I bolted this one to my engine.
Looking forward to hearing your advice,
Jon
July 19th, 2021, 3:46 PM
#2
Forgot to mention - I only used the block itself (and the oil pan since I had to change the front cover.) Everything inside - camshaft, pistons, balance shaft, etc are from the original engine. The marine camshafts are slightly different to the automotive ones (I would assume the higher lift explains the difference in base timing?) so mechanically it's still an '09, just shoved into an '02 block.
July 19th, 2021, 6:20 PM
#4
CF Monarch
July 20th, 2021, 12:06 AM
#5
Thanks! And thanks for the reply. Was definitely the first thing I checked - 1,3 and 5 down the right side (looking at the front of the engine) and 2,4 and 6 down the left. I did double check the placement on the cap also.
I know people always say to make sure plug wires aren't laying on top of each other, but is that actually a thing I need to worry about, or is it another "old wives' tale"? My wires are fairly well routed but a few of them probably contact for a few inches - I will happily go out and buy another set of wire separators if it will help my issue.
My latest idea is this:
I ended up having to install an MSD 6AL ignition box to my engine. I did this because of the original ignition amplifier box dying, and the cheapest (used!!!) Replacement available was almost $500. I bought the MSD box for half of that, and if it ends up dying in 5 years I can just buy another one before I even come close to the cost of a possibly bad used module off of eBay. It seemed like the best idea. Now, MSD does offer a "marine" version of their controller, but it does not natively accept as hall effect input so I would have had to have purchased a $300 distributor as well just to use the marine one. Mine is a freshwater boat, so I made the decision. Now that being said, will me using an "automotive" ignition box effect the base timing I should be setting? The marine carb'd 4.3's are specced at 10* BTDC base timing, where as from what I'm seeing most people are setting automotive carb'd 4.3s at between 0 and 6* BTDC. What I'm asking is - is base timing dictated by the hardware (camshaft profile, etc) or the control unit being used to fire it? If not, is it reasonable that my engine would just require a different base timing than a stock unit with a stock carb and intake manifold, and I just need to quit worrying about nailing it down to exactly 10* and just time it to where it runs best?
I've been told that now it runs, forget the timing light and the "specs" for timing - take it out to the lake and advance timing until you get spark knock, back it off 2* and nail it down. Is this advisable?
July 20th, 2021, 11:50 PM
#6
Thanks! And thanks for the reply. Was definitely the first thing I checked - 1,3 and 5 down the right side (looking at the front of the engine) and 2,4 and 6 down the left. I did double check the placement on the cap also.
I know people always say to make sure plug wires aren't laying on top of each other, but is that actually a thing I need to worry about, or is it another "old wives' tale"? My wires are fairly well routed but a few of them probably contact for a few inches - I will happily go out and buy another set of wire separators if it will help my issue.
My latest idea is this:
I ended up having to install an MSD 6AL ignition box to my engine. I did this because of the original ignition amplifier box dying, and the cheapest (used!!!) Replacement available was almost $500. I bought the MSD box for half of that, and if it ends up dying in 5 years I can just buy another one before I even come close to the cost of a possibly bad used module off of eBay. It seemed like the best idea. Now, MSD does offer a "marine" version of their controller, but it does not natively accept as hall effect input so I would have had to have purchased a $300 distributor as well just to use the marine one. Mine is a freshwater boat, so I made the decision. Now that being said, will me using an "automotive" ignition box effect the base timing I should be setting? The marine carb'd 4.3's are specced at 10* BTDC base timing, where as from what I'm seeing most people are setting automotive carb'd 4.3s at between 0 and 6* BTDC. What I'm asking is - is base timing dictated by the hardware (camshaft profile, etc) or the control unit being used to fire it? If not, is it reasonable that my engine would just require a different base timing than a stock unit with a stock carb and intake manifold, and I just need to quit worrying about nailing it down to exactly 10* and just time it to where it runs best?
I've been told that now it runs, forget the timing light and the "specs" for timing - take it out to the lake and advance timing until you get spark knock, back it off 2* and nail it down. Is this advisable?
I know people always say to make sure plug wires aren't laying on top of each other, but is that actually a thing I need to worry about, or is it another "old wives' tale"? My wires are fairly well routed but a few of them probably contact for a few inches - I will happily go out and buy another set of wire separators if it will help my issue.
My latest idea is this:
I ended up having to install an MSD 6AL ignition box to my engine. I did this because of the original ignition amplifier box dying, and the cheapest (used!!!) Replacement available was almost $500. I bought the MSD box for half of that, and if it ends up dying in 5 years I can just buy another one before I even come close to the cost of a possibly bad used module off of eBay. It seemed like the best idea. Now, MSD does offer a "marine" version of their controller, but it does not natively accept as hall effect input so I would have had to have purchased a $300 distributor as well just to use the marine one. Mine is a freshwater boat, so I made the decision. Now that being said, will me using an "automotive" ignition box effect the base timing I should be setting? The marine carb'd 4.3's are specced at 10* BTDC base timing, where as from what I'm seeing most people are setting automotive carb'd 4.3s at between 0 and 6* BTDC. What I'm asking is - is base timing dictated by the hardware (camshaft profile, etc) or the control unit being used to fire it? If not, is it reasonable that my engine would just require a different base timing than a stock unit with a stock carb and intake manifold, and I just need to quit worrying about nailing it down to exactly 10* and just time it to where it runs best?
I've been told that now it runs, forget the timing light and the "specs" for timing - take it out to the lake and advance timing until you get spark knock, back it off 2* and nail it down. Is this advisable?
Went to the lake today, and started by again verifying base timing. (I also quadruple-checked my sparkplug wires, and also purchased a new separator kit so now they don't contact eachother at all. Routed them properly away from active wires, etc. Spark plug wires aren't the problem, unless I got a bum set. They are Accel wires - think it's likely I got a bad set? I couldn't see any spark leaking when I started the engine after dark.
I started it, warmed it up, and double-checked it was at 10* BTDC. I was still acting on my previous idea of a mismatched/incorrect balancer pulley, so I adjusted timing both ways +/- 15-20 degrees(ish), both of which make it run worse/barely run at all. I put it back at 10* BTDC and tried again and it's got noticeably more power than the other timing settings, but it still falls on its' face and starts popping through the carb at... I'd say 2500-ish RPM? Runs okay if you baby the throttle up and push through the carb pops, but I don't like doing it - it feels like it's bad.
So now my suspicion lies upon fueling issues. I pulled my feed line from the tank (these boats have a small check ball to "stop fuel leaks" if you blow a hose, and I hoped maybe that was restricting flow). It wasn't. The inside of my fuel line is crystal clean, not a trace of rust or water intrusion or garbage in the tank.
My suspicion has now moved to the pump itself. It's the factory pump that came on the boat, and pretty much all the other pumps on the boat (bilge pump, bilge blower, etc) are starting to get weak/die so I'm hoping that's my problem. Apparently, Edelbrock carbs are really particular about fuel pressure, so I'm going to grab a fuel pressure tester tomorrow and see what the little guy has left. I'm sincerely hoping the fuel pump is just weak as **** and puts out enough to idle the engine, but not enough to keep up with full throttle. I'll swap the fuel/water filter while I'm at it just for ****s and grins, and failing that, I'm laying the blame somewhere in the carb.
I really don't think my timing is off. I know that conventional wisdom would say that I'm an idiot, I've done some of the tests wrong and somehow my timing IS actually off, but unless one of you guys thinks I'm really wasting my time, it's fuel pressure day tomorrow.
July 24th, 2021, 2:47 AM
#7
Fuel pump. It was the stupid ****ing fuel pump.
enough to (very slowly) trickle fuel into the bowl, but not enough to keep up with WOT.
took her out last night with the wife and added some timing to make use of the high octane ethanol free fuel they sell on the lake. It runs better than it ever has - up on plane in half the time it took with the old engine, and although my Speedo is still broken (I assume clogged pickup tube...), and when you trim the drive up at speed, you can really feel the speed increase more than you used to. Engine temps are down now without running lean all the time.
enough to (very slowly) trickle fuel into the bowl, but not enough to keep up with WOT.
took her out last night with the wife and added some timing to make use of the high octane ethanol free fuel they sell on the lake. It runs better than it ever has - up on plane in half the time it took with the old engine, and although my Speedo is still broken (I assume clogged pickup tube...), and when you trim the drive up at speed, you can really feel the speed increase more than you used to. Engine temps are down now without running lean all the time.
The following users liked this post:
Rednucleus (July 24th, 2021)
Trending Topics
July 24th, 2021, 7:57 AM
#8
CF Monarch
Fuel pump. It was the stupid ****ing fuel pump.
enough to (very slowly) trickle fuel into the bowl, but not enough to keep up with WOT.
took her out last night with the wife and added some timing to make use of the high octane ethanol free fuel they sell on the lake. It runs better than it ever has - up on plane in half the time it took with the old engine, and although my Speedo is still broken (I assume clogged pickup tube...), and when you trim the drive up at speed, you can really feel the speed increase more than you used to. Engine temps are down now without running lean all the time.
enough to (very slowly) trickle fuel into the bowl, but not enough to keep up with WOT.
took her out last night with the wife and added some timing to make use of the high octane ethanol free fuel they sell on the lake. It runs better than it ever has - up on plane in half the time it took with the old engine, and although my Speedo is still broken (I assume clogged pickup tube...), and when you trim the drive up at speed, you can really feel the speed increase more than you used to. Engine temps are down now without running lean all the time.
July 24th, 2021, 6:32 PM
#9
electric. Unfortunately it’s an 09 - no provisions for mechanical pump. I honestly wish it did though. Would have stopped me from having to spring for an expensive rotary vane pump and then A regulator to get it down to usable pressure. The factory pump is unavailable, unless I wanted to go with a sketchy amazon/eBay unit.
I did not.
I did not.
July 24th, 2021, 6:46 PM
#10
CF Monarch
electric. Unfortunately it’s an 09 - no provisions for mechanical pump. I honestly wish it did though. Would have stopped me from having to spring for an expensive rotary vane pump and then A regulator to get it down to usable pressure. The factory pump is unavailable, unless I wanted to go with a sketchy amazon/eBay unit.
I did not.
I did not.