#26
IP: 69.204.29.189
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Quote:
maybe you bought yours new or in excellent condition? or a complete overhaul...maybe with a short block from mmi? my a 4 was well used....more or less had to take it sight unseen because a 4 that came with the c&c 30 i purchased over ebay sight unseen while mildly intoxicated and challenged by my girlfriend at the time -- for $1800 -- had been invaded by water for several years so was toast...-- so i drove the 500 mi to Boston to get the a 4..saw it run in the seller’s garage, but really i knew nothing at the time, it was ok, but blew smoke from the start so it wasn't in the best of shape....and that valve was always bad...and i compounded the problem by adjusting the valves myself [later when the engine was partially redone by a pro..he begged me to let him adjust the valves -- which i was only too willing to do---] yes the #4 cyl is furthest back and lowest...so i think water, fuel pool there when it's not running. I'm really not sure if it's the hottest or coolest. Actually i think it's the coolest which is why its valves are more likely to stick. also, i originally installed a new water distribution fitting, as per don's instructions, i drilled an extra hole pointing to the rear....which may have been a mistake, maybe that # 4 is getting too much water? also, my friend, i see you're in California, not this frozen wasteland, so while you can run your a 4 all year should u choose to, i can only do so for 4 months max / year...so the poor motor has to sit in a very damp climate, makes for condensation, etc., and avg. temp is around 25 f...way lower in dec. and Jan...even in the summer, lake Erie water temp which i use to cool it...is max of 74 f, and only that for a few weeks in July. so every time i start up it’s getting shocked with very cold water. actually, since you asked, i have a few questions which I’ve always wondered about.. 1. how would i know if there is water leaking into or out of the head, manifold, or block? 2. more importantly, the motor almost always blows some white smoke out when running. I’ve assumed it's just caused by mixing 75 f lake water with ambient engine head temp of 150 f or more. but seriously does that indicate a problem? and yes, I’ll spring for a comp. tester and check the comp in the 4 cyls... so can you see that our engine situations are really not very comparable? [as a sign of my loyalty, if i ever have to deal with major engine problems again, I’ll get an mmi short block and try to do everything right from the beginning.] meanwhile..good news...in spite of my recent crabbing, the motor usually runs quite well -- starts instantly and gets me in and out effortlessly may not be the fastest at top speed but on a 30' boat, 12,000 lbs. loaded, i calculated max hull speed is about 5 k...and going thru the marina that fast only draws glares -- even from the zillion hp rocket boats around... so thank you again and I’ll keep you posted. Maybe even contact you on my next trip out to LA to see my daughter and my new grandson…
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keithems [1976 c&c 30 mk 1] Last edited by keithems; 07-10-2022 at 12:59 PM. |
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TimBSmith (07-11-2022) |
#27
IP: 69.204.29.189
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about last nite
tried the new spark plugs....both non resistored--autolite 437 and the champ j 8 c.
both ran fine...so i'm happy however, i did notice that the wires also say they are resistored..can they be gotten without resistors? could that also be an issue? just kind of curious; as long as things are fine, i'd rather leave well enough alone...
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keithems [1976 c&c 30 mk 1] |
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TimBSmith (07-11-2022) |
#28
IP: 138.207.177.95
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Quote:
Back to the original issue - it still makes no sense at all. I have used J8s, RG12s, Autolites, and NGKs over the years. Unless there was something wrong with them, I NEVER could tell the difference in the near term, the distinction was many hours later when and if they got fouled. You may have one defective plug, that happens, but don't even have a theory about why no RJ-12 would work unless they are coming gapped wrong and you aren't setting the gaps or checking them. I'll see if I can get a better angle, but from this it looks like the hot area around the plugs is bigger at #1 and gets smaller as you go back to #4. Last edited by joe_db; 07-12-2022 at 03:37 PM. |
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TimBSmith (07-12-2022) |
#29
IP: 138.207.177.95
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Note on the wires, the coil to distributor wire gets 4 times the use of the rest of them. In my experience that one dies first and before it is all the way dead you'll have all kinds of hard-starting issues.
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#30
IP: 209.6.152.28
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Regarding closure on this case and Joe_DB post...
Pardon my musings. If you read this through, please do me the favor of correcting any misunderstandings. I am leaving any carburetor discussions out of this thread.
I am trying to synthesize from the weekend and today's plug threads. Joe's post was a Godfather moment for me "Just when I thought I was out...they pulled me back in..." I had decided for many reasons to leave this case well enough alone.. Though my thoughts have remained unsettled on it. I want to be clearer on what I should learn from and do in this circumstance. While I am pleased that Keith's motor is running well and from plugs to distributor to mix and heat distribution a lot of ground was covered; I left the case without a sense of improved or completed diagnosis method and resolution. Keith is doing upstream work on the distributor etc. and that work and his findings will resolve any questions about upstream ignition issues. I am sitting with unsettled curiously, scanning threads for: 1) "Bad plug" tests that are definitive by testing resistance, which seems very doable and sensible. Providing some insights on manufacturing vs. running conditions that compromise a plug. We can also easily test if a plug itself is discontinuous(which was a revelation to me). 2) Low invasive ways of evaluating plug environment for fouling risks and methods for improving fouling prone plug environments. -Your FLIR? image, infrared temp, and other info on heat distribution is useful. -Detailed pictures of plug condition(viz prior post) is also useful, -Maybe imaging inside the cylinder which would also tell a story. -Maybe more frequent plug monitoring, gapping, and cleaning in suspect environments that need to lived with until improved. -Cylinder pressure indicators in suspect plug environments. -My interest is improving diagnostic data collection in these cases. (Another case resurfaced today). 3) Improving my understanding of coil testing. When discussion of spark strength is raised, so is my curiosity. Assuming a timed and functioning distributor. -I understand that the secondary winding (capacitance/resistance that is measurable) if charged correctly from the primary winding releases the same high voltage every time the distributor creates an open circuit. -As long as resistance of plug wires and plugs/type/gaps are constant an equally strong spark would occur across every plug. -Some plugs may have capacitance, materials, and geometry that leads to a different spark profile, but this should not matter from cylinder to cylinder. 4) The subtilties of cooling and fuel distribution by cylinder are fascinating. That said, our carburetor and fuel flow is hardly graceful and the mix across cylinders perhaps more variable that say a honda accord's engine. -So I wonder out loud how much variation any appropriately gapped compatible spark plug would make by itself as a long term solution to either poor combustion environment or poor ignition distribution? If you have read this far, please refine my unsettled thoughts and point me to a diagnostic checklist that helps me ensure that if/when I see this issue I can reduce the problem thoughtfully. Thankful. Fair winds.
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Tim Smith Oasis Pearson 30 1974, Number 572 Boston, MA USA |
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jcwright (07-12-2022) |
#31
IP: 68.134.222.100
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There is a lot you can do.
Here is my scope connected to the #1 plug lead: You can see the plug fire, the points close, and the plug fire again. You can use a FLIR camera to analyze the engine. You can put a timing light on the ignition to dial in the advance. You also can do a lot with nothing but your ears and eyes. LOOK at the plugs. I posted a chart to interpret what you see. Also look for soot traces up the insulator, I had one leaking combustion gas through the plug. LISTEN to the engine. Run it with a bit of load and pull the plug wires one at a time. The RPM drop and engine roughness should be about the same for every plug. If one pull does nothing, that cylinder isn't even firing. If 2 aren't firing, you may have swapped plug wires and have them in the wrong order. FEEL them. A quick light touch on the plug boot will give you a rough temperature check. If one is significantly colder than the rest, you have an issue. |
#32
IP: 67.184.216.83
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Also a few years back DR N Dutton suggested purchasing an inexpensive "induction" pen light that you hold next to a plug wire and it lights with every firing for that wire. Does not measure "quality" of spark but does indicate very quickly that you do have spark. Remember it being about $5 on ebay.
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TimBSmith (07-13-2022) |
#33
IP: 104.174.83.118
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We've had a couple of convenient spark tester schemes. The one Sam refers to is from Lisle, available on Amazon, eBay, Walmart and others:
Then there was the spare spark plug mount in the alternator/lifting eye bracket. Pull the plug wire in question, put it on the test plug and crank:
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
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