Post by: dat1dsm on July 20, 2014, 10:53:39 AM
Post by: bbfsouthwind on July 20, 2014, 03:31:49 PM
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Post by: dat1dsm on July 20, 2014, 04:24:51 PM
Post by: Flusher on July 20, 2014, 05:43:47 PM
You might also check your valves for straightness and seal if they did hit. With the heads assembled, position the combustion chamber surface level, with plugs installed, and the valves closed. Then pour some rubbing alcohol into the chambers. Monitor the intake and exhaust ports for any leakage.
If you have the heads disassembled, roll the valve stem on a flat surface with your hand while watching the valve head for runout. You could also chuck them in a drill press to watch for runout.
Good luck,
Joe
Post by: GT Jets on July 20, 2014, 05:47:42 PM
JMHO.
GT
Post by: Flusher on July 20, 2014, 05:51:34 PM
I can’t tell which heads you have, but I run Autolite 26 plugs which have a short thread (.460). It appears that the Autolite A6 plugs have a long thread (.750) and will protrude into the combustion chamber. Even though both of these plugs have the same 14mm thread, the 26 has a tapered seal and the A6 has a gasket.
Oops, I missed the first pictures :-[
Post by: dat1dsm on July 20, 2014, 07:13:37 PM
I don’t see any marks on your pistons and I would doubt that those small domes would really come near the plugs. Take a look at your valves for a witness mark where they might have hit the plugs. I forget which valve (intake or exhaust) will smack a TDC tool, but if you have the long reach plugs installed when you need the short, the valves could hit the plugs. I can’t tell which heads you have, but I run Autolite 26 plugs which have a short thread (.460). It appears that the Autolite A6 plugs have a long thread (.750) and will protrude into the combustion chamber. Even though both of these plugs have the same 14mm thread, the 26 has a tapered seal and the A6 has a gasket.My heads are still intact with motor. These pictures where before I assembled the motor back together. I was doing a head gasket changed and new valve seals along with pressure test.
You might also check your valves for straightness and seal if they did hit. With the heads assembled, position the combustion chamber surface level, with plugs installed, and the valves closed. Then pour some rubbing alcohol into the chambers. Monitor the intake and exhaust ports for any leakage.
If you have the heads disassembled, roll the valve stem on a flat surface with your hand while watching the valve head for runout. You could also chuck them in a drill press to watch for runout.
Good luck,
Joe
Detonation killed those plugs..
JMHO.
GT
Detonation? I was messing with the distributor a lot to try and get it to run good but either way I turned it, it still wouldn't sound/run right. Like I mentioned earlier, I messed with dizzy and got it as best as I could (still sounded not good) said fuck it and drove it like and that's when it blew a sparkplug porcelain out of its thread. Later the next day I noticed that on the other side of motor, one of sparkplug wires wasn't on. So I'm not sure if it was like that the whole time when I was messing with the timing.
Post by: dat1dsm on July 20, 2014, 07:15:10 PM
Post by: Hoofy on July 20, 2014, 07:31:13 PM
Post by: dat1dsm on July 20, 2014, 07:37:15 PM
Post by: 86caribbean on July 20, 2014, 10:01:42 PM
Post by: GT Jets on July 20, 2014, 10:24:53 PM
First off, detonation will not bend the ground strap....the only thing that can alter the ground strap gap or position is a mechanical interferance with the piston dome or debris in the cylinder. It does not look like you have a large dome on the top of the piston, looks like a closed chamber dome in an open chamber head and looks like you are using the correct short reach tapered plug. As far as ignition timing, set base around 15-18 and total 35-38 deg. and that should be fine. With those pistons and an open chamber head I don't see your compression being more than 10.4:1 or there about. As we know boat engines run on the cool side and with that compression and timing set correctly and runing at least 91 octane, you should have no detonation issues. How far in the hole is the piston at TDC?, Block been decked a large ammount? also have the heads been milled a large amount?...has anything else been recently changed?...It's going to wind up being something stupid. :screwy:
WTF are you talking about? :screwy:
I have seen aggressive tunes with too much timing cause detonation literally dozens of times... Detonation will ABSOLUTELY cause physical damage to the spark plug extremely similar to what the OP has pictured.
He already stated in as many words that the timing was NOT adjusted right and was all over the place and he drove it while running like crap.
Betting a set of new plugs gapped to .035" and a max timing of 36 degrees makes it purr like a mountain lion. JMHO
Would be willing to also bet the timing was running 40+ degrees advanced when it ran the best because of the dead hole due to the disconnected plug wire.
GT
Post by: dat1dsm on July 20, 2014, 10:32:22 PM
WTF are you talking about? :screwy:Hopefully your right haha.. what's the sparkplug you guys recommend? The short ones?
I have seen aggressive tunes with too much timing cause detonation literally dozens of times... Detonation will ABSOLUTELY cause physical damage to the spark plug extremely similar to what the OP has pictured.
He already stated in as many words that the timing was NOT adjusted right and was all over the place and he drove it while running like crap.
Betting a set of new plugs gapped to .035" and a max timing of 36 degrees makes it purr like a mountain lion. JMHO
Would be willing to also bet the timing was running 40+ degrees advanced when it ran the best because of the dead hole due to the disconnected plug wire.
GT
Post by: GT Jets on July 20, 2014, 10:34:15 PM
GT
Post by: Flusher on July 20, 2014, 10:54:48 PM
Hopefully your right haha.. what's the sparkplug you guys recommend? The short ones?
Start with Autolite 25 plugs.
Post by: GT Jets on July 20, 2014, 11:00:26 PM
Start with Autolite 25 plugs.
If you indeed do have tapered seat heads, I concur... :thumbup:
GT
Post by: dat1dsm on July 20, 2014, 11:02:13 PM
Post by: dat1dsm on July 20, 2014, 11:06:04 PM
Post by: GT Jets on July 20, 2014, 11:18:03 PM
GT
Post by: dat1dsm on July 20, 2014, 11:39:04 PM
I would think you would be OK running that plug. What ignition system are you running?Mallory distributor and mallory coil. No resistor box. I ran it direct cus I was having problems with it last time out. Before I replaced head gaskets, other than milky oil and shot out jet pump, motor responded real quick and sounded good
GT
Post by: GT Jets on July 20, 2014, 11:43:46 PM
Mallory distributor and mallory coil. No resistor box. I ran it direct cus I was having problems with it last time out. Before I replaced head gaskets, other than milky oil and shot out jet pump, motor responded real quick and sounded good
Ok, what do you mean "no resistor box" I hope this means you are running an internally resisted coil?
The ballast resistor is there to keep the coil from catching fire if the key is left on.... Not trying to scare, but make sure that is correct. If not an internally resisted coil, it needs to have the resistor...
Gap those new plugs at .035" and run it...
Post by: dat1dsm on July 20, 2014, 11:47:30 PM
I ment a ballast resistor. I was having problems with it. so I ran it direct.
Ok, what do you mean "no resistor box" I hope this means you are running an internally resisted coil?
The ballast resistor is there to keep the coil from catching fire if the key is left on.... Not trying to scare, but make sure that is correct. If not an internally resisted coil, it needs to have the resistor...
Gap those new plugs at .035" and run it...
Post by: GT Jets on July 20, 2014, 11:58:21 PM
I ment a ballast resistor. I was having problems with it. so I ran it direct.
Buy another one...... :-\
Read the warning on the MSD cut sheet...
You may have an internally resisted coil, but it will say it right on the body of the coil somewhere...
http://www.jegs.com/InstallationInstructions/100/121/121-8202.pdf (http://www.jegs.com/InstallationInstructions/100/121/121-8202.pdf)
GT
Post by: dat1dsm on July 21, 2014, 12:00:59 AM
Post by: GT Jets on July 21, 2014, 12:06:31 AM
Ok. Ima get some new plugs and gap em .35 and set my idle at about 15deg. And see how she runs. Pull plugs out and see how they look? What plugs again? Ap26 or 25
Idle timing is pretty much irrelevant if you do not know how much timing is built into the distributor... Find a way to get the timing at >2,500 RPM to approx 36BTDC.
As for the plugs, either will work, they are 1 heat range away from each other. I run MR43T AC Delco, good enough for the factory, good enough for me... The "M" denotes a marine plug, just nickle plated is all.. ;)
GT
Post by: dat1dsm on July 21, 2014, 12:08:07 AM
Post by: 86caribbean on July 21, 2014, 07:37:56 AM
Post by: dat1dsm on July 21, 2014, 08:58:01 AM
GT, after 25 years of building racing engines, dyno tuning them along with competing, I have NEVER seen colliding flame fronts (detonation) bend or close a spark plug ground strap. Now destruction of the porcelain insulator is a no brainer. Everything else that I read on this subject is true and common sense, so no disrespect and I do know WTF I’m talking about. This person faced with this problem will find the cause, and it most likely will be a mechanical interference issue. . Perhaps as detonation was occurring pieces of the porcelain insulator broke apart, and that’s what caused the ground strap to be hit and close down.Oh well that kinda worries me back some more haha. I was hoping it was something simple as detonation. I'm also hoping it's a possibility that when I had my heads off, that when I set them on the ground or when the shop had my heads they maybe set them down little too hard and closed up the gaps. Cus these heads are some heavy suckers. but I put some other plugs in there and we'll see what happens when I turn it on. Hopefully all is fine
Post by: bbfsouthwind on July 21, 2014, 09:04:33 AM
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Post by: dat1dsm on July 21, 2014, 09:09:11 AM
You left the spark plugs in the cylinder heads when they were removed for machining and pressure checking?I would have no doubt that the physical damage was caused by that if that is the case.Well when I gave them the heads, I gave them the heads with plugs still on. When I got them back they where still on. I'm not sure if they took them off before doing work and put them back on when returning them
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Post by: bbfsouthwind on July 21, 2014, 09:11:13 AM
Post by: GT Jets on July 21, 2014, 09:17:28 AM
GT, after 25 years of building racing engines, dyno tuning them along with competing, I have NEVER seen colliding flame fronts (detonation) bend or close a spark plug ground strap. Now destruction of the porcelain insulator is a no brainer. Everything else that I read on this subject is true and common sense, so no disrespect and I do know WTF I’m talking about. This person faced with this problem will find the cause, and it most likely will be a mechanical interference issue. . Perhaps as detonation was occurring pieces of the porcelain insulator broke apart, and that’s what caused the ground strap to be hit and close down.
The ground electrodes can get very hot when the engine runs extremely retarded ignition timing. Then it could have likely run extreme advanced, causing the damage to the insulator.
In light of the new and left out information by the OP, I apologize for the rum induced comment, yet stand by the intended fact that detonation can totally close the gap on a spark plug without ANY physical contact whatsoever.
Had it happen numerous times on pump gas restricted race engines. Seen it several times on others rigs.
Race fuel burns too slow to do it I suspect.
No harm no foul.
GT
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Post by: GT Jets on July 21, 2014, 09:30:29 AM
Oh well that kinda worries me back some more haha. I was hoping it was something simple as detonation. I'm also hoping it's a possibility that when I had my heads off, that when I set them on the ground or when the shop had my heads they maybe set them down little too hard and closed up the gaps. Cus these heads are some heavy suckers. but I put some other plugs in there and we'll see what happens when I turn it on. Hopefully all is fine
Your killing me.
Consider the spark plug a highly tuned precision instrument vital to the survival of your engine.
Quick story and I won't beat you up any more.
Working on about a 1991 Chrysler New Yorker around 1994, 3.0l V6. Customer complaining of a rough idle and intermittant hard start.
Car had been to four different shops, none of which could fix it.
I worked at a Chrysler dealer and was the drive ability tech.
After driving the car. It warmed up and drive like a pile of crap.
Brought it into the bay and hooked it to an oscilloscope, Bam.. three cylinders spiking like a big dog.
Pulled the plugs, they were brand new proper number plugs, the gaps were all over the place. From .024" to.040".
Regapped and reinstalled. Car ran perfect.
Customer had her car tuned up at a Precision Auto just three weeks prior to my getting it.
Always put in a fresh, properly gapped plug. Otherwise you will find yourself chasing your own butt.
Lecture over.
GT
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Post by: dat1dsm on July 21, 2014, 09:32:35 AM
Your killing me.Haha. Okay. I will do all that. Do it right do It once. New plugs going in
Consider the spark plug a highly tuned precision instrument vital to the survival of your engine.
Quick story and I won't beat you up any more.
Working on a Chrysler New Yorker about 1994, 3.0l V6. Customer complaining of a rough idle and intermittant hard start.
Car had been to four different shops, none of which could fix it.
I worked at a Chrysler dealer and was the drive ability tech.
After driving the car. It warmed up and drive like a pile of crap.
Brought it into the bay and hooked it to an oscilloscope, Bam.. three cylinders spiking like a big dog.
Pulled the plugs, they were brand new proper number plugs, the gaps were all over the place. From .024" to.040".
Regapped and reinstalled. Car ran perfect.
Customer had her car tuned up at a Precision Auto just three weeks prior to my getting it.
Always put in a fresh, properly gapped plug. Otherwise you will find yourself chasing your own butt.
Lecture over.
GT
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Post by: 86caribbean on July 21, 2014, 09:45:09 AM
Post by: dat1dsm on July 21, 2014, 10:32:49 AM
As we get more information from the owner, it's all starting to make sense, leaving the sparks plugs installed in the head is a big no, no. First rule to go by is, spark plugs are the first to be removed and the last to go back in. I said it before, and I'll say it again, it's going to wind up being something simple and stupid. The plugs being left in the heads while being carted all over the place is the reason for the ground straps being damaged or closed. We all know how destructive detonation and or pre-ignition can be for any engine, but this was most likely never the "real" cause of smashed plug tips. It was just a simple mistake made by the owner of not removing the plugs from the heads when removing them and who knows where they went and how they were handled, then re-installing the heads without even looking at the condition of the plugs. Hey, were human and we learn from our mistakes. Throw a pair GM R43TS plugs in with a gap of .035-.040 and set your timing properly and hit the water and don't look back....Cheers,Are those aldelco plugs shorter than the auto lite 26?,
Post by: GT Jets on July 21, 2014, 12:01:37 PM
Are those aldelco plugs shorter than the auto lite 26?
The R43TS is an extended tip plug, it is about .030" deeper in the hole, the MR43T is a standard tip plug and would be .030" shorter than the Autolite plugs.
The only reason I recommended the MR plug is that I buy them for all three of our boats... They don't rust and are quite cheap. (though not as cheap as the Autolite plugs). I have had the Autolites push insulators on the race boat. Never seen it happen on any other plug on my stuff.
Imho, the R43TS will work fine. cheaper than the MR as well.
Just keep the gap at .035"...
GT
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Post by: dat1dsm on July 21, 2014, 12:04:27 PM
Post by: jamiemwedmore1234 on July 21, 2014, 01:52:24 PM
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Post by: 86caribbean on July 21, 2014, 02:24:25 PM
Post by: dat1dsm on July 27, 2014, 05:12:06 PM
Post by: GT Jets on July 27, 2014, 05:14:29 PM
:-\
Post by: dat1dsm on July 27, 2014, 05:33:29 PM
Rear cam plug rusted through?I'm not sure GT. I doubt it. When I had heads out and all that, everything looked fresh. Previous owner had it rebuilt. Could it be those valve covers I put? I capped them and had to breather on them. Straight shut
:-\
Post by: Flusher on July 27, 2014, 06:12:43 PM
Could it be those valve covers I put? I capped them and had to breather on them. Straight shut
You need to have good crank case evacuation or, at the minimum, good free flowing breathers. It is the nature of a reciprocating piston engine to build crank case pressure with just the rotation of the crank (not considering blow-by at this point).
A V-configuration is the worst at this, but let’s consider the best possible design, a horizontally opposed boxer configuration with both connecting rods on a common crank throw. In the boxer configuration, while one piston is approaching TDC, the other is approaching BDC. Sounds good so far, however the geometry of the connecting rods dictate that the pistons move at different rates relative to TDC and BDC. That means that the volume of the crankcase changes as the crankshaft rotates, thus building crankcase pressure with nothing more than rotation of the crank assembly. Then compound that with blow-by. All piston engines will have some degree of blow-by. The weaker the piston ring seal, the more blow-by that engine will have. You need some way to vent this pressure or better yet, evacuate that pressure or gaskets and seals can become overwhelmed and leak. Ideally, a slight vacuum pulled on the crank case to just below atmospheric pressure would virtually eliminate any leaking seals and gaskets as well as reducing pumping losses.
Too much vacuum can also be detrimental. First, a vacuum pump can produce so much vacuum that gaskets can be pushed into the engine by atmospheric pressure. Then the necessity to reverse the crank seals to withstand atmospheric pressure acting against negative crank case pressure becomes apparent. You can also run into issues with components requiring splash lubrication, such as wrist pins, when the cloud of oil (windage) slinging around with the crankshaft is pulled out of suspension.
Bottom line; make sure that you have good crank case ventilation.
Good luck,
Joe
Post by: dat1dsm on July 27, 2014, 07:53:16 PM
Post by: GT Jets on July 27, 2014, 07:56:27 PM
Post by: dat1dsm on July 27, 2014, 08:10:57 PM
You need some big 'ol hillbilly breathers in those badboys... 8)But do you see how my old covers have that breather type or whatever thing those are sticking up high. And the new ones just have for the cap^breathers. You think since I capped them with the caps, it built pressure and blew the rear main?
Post by: GT Jets on July 27, 2014, 08:18:39 PM
But do you see how my old covers have that breather type or whatever thing those are sticking up high. And the new ones just have for the cap^breathers. You think since I capped them with the caps, it built pressure and blew the rear main?
I don't rightly know, you haven't shown the breathers yet... :-\
GT
Post by: Flusher on July 27, 2014, 08:24:12 PM
You think since I capped them with the caps, it built pressure and blew the rear main?
Indeed, if you put plugs in.
But you may have gotten lucky and the rear seal didn’t blow, it just got overwhelmed with pressure and sprayed oil.
Are we talking quarts of oil or just everything got coated with oil? A little oil goes a very long way.
Post by: dat1dsm on July 27, 2014, 08:25:38 PM
Post by: Flusher on July 27, 2014, 08:53:07 PM
Point being, it could be something small.
I would throw in a set of K&N push-in breathers and try it again. Be advised, these will make a mess also.
[attachimg=1]
Engines are remarkably robust yet surprisingly fragile. Look at it his way, you are learning a lot.
Post by: dat1dsm on July 27, 2014, 11:23:31 PM
The first time getting my current boat wet, I had a similar problem. There is a spade that is part of the front oil pan gasket set that pushes through the timing cover to retain that part of the of the oil pan. The previous owner removed the timing cover without removing the pan and used blue RTV to seal it back up. One of the holes (one on each side) on the timing cover didn’t get filled with RTV and at the first application of throttle, it became an oil geyser that hosed down the entire starboard side.Will do. Gonna pull motor out this week. Replace rear main seal and put it back in a long with some breathers. Hopefully that solves my problem. Tired of all these headaches haha. It's one thing after another
Point being, it could be something small.
I would throw in a set of K&N push-in breathers and try it again. Be advised, these will make a mess also.
(Attachment Link)
Engines are remarkably robust yet surprisingly fragile. Look at it his way, you are learning a lot.
Post by: dat1dsm on July 28, 2014, 11:42:36 AM
Post by: Flusher on July 28, 2014, 02:18:19 PM
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Post by: dat1dsm on July 28, 2014, 02:31:06 PM
Mk4 will be a 2-pieceMk4? do the serial number on pic mean it's a mk4?
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Post by: Flusher on July 28, 2014, 03:32:14 PM
Mk4? do the serial number on pic mean it's a mk4?
If you do a Google search for "big block Chevy casting numbers (and your number)" you will find many reference charts. If you post your number, I can look it up for you in my parts interchange book if you have difficulty finding what you need. I was just making a statement based off of the shape of the water passages. The gen5 and gen6 are a different shape.
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Post by: dat1dsm on July 28, 2014, 03:33:38 PM
If you do a Google search for "big block Chevy casting numbers (and your number)" you will find many reference charts. If you post your number, I can look it up for you in my parts interchange book if you have difficulty finding what you need. I was just making a statement based off of the shape of the water passages. The gen5 and gen6 are a different shape.Yeah I did Google and bunch different came up. Different 454's some said even 427's. If you can look it up I'd appreciate it
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Post by: Maker on July 28, 2014, 03:36:54 PM
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Post by: Flusher on July 28, 2014, 03:41:57 PM
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Post by: Flusher on July 28, 2014, 03:43:45 PM
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Post by: Flusher on July 28, 2014, 03:53:35 PM
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Post by: dat1dsm on July 28, 2014, 05:48:50 PM
If 3963512, 69 427 & 70-76 454 2 & 4 bolt mains. I will verify in my book when I get home.Third digit is a 6
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Post by: Flusher on July 28, 2014, 08:26:15 PM
If 3963512, 69 427 & 70-76 454 2 & 4 bolt mains.
4.250 bore, 9.8 deck height
Mark IV
Post by: dat1dsm on July 28, 2014, 08:54:32 PM
4.250 bore, 9.8 deck heightSweet. Thanks Flusher. I'll order a 2 piece rear main seal and oil pan gasket. Recommend any special type rear main seal? I usually go thru summit. Next day shipping.
Mark IV
:)
Post by: Flusher on July 28, 2014, 09:23:38 PM
Recommend any special type rear main seal?
I wouldn't go cheap.
I really like the 1-piece oil pan gaskets. I think mine is from SCE.
Put a little dab of silicon in the corners where the gasket transitions from flat around the rear cap and timing cover to help prevent leaks.
I like to slightly misalign the rear main seal relative to the block/cap and put a little dab of silicon where the seal halves meet.
Double check everything. Be patient and meticulous.
Post by: Flusher on July 28, 2014, 09:25:00 PM
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Post by: dat1dsm on July 28, 2014, 09:37:12 PM
I wouldn't go cheap.Sce? Okay silicone seems to be key factor on a lot of gaskets. Will do.
I really like the 1-piece oil pan gaskets. I think mine is from SCE.
Put a little dab of silicon in the corners where the gasket transitions from flat around the rear cap and timing cover to help prevent leaks.
I like to slightly misalign the rear main seal relative to the block/cap and put a little dab of silicon where the seal halves meet.
Double check everything. Be patient and meticulous.
Before I do any of that I would try just changing the breathers after cleaning with citrus cleaner.Cleaning? And yeah that's exactly what my uncle told me (he's a good mechanic) but I think I might as well do it now and not worry about doing it later. Plus I had a mysterious leak back there last time out too. And I'm thinking it was rear main because I was getting oil shooting up from the flywheel spining. Like how it's doing now but very little.. and
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Post by: dat1dsm on July 29, 2014, 01:08:43 AM