Whats everyone's opinion on these cracked spark plugs..OT
[ May 12, 2003, 03:00 PM: Message edited by: rugerman1 ]
[ May 12, 2003, 03:00 PM: Message edited by: rugerman1 ]
Whats everyone's opinion on these cracked spark plugs..OT
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I use the Bosch Platinum 4 plugs in my Tacoma V6 and have had no problems. Hard to say what is fracturing the porcelain insulator in the plugs at the link you posted.....detonation as suggested has to be causing this. All associated with running too hot also and too lean as indicated by the white color of the plug tips and the black band on the upper plug insulator. If the plugs weren't torqued properly (left too loose) that may cause them to run too hot also, assuming here that the correct plug is being used.
MolaKule
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I agree withn 7Tford, too hot a combustion or preignition.
I would concerned as to whre the ceramic material from the tips might have gone?
I would concerned as to whre the ceramic material from the tips might have gone?
WOW..those look like they may have been exposed to nitrous oxide and/or 15:1 A/F ratios!!!
Or those plugs are way way to hot a heat range forthat particular application.
MolaKule
Staff member
The most likely scenario for the bent electrode is that when the ceramic insulator flew from its roost, it impacted the electrode and bent it away from its normal position.
Good grief! The plug is too hot for the application. I think everyone seems to agree. But you probably should arrange to have a mechanic check the cylinder head, pistons, and cylinders--and don't be surprised if he tells you it's rebuild time.
I've seen similiar pictures out on the web. Many are of the opinion you should only use bosch platinum in naturally aspirated engines. Seems to be some issues with these plugs burning up in at least some turbocharged or supercharged cars. I think some auto makers like Volvo, Audi, and Saab are saying not to used them with their turbos.
The plugs in the pics above are from a 4.0L Jeep engine...8.8:1 compression ratio,bone stock everything else (ignition,air filter,injectors etc.)..I mean if this happens to these plugs in this 1960's technology Jeep engine...what will happen to them in a high winding 4 banger with turbo!By the way I use Champion Gold Truck plugs in my Jeeps and they are great in this application...the Bosch plugs pictured above are from another Jeep engine,taken from a forum I frequent.
I didn't realize that jeeps took such a projected tip like that. I always was under the impression they used a RC9YC like my neon. Perhaps a wrong application can also be faulted here?
Did some research, my '87 does in fact take the same plugs as the neon, but the newer jeeps with the HO engine have a different plug design, RC12LYC. I think the L stands for projected nose, but i'm not totally sure.
The HO Jeep motor uses "High-Port" designed heads...came out in 1991...as compared to the non HO 4.0L engine...hence the projected plug...this design...along with intake changes and injection upgrades gave the HO 4.0L 30 HP over the non HO.BUT...the torque on both didn't change all that much...and actually the older engine design had the torque come on near the bottom end of the RPM range...rather than the top end as with the HO model...so actually the older model would seem to be better suited for it's application (low speed off-roading)than the newer version...but you can't buy it anymore so the new HO is here to stay.They both great,long running,gobs of torque tractor engines
i put some in my honda civic and eventually ended up with a sputtery idle. seems one of them had the electrode blast right off it, leaving a 1 mm gap.
putting stock NGK's in solved that.
putting stock NGK's in solved that.
I have had bad experience with bosch plats in toyota's. I find that they are a very sub-standard product and will never use them again. If those are the recommended plug for your application I would be letting bosch know about it as they more than likely have ruined your engine. On a standard bosch crapimium I have witnessed the cracked insultator(didn't let go) on 1 plug out of a set that I had removed due to detonation under high boost levels(car also had a horrible idle from the getgo). These plugs all by themself caused the detonation. Now its only Nippondenso and NGK for me. My advise is get them out asap if you run Bosch espcially if they are used in a toyota.
[ May 21, 2003, 03:13 PM: Message edited by: supraturbo ]
[ May 21, 2003, 03:13 PM: Message edited by: supraturbo ]
Propflux01
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I have noticed that the Bosch plats caused misfiring in many cars I have worked with except those that have low-powered ignitions (some Dodge's, Older point-fired VW's, etc.) on higher firing ignitions it seems the voltage is too much for such a small electrode (even Gold, the best conducter of electricity, needs to be thicker for higher volts), and starts to burn away the recessed tip in the Plats, causing the misfire. I find this only with the Bosch Plats, the regular Bosch plugs are hard to beat, especially in air-cooled engines.
So tell me, did you set the gap on those? And if you did, what tool did you use to do it with?
FWIW, years ago I worked in a tune-up shop and the new owner did a lot of things the way the franchise told him to as far as purchasing parts to stock in the shop. We were a new crew so we didn't have a clue either. OTOH, he did emphasize that the cars would either be fixed or we'd at least know what was wrong and document that on the Repair Order.
Anyway he started out buying the Bosch Super and Platinum plugs. I can understand the Supers to an extent since they were $.79 ea from the warehouse and no one else came close to that.
It didn't take us long to figure out that the Plats were good for a recheck so we kinda stopped selling them. After a couple of years we were able to get the boss to start buying Autolite plats.
The Bosch Supers tended to make engine run a bit rough at idle. Our theory is that the center electrode is pretty hard on those and it affected ignition of the flame kernel. Richening the idle mixtures on carb cars helped but a lot were still sealed so we just had to let them go. We tried to get him to move to Autolites as the next cheapest but they were 1.09ea and he wouldn't budge. So we took to doing diagnoses on every car that wasn't perfect so that we wouldn't have to see it again for rough idle.
The Supers were good for one thing. The porcelain is hard but brittle and would snap right off every time if you weren't on it correctly. Since we would do this fast we were pretty rough and if the porcelain didn't snap off we knew the plug was OK. Other brands you can crack the porcelain and not know for a couple of days until the PO'd customer comes back. For instance, at the time we knew that if you dropped a Champion you'd better just throw it away because it's cracked even if you can't see it yet. Champion has been bought since then so it may be different now.
FWIW, years ago I worked in a tune-up shop and the new owner did a lot of things the way the franchise told him to as far as purchasing parts to stock in the shop. We were a new crew so we didn't have a clue either. OTOH, he did emphasize that the cars would either be fixed or we'd at least know what was wrong and document that on the Repair Order.
Anyway he started out buying the Bosch Super and Platinum plugs. I can understand the Supers to an extent since they were $.79 ea from the warehouse and no one else came close to that.
It didn't take us long to figure out that the Plats were good for a recheck so we kinda stopped selling them. After a couple of years we were able to get the boss to start buying Autolite plats.
The Bosch Supers tended to make engine run a bit rough at idle. Our theory is that the center electrode is pretty hard on those and it affected ignition of the flame kernel. Richening the idle mixtures on carb cars helped but a lot were still sealed so we just had to let them go. We tried to get him to move to Autolites as the next cheapest but they were 1.09ea and he wouldn't budge. So we took to doing diagnoses on every car that wasn't perfect so that we wouldn't have to see it again for rough idle.
The Supers were good for one thing. The porcelain is hard but brittle and would snap right off every time if you weren't on it correctly. Since we would do this fast we were pretty rough and if the porcelain didn't snap off we knew the plug was OK. Other brands you can crack the porcelain and not know for a couple of days until the PO'd customer comes back. For instance, at the time we knew that if you dropped a Champion you'd better just throw it away because it's cracked even if you can't see it yet. Champion has been bought since then so it may be different now.
fwiw, having to hot of a plug wont make it crack.
those plugs look like they were beat with a hammer on the tips.
those plugs look like they were beat with a hammer on the tips.
i thought silver was the best conductor?
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