Bosche Spark Plugs giving problems..?

JacKniK · Feb 2, 2008

Hi

I installed some Bosch Platinum+4 spark plugs in my 03 GT at least 6 months ago. One of the plugs striped the thread out my cylinder wall. A mechanic told me it was because those spark plugs are the wrong size for my car and told me to change them...

Is that true, because i have friends with them and they haven't had any problems b4. Plus they fact that they make them just for the car would make me think that they should be correct. I want to think it was my fault during installation more than anything else.

He also quoted me a $200 charge to fix just the one cylinder. Is that a good deal?

I would really appreciate any help on this matter from someone who know about this subject.

Thank you.

Killa · Feb 2, 2008

You get what you pay for, its your fault to listen to those people work at auto part store, those plug is common giving problem to any cars.

Dragstr05 · Feb 2, 2008

Only plugs I would put in mine are motorcraft and NGK. Running motorcrafts right now, no reason to run anything different.

As far as your stripped threads...its a common problem. Way more common than for should have been comfortable with, but it happens. Thats assuming your plug blew out of the head. If it happened during install that wasn't the plugs' fault.

The tool I got a couple months ago to repair stripped threads in the cylinder head was around $150 and I still needed someone to help me out cause I wasnt sure how to use it. If they can do it right for $200 its a good deal. Make sure they know what they are doing, any mistakes and your head might be trashed.

MichaelsLilGray · Feb 2, 2008

Id add autolight to that list. This is the way ive heard it said before.. You drive a domestic.. use domestic plugs.. Bosch is German.. your car isnt. Now a plug is a plug... but keep in mind... the gapping isnt correct on the +4... or any other bosch for that matter. The stripping was probably you... they arnt the easiest thing to work with.. a plug is a plug if its the correct size.

Mustang5L5 · Feb 2, 2008

The +4's are a marketing gimmick. They are a terrible plug design. The spark can only use one electrode at a time. It doesn't do any crazy lightning bolt zig zag spark pattern or anything. It just zaps over to ONE electrode. The other 3 just block the air/fuel mixture from seeing the spark. Plus they are expensive as hell.

Throw them in the trash and buy 8 motorcraft AGSF-32-PM (or SP-493) plugs and gap them at 0.054". I know that autolites are technically the same plug, but i've been hearing that with use the resistances of the autolites falls farther out of spec than the equivalent motorcraft plug. I used to say get either plug, but now i'll just say get motorcraft parts for everything if you can.

The stripping of the wall is due to the heads on these cars having only a few threads and being aluminum. It's mostly due to the installer overtorquing the plug. I beleive the torque is 14 ft-lbs and you should not exceed that.

If your friends are running +4's.....tell them to throw them in the trash too

MichaelsLilGray · Feb 2, 2008

Mustang5L5 said:
The +4's are a marketing gimmick. They are a terrible plug design. The spark can only use one electrode at a time. It doesn't do any crazy lightning bolt zig zag spark pattern or anything. It just zaps over to ONE electrode. The other 3 just block the air/fuel mixture from seeing the spark. Plus they are expensive as hell.

Throw them in the trash and buy 8 motorcraft AGSF-32-PM (or SP-493) plugs and gap them at 0.054"

The stripping of the wall is due to the heads on these cars having only a few threads and being aluminum. It's mostly due to the installer overtorquing the plug. I beleive the torque is 14 ft-lbs and you should not exceed that.

If your friends are running +4's.....tell them to throw them in the trash too

I want to say your close.. but not right LOL Max tourqe is 14... if you check in your haynes it says from 7-14... but to be anywhere from 9-11 is great. best rule of thumb.. tighten hand tight.. when you cant tighten anylonger just another 1/8th turn

JacKniK · Feb 2, 2008

Thanks for all the advice, i now know i can trust that mechanics advice too.

SVT32VDOHC · Feb 4, 2008

Torquing them is probably worse than just hand tighten, then a 1/8 of a turn. I say this because some may not know how to use a torque wrench, or they might have an inaccurate torque wrench.

streethorse · Feb 4, 2008

SVT32VDOHC said:
Torquing them is probably worse than just hand tighten, then a 1/8 of a turn. I say this because some may not know how to use a torque wrench, or they might have an inaccurate torque wrench.

Yeah , I changed mine yesterday and used your method as I dont have
a tq wrench yet. I used Bosch single platnium. They run perfect.
I am going to recheck them as you guys got me parinoid about about blowout.

MichaelsLilGray · Feb 4, 2008

streethorse said:
Yeah , I changed mine yesterday and used your method as I dont have
a tq wrench yet. I used Bosch single platnium. They run perfect.
I am going to recheck them as you guys got me parinoid about about blowout.

so you went back and got more bosch plugs? ROFLMAO

streethorse · Feb 4, 2008

MichaelsLilGray said:
so you went back and got more bosch plugs? ROFLMAO

No, I didnt start this thread, I had Motorcraft before.

Mustang5L5 · Feb 4, 2008

The Bosche singles are ok plugs. I personally wouldn't run them. It's the +2 and +4's that I usually recommend people avoid.

My personal preference is OEM motorcraft plugs, but that's me

Notchbck93 · Feb 4, 2008

Every fastener has a torque value and it's for a good reason; longevity/reliability.

I have an inch lb torque wrench and certain plan to check the torque on my plugs.

If these are the washer style plugs, you first crush the washer, back the plug off and then torque the plug to get the proper torque... Simply torquing the plugs with a soft washer will cause problems.

NGK depicts the importance of torquing plugs:

http://www.ngksparkplugs.com/techinfo/spark_plugs/installation.asp

Supposedly why Motorcraft is important to stick with: use discression.

http://www.shotimes.com/SHO3motorcplugs.html

This is from 5.0 mag used on a 4v blown cobra

http://www.mustang50magazine.com/techarticles/m5lp_0507_brisk_spark_plugs/index.html

UTI Brisk test

http://www.briskusa.com/test_results05_universal.htm

Has anyone on here actually used Brisk plugs?

SVT32VDOHC · Feb 4, 2008

I agree with sticking with Motorcraft. All my cars have gotten Motorcrafts when doing plugs. And if I decide to do plugs on the 2V it is getting Motorcrafts. I am paranoid about the blow out now too, but I guess I will give it a shot.

bdcardinal · Feb 4, 2008

to prevent the blowout, get the extended length plugs and tighten properly. check the torque every year or so. buy an accurate torque wrench and there shouldnt be a problem.

Bosche Spark Plugs giving problems..?

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