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Gonzo

Article: My All Time Worst Spark Plug R&R's --- simple job turned impossible.

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My All-time Worst Spark Plug R&Rs

I’ve been changing spark plugs almost as long as I’ve been able to hold a socket wrench. I’ve changed plugs on everything from the family lawn mower to huge engines, and over the years there have been a few of them that are memorable only because they were such a pain in the toolbox to get out. A few were rusted into place, or the threads were stripped, and a few that broke off in the head, but the ones I remember the most are the ones that had you muttering to yourself that you’d never do another one again.

Now, I could mention the trouble with getting the spark plugs out of the Ford Triton 3 valve engines and how difficult those can be, but they are only tough because of the design aspects of the engine. Not that they are that difficult to get too. I’ve tried taking them out with the engine cold and with the engine hot. I prefer the hot method. Once I started taking them out that way I haven’t had near the hassle as taken them out cold (as per the procedure from Ford). Although, they are tough enough to extract, and a few choice words for the engineers may be in order, they don’t require the dexterity of a gymnast to get them out.

The transverse engines, any thoughts? Yea, I’ve got a few, especially the ones that half the intake has to be removed to get to the back plugs. What a genius design from a maintenance stand point. Yea, it sure does make for a compact engine bay, and yes, they don’t need changed as often as the older models do, but still.... what a hassle. Some of the transverse engines required you to remove the upper engine mount (the dog bone) and rock the engine in one direction to gain access the back plugs. A lot of guys would rock the engine back and forth, and when the engine was in the right spot they would jam on the emergency brake. It worked, but holy cow... dangerous! If the E-brake didn’t hold in the middle of your changing them, it could be even more difficult to extract the mechanic than just the spark plugs! The best method was to get the proper tool (Oh, gee another tool to buy) and use it to crank the engine to the right spot.

All those weird spark plug designs and sideways motor layouts had their issues, but nothing compared to the contortionist you had to be on other vehicles, or even worse how a job that looks to be only an hour or two turns into an all-day affair. One in particular that I remember so well is the mid 70‘s Chevy Vega. You know, the little car with the aluminum engine and the notorious oil consumption, yea that one. Well, there is another Vega that was available that didn’t have the little 4 cylinder engine in it. It came from the factory with a V8 squeezed under the hood.

Why do I remember this so well? I had a customer with one who wanted the spark plugs replaced. Back in the day, there was a national chain of tune up shops that was offering a 29.95 tune up for any factory original car. My customer had already asked me what I would charge and he didn’t like my price at all. The 29.95 looked like a bargain so he headed right over there.

A day or so later I got a call from the tune up place. They were questioning whether or not it was a factory set up, because they couldn’t even see the plugs. In fact, they couldn’t find it in their labor guides, either. The customer told them I did all his work, so they assumed I must have been the guy who “shoe-horned” this V8 in there. I laughed, and told them it was definitely factory assembly. The problem was the only way to remove all the plugs was to first remove the entire motor. Hey, they advertised it; they said they would do any factory car for that price, so do it!

They ended up pulling the motor and changing the plugs for the advertised price, but with one stipulation. Never to bring it back.

Another fabulous design that needs to be put on the list of all time dumb designs is the mid 80‘s GM 4WD van with a V8 engine. Now here’s one that you’ll get a work out trying to get to all the plugs. One from the deck lid, one from inside the wheel well, one with the dog house removed. Oh, and the last one... good luck. It’s buried in there to the point that you have to put your socket, swivel, and extension onto the spark plug in sections and then you might manage an eighth of a turn with the ratchet. You’ll need a change of clothes before going home on this one, because you’ll be covered in grease from head to toe as you bear hug the cross member, steering linkage, and countless other components just to get to the plugs.

It’s one of those jobs when the customer tells you they need a tune up the mechanic starts questioning their career choice. The customer says, “How come every time I ask a mechanic about tuning up my van they don’t want to do it?” Try it sometime… you’ll find out why.

What can be even more frustrating is when a car comes in with a misfire and it’s diagnosed as a faulty spark plug. The dead hole is the one that is just a fraction of an inch from the evaporator case. You can’t even see the plug, but you gotta get to it somehow. After what seems to be hours you manage to find the right combination of sockets and swivels to get that sucker out only to find the plug is completely shot. You suggest to the customer that it’s time for a tune up, and they tell you that it was just done a week ago. A little more investigating and you find that all the other plugs are brand new...except for the one you just wrestled out. Now, I have two people I want to have a little wall to wall conversation with. The engineer who designed this fiasco and the *#@^! mechanic who only changed 7 plugs.

I know I haven’t seen the worst of the worst, but I’ll bet there are mechanics out there who have run across worse ones than me. How about you guys telling me your worst of the worst? Send an email or text, and I’ll compile a list and put it into story form for later publication. If anybody knows which spark plug changes are the worst, it’s you guys and gals out in the service bays. Misery loves company, so think about your worst spark plug changes and let me know.

 

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gonzo: Over the years one of my considerations in owning a vehicle was how easy it is to change spark plugs. One thing they have improved on that you did not mention is on newer vehicles you see "Iridium" type plugs being used, good for over 100,000 miles, at least that's the claim! So you don't have to do it as much. If your in the business of reparing cars, I don't know if that's a good thing, but for the automobile owner I guess it is.

 

Also, what about the vehicles that used "wasted spark" This meant you had to change two spark plugs per cylinder. Gonzo, I bet you could come up with stories just on this one , trying to explain this to customers why a 4 cylinder needs 8 spark plugs replaced!

Edited by kenk
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Most Mercedes Benz cars use 2 plugs per cylinder. That translates into 16 spark plugs on a v8. At least they're not hard to change but 16 plugs take a minute to swap out.

 

The biggest problems we find are when compound issues hinder the spark plug access. Get a s10 with a bad motor mount and you can't get a socket onto the middle plug, the steering shaft blocks your path. Camaro's are the absolute worst in my book, I mentally blocked out the last one I did. GM must have learned from the Vega. Anything with van in the model name means covered in grease and cuts. Now you know why I specialize in tires and not tune ups.

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Most Mercedes Benz cars use 2 plugs per cylinder. That translates into 16 spark plugs on a v8. At least they're not hard to change but 16 plugs take a minute to swap out.

 

The biggest problems we find are when compound issues hinder the spark plug access. Get a s10 with a bad motor mount and you can't get a socket onto the middle plug, the steering shaft blocks your path. Camaro's are the absolute worst in my book, I mentally blocked out the last one I did. GM must have learned from the Vega. Anything with van in the model name means covered in grease and cuts. Now you know why I specialize in tires and not tune ups.

Ah, those camaro's and dual plug engines. A lot of people don't look at the needed repairs before they buy something, and then... they wonder why it costs so much. And, yes... the new plugs last longer Ken, I think that's why they feel it's OK to bury them below all the piping and electric stuff. So much for things being easier because their a newer design. ROFL........ :)

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How about the cheapo that doesn't want to buy new wires and then the plug wire boot breaks on spark plug and the customer gives you that look like it's your fault. I forgot we let engines go 130k without removing plugs and no dielectric grease on plug to stop them from getting stuck.

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I usually require plug wires with spark plug change or at least give customer the heads up that they mayfall apart. So if customer isn't prepared to handle worse ccase scenerio then I. Decline the job. Not worth the dumbfounded look n "what do we do now" moment.

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What we do in our shop to remove the spark plugs from a 3 valve ford triton engine is we do a fuel / air induction service. Leave it sit overnight. Then the following day, remove the ignition coils, and using a 1/2 drive impact gun, remove the spark plugs. When they start turning, don't leave up on the gun until they are out. This has work every time for us.

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How about the great design of the Chevrolet Chevette. Removing the a/c compressor to change the distributor cap, rotor , and wires. Brilliance at its best.

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What we do in our shop to remove the spark plugs from a 3 valve ford triton engine is we do a fuel / air induction service. Leave it sit overnight. Then the following day, remove the ignition coils, and using a 1/2 drive impact gun, remove the spark plugs. When they start turning, don't leave up on the gun until they are out. This has work every time for us.

Dave, are y'all running them out with the engine hot or cold? We started doing it engine hot with an impact and have not broken a plug since.

 

I like the induction service idea. May give it a try to loosen stuff up.

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http://www.gonzostoolbox.com/KnowledgeFolder/3valvesparkplugremoval.html

 

This is an article I wrote years ago about taking out those 3 valve spark plugs. The magazine editors said they didn't want to upset Ford by telling them their method wasn't working well out in the field. But.... it may still go out later ... IF I keep bugging them to print it.

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Dave, are y'all running them out with the engine hot or cold? We started doing it engine hot with an impact and have not broken a plug since.

 

I like the induction service idea. May give it a try to loosen stuff up.

We have done it both cold and hot. But mostly cold.

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http://www.gonzostoolbox.com/KnowledgeFolder/3valvesparkplugremoval.html

 

This is an article I wrote years ago about taking out those 3 valve spark plugs. The magazine editors said they didn't want to upset Ford by telling them their method wasn't working well out in the field. But.... it may still go out later ... IF I keep bugging them to print it.

Nice one. Agreed, the Ford method is garbage in practice. Once our master tech mentioned doing it hot and seeing it work in practice, we never looked back.

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How about the great design of the Chevrolet Chevette. Removing the a/c compressor to change the distributor cap, rotor , and wires. Brilliance at its best.

My mother in law had one of those. Every time the car came back from the dealer "tune up"-The A/C was not working!

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