Advice on back plugs

[apierce]

Hey folks,

I tried to replace my plugs recently and while doing so found that my back two plugs are in tough shape. There is a lot of rust down there...I assume because the pitch of the engine would make the water flow back there. When I tried to get a socket down there the first time it just spun on top of the corrosion. After 30 minutes of wd-40, scraping, and blowing air I managed to get mediocre grip on it but it wouldn't budge.

I am pretty scared of breaking those plugs trying to get them out. Does anyone know how I should handle this? I was thinking of using an impact wrench but again I am worried about cracking them.

If I can get them out do any of you have a trick to keep the water out away from these two plugs?

Thanks

Adam

[luxuryrules]

Skip the WD40 and go right to liquid wrench, or PB blaster, or something similar. Let it soak down there for a while, then get the socket down there and make sure you are 100% on the plug. Use a breaker bar to get it moving, but only move it part of a single turn. Let it sit for a while to ensure that the penetrant has dried. Then, spray some compressed air down the plug tubes to blow all that stuff out of there (otherwise, you pull the plug and it drops down into the cylinder....). Be thorough about getting all the stuff out. Then, and only then, are you ready to change the plugs.

Beyond that, you probably already know to use anti-seize on there because these are aluminum heads, right? 7 feet of torque is all you need on the plugs, and of course you want to thread them in by hand at first to be 100% sure they aren't cross threaded.

Good luck!

[bojo68]

Ya might wanna try doing it with the engine hot. There could be some aluminum expansion, thereby letting the plug come out easier. Considering how common it is for threads to come out of aluminum heads with plugs, I'd suggest ya might wanna leave no stone unturned in trying to avoid a brute force situation.
Admittedly, I don't remember how much threads these plugs have on them, but if they're the short ones, it's especially important.

[luxuryrules]

Ya might wanna try doing it with the engine hot. There could be some aluminum expansion, thereby letting the plug come out easier. Considering how common it is for threads to come out of aluminum heads with plugs, I'd suggest ya might wanna leave no stone unturned in trying to avoid a brute force situation.
Admittedly, I don't remember how much threads these plugs have on them, but if they're the short ones, it's especially important.

Five to six, if memory serves.

[Bluegrass]

Take it slow and easy with cleaning and soaking the plug well area because you lose the threads or break a plug off, it means the head/s have to come off.
Believe it or not this is still a major problem on motors from 06 upward.
First it was to few threads blowing plugs right off the motor and taking coils with it.
Then on the 3 valve motors, a redesign froze plugs in place.
New plug design didn't fully solve the problem.
Trick so far is to change them at about 30k so they don't get a chance to set in place and cause a major problem.
Owners get in to a real pickle just haveing a dealer do the plugs and get into this big problem that ends up costing the owner big bucks because a simple plug change turns into a major fight with the dealer and Ford.
Good luck.

[apierce]

thanks for the tips guys. My car is sitting at the dealer right now for unrelated reasons but you have convinced me not to let the do it.

Luxuryrules....just so I don't screw up your directions...you mention "a while" for letting the penetrant soak and then dry after the turn. Could you ballpark me what kind of times you are thinking for those.

Much thanks

Adam

[luxuryrules]

Couldn't begin to guess, my main concern is just making sure nothing drops into the cylinder when the plugs come out, so just use your judgement (and a good light) to figure on that.

Maybe put a qtip in something long to swab around down there and ensure it is dry (or at least not soaked)?

[bojo68]

Take it slow and easy with cleaning and soaking the plug well area because you lose the threads or break a plug off, it means the head/s have to come off.
Believe it or not this is still a major problem on motors from 06 upward.
First it was to few threads blowing plugs right off the motor and taking coils with it.
Then on the 3 valve motors, a redesign froze plugs in place.
New plug design didn't fully solve the problem.
Trick so far is to change them at about 30k so they don't get a chance to set in place and cause a major problem.
Owners get in to a real pickle just haveing a dealer do the plugs and get into this big problem that ends up costing the owner big bucks because a simple plug change turns into a major fight with the dealer and Ford.
Good luck.

Guess that explains why ya see them on ebay. One would think that after 16 yrs of production, ford could figure out a spark plug. Doesn't look like they want to to me. I can't believe they're not smart enough to know better, and that only leaves they're doing it on purpose to screw people..

[luxuryrules]

I can't believe they're not smart enough to know better, and that only leaves they're doing it on purpose to screw people..

They're simply trying to cut production costs left & right. First by making the tops of the heads too thing, thus resulting in only a couple of threads for the spark plugs. Then by taking a shortcut cutting threads (and leaving excess scrap in the way) is what is freezing them in place (as I understand it).

Stupid? You betcha. Malicious? Nope, not in the least. The reason it's still happening after sixteen years is simply because they try to tweak things from year to year in order to improve performance and/or reduce cost, and they don't always (or in this case, never) manage to get it 100% right.

[mikemark8]

I would NOT try to remove plugs on a HOT aluminum engine-plugs are different material and the expansion rate with aluminum is different, the aluminum would be softer at high temps and would add to your problems. It should be done when the engine is cool and the PT blaster has had plenty of time to do it's job, then take it real slow-it is not the kind of thing you want to rush through.

[bojo68]

aluminum engine-plugs are different material and the expansion rate with aluminum is different.

Yep, aluminum expands MUCH faster than iron/steel, therefor the hole the spark plug is in will be bigger with temp rise than the plug will.

[mikemark8]

It will not be 'bigger' (aluminum expands, so the 'hole' will technically be smaller) and aluminum will be softer with heat-and if there is any issue with threads, and there probably is, you could damage the aluminum threads removing the plugs.

I know from years of shop experience that any auto with aluminum heads does not get touched while hot-in fact that is generally a bad idea on ANY hot engine, but it is worse because aluminum is easily deformed with heat and manipulation. Seen it before, trust this-you are not doing yourself a favor by trying to remove those plugs while the engine is hot. As it is, there are not a lot of EXTRA threads to play with, screw up two or three and you will risk tossing a plug, common problem with these engines.

[bojo68]

It will not be 'bigger

Guess we're just gonna have to disagree on this one. I've got some shop experience too, about 39 years so far.

[mikemark8]

I have no doubt you have a lot of experience with engines but aluminum heads and blocks are another thing and have not generally been around for '39 years'-they have become popular mostly in the past 15-20 years mostly on smaller, front drivers. Aluminum expands at 4 times the rate of steel, and is more 'course' in that it does not have as fine a finish as a machined steel surface. The expansion will also have a tendency, when hot, to 'tighten' the fit between it and steel, which can and often damages the machined threads when you try to remove it-aluminum is softer than steel. Don't believe me? Google 'remove plugs from hot engine' and especially look at any sites that have 'aluminum' in the site. Universal agreement, it is a bad idea.

You are correct, we disagree-I have seen many mechanics, old-timers and newbys who rush into a job without thinking about the fact that they are causing more problems than they are repairing-anyone who removes a plug from a hot aluminum engine,especially an engine that is known for minimal thread depth, is asking for trouble.

[bojo68]

Oldsmobile and Buick had aluminum v8's in the early 60's, Range Rover bought the patent, and still uses them, not very well either.(the sleeves slide down and the engine freezes) Aluminum heads have been out in greater #'s for just as long, maybe not on american stuff, but they're out there. It's been said that vw aircooled are 1" bigger hot.(can't stand them myself, so don't know, don't care)

[mikemark8]

correct, they were 'around' in the 60's and 70's-and not real successful generally since steel blocks and aluminum heads were a bad combination (my new 1973 Vega Gt being a good example). I will stand with my statement-do not remove plugs from a HOT engine, it can only cause trouble.

[bojo68]

I'll stand by mine too, regardless I think the one to have the best input on this is Fordace, he's been around for all the trials and turbulations of these specific heads...

[apierce]

Well I cleaned them out the best I could after work today and can get a pretty good grip on them now. I tried unsuccessfully to turn them, so for now I sprayed them down and will try tomorrow morning. Here's hoping...

[bojo68]

correct, they were 'around' in the 60's and 70's-and not real successful generally since steel blocks and aluminum heads were a bad combination (my new 1973 Vega Gt being a good example). I will stand with my statement-do not remove plugs from a HOT engine, it can only cause trouble.

Your Vega had an aluminum block impregnated with silicone,(supposedly the rings ran on the silicone, but the oil filled the area in between the silicone pieces) and no sleeves, hence some of the problems. Far as aluminum heads and iron blocks being a bad combo, tell that to somebody with 400k+ on a 4.5 Mercedes.

[Bluegrass]

The lowly old Briggs & Stratton single cylinder motors without steel sleeves are a 12% silicon/alum alloy and run the rings directly on the bore with long life.
I have done many builds of these motors for kart racing and the breakin after honeing turns the oil silver until it is complete, then the wear rate goes to a low value.
The fuel used in these motors is alcohol which does not do anything for cylinder lubrication so the wear rate under racing conditions is higher than for a gas motor hence the need for freshing the motor more often than in general utility applications.

[apierce]

Since I am sure you guys are on the edge of your seats....I finally got the back two plugs out. I soaked them down with PB blaster and let them sit overnight. The next morning one of them came out by hand with a lot of effort. The other one still wouldn't budge. After a while I took a risk and put an impact wrench on it at a low psi and it ended up loosening up. I loaded the new ones up with anti-seize so hopefully my next plug job won't take an entire weekend.
Thanks for the help
Adam

[mikemark8]

glad you had a good outcome-when you threaded in the new plugs, did they go in smoothly? I can imagine what went through your head when you used an air gun on the one plug:eek: but it's great that it worked out for you.:drink: Nice going!

[apierce]

they went in fine by hand. one plug had rusty threads when it came out but it wasn't a problem to put the new one in.

well, the idea behind the impact gun (which may well have been flawed) was that the "pounding" versus the constant force might jar it loose without breaking it. For example, I have broken off a lug or two by hand but never with an impact gun. I turned down the psi to around 70 and gave it a go...don't get me wrong, I wouldn't recommend it or anything, but I got lucky

[bojo68]

Glad ya got it. I haven't really kept track of exactly which mod motors had the spark plug spitting problems, but I don't think it was any of the mark's?? Was Kinda hoping Fordace would chime in on this one.

[luxuryrules]

Glad ya got it. I haven't really kept track of exactly which mod motors had the spark plug spitting problems, but I don't think it was any of the mark's?? Was Kinda hoping Fordace would chime in on this one.

The Marks never had an issue with spitting plugs. It mainly revolved around the Triton motors and some of the SOHC models.

[turborich]

I would NOT try to remove plugs on a HOT aluminum engine-plugs are different material and the expansion rate with aluminum is different, the aluminum would be softer at high temps and would add to your problems. It should be done when the engine is cool and the PT blaster has had plenty of time to do it's job, then take it real slow-it is not the kind of thing you want to rush through.

I agree 100% on this. Let the engine cool or you rip the threads out.

[turborich]

Quite a few people have had plugs spit out of their mark. I have read about it on different Mark VIII sites. It may have been from over torque though, That would be my guess. I know the lightning 5.4 liters had issues though.

[93' Blue on blue]

Thats very true, turborich. Happened to GMAN on the other forum less than 2 weeks ago. Becoming more and more common now as these cars get older and their original plugs are being changed out.

[slow84lx]

Lots of Cobra 4v Mustangs have spit a plug out also.

Completely agreed on never removing a spark plug from a hot aluminum head. You might get lucky once or twice, but it won't take long before you are repairing threads.

[luxuryrules]

Becoming more and more common now as these cars get older and their original plugs are being changed out.

.... well... yeah. The Mark motors can develop plug-spitting problems as a result of operator error when changing plugs, but that applies to just about any motor with aluminum heads.

When I think of 'plug spitting issue' I am thinking of ones that have a tendency to shoot the factory plugs out of there, when there is a genuine design flaw and no opportunity for a ham-handed amateur to cross thread or strip the plugs. I know of a couple guys who have shot plugs out of these four valvers (Mustangs, both), but both of them had recently changed plugs and had very little wrench experience (one asked me if he should use an impact on the plugs).

So, yeah, I guess potential for spitting plugs on a Mark, but I wouldn't chalk these four valvers up on the problematic list as they are nowhere near the level of the Triton or PI 4.6.