I have changed lots of plugs in my life but what happened. Here is my story.
I had a problem after a plug change. Why? Did I break something in the ignition. I need recommendations for next time.
1997 855 GLT 75,000 odometer miles.
I just installed a set of Bosch #7555 (FR7DC) plugs that I purchased from IPD about 2 years ago. They replaced some Platinum 4 Bosch units that began to misfire intermittently after 15000 miles (never again will I use them).
Why did the engine have to be cranked over for a minute to minute and a half before finally firing all cylinders up to the engine idle speed? (ran real rich and then leaned to normal through the start up). Are the plugs the issue or is it my install procedures?
The car now starts and operates fine, but how can I avoid this again? I hope the long cranking period did not screw up my car?

My plug change procedure:
Removed the head cover plate, detached the turbo crossover pipe, detached accelerator cable, carefully pulled each Bougicord from plugs, removed each plug with 5/8" plug socket with 1/4" drive ratchet, sprayed aerosol brake cleaner into each plug hole to clean the plug female threads, verified plug gap, applied a slight bit of anti-seize to each plug, installed to proper torque, reversed procedures and had my long start up problem.
What did I miss?
R.E.C.

Just to be safe, I recommend using a shop vac with a home made narrow attachment to clean the plug area out. That way you don't risk getting all the stuff in the wrong place.

The anti-seize is fine, and recommended to prevent the plugs from seizing into the aluminum head. Dunno where others are getting impression not to use anti-seize on aluminum heads. I have used in ALL cars for over 20 years and no problem.

The only thing you did wrong was spraying the brake cleaner into the plug hole- egaaaad! What on earth was that about??

The brake fluid is not designed for the combustion chamber. Doubt if you damaged anything - however, may had screwed up the 02 sensors?

However, as long as you aren't throwing your CEL- the 02's are likely A'OK.

Suggest a good old fashioned "italian" tune-up ?

I am a big proponent of anti-seize compound. I use it everywhere.

I do not use it, however, on spark plugs in aluminum heads.

The torque specs for most all spark plugs are for unlubricated surfaces. Lubricating the spark plugs will result in an over-torqued thread.

Over-torquing aluminum is dangerous.

I would like to Email the anti seize manufacturer and get their perspective.
I agree that we are talking about very small torque increments that could easily strip the threads in the head-hope I get a fair & educated answer.
REC

I use anti seize and a small racket to torque by hand.

Use a 24" half inch breaker bar to tighten your plugs- and yes you'll strip the heck out of them.

This is not rocket science - just tighten carefully and you'll be jes fine.

You want the anti seize precisely because YOU DO NOY want the plugs to grow into the head.

I'd swap back the old ones to see if you did not contaminate the gap with your
brake cleaner and/or anti-seize paste.... I doubt very much but it could be possible

FYI: SPARK PLUGS TORQUE 25 Nm - 18.5 ft/lb - NOT LUBRICATED

--
Dennis

All I did was remove the cover plate, pull out the plugs, put new plugs in, attach the wires and cover plate and it was good to go. Nothing more.

Don't spray anything into the plug hole.

I agree with Mike. I've never sprayed anything into the open spark plug hole. I usually used canned or compressed air to blow out as much foreign material as possible BEFORE removing the old plugs. Then put the new plugs straight in.

Heh Trey;
Where is the best spot to pick up a can of compressed air?
I know they sell some for cleaning off computer keyboards at your local Staples or Office max but I wasn't sure that is strong enough for blowing out the spark plug cavity.

I usually loosen the plugs a few turns and then blow out the area with the plugs still blocking the hole.

you sprayed brake cleaner into the open hole? That would also push any dirt into the cylinders also.

I suspect thats why your car ran that way when you fired it up. It had to burn off the foreign material. Who told you to do that?? I've never done that.

Yes. It is important to use a soft brush or an airline to blow any debris from around the spark plug holes, prior to removing the plugs themselves. As far as spraying anything into the plugholes; it should never be done in my opinion. Even to clean the threads.

In fact the only addtitve i would ever recomend would be redex, but that should only be used if you suspect serious gunge problems in your cylinders.

Personally - i prefer not to use any additives at all during plug changing. Any redidue that has built up over the years in your cylinders should be treasured, as it (in most cases) helps to increase compression.

Anyway - thats my two pence's worth.

Hope it helps somebody...

Tony - Volvo 440 1.8 - 1992

Thank y' all for the advice.

In the future I will use compressed air to clean the deep plug chamber with a shop vacuum running, remove plugs (one at a time), clean spark plug threads with radial nylon brush and reinstall the new plugs (one at a time to keep any foreign matter from entering).
I thought that Brake cleaner would work well because it would bathe the threads clean and evaporate quickly. I now realize that the brake cleaner entering the plug & combustion chambers did more harm than good.
Now that I slept on it, I am now wondering whether the O2 sensor may have got thrown way off kilter from the brake cleaner, thus causing the long start sequence. The engine finally started after the O2 sensor was satisfied.
The idea of having even lower compression (less power) in the future from the washing off of deposits make me want to kick my other cheek.

R.E.C.

Does anybody know of any decent additives that my help increase compression then? I think that the Redex stuff I mentioned produce a fuel additive that adds some form of lubricant into the cylinders, which would probably do the trick... While this was fine for earlier simple engines, are they safe for use in today's computerised engines?

I do not know of any additive to incressure compression except to go to a thicker viscosity oil-i still would not do that.
to compensate for compression loss due to engine wear, I would go to the website: www.ipdusa.com has a adjustment procedure to increase your turbo wastegate setting 10-15 percent. The EEC can compensate back the fuel system so that you do not have to be concerned about preignition, pinging and all.
REC

I doubt if you did anything to affect the compression. But the brake cleaner may have fouled the plugs temporarily, thus causing the hard starting. So relax. Everything is probably okay.

It was a good idea you had to use anti-seize on the threads. Nothing wrong with this with aluminum heads. In fact this is where it is supposed to be used--dissimilar metals which invites galvanic corrosion and thus frozen plugs..

Probably this mantra about not using anti-seize on aluminum heads comes from the Corvair/Porche quarters. Indeed, don't use anti-seize on the threads of an air-cooled engine (all of which have aluminum heads, and were some of the first to have alumimum heads in production cars), as it acts as an insulator and makes the plug run too hot. But on a water-pumper engine, this is not a problem.

Not using the anti-seize on the air cooled engines was not that great of a problem, as the plugs ate up rapidly and needed to be exchanged every 10,000 miles or so for optimum performance, whereas now in a Volvo they will run 100,000 K and still be going strong. But try getting them out of an aluminum head after that time if they have no anti-seize. You just might take pieces of aluminum thread with you as you screw the plug out.

And then when you are torqueing the plug back in and you almost get to the torque specs and, bang , there go the rest of the aluminum threads in the head. Off comes the head and away it goes to the machine shop and there go the greenbacks flying from your wallet. And there goes your ride for a month.

You did good on the plug change except risking blowing pieces of debris into your combustion chamber and thus risking scratching the cylinder walls. With luck, which you probably have, it just blew on through and out the exhaust. That and introducing a liquid into the combustion chamber whose properties are unknown to you, which is never a good idea.