Yummybud924

My problem is that the spark plug holes for cylinder 3/ 4 look like crap, especially #4.

for # 3 the threads look alright except the surface where the washer on the spaark plug seals has black stuff stuck to it on some parts so I don't think the spark plug washer will seal airtight.

then the real problem is spark plug hole #4 when I took out this spark plug it had what looked like to be corroded metal (looked like saw dust) stuck between the washer and the surface on the block. when I cleaned it off there is now pitting ont en the surface where the washer sits.

I'm not sure if the washer on the spark plug is soupose to seal if it is then the pitting on the head where the washer goes would prevent it from sealing airtight.

also even worse about 1cm of the start of the threads is a few mm wider than the rest of the threads for spark plug 4 as if a helicoil is installed but it doesn't look like a helicoil.

what worries me also is all the saw dust looking stuff ont he old spark plug stuck between the washer and the block and some of it fell into the spark plug hole. I thought maybe this was what kept the plug sealed before I took it out and now it might leak.

the spark plug still seems to tighten but I'm worried that the washer might not seal with the surface on the head becasue there is pitting for #4 and on #3 there is material stuck on the surface.

so is the washer on the spark plug suppose to seal it so it doesn't leak pressure?

I will alsso be using antiseize on all the plugs now. hopefully they will torque without stripping as the threads on # 4 also don't look great and 1cm is basicly not there .

Yummybud924

now looking at my old spark plug one of the washers has parts of it shipped off and it is corroded pretty bad so I think the washer corroded with the aluminum head and when I removed it parts of it chipped off / pitted where the spark plug washer sits. so the surface where the new washer will seal is pitted and not completely flat and on the other wone it is slightely raised due to material stuck on it.

Yabo

run a tap through it, vacuum the hole out, then put the plug back in and see how it goes

Yummybud924

I don't tihnk a tap is necessary.

the main problem is that where the washer on the spark plug seals to the head there is pitting on the surface on the cylinder head so if the washer on the plug is suppose to seal it wouldn't .

I'm worried that it will leak compression.

Yummybud924

is there any kind of sealant you can put between the washer and the head or on the threads to prevent it from leaking (assuming it will leak).

Yummybud924

also for the #4 spark plug hole about 1cm of the begining of the threads look too wide as if it was drilled and a helicoil was installed so there isn't as much thread. I'm worried that this may cause the plug to blow out in the futur.

also when using antiseize I read that you have to use les torque. I'm scared of stripping the threads but also I don't want to undertorque it and have a plug blow out. dry tq is 18-22 ft-lbs. what should my tq be with antisezie?

I've read you should reduce it by 30-40 % so 12-15 ft-lbs should be maximum with antisezie?

yellowline

I haven't seen that. I torque normally with antiseize and haven't had a problem with any car.

KuHL 951

I also use antiseize on plugs and never use a torque wrench. I have a good feel for what's too tight. As far as the corrosion on the seat I bet someone used aftermarket plug wires with funky boots and water got down in the holes from washing the engine or the motor sat exposed to rain during an extended period of storage. Any water or moisture that gets trapped in the plug wells will steam off with normal operation. There really isn't anyway to resurface that seat without welding and machining. If they are just small surface irregularities the crush washer on the plug should seal them. Did the plugs seal before?

Yummybud924

well before like I said there was corroded metal stuck between the washer and the seat on the head when I removed it it was powderry corroded metal that was from both the washer and the seat on the head so there is som pitting. the washer will clamp but it would not seal if it needs to seal.

if it leaks or the spark plug blows out I'll be screwed. the threads also really begin 1 cm into the whole unlike the other plugs so there is less thread but it did not blow out before so I'm hoping it won't now.

so are the threads enough to stop the compression from leaking out or does the washer have to seal on a flat surface?

KuHL 951

The powery stuff is a corrosion byproduct of aluminum oxide from the seat on the head. If the crush washer on the old plug was copper then the corrosion could have been serious if water had been trapped down there for any length of time, the copper would be uneffected. If the crush washer was aluminum you would have that powder and pitting on both surfaces. You didn't say if you thought the plugs leaked before? If they sealed before I assume they would seal again. Look for an aluminum sealing washer if you are replacing plugs. You won't know if the plugs will seal until you start it up. I can't stress enough how important it is to keep water out of those plug holes; that's why the Beru boots are so good.

Yummybud924

yes the washer on the spark plug was also badly corroded and it is not copper.

I have no idea if it leaked before but it was stuck on tight before because of the corrossion so that may be what kept it from leaking. It ran good before.

I will use antiseize to help this time but like I said for spark plug #4 there is pitting now where the washer will sit so it will most likely still tq to spec but the washe will be on a pitted surface.

also for cylinder #4 I'm not sure if someone installed a helicoil or something but the threads really start 1cm into the hole so there is less thread and I though maybe the chance of the plug backing out and blowing out.

there are still threads at the ist 1cm of the hole but it is bigger than the threads on the plug so i'm guessing it's a helicoiled plug hole.


the hole for spark plug 4 has good threads and no pitting hoeverinstead the surface where the washer sit has raised areas because thin pieces of the corroded washer have stuck to this surface.


so should I still torque to 18-21 ft-lbs even with antiseize? I read that with antiseize you can strip threads on aluminum if you go to the reg dry tq specs.

I read the rule of thumb is to reduce the tq spec by 30-40 % when using antiseize.

Yummybud924

I will start the car within the next few weeks once I complete my timing belt replacement which I'm almost done....

KuHL 951

Using that 'rule of thumb' I would be very uncomfortable torqueing my 17" wheels to 55 ft-lb...I wouldn't make to the first freeway onramp before they would be gone. I'm not sure where that rule of thumb came from but I've used antisieze forever without changing torque specs.

Yummybud924

I'm just worried because the alluminum head will strip easily and if it does I'm seriously screwed as that would mean the head needs to come off and I don't have time for that now so the car would have to sit until next summer.

MM951

Try running a spark plug thread chaser thru it. Just thread it in like a sparkplug then pull it out. vac up whatever may be in ther (or if you have compressed air and GOGGLES blow the cylinder clean)