Opened engine to find my worst nightmare... advice needed.

[Arith2]

I am pretty sure you have to disconnect them anyway. It would be a pretty big pain in the ass to do the engine pull without disconnecting the AC lines. Might be possible, but I'm not sure it is worth it.

It's pretty much impossible. I forgot to mention this.

You're to have to open the A/C system. The way to do it safely, for you, is to first make sure the area is WELL VENTILATED, and take a small screw driver pushing down on one of the A/C post valves. I'd not do this all at once because breathing the refrigerant in is very bad for you. R-13 in the early 90s wasn't really harmful to people but R-134a is. New cars have switched to R-1234yf which can be deadly to humans. They get progressively better for the environment though. Just so you know, this it is illegal to dump refrigerant into the atmosphere like it's illegal to pour oil down the drain. The system should be at around 70-80 psi throughout so it doesn't matter which valve you use. The pressure equalizes when the compressor is off for like 30 minutes so you won't have 150psi spraying out. It does come out aggressively to still push the screw drive out of your hand. Wear a rubber glove and long sleeve shirt.

[heinzboehmer]

Would pulling the front end off would require messing with the AC lines and stuff? Honeslty I have no clue what I’m doing with that

I've pulled the front end off multiple times and have always just moved the condenser out of the way and rested it on top of the engine. The lines are not rigid all the way, so you can move the condenser around.



You obviously won't be able to rest the condenser on the engine, but it's possible that you can move it out of the way enough so that you have room to do everything. At the end of the day, having the front end off is not a necessary step for removing the engine, but rather something that will make your life easier by giving you more space to work with, so having to work around the condenser is not going to stop you from pulling the engine.

[heinzboehmer]

You're to have to open the A/C system. The way to do it safely, for you, is to first make sure the area is WELL VENTILATED, and take a small screw driver pushing down on one of the A/C post valves. I'd not do this all at once because breathing the refrigerant in is very bad for you. R-13 in the early 90s wasn't really harmful to people but R-134a is. New cars have switched to R-1234yf which can be deadly to humans. They get progressively better for the environment though. Just so you know, this it is illegal to dump refrigerant into the atmosphere like it's illegal to pour oil down the drain. The system should be at around 70-80 psi throughout so it doesn't matter which valve you use. The pressure equalizes when the compressor is off for like 30 minutes so you won't have 150psi spraying out. It does come out aggressively to still push the screw drive out of your hand. Wear a rubber glove and long sleeve shirt.

I do not recommend doing this at all. Venting refrigerant to the atmosphere is incredibly harmful. R134a has a global warming potential of 1430, meaning that releasing one gram of R134a would have the same global warming effect as releasing 1,430 grams of carbon dioxide (wikipedia).

Also, he'll need to refill his AC system anyway, so why not get the correct tools and drain the system correctly instead of dumping everything into the atmosphere?

[Albertan]

I do not know why people do not drop everything out the bottom. It is way easier. Jack car up about 2 ft. Lower engine and trans with engine hoist. Leave engine on crossmember. 4 bolts plus sway bar and some suspension. Easy. Roll all away on a skate board or wheel dolly.

[SteelGreyM]

I do not recommend doing this at all. Venting refrigerant to the atmosphere is incredibly harmful. R134a has a global warming potential of 1430, meaning that releasing one gram of R134a would have the same global warming effect as releasing 1,430 grams of carbon dioxide (wikipedia).

Also, he'll need to refill his AC system anyway, so why not get the correct tools and drain the system correctly instead of dumping everything into the atmosphere?

So it seems that AC will need to be drained no mater the option of removal I choose. Thats too bad I was really hoping I could get away without doing that because I have never done it before nor do I know much about it all. Im sure something exists online about it.


I just got back from the machine shop with my head. They didn't do any work yet but I just had them inspect it and all that. He took a look at the damage between the cylinders and said that he cant really tell if it will come out with .3mm. But he says there is a good chance it will. We did a ghetto on the spot "pressure test" on the valves and cyl 1 was leaking. Those valve seats will need to be re finished and if they are still not sealing properly I most likely have some sort of bent valve - but he doubts it.

I showed him photos of the block and that nick in the wall. It *may* be able to be honed out. If not I will need to hope that my piston rings don't go up that high. I remember someone here said only the bottom ring needs to be underneath it -which it is - but he said if you want it done right you really want all rings to not hit that area.

unfortunately, since budget is somewhat of an issue with this (college kid problems) I won't be honing out all cylinders because that would require new rings all around. He recommended that I buy a full set of new pistons but if I want I can get away with just 1 + 6 pistons. we can put them all on the scale and even them up as nicely as possible. Plus we can coat the piston walls with a moly like substance that will not only help lower friction but also help fill clearances.

Only good news I got today is that theres a very good chance that the crank and bearings are perfectly fine.

What im really trying to avoid here is a bore out job... at that point id rather just get a new block and call it a day.

This all really comes down to 1 thing... can the small nick in the block be negated. If so, id need a rehone on 1 cyl, head resurface, valve seats grinded, block sanding, 2 pistons + rings. And obviously the head gasket.

Plan of action here is to get the block done first. If thats unrepairable ill cut the whole plan off there and buy a new block.

[heinzboehmer]

So it seems that AC will need to be drained no mater the option of removal I choose. Thats too bad I was really hoping I could get away without doing that because I have never done it before nor do I know much about it all. Im sure something exists online about it.

Luckily, draining and refilling the AC system is no big deal.

https://nam3forum.com/forums/forum/m...rvice-charging

[SteelGreyM]

Luckily, draining and refilling the AC system is no big deal.

https://nam3forum.com/forums/forum/m...rvice-charging

Fantastic!

I guess the last question is should I go up to a .7mm head gasket if im removing .3mm - .4mm of surface? I think that will restore factory specs.

[ClevoCapri]

Just buy one piston and rings. Get the block decked. Light hone of the bore, skim the head and chuck it back together. That will get it going again. Then start saving for a replacement!

[andrebxp]

Looks identical to my S54 when I blew the gasket between 5 + 6.

I ended up buying a blown motor and using the head, block, and pistons off that blown one since it spun a bearing.

[SteelGreyM]

Just buy one piston and rings. Get the block decked. Light hone of the bore, skim the head and chuck it back together. That will get it going again. Then start saving for a replacement!

Lol i was kinda thinking the same. Might just be the best choice to bite the bullet and get a new block and pistons. I like to do things properly and id be kidding myself if I said thats proper.

Screw all this. Im gonna buy a new block. If you know anyone selling one.. send them my way

[Arith2]

I do not recommend doing this at all. Venting refrigerant to the atmosphere is incredibly harmful. R134a has a global warming potential of 1430, meaning that releasing one gram of R134a would have the same global warming effect as releasing 1,430 grams of carbon dioxide (wikipedia).

Also, he'll need to refill his AC system anyway, so why not get the correct tools and drain the system correctly instead of dumping everything into the atmosphere?

Global Warming....

[beefaroni]

I have never heard of a head gasket blowing out like this. As if my auto-chondria wasnt already bad enough

[Icecream]

I do not recommend doing this at all. Venting refrigerant to the atmosphere is incredibly harmful. R134a has a global warming potential of 1430, meaning that releasing one gram of R134a would have the same global warming effect as releasing 1,430 grams of carbon dioxide (wikipedia).

Also, he'll need to refill his AC system anyway, so why not get the correct tools and drain the system correctly instead of dumping everything into the atmosphere?

Given the millions of cars that leak their r134a out (with no regulation or checks) and the wide availability of refrigerant available at parts stores for people to refill back into their leaky systems to, you guessed it, leak again, it stands to reason the r134a from this M3 will effectively make zero difference to the planet. No one really gives a f*** about the environment, if they did they we would all stop reproducing and live in mud huts lol. Carry on.
But it is true, you do not need to disconnect anything from the AC system, just swing it aside carefully like I did (didn't want to hurt the environment) and absolutely take the front end off since it is so easy to do.
Also, OP, where are you located?

[SteelGreyM]

Given the millions of cars that leak their r134a out (with no regulation or checks) and the wide availability of refrigerant available at parts stores for people to refill back into their leaky systems to, you guessed it, leak again, it stands to reason the r134a from this M3 will effectively make zero difference to the planet. No one really gives a f*** about the environment, if they did they we would all stop reproducing and live in mud huts lol. Carry on.
But it is true, you do not need to disconnect anything from the AC system, just swing it aside carefully like I did (didn't want to hurt the environment) and absolutely take the front end off since it is so easy to do.
Also, OP, where are you located?

I like to say I care about the environment but at the same time im catless so count me out of this conversation lol.

Im in Chicago

[Papermaker]

Bring the thread back to detonation, from memory I think the technical definition of detonation is the uneven ending of combustion gases, meaning the outside edges of the combustion chamber gases are heated above the stable temperature of the air/fuel (A/F) mixture. The mixture forms free radicals that are unstable and start to burn explosively. When the frame fronts ignite, they travel across the combustion chamber and meet somewhere near the middle causing a violent release of energy. The ping or knock you hear is the sound of the flame fronts meeting. As they meet, they tear pieces of the combustion chamber and piston crown from their surfaces. The force is also transferred to the rod, crank and block.

In the seventies my father owned a 1968 Pontiac Grand Prix with a 428 ci engine. It detonated all the time regardless of the fuel octane or ignition timing. It didn't seem to bother the engine as far as I could tell. The engine designs in those days were so heavy they were inadvertently strong enough to withstand the harmful effects of detonation. In the light aircraft world Lycoming and Continental and other similar AC engine designs were built to power the AC only, not to withstand detonation. 30 seconds of detonation in one of these engines usually required complete disassembly and inspection. So, the answer about rod, crank and block damage is it depends. What to BMW dealer shops and M3 race teams do when the engines suffer detonation?

Okay, with limited information I'll take a guess about why you had detonation. Remember when the head gasket failed both combustion chambers shared their chambers with each other. During the intake stroke of the cylinder was drawing mixture through the intake valve and whatever was in the cylinder next to it. Depending on where the others cylinder is in one of the four cycles it could be drawing burning power stroke or exhaust gases which would add heat to that cylinder and possibly super heating the gasoline mixture to it's unstable level. The reverse cycle could occur when as the other cylinder went through it's 4 cycles.

Papermaker