Blue smoke upon acceleration, after decelerating in gear, M66

[tardcart]

wow! sorry to doubt you. Ive never seen that. are they volvo plugs? I see Germany on them, but dont recognize the clunky tractor electrodes. only the 1/2 turn loose are damaged? did it actually run like this? may be you have made a discovery that electrodes are not necessary. you will be rich. I dont understand why they would be missing and why loose would play a part in that. better hope the answer is consumed by spark searching for a ground, but doubt that. I would think 1 2 and 4 cylinders are scored. You could see if 3 and 5 are higher compression. lucky that mechanic is not working on helicopters ( I often observe that about my self)

[tardcart]

so I just looked up electrode loss and the high frequency vibration of loose spark plugs will cause that. also detonation on highly boosted engines which would not be your case. the result is ruined piston, rings and bore. might be time to call a lawyer.

[erikv11]

erikv11; No smoke at all, on cold startup after sitting overnight. ...

Strong argument against leaky valve stem seals.

Sadly this is looking like ruined piston rings. As mentioned, definitely do a compression test.

[abscate]

It is also possible to have trashed oil control rings and good compression, unfortunately

If it is pieces of spark plugs that killed it though, it would kill both

I’m optimistic that didn’t happen. I’m amazed at the size of things that can go through an engine and not damage it. Our VWs would drop whole valve seats and we would bolt a used head on and drive it as a sole family car for 5 for two years.

[imaV70Rdriver]

Many apologies for the delayed update. Who knew there was a page two, with more queries?!

tardcart: Volvo 5254T4 spec plugs. Says "VOLVO" and "R6" on the ceramic. It ran for about 3-4 months, until it didn't. Those 1/2 turn, 1/4 turn figures were with a sparkplug socket and extension placed on the plug. I wiggled/turned the socket until it found home on the plug, only to find I could turn the plug. To finger tight, I needed to turn as indicated, then put a socket on it to torque.

Now for the news. I did a compression test today, on a warmed up engine with unpleasant results. Oddly, the trouble doesn't completely correspond with the plug damage. Before anyone asks, I performed the test carefully, ensuring a good seal prior to doing the test on each cylinder. From the front...
cyl 1. 102psi after 9 cranks
cyl 2. 119psi after 8 cranks
cyl 3. 60psi after 14 cranks
cyl 4. 109psi after 6 cranks
cyl 5 119psi after 8 cranks

All plugs were "white" with very hard "white buildup", cyl 3. being the worst, I needed to chip it off. And brass brushed all plugs before reinstalling.

RHP: No oil in the pipe leading from the turbo to the intercooler, just a light black soot. Didn't check the other due to compression test results.

A minor saga and lesson follows for the curious:

I used the free tool rental from "autozone" (one of our local parts suppliers), to get a compression tester and borescope. Yesterday I pulled plug 3 because it was easy to get at, and stuck the camera down the hole. Even with the dismal light on full, I really couldn't see any more than the top of the piston. Let's attach the mirror! With no instructions, but looking simple enough, I did so, and again put the camera down the hole. In short order the 10mm x 13mm mirror on it's 2 1/2 inch long iron containing metal rod, along with its plastic retaining clip, had removed themselves from the camera, and settled on the piston. What to do? With some luck, and about an hour and a half of exhausting precision work, I fished the mirror out of cyl 3 with a magnet, and after some effort, abandoned the plastic clip. Funny that cyl 3 was the cylinder where I lost the plastic clip, and it is also the really low psi cyl. Jammed in the valve? Or other? Should I try the mirror again?

Today, to prepare for the compression test, I undid/loosened, the turbo to intercooler over-engine-pipe, and plug coils so I could get at testing quicker. Then started the engine and let it warm up. No gas, just idle. I wanted to keep the turbo cool. When warm, I removed intercooler over-engine-pipe, plug wires, plugs, injector electrical connections, cam position sensor electrical connections, and two ground wires on valve cover. Then I did the compression test, with results above.

After doing the compression test, I thought I'd use the camera with the same mirror to check cyl 1. but this time I'll tape the livin bjesus out of it with electrical tape, eight layers over 2 1/2 inches. Stupid me thinking nothing could go wrong with this setup. Seems the warmed up engine was sufficient to soften up the glue on the tape, and the electrical tape itself, and somehow, the mirror again ended up on the piston, this time piston 1. Unable to fish it out per yesterday, today...

...from the sewing kit I obtained some substantial thread type product, and hot glue adhered it to a neodymium magnet, wrapped over and over, and glued and glued, and dropped it down the hole in search of the rogue mirror. With the aid of various other instruments, like bent copper wire, I located and got the mirror to the hole but it was turned sideways and wouldn't come out of the hole. I obviously pulled too hard as I ended up yanking the magnet off the string, where it found one of the valves, with the mirror attached. Well now I really needed a good idea but all I could come up with was to do the same thing again, but better. I again hot glued and tied (this time) upholstery thread to another neodymium magnet and forced it through the hole, and with much wrangling, got the mirror in line with the hole. Then I used the copper wire hook to hook around the mirror and gently coax it up the hole a bit, and then used a combination of magnet and hook to fish it out. Then I went after the magnet. Two hours later I was back to square one.

So the lesson is ...don't put things in a hole...unless you can be sure you can get them out...or something like that. But seriously, watch the garbage tools when working around engines with the plugs out!

I put things back in working order, and the car runs fine.

So the ultimate question is...what are my options? 300hp isn't really enough, so rebuild really well, with upgrades? Must be CARB approved. Buy a used motor and take my chances? Everything else has been well maintained and everything works, with new air con sys, all wheel drive, 4-C active suspension, 4-pot Brembos all around, and a 6-speed, all in good order. I really like this car and would need to spend a lot of money to get the same features on a newer car, if lucky enough to find. All comments and suggestions welcome.

Boroscope mirror lodged in cylinder at sparkplug hole

[tardcart]

You did the impossible getting the magnet off the valve. your back must hurt bending over the engine that long. Just run it as-is while you keep an eye out for another engine. If you ever take the head off report what damage if any you observe from the electrode loss cylinders. another thing to not put in the spark plug hole is the little red pipe on wd40. A friend gave his cylinder a blast and it shot right in and wouldn't come out. I advised to not worry but was thinking of molten plastic gumming up the rings. we dont even need to get on the topic of rags getting sucked into the intake and dissapearing

[abscate]

On a coil on plug car, right after you pull the plug, you put the coil right back on the hole. You don’t leave the M6 in the coil, as it is just dying to make the little jump and then the long dive into the engine...yelling Geron...ivolvooooooo!

[imaV70Rdriver]

tardcart: My late father pressed perseverance, many times reminding me life's tasks are often neither easy nor fun, but must be done. He'd show me "once", how to do something, never twice. Thanks for recognizing and acknowledging the difficulty with the magnet on valve. I was on the verge of pulling the head. And yes, my back is quite stiff today.

I'll run it as is for now, as suggested. Anyone got links to a shop 5254T4 rebuild manual with specs and tolerances? Or a source for such?

This is a link to the "not-to-be-used" borescope. The black plastic ring is "lost" in cyl 3. (thinking of molten plastic gumming up the rings) I'll also watch the rags in the future.

https://www.autozone.com/loan-a-tools/l ... 787837_0_0

abscate: I've lost way too many bolts over the years, now I try to store them in their correct holes. As for the M6's from the coils, I screw them into the holes for the blue engine cover that had to be removed, out of the way a bit.

I'll update with pics if I get into the engine in the future. Thanks for the comments. Safe driving all.

[abscate]

abscate: I've lost way too many bolts over the years, now I try to store them in their correct holes. As for the M6's from the coils, I screw them into the holes for the blue engine cover that had to be removed, out of the way a bit.

magnetic cup at the work space - you can both safely store and organize fasteners until, on a big job, you measure and label them into their own baggie.

You can also just return them to the holes with a couple of finger twists.

I still remember when I lost an intake manifold bolt - an odd duck, put out an appeal, and Kally posted where I had dropped it and where it was stuck - from 150 miles away.

[EngineeringBloke]

Just great job for recovering from the mirror and magnet drop. Well done for persevering. It was a good thing to do.