I think this is the end

"roflcopter" (roflroflroflcopter) 04/10/2015 at 20:27 • Filed to: None

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I had the LOLvo all running again earlier this week(you might have seen the post) and decided I should check the compression out of curiosity and the timing definitely needed to be adjusted as it was idling funny and power was way off from where it used to be. As soon as I got off work I stopped by my buddy's shop and tested the compression. It was way better than expected at around 118-118-125-130, which is a bit of a large spread, but all high enough it should run with no issues. Next up was the timing. I went ahead and advanced it a decent bit to hopefully get rid of the backfiring and gain back some what little power this car has and it idled much better. Went a little further and it seemed to stumble a bit and not be nearly as happy so I planned to back it back off and go drive it around the block and see if I was happy.

After backing it off, I try to start it and hear a faint pop and then the motor starts turning over at a much higher RPM(but not starting). After checking to make sure the ignition and fuel systems were still working properly I throw the compression tester back on the motor. Turns out something let go and I'm making damn near zero across the board.

If no one offers me more than scrap prices by the end of the weekend it will be making the short journey to the scrap yard and I'm going to go buy myself a nice bottle of scotch.

You can tell a Finn but you can't tell him much > roflcopter 04/10/2015 at 20:30

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Sorry man.

TopSirloin > roflcopter 04/10/2015 at 20:38

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Bye bye valve heads.

pip bip - choose Corrour > roflcopter 04/10/2015 at 22:52

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LS swap?

roflcopter > pip bip - choose Corrour 04/11/2015 at 11:42

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If I had the funds to do anything with it currently I would definitely be keeping it and doing something stupid, but a complete lack of money has made that impossible.

brianbrannon > TopSirloin 04/11/2015 at 11:53

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Timing belt is easy to change...

TopSirloin > brianbrannon 04/11/2015 at 14:30

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That's not what happened.. The timing was advanced too far and valves were still open when pistons were headed up, likely smashing into the still open valves and breaking them, thus losing all compression. Cylinder head is probably toast.

brianbrannon > TopSirloin 04/12/2015 at 11:10

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Adjusting your ignition timing doesn't change when the valves are open relative to piston position. P.S. I was a Volvo tech in a former life.

TopSirloin > brianbrannon 04/12/2015 at 15:02

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This is my line of thinking when trying to solve rough idle or backfires, straight from the internet..

" Ignition timing , in a spark ignition internal combustion engine (ICE), is the process of setting the angle relative to piston position and crankshaft angular velocity that a spark will occur in the combustion chamber near the end of the compression stroke ."

To me this means altering intake valve timing/exhaust valve timing to most efficiently convert the air and fuel mixture within the cylinder at the point in which the cylinder is at it's smallest (piston at TDC), so I'm not sure how you consider ignition timing to operate independent of valves and pistons. They're inextricably linked. Are you isolating actual sparkplug pulse timing with what you're referencing?

brianbrannon > TopSirloin 04/12/2015 at 15:34

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The only thing you are changing when turning the distributor is when the spark plug fires relative to the piston position. Your article references crankshaft position (piston position) only, no mention of valve position because they are not linked. The valves in your engine won't ever hit the pistons because they don't reach down into the cylinder bore. It's a non-interference engine.

To get zero compression your timing belt came off or skipped teeth or the camshaft broke. A quick check is to look at the cam through the oil fill hole while someone cranks the engine.

TopSirloin > brianbrannon 04/12/2015 at 15:49

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ahhh mechanical ignition time.