I've acquired a kitcar that has been sitting for around 20 years. Since it had a fiberglass body, its mostly in decent condition save for a rusted through passenger side floor pan. Of course all the stuff like spark plug wires and other "soft" parts are deteriorated.
The owner says it ran fine when parked way back when.
I'm wondering if I need to completely rebuild the engine (its not seized as I can turn it over manually) or just replace all the deteriorated parts and rebuild the carbs? IE, do I need to crack the case open and take the heads off and all that?
Rebuild or not?
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Marc
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Re: Rebuild or not?
What's the ID number on the case? Some are such losers that it's hardly worth your time & effort to salvage, hopefully this isn't one of those. Grab onto the crankshaft pulley and push/pull it with all your might. It should only move a very small amount, ~.006" - you can just see that, the sound is a better indicator. A light little knock is normal, a deep thud or clunk would be a bad thing, indicative of a thrust bearing that's moving in its bore - a complete teardown is necessary to address that problem.
There are some things that need to be done when putting an engine into longterm storage, such as removing the rockerarm assemblies so the valves will all be shut and no springs are compressed. The biggest issue is atmospheric moisture/condensation; it'll rust the cylinder walls, valves & seats, and collect in the bottom of the sump where it'll cause an acid-like attack on the magnesium case. The fact that you can turn it over by hand bodes well, but don't crank it until you've dropped the oil (don't want to circulate any nasty stuff through the oil passages). If the first thing that comes out is water you need to be concerned about corrosion on the bottom of the sump...if you're lucky, nothing will come out but oil - clean the strainer, button her up and put some oil back in.
You may be able to drive it even if some of the valve springs have been weakened, but you also want to check that none of the valves are sticking in their guides. For an initial check, take off the valvecovers and watch the valvetrain work while an assistant rotates the crank (I'd continue to avoid using the starter just yet). Grab onto the rockerarms and tug at them as they move to see if any excessive play develops.
You can buy a boroscope (inspection camera) for $100 from Harbor Freight and peer inside the chambers, or if you feel lucky just squirt a tablespoon of light oil or ATF into each chamber and crank it over (assuming things have checked out OK to this point, it should be safe to use the starter).
Now would be a good time to do a compression test. Adjust all of the valves to about three times normal lash and leave them loose until it's been run for at least a few minutes (they'll clatter, but the extra hammering will clean some of the rust off the valve seats and faces)...then run another compression test; if the readings are >100 and fairly even (say, within 20%) it should be worth going through the carbs and firing her up. Keep the revs down at first and be observant as you press it further for any signs of valve float. It IS possible to replace the valve springs with the heads on, but it's a rather kludgy operation and IMO not worth going through until you're satisfied that no major surgery will be needed.
Another problem that develops when a car is idle for a long time is the clutch disc tends to rust to the flywheel and pressure plate (again a result of atmospheric moisture). Using a stick against the seat frame to hold the pedal down or adjusting the cable super-tight will prevent this from happening. Usually it's possible to break it free by starting off in gear and romping hard on & off the throttle with the pedal depressed (best done in a parking lot or deserted stretch of road with your hand on the key so you can switch off if a sudden stop is needed) but if that fails the engine has to come out...just something else to consider as you're trying to decide whether to yank it or screw around trying to revive it in-place.
There are some things that need to be done when putting an engine into longterm storage, such as removing the rockerarm assemblies so the valves will all be shut and no springs are compressed. The biggest issue is atmospheric moisture/condensation; it'll rust the cylinder walls, valves & seats, and collect in the bottom of the sump where it'll cause an acid-like attack on the magnesium case. The fact that you can turn it over by hand bodes well, but don't crank it until you've dropped the oil (don't want to circulate any nasty stuff through the oil passages). If the first thing that comes out is water you need to be concerned about corrosion on the bottom of the sump...if you're lucky, nothing will come out but oil - clean the strainer, button her up and put some oil back in.
You may be able to drive it even if some of the valve springs have been weakened, but you also want to check that none of the valves are sticking in their guides. For an initial check, take off the valvecovers and watch the valvetrain work while an assistant rotates the crank (I'd continue to avoid using the starter just yet). Grab onto the rockerarms and tug at them as they move to see if any excessive play develops.
You can buy a boroscope (inspection camera) for $100 from Harbor Freight and peer inside the chambers, or if you feel lucky just squirt a tablespoon of light oil or ATF into each chamber and crank it over (assuming things have checked out OK to this point, it should be safe to use the starter).
Now would be a good time to do a compression test. Adjust all of the valves to about three times normal lash and leave them loose until it's been run for at least a few minutes (they'll clatter, but the extra hammering will clean some of the rust off the valve seats and faces)...then run another compression test; if the readings are >100 and fairly even (say, within 20%) it should be worth going through the carbs and firing her up. Keep the revs down at first and be observant as you press it further for any signs of valve float. It IS possible to replace the valve springs with the heads on, but it's a rather kludgy operation and IMO not worth going through until you're satisfied that no major surgery will be needed.
Another problem that develops when a car is idle for a long time is the clutch disc tends to rust to the flywheel and pressure plate (again a result of atmospheric moisture). Using a stick against the seat frame to hold the pedal down or adjusting the cable super-tight will prevent this from happening. Usually it's possible to break it free by starting off in gear and romping hard on & off the throttle with the pedal depressed (best done in a parking lot or deserted stretch of road with your hand on the key so you can switch off if a sudden stop is needed) but if that fails the engine has to come out...just something else to consider as you're trying to decide whether to yank it or screw around trying to revive it in-place.
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PEPPE
- Posts: 763
- Joined: Tue Jun 12, 2001 12:01 am
Re: Rebuild or not?
sometimes i discovered also sticking pressure relief valves, causing explosion of the oil cooler.