3100 diagnosis (huge knock)

[rfingon]

Hey all,

I have the engine out of my '96 GA SE. Prior to my ripping it out,
I was driving down the road after getting a fresh tank of gas. One and a half minute later, my engine cuts out and flashes an oil light. I coast it off of the main drag and wait three minutes. The oil is a quart low. I try to start the car and the battery sounds like it is going to die, then slowly the engine gets gas and fires, followed by a horrendous knocking--meanwhile the engine sounding kinda like it was missing. I turned it off and ol' Dempsey dawg (see immediate left) and I start hoofing it to the nearest phone (left the damn cell charging at home) to call a friend for a ride. I tow it to my house and proceed to pull the 3100 from its perch.

I finally got it on an engine stand tonight and drop the oil pan. The bottom of the pan seems sludgy, although in the middle of the pan I can feel some finely ground metal particles (not many), and the front of the pan (serpentine side) has some small metal chunks (1mm x 9mm the largest). A visual inspection of the rods and crank does not reveal anything out of the ordinary (stated the greenhorn!javascript:smilie(':D')
big grin.) I was able to wiggle all of the connecting rods a little except for one in the middle (dunno if it was cyl 3 or 4). I am wondering what to rip apart next. Any advice would be appreciated. I also took some pics but haven't uploaded them up to me computer yet, and I would like to rip off that one plate covering the crankshaft and take some more pics.

Me motor only has 131, 600 mi on it.javascript:smilie(':toilet:')
Toilet

[thegrimone]

lifter maybe? pull the valve covers and then the push rods, hand turn the motor and see if it binds up.

[rfingon]

Sounds good to try. Just out of curiosity, how loud of a knock would a lifter make? When I first heard the knocking, it was friggin' loud. I guess that is initially why I thought I spun a bearing.

[rfingon]

I ripped the valve covers off, and since I have never taken out pushrods before, I decided to ratchet turn the crank anyway. What I noticed was the front rocker arms were moving (on both sides of the engine), but no rear ones. Does this suggest that my cam is broken? I hand turned the engine several times. In addition, does this indicate some severe valve (or piston) damage? I have a line on a used 3100 with low miles for $500, and I am thinking of going this route to get the GA going again.

[thegrimone]

yes if only half the rockers move then the cam is broken in 2 or more pieces. You may have done damage to your pistons and/or valves on the cylinders that were not running. If you can get a whole engine for 500 and it runs go ahead its going to cost more than that in repair.

[rixGAphx]

Precisely.

Your cam broke.
The rear bearings on the camshaft *prolly* seized from lack of oil, causing the breakage;
And/or, the oil pump (driven by a gear on the rear of the cam) failed to pump oil to the rest of the engine, including the crank and rod bearings, when the cam broke.

You did NOT damage the pistons or valves as a result of the cam breakage.
The 60*V6, in OHV form like our 2.8/3.1/3.4's, have 'free-running' valves that never contact the pistons even when the valve train fails.

Most OHV engines are like this.
Many SOHC heads, especially 2-valve, are also free-rrunning'.
*Most* DOHC heads, with 4 valves-per-cylinder, have so little clearance that the valves, when open, will be SMACKED by the pistons at TDC.
* * *
To rebuild this engine, you at least need a new camshaft, and to have a machine shop remove the old cam bearings and insert new ones (not a DIY job).
Plus a gasket set, and if yer smart a set of rings, bearings (crank and rod), oil pump, and new timing gears/chain.

IMO, your parts plus cam bearing machine work would be right about $500.
Plus your labor.

But you would have a much better ('fresher') block than the $500 j/y of unknown history.

Good luck,
-Rick

[rfingon]

I went down to Pleasanton KS and picked up the $500 3100 out of a 1997 Buick Century. The shop owner purchased the car from auction and parted out the car, which had been hit in the side. It has 17K miles on it, and it looks super clean. He had placed Marvel Mystery oil in the cylinders, and prior to my arrival, he turned it over (I am assuming that he used the starter, as the tranny was still hooked up to it) and shot oil about 30-35 ft out of the spark plug holes (his garage was a bit of a mess after that). So I would say this block has great compression.

I keep reading on previous posts that 3100's are plentiful and cheap. After using the internet to find salvage yards within a 100 mi. radius of Lawrence and doing a bunch of calling around, most garages wanted an average 0f $700-900 +/- a core. Alot of these engines had around 100K miles on them as well. I conclude that 3100's are no longer cheap, and I got a good deal.

[rfingon]

BTW, thanks for the great info Matt and Rick. I really enjoy the extra info I get or read on this site. Kudos.

[rys99grandam]

Screaming deal, cant go wrong with a 17k motor thats only what 10 years old now? thats like 1ishk a year!

Lets us know how she go after you put her in.

[rfingon]

I most definitely will.

[rfingon]

Looking at both of these engines, I have to swap the heater core lines and the fuel lines with the disconnects. Quick question: do I have to remove the upper intake manifold to disconnect those fuel lines?

[thegrimone]

I don't think its possible to do while the UIM is on.

[SpoCom2nr]

Originally posted by rfingon
I ripped the valve covers off, and since I have never taken out pushrods before, I decided to ratchet turn the crank anyway. What I noticed was the front rocker arms were moving (on both sides of the engine), but no rear ones. Does this suggest that my cam is broken? I hand turned the engine several times. In addition, does this indicate some severe valve (or piston) damage? I have a line on a used 3100 with low miles for $500, and I am thinking of going this route to get the GA going again.

It could be. I seen a camshaft on your engine snapped in half once...

[bballr4567]

Originally posted by SpoCom2nr
It could be. I seen a camshaft on your engine snapped in half once... Yup. IIRC about a month ago someone had the same exact thing happen except it was the 3400.

[rfingon]

A brief update. To get this Buick Century engine in my car, I also had to use the exhaust manifold and the motor mounts. Actually had that motor just about dropped in when I noticed that the guide pin (or collar, if that is what it is called) on the firewall side of the engine is installed on my block. On my '96 GA, the guide pin is on the tranny. I have one pin too many, so I would like to get this out of the Buick block.

Next question, how in the bejeebers do you get this pin out? I was thinking about drilling it out with a 3/4 " bit. If anybody here has dealt with this situation before, any suggestions would be greatly appreciated. The swap has come to a grinding halt....

[rixGAphx]

It's a steel dowel, and it's much easier, and more common, to release it from the aluminum tranny/bell housing than from the iron block.

So the question isn't so much why is there a dowel in the block, as why didn't you remove the dowel from your tranny when you separated it.
Or rather, how did you get the dowel to release from the orginal engine?
The same technique should work for removing the same piece of metal from the Buick block.

Either way, its a press-fit. Mebbe a little bit of 'knurling' on the dowel, but nothing significant.
WD-40 the hell out of it, to dissolve any rust-welding.
Grind the round shank of the dowel, to put enough of a 'flat' (or a couple 'flats') onto it for great grip with a wrench.
Pound on it, to dislodge the steel from the iron (or the aluminum, depending on which you're removing).

Heat and cold are your friends.
First, heat the surrounding iron/aluminum for expansion, using heat lamp or whatever to get it to about 100*F.
Use dry ice to chill house-brand vodka to -20*F; drip it onto the steel dowel to cause a tad of shrinkage.
TWIST like crazy on that wrench, since you only have a few seconds before the warm surrounding metal and the cold dowel 'neutralize' their temperature difference.

I *think* it would be easiest to use a press to push the dowel out of your tranny.
A portable press can be made out of some scrap steel and a couple of large C-clamps.

Hope this helps,
-Rick

PS: Drilling it out might work, just take care not to damage the hole.
The dowel needs to be a tight fit when the whole thing is assebled.

[rfingon]

Thanks Rick. I couldn't tell you why that pin stayed with the transaxle, but it did when we separated it originally. I think I will try to tackle the one in the aluminum housing of the transaxle. Unfortunately, I have no access to a heat source, like an oxy acetylene setup. I will try the press method.

[rfingon]

oops forgot about the ol' propane torch, and that is plan B (if the press idea doesn't work).

[rfingon]

Rick, you're the man! I went with plan B with some dangerous modifications (don't try this at home): a propane torch and some freezer-chilled 95% ethanol. If I went to work I could probably scrounge some free dry ice. I lightly heated the aluminum surrounding the dowel with the cool part of the flame -- no heat directly on the dowel. Then I applied some ethanol from my chilled squirt bottle (a.k.a. the dangerous part -- if the aluminum is too hot you could get a flash from the ethanol and start a fire). With vice-grips already grasped, I wiggled on that baby and she seemed to break loose slightly. I turned off the torch and grasped the vice-grips again and pulled it out like a tooth. The dowel was quite rusted, so methinks that is why she stayed in the bell housing.

Finally, I am off to put a "new" powerplant in the GA.

[rfingon]

I have the engine in the GA, but at first it wouldn't start. The battery was drained from three weeks of not being used. I trickle charged the battery and tried to start it tonight, and it will not turn over. I get an oil light, check engine light, brake light, radiator light, and theft system light. A couple of the relays are clicking (one near the battery, and one on the passenger firewall). Any ideas??....

[rfingon]

Is 5 consecutive posts in a row some kind of record? Ladies and gentlemen--crisis has been averted. Apparently, I forgot to hook up a crucial black cable to the starter (what a rookie mistake). Once hooked up, she fired up and was idling quite rough (burning out the Marvel Mystery Oil). The check engine light was flashing, then after another car start it was a solid light. I took the car around the block while it was running rough, then just let it idle for about 5 minutes. She is running smoothly now and I am resetting the PCM by letting it sit for 10 min. with the negative cable off.

I am a pretty happy camper right now (after three weeks of not having the GA around).