1995 L67 junkyard engine exploration

[2seater]

Got back to more disassembly today and glad I did. Found a couple things that will need work if it is to go back in service. A quick dial caliper measurement appears to indicate the cylinders are at least .010" oversize. I don't see it indicated on the piston top but it might be in the part number which is visible? numbers on top are 23631C and D26 A1.

 

     The block is rusty on the front exterior but the rear is pretty clean and it looks like there is a recently installed block drain plug? I didn't do any clean up before the photo. I also took a better photo of the misalignment of the timing chain damper. This is the worst I have seen. When I mock mine up on assembly I check this alignment and shim the damper out further but only .050-.060" is available unless the cover is relieved for more clearance.

 

     I stamped the rod caps with numbers and removed the caps and pushed the pistons out of the block. The rod bearings confirm it is .030" undersize. Luckily the crank looks decent but will have to see where we are clearance wise. It probably is at the limit of undersize now. The first piston I removed confirmed the rods have different markings than the LN3 and are indeed floating piston pins. The first piston also shows damage to one of the oil ring side rails. It is folded upwards which would seem to be damage from installation? Pistons #'s 4, 5 and 6 have one or more rings stuck in the grooves, corrosion and rust. One photo is an LN3 piston alongside. Very similar design although the ring spacing is a little different as well as the thickness of rings.

 

    I reinstalled #1 piston assembly so I can set up to check out the cam timing and specs. More from curiosity than anything, just to compare to our naturally aspirated LN3 engines. 

 

[DAVES89]

On 1/28/2021 at 7:36 AM, 2seater said:

I do not have a starter for it and I have no idea why it didn't run. It actually was an accident victim, and I simply chose the engine out of several cars that were lined up, which I pointed out to the worker with the giant payloader who scooped it up and carried it away to be relieved of it's heart. It was a somewhat uncertain time for the yard and the counterman originally quoted me a little higher price, like $225. He lowered the price when I came to pick it up and called it a core engine, but I am not sure why? There is no doubt their familiarity with Dave has a positive effect on their attitude?

 

I intend to pull the heads and maybe a few bearings to look inside, even if it was a runner. I already know the crankshaft is different for two reasons, it has a one piece rear seal and the flexplate bolts on with eight bolts rather than six. I also know the rocker arms in the head have roller trunnions rather than the sled type pivot, but the arm itself is just stamped steel, similar to ours. The internal condition will determine what becomes of the longblock. 

I don't think we will be getting a "Dave's discount any longer. I needed some fog lights [H11] for my wife's Enclave and rather then pay $33.99 for a pair I went to Gibson's. They were fair on the price [$5.00 for a pair] but checked my tool bag. New guys on the counter as there was a bit of a shake up again. Both Paul and Pete are out due to some back door dealings that I believe were tied to batteries and tires. Much better selection of tires since Paul has left.

[Ronnie]

Dave, if your Enclave is like my Equinox you might want to keep an eye peeled for some good windshield wipers at Gibsons. I bought some for my Equinox at Advance and they were over $60 for the pair.

[2seater]

   I don't like to hear that about Gibson's but I guess it is to be expected there would be greater scrutiny. At least they are still in business which is still a big plus.

 

   I did get a chance to check the camshaft specs this morning and it was enlightening, at least to me. The intake duration at .050" is a few degrees less than the LN3, and it opens five degrees later, probably due to the filling ability of a pressurized and denser atmosphere in the intake. On the other hand, the exhaust has about seven degrees greater duration and opens five degrees later. Getting more work from the greater charge?? I am not sure how those specs would work if it were run normally aspirated or how it would like the greater exhaust backpressure if turbocharged. I think there is some aftermarket support for this engine but it is by no means decided if it will be resurrected. Yes, it is a no name dial indicator with a cracked bezel, all that is needed for this level of accuracy?

[Ronnie]

31 minutes ago, 2seater said:

I think there is some aftermarket support for this engine but it is by no means decided if it will be resurrected

To be honest, if I was going to spend big money to freshen up an SC engine I don't know that I would start with an engine that has already been gone through once before for unknown reasons. The crank being .030 under tells me more probably happened to it than just normal wear. Usually a crank that is just worn and/or a little out of round will clean up at .010 or .020. I always suspect a rod knocking when I see a crank that had to go to .030 to clean up. Do you see any indication that a rod has been changed or one has been resized?

 

[2seater]

I agree with all of the above concerns and to top it off, I got the inside mic out and confirmed the cylinders are .020" oversize. No doubt something happened to this engine, no oil, overheated, or something else, but it has been gone through fairly recently. It is probably why that chain tensioner has so little wear, despite the terrible alignment. I will need to retrieve my big slow speed electric drill from my cottage to run the bottle brush hone through it see the true condition of the cylinders. If the cylinders are decent, and the bearing clearances are reasonable, it could go back together with rings and bearings and set it aside. I wholeheartedly agree it would be a foolish investment to do any additional machine work. To be determined. 

 

One thing I wanted to mention but keep forgetting: the plastic vacuum tubing and fittings pretty much just crumbled and snapped in pieces when removing them. I know Padgett often mentions, on the other forum, cooling the engine makes the accessory parts last longer. Unknown why, but all that spaghetti acted like it was fifty years old rather than twenty five. 

[2seater]

I found this old online printout degree wheel that I had marked up ages ago. I added the same opening, closing and centerline information in red for the ‘95 s/c engine. The numbers themselves don’t mean a lot but the overall pattern shows everything happens five to seven degrees later. The wheel represents the camshaft which turns clockwise. One other interesting item is the intake valve closing is essentially the same, which would pretty much make the dynamic compression about the same. Just some trivia

[Ronnie]

Could only guess about the reason for the cam timing differences. Perhaps to compensate for the difference in the distance from throttle plate to the valve in the SC engine???

[2seater]

I don’t know for certain either. From the little I know or have read, advancing valve timing favors low speed power and later helps the high end. My guess would be low speed power is already strong enough with the supercharger so they adjust the cam timing toward the higher end? 

[DAVES89]

This post is a lot more interesting then two [long time posting] guys "over there" asking where a relay is for the fuel pump and headlights

[2seater]

The incoming "named" snowstorm, the first of the entire winter season may impact my plans to get to my cottage to retrieve the big drill. For more useless information: I have been using it, actually my two boys, with a 7" diameter hole saw installing led can lights in the cottage ceiling?

 

Not knowing the outcome of the cylinder condition gives me time to think about what will become of the block? It may end up as a doorstop unless I could convince myself to do something extra with it. I now suspect it is probably worth about what I paid for it. I did get the supercharger and associated parts, the alternator and power steering pump and reservoir. The oil pan is junk, the major bracket on the front of the engine that carries the two previously mentioned items and multiple idlers and tensioners is cracked. The crank may be okay but has no future if something is wrong or goes wrong in the future. If the block is toast and the crank is okay, it will have no home as it will only fit an L27 or newer engine with a one piece rear seal and I don't have one. Rods would be nice to save but I have no other engine with pistons designed for locks for floating pins. I hope I get this musing out of my system before I do something silly?

[DAVES89]

I have a Milwaukee 1/2" electric drill that you can use. Just let me know. I am a lot closer then your cottage and am leaving for Texas next week so won't need it for a while.

Edited February 4, 2021 by DAVES89

[2seater]

I may take you up on that. Leaving town just as our first subzero summer like weather arrives ??

[Ronnie]

4 hours ago, 2seater said:

... Leaving town just as our first subzero summer like weather arrives ??

The man has no fear of the highway. He thinks no more about driving a 30 year old Reatta across the country than he does about driving it across town. ?

[DAVES89]

Either I am real brave or real stupid, the line is pretty thin.

The Enclave is the vehicle of choice next week as there is still more stuff to haul down. I come back in March for a week and then the 'vert goes back [to stay] in April. 

[DAVES89]

2seater, I am around most of the weekend if you want to borrow that drill.

[2seater]

13 hours ago, DAVES89 said:

2seater, I am around most of the weekend if you want to borrow that drill.

It looks like I am good for the drill. I just received a text that my son had just finished plowing the cottage, unbidden? I needed to get up that way anyway as his birthday is Monday, about 10 miles from the cottage, so perhaps there is a gift enhancer involved? Naw, he isn't that way at all. Thanks anyway!

[Philbo]

On 2/4/2021 at 1:31 PM, Ronnie said:

The man has no fear of the highway. He thinks no more about driving a 30 year old Reatta across the country than he does about driving it across town. ?

I'm the same way lol. That's what roadside assistance is for. 

[2seater]

The recent run of subzero temperatures has encouraged me to work on projects inside the house, rather than in the garage, despite the work area in the rear of the garage being heated to a moderate level. That said, I did get back to cleaning up the cylinders for a closer inspection.

 

Despite being discolored and stained all cylinders save one cleaned up well enough to be considered for reassembly. The bottle brush style hone doesn't really remove material but it does remove the overlying film and debris. #1 cylinder has parallel scratches on the minor thrust side. The scratches are deep enough to feel through mechanics type gloves. I have included a photo of the same side of the corresponding piston, which doesn't show major problems but it is the same one that has the upper oil ring rail folded upwards. I haven't tried it, but surmise that ring is locked it place and does not rotate, causing that specific damage?

 

While looking at the pistons again I noticed the S/C pistons have a wider thrust face than the n/a, even though the overall design and dimensions are very similar. I haven't tracked down what or where the pistons came from, other than they are oversized. I would guess even if they are aftermarket it would relatively match the OE design. Thrust face of n/a is 2.375" wide and the S/C is 2.75". A small difference but interesting. Many more modern engines have different widths on the major and minor thrust face, probably for the ever so slight friction reduction where the minor thrust can be considerably narrower.

 

Overall it looks like I got what I paid for, a core engine. It could be repaired, or simply reassembled with new rings and bearings and it would likely run okay, but for now, it is going to be wrapped up and placed in the corner. Just not worth investing substantial money in it. I promised myself I would gauge the bearing clearances but I don't intend to spend much time doing that. If I can find some plastigage that will be close enough for this purpose. I will keep it around for a while as the Ford 3.8 pistons from around the turn of the century would fit the rods, compression height and they are a floating pin design. Since the Ford had a .011" larger bore diameter, some oddball oversizes could be had but the tiny 7cc dish would make compression ratio very high, probably 11.5:1+. Maybe an E85 engine? Nah! 

[Ronnie]

20 hours ago, 2seater said:

Overall it looks like I got what I paid for, a core engine. It could be repaired, or simply reassembled with new rings and bearings and it would likely run okay, but for now, it is going to be wrapped up and placed in the corner. Just not worth investing substantial money in it.

I agree with this. ^^^

 

When I look at the photos of the pistons, I wonder if there hasn't been some overheating over a period of time, that caused that buildup under the oil rings that appears to be baked on? Maybe for some reason there wasn't enough oil hitting the bottom of the piston to keep them cool. Oil that is slung by the crankshaft rotating and hitting the bottom of the piston, plus oil being scrapped off the cylinder walls by the oil rings onto the skirt, helps cool the pistons. For some reason that might not have happened as it should. Maybe very low oil pressure?