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There have been a few threads in the past about using the 3400/3100 mains and pan on the 3.4 DOHC. Well, I got bored tonight (actually, I finally got my own engine hoist and stand) and decided to turn over the crate 96 (possibly 97?) 3.4 DOHC and pull the pan off and give the 3100/3400 pan a shot. I also wanted to pull the pan so I could find out how the factory assembles and preps a new engine.
The pictures explain it all...
1. The first pic, is the front side of the oil pan. None of the bolts line up at all. The one nearest the flywheel is 4-5 MM off, the one nearest the harmonic balancer that is not shown in the picture is also nowhere near the correct spot. In order to get these to line up, you would have to drill and tap the bolt holes into the block. The real problem is the one nearest the flywheel since its hole is right where the 3100's pans seal is, and you also cannot drill and tap a hole that intersects another hole, It just doesn't work at all. Worse, the various bolt holes from the old pan will not allow for a proper seal on the 3100's pan.
2. and 3. Much of the same, except some of the holes are only 1-2 MM off. Like that one bolt by the flywheel, this means nothing but trouble, Ovaling the holes on the oilpan might work, but... Probably not a good idea. So, NONE of the bolts truely line up, and that sucks.
So it's a heck of a challange to mount the 3100/3400 pan on the 3.4 DOHC block, It seems like the best answer if you absolutly have to do this (why?) is to somehow weld up all the old oil pan holes on the block all the way through, then re drill and tap all the holes, in other words, start fresh. Obviously a mod that is probably not wort doing. Especially when you try to fit the 88' Fiero's front engine bracket on with that massive aluminum pan, Not a prayer in the world that it will fit.
Pics 4., 5. and 6. are a nice comparison of what the 3100/3400 mains look like next to the stock 3.4 DOHC's. What a difference!! Even ignoring the mounting points on each side of the 3100's caps, it's painfully obvious just how much more stout they are. I could be wrong, but the 3100 mains appear to be steel, while the 3.4 DOHC's appear to be cast iron. In order to use them you must line bore the caps with the block. The rear main is identicle between the two engines, its the front 3 that are different. Even after you've installed the 3100 caps and line bored, there is now a definate option of adding some sort of custom main cap girdle and windage tray. The 3.4 DOHC already has a windage tray, which sorta serves as a girdle too.
Pics 7., 8. and 9. show what the engine looks like with just the pan removed. Pretty isn't it? You can also note that the oil level on the dip stick is acually just below the crankshaft and just above the windage tray, well at least untill the engine is running.
I have learned that from the factory, there isn't much thick assembly lube used. The only thing that was in the oilpan was what looked, felt, and smelled like normal engine oil, after letting that drain out of the pan, there was a greasy residue on the bottom of the pan, and straight grease below even that. The lifters and cams have big clumps of grease on them, still. All this points to how important it is to prime the oil pump, and the whole oil system till every component has it's hydrostatic layer. Don't ask me how this should be done, but it should. I have no doubt that if you were to toss the engine in, throw oil in and start it, you WILL do some damage to the bearings. I didn't pull any caps, so I don't know what they use on the bearings. Pretty cool to see all this.
The pictures explain it all...
1. The first pic, is the front side of the oil pan. None of the bolts line up at all. The one nearest the flywheel is 4-5 MM off, the one nearest the harmonic balancer that is not shown in the picture is also nowhere near the correct spot. In order to get these to line up, you would have to drill and tap the bolt holes into the block. The real problem is the one nearest the flywheel since its hole is right where the 3100's pans seal is, and you also cannot drill and tap a hole that intersects another hole, It just doesn't work at all. Worse, the various bolt holes from the old pan will not allow for a proper seal on the 3100's pan.
2. and 3. Much of the same, except some of the holes are only 1-2 MM off. Like that one bolt by the flywheel, this means nothing but trouble, Ovaling the holes on the oilpan might work, but... Probably not a good idea. So, NONE of the bolts truely line up, and that sucks.
So it's a heck of a challange to mount the 3100/3400 pan on the 3.4 DOHC block, It seems like the best answer if you absolutly have to do this (why?) is to somehow weld up all the old oil pan holes on the block all the way through, then re drill and tap all the holes, in other words, start fresh. Obviously a mod that is probably not wort doing. Especially when you try to fit the 88' Fiero's front engine bracket on with that massive aluminum pan, Not a prayer in the world that it will fit.
Pics 4., 5. and 6. are a nice comparison of what the 3100/3400 mains look like next to the stock 3.4 DOHC's. What a difference!! Even ignoring the mounting points on each side of the 3100's caps, it's painfully obvious just how much more stout they are. I could be wrong, but the 3100 mains appear to be steel, while the 3.4 DOHC's appear to be cast iron. In order to use them you must line bore the caps with the block. The rear main is identicle between the two engines, its the front 3 that are different. Even after you've installed the 3100 caps and line bored, there is now a definate option of adding some sort of custom main cap girdle and windage tray. The 3.4 DOHC already has a windage tray, which sorta serves as a girdle too.
Pics 7., 8. and 9. show what the engine looks like with just the pan removed. Pretty isn't it? You can also note that the oil level on the dip stick is acually just below the crankshaft and just above the windage tray, well at least untill the engine is running.
I have learned that from the factory, there isn't much thick assembly lube used. The only thing that was in the oilpan was what looked, felt, and smelled like normal engine oil, after letting that drain out of the pan, there was a greasy residue on the bottom of the pan, and straight grease below even that. The lifters and cams have big clumps of grease on them, still. All this points to how important it is to prime the oil pump, and the whole oil system till every component has it's hydrostatic layer. Don't ask me how this should be done, but it should. I have no doubt that if you were to toss the engine in, throw oil in and start it, you WILL do some damage to the bearings. I didn't pull any caps, so I don't know what they use on the bearings. Pretty cool to see all this.
Attached Files
Also using the other side of the caliper will give you an exact reading.
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