Guest bobnagga Posted April 24, 2004 Share Posted April 24, 2004 hey. I got this '78 sbc 305 to drop in my '82 ZX. I've been calling around town to welding shops and such to find someone who may be willing to custom fab me some motor mounts. All the places either "don't do that sort of thing" or they just charge entirely too much for $40 worth of metal. So I've come up with another solution. adapt the existing motor mounts in the z to fit those of the 305. Basically what (i think) I"ll need to do is drill two holes crosswise in the l28 mounts and one hole in the 305 mounts. I will then get a buttload of washers and be able to move the engine back and forth on the ZX mounts to get the best possible position. This will also lift the engine enough for the oil pan to clear, and If I do it right it'll even look real proffesional like. So what's going to happen is the SBC mounts are going to "float" (for lack of a better word) above the L28 mounts on two big ass bolts. It should work. I took some measurements. It is 17 1/2 inches from the FRONT of the ZX mounts to the back of the L28. It is 18 3/4 inches from the front of the 305 mounts to the back of the motor. The space between the 305 mounts is at least 6 inches and the ZX mounts are only like 2 inch wide. That gives me 3 - 4 inches to play with and be able to position the motor. Any thoughts on the subject would be of great help. thanx. Andrew Quote Link to comment Share on other sites More sharing options...
Guest greimann Posted April 25, 2004 Share Posted April 25, 2004 Not a lot of welding (none) required. Use the clamshell style Chevy mounts and a spacer. http://home.earthlink.net/~dvgreimann/details.html Quote Link to comment Share on other sites More sharing options...
Guest bobnagga Posted April 25, 2004 Share Posted April 25, 2004 yeah, but I was going to use washers instead of spacers so as I can position the engine forward or backward in the compartment and put it exactly where I need it. And I was also going to weld a plate to the sides of the ZX mounts so as to give them some added rigidity. but yeah. That's what I was thinking... No custom fabrication necessary. Quote Link to comment Share on other sites More sharing options...
Guest bobnagga Posted April 26, 2004 Share Posted April 26, 2004 yeah. I took all my measurements today. And guess what? The ZX motor mounts aren't the same angles from side to side. I suppose that means that the L28 sat in there crooked. I didn't know that and I don't want that. So I guess my original idea won't work out. So that means I HAVE to have a custom adaptor plate made. But greimann, I been lookin at your mount pics and I'm starting to get ideas. Mine'll be a little different. Basically tall and thin. The ZX cradle bolt holes will be on one end and a 2" long cylender at the other that the 305 mounts bolt into. I'll still use spacers so as to be able to move the engine front to back. I think I'm gonna steal your tranny mount design tho... Quote Link to comment Share on other sites More sharing options...
TOMAHAWKZ Posted April 28, 2004 Share Posted April 28, 2004 if you come up with something and want pro results check out http://emachineshop.com Quote Link to comment Share on other sites More sharing options...
Guest bobnagga Posted April 28, 2004 Share Posted April 28, 2004 hey I checked out that site, but I found a machinist here in town. I guess he's the highest paid in town. but he takes on these side projects and does all kinds of conversions (but he's never done a ZX). He's coming to check out the car here next week and basically give me my estimate. He rough guessed me $4 - 500. but that's cool. I guess he wants to hang the engine in the car and center it up and get his measurements that way. If he's as good as he says he is, I may have him make me a new bell housing for my ZX 5 speed that will bolt to the 305... but at this point that's only purely speculation. Anyways. I'll keep posting and I'll eventually get those pics up I keep promising. Quote Link to comment Share on other sites More sharing options...
labrat Posted April 28, 2004 Share Posted April 28, 2004 With a ZX body and SBC motor, you can use the '72 chevy truck motor mounts listed in the JTR manual, they will bolt to the frame horns on the crossmember perfectly. You just need to come up with a series of spacers to lift the oil pan above the crossmember. I have a '72 350 in an 81 ZX, and I used about 3 1/4" to 3 1/2" on each side. The bolt holes all lined up perfectly and the angles are precise. If you want, you can slot the boltholes in the crossmember fore-and-aft, and this will allow 1/2" of adjustment or so to line up trans mount and u-joint angle. To ensure the engine is level in the car, check clearance between oil pan and crossmember, and make sure it's even all the way across (mine is one finger's thickness all the way across). Just buy the motor mounts to get the bolt hole spacing, make a template, start with 1" thick blocks of aluminum, and drill the bolt holes. 3 plates on each side, then fine tune with washers. Worked for me, anyway, and no expensive machine work needed. Total investment, about $50.00 including 3/8" drillbit and 6 grade 8 bolts. Another advantage of this is the increased leverage of the motor mounts on the engine. With cheap $6.00 autozone mounts, my motor torques maybe 1/2" under full power... my $.02 Bill P.S. with a flat bar stock trans crossmember and 2" of spacers between the trans mount and crossmember, my transmission output shaft is laser-beam straight with my diff input shaft. Laser level locked into front yoke cast a dot directly on pinion flange, even while rotated 180*. U-Joints are nice and straight, and I get NO driverline vibrations. Diff mount is competely stock. Quote Link to comment Share on other sites More sharing options...
spdsk8r Posted April 28, 2004 Share Posted April 28, 2004 I pretty much did what labrat did. Very easy and very cheap. Check pics of my motor mounts. http://www.datsun-280zx-lt1.com/Spdsk8r.html Quote Link to comment Share on other sites More sharing options...
labrat Posted April 28, 2004 Share Posted April 28, 2004 Speedsk8r, Yup, my motor mounts look almost exactly like that, slightly misaligned and all! You got yours maybe 1/2" lower (maybe due to moroso oil pan). That's a trick trans mount, I wish I had thought of that before I cut the stock one out. Leaves lots of room for exhaust routing. Oh well... Bill Quote Link to comment Share on other sites More sharing options...
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