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Post by sigmfsk on Oct 15, 2011 6:50:24 GMT -5
I think the key thing for engine swaps is that all you need to do is change motor mounts, and you can put a big block on a small block subframe (and presumably, a small block on a big block subframe). Ghostbluesman wrote: > ...all I had to do was replace the motor mounts form the 360 with 440 versions... www.bluesbrotherscentral.com/forum/topic/8988-car-partcom-interchange-between-74-77-monacos/page__view__findpost__p__110661I think there might actually be some differences in a small block subframe vs. a big block subframe, but it seems clear that they don't affect engine swaps. The 74 parts catalog, page Illus. 13-2 shows the frame with a listing of all the "parts types". I looked for all the part types on the actual frame, and got: frame 13-01-1 sidemember (serviced in 13-01-1) c/member 13-10-1 c/member no. 1 13-11-5 c/member no. 2 13-11-5 So I looked up 13-01-1 13-10-1 13-11-5 and the only part type that has different part numbers is 13-01-1 (one part number for small block, a different part number for big block). So if I'm reading that correctly, the actual three CROSSmember pieces are the same for small/big block, but the SIDEmembers are different. Why would the sidemembers be different? Presumably they both mount wheel wells the same, radiator the same, etc. Maybe beefier? Maybe they're exactly the same and the documentation is in error. We'll probably never know unless we have a clean unattached big-block subframe and small-block subframe next to each other for analysis. Here's a thread on the 74-77 c-body subframe topic, but I don't see much there over what we know above. www.cbodydrydock.com/forum_viewtopic.php?5.91000
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Post by Lord Vadus on Oct 15, 2011 9:00:01 GMT -5
The differences in sub-frames do not effect engine swaps. If you save the motor mounts from the big block, it's a direct drop-in replacement and extremely hassle-free. The design was carried over until the end of the C-body platform, with minor tweaking and allows any V8 to be easily interchanged.
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Post by sigmfsk on Oct 15, 2011 11:59:32 GMT -5
The differences in sub-frames do not effect engine swaps. Hi LV: Do you know of any differences? Or are you only confirming that a big block (with motor mounts) plugs into a small block subframe without any problems? I'm wondering if there actually are any differences, or if only the parts manual indicates that there are differences (or maybe you know some other reason there are differences). thanks, arthur
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Post by Lord Vadus on Oct 15, 2011 16:23:26 GMT -5
Hi LV: Do you know of any differences? Or are you only confirming that a big block (with motor mounts) plugs into a small block subframe without any problems? I'm wondering if there actually are any differences, or if only the parts manual indicates that there are differences (or maybe you know some other reason there are differences). thanks, arthur I'm confirming that the big block will drop in and bolt up without any problems whatsoever, provided you keep your original motor mounts. This was part of the test-fitting stage for my project and it proved to be an exceedingly painless implementation. My theory on this is that it was easier for Chrysler to use 1 subframe for their cars and, as a result, not have to engineer several separate components for the steering and suspension. This is also one of the only ways that they can offer a range of motors from 318 through 440 on a platform.
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Post by sigmfsk on Oct 15, 2011 19:56:09 GMT -5
I'm confirming that the big block will drop in and bolt up without any problems whatsoever, provided you keep your original motor mounts. ... My theory on this is that it was easier for Chrysler to use 1 subframe for their cars and, as a result, not have to engineer several separate components for the steering and suspension. This is also one of the only ways that they can offer a range of motors from 318 through 440 on a platform. Cool, thanks for the clarification. Here's the info from the parts catalogs for 75 and 76. 75 and 76 info is the same as each other, but this info is different than a 74. The 77 parts catalog has the info in a different format, so I didn't check it, and guess that it is the same as 75 and 76. I believe it is the case that as far as we know, all the subframes that came on 1974-1977 c-body Monacos were exactly the same, other than the info in the parts catalogs that says we have 4 different types of subframes: 74 small block 74 big block 75+ small block 75+ big block 74 small/big differ by the sidememebers 13-01-1. 75+ small/big differ by that sidemember AND the crossmember that holds the motor mounts If we ignore the sidemembers, the parts catalogs says that there were three different crossmembers that holds the motor mounts: 74 (both small block and big block) 75+ small block 75+ big block So you are confirming that both a - small block + motor mount - big block + motor mount plug into a 74 small block subframe I think Ghostbluesman is confirming that both a - small block + motor mount - big block + motor mount plug into a 75 small block subframe But "plugin" doesn't necessarily mean "the engine would be located at the same position as if the car came with a big-block subframe" or "supported with the same rigidity". Maybe the drive-shaft angle would be different by a few degrees. Maybe supports were stronger. Or maybe there were no differences. Anything's possible, but it seems something funny is going on with the parts catalog changing info for 75. When I strip down my big block 76 parts car at the end of the project, I'll see if I can tell any differences between it a 74 big block subframe. thanks, arthur
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Post by cbodymopar on Jan 17, 2012 11:52:24 GMT -5
I have never tried putting a big block in a small block car, but i know that you can't put a small block in a big block car without modifications.
1st off the small block engine mounts will set the engine at a slight angle where transmission is leaning towards rear passenger wheel. I put 1/4 inch spacers on the driver's side motormounts to set the mount back further letting transmission swing to center. After that you will run into a drag link problem. It will hit the oil pan as the engine sits back futher than stock. also the transmission bolt to crossmember will not line up, you will need to make the hole a slot or redrill a hole further back. back to the drag link, you will have to modify it or the oil pan to make work.
I would assume you would run into same issues on big block install on small block car, or in reverse situation.
If you look at the 2 different frames, you can tell that the engine support mounts welded to the frame are in different location.
One side note, I cant ever recall trying this in a 74 monaco but I know I run into this situation with a 74 fury 111, along with several other big block c-body cars 74-78.
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Post by sigmfsk on Jan 19, 2012 19:25:23 GMT -5
If you look at the 2 different frames, you can tell that the engine support mounts welded to the frame are in different location. Hmmm. I don't really know, here's a pic of a small block subframe: from www.bluesbrotherscentral.com/forum/topic/8327-theres-a-new-marin-county-sheriff-in-town/page__view__findpost__p__118452where AZBlues posted: > ...the engine frame mounts look an awful lot like mine, where a > 318 was once parked. And here are some pics of my 440 subframe, from my Marin County thread: As far as I know the swap is good; it sounds like it worked fine for Ghostbluesman. your friend in always double-checking though, arthur
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Post by sigmfsk on Jan 24, 2012 18:30:34 GMT -5
If you look at the 2 different frames, you can tell that the engine support mounts welded to the frame are in different location. Hmmm. I don't really know, here's a pic of a small block subframe: Well, cbodymopar has me convinced that the small block subframe has the ears for the motor mounts in a different position than on a big block subframe. To refresh our memories, here's a pic of a subframe showing the mounting ears for the motor mounts (this is a small block subframe copied from earlier in this thread) Now keep in mind that I'm not doing a small/big swap, so whatever the situation, it doesn't really affect me. But I've enjoyed cbodymopar sharing his info and pics and thought to record it here. The above is a pic of a big-block subframe. On a big block, the forward mounting ear lines up with the tip of the mounting bolt on the steering gear (see the blue line). On a small block, the mounting ear is forward (for an estimate, see the red line). The following two pics are a small-block subframe. The difference isn't obvious (unless you know what you're looking for), but the small block ear is further forward (compare to where it lines up on the steering gear mount and mounting bolt) It looks like you can actually see the difference in a small block subframe by looking at that first pic in this post. Slight, but noticeable. I think if you put a small block in a big-block subframe, you'd get some serious binding (attempting to wedge the transmission in the mount with 1/4" less space). If you put a big-block in a small-block subframe, maybe the problem would not be so bad (or maybe the front of the crank pulley would hit the crossmember). Maybe it there would be no noticeable problem, but I wouldn't want to risk it. I'd want to put it where we know it will work. One thought is that cbodymopar believes that if one didn't want to move the ears around, some engine-swap offset motor mounts would solve the offset problem. The following page: www.engine-swaps.com/Pages/Products.htmllists: '73 & Up A, B, C, F, M, J-Body but when you click on the link c-body isn't listed. But it looks like they'd work. And this isn't directly subframe related, but if using a big block in a small block subframe, it would be a good idea to use big-block torsion bars. thanks cbodymopar! Everyone, if you do a motor / subframe swap, please post pics or info on how things turned out. your friend in info sharing, arthur
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Post by AZBlues on Jan 24, 2012 23:18:20 GMT -5
Hmm, very interesting. Looks like I'll be making a set of offset mounts for this BB swap. But others have bolted the RB in on small block mounts, apparently, so now I wonder how well those swaps came out? -AZB
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Post by sigmfsk on Jan 25, 2012 3:58:13 GMT -5
But others have bolted the RB in on small block mounts, apparently, so now I wonder how well those swaps came out? -AZB Great pic of your small block subframe, AZBlues. I checked my big-block Fury and didn't see any obvious problems if the block was to be moved forward 1/4": The offset motor mounts talk about needing to modify the ears: and cbodymopar pointed out that high volume oil-pumps might require a bit of grinding on the subframe: It seems to me, though, that if these offset mounts put the motor into its original position (with relation to the subframe), that high volume oil pumps might require a bit grinding on a big-block subframe. Unless that area of the subframe is different on a small block vs. big block. your friend in measure twice, grind once, arthur
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Post by cbodymopar on Jan 25, 2012 8:01:48 GMT -5
One thing I didn't get pics of were the passenger side! the biggest problem you would run into is trying to line up the transmission.
As you can tell in the pics, the mounts are roughly 5/8 to 3/4 inch different
On the Passenger side they are 3/8 to 1/2 inch different.
this would set the engine/transmission at a slight angle. I'm sure you could pull the transmission over to line up but I believe you would be putting all the mounts in a bind.
If I get some extra time, I will pull a 360 out and put 440 in to show in better detail
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Post by sigmfsk on Mar 2, 2012 19:13:34 GMT -5
I pulled the motor on the big block Fury, so I was able to get a good comparison pic between AZ Blues' small block subframe, and my big block subframe:
My subframe isn't as clean or easy to see as AZ Blues' but I think there's enough detail there, along with cbodymopar's pics and info, to see what's going on.
your friend in things lining up, arthur
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Post by sigmfsk on Apr 16, 2012 16:53:45 GMT -5
Here: bluesmobiles.proboards.com/index.cgi?board=details&action=display&thread=370#ixzz1sF4lRnThcbodymopar reports that a big block would be in a bind if it was put in a small block subframe: > As you can tell in the pics, the mounts are roughly 5/8 to 3/4 inch > different > > On the Passenger side they are 3/8 to 1/2 inch different. > > this would set the engine/transmission at a slight angle. I'm sure you > could pull the transmission over to line up but I believe you would be > putting all the mounts in a bind. Here: bluesmobiles.proboards.com/index.cgi?action=gotopost&board=owners&thread=46&post=4189countrybunker reports that shumacker ind. says > you can bolt the big block right into the small block k frame as is, with > factory mounts but the motor would be 1" forward, and 3/4" taller in the > engine bay. It seems that a big block can be bolted into a small block subframe. And everyone agrees that it won't be in the same place as stock, which seems that we'd all agree that it won't bolt to the transmission crossmember as stock. It seems that cbodymopar assesses that the resulting transmission centerline angle will be problematic, while Schumacher Creative Services (the engine swap motor mount guys) have no such assessment. I don't know who's right. I'm just logging everything here for reference.
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Post by spanks79 on Apr 16, 2012 19:48:50 GMT -5
Ok, I had to edit this post. I re read the facts and misunderstood the details. So basically, cbodymopar says it won't work based on his experience, Schumacher says it will work but place engine in a different location, are we to assume they have first hand experience at this? Based on the facts and pictures in this thread I am inclined to believe there will be some challenges to overcome when doing this swap.
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Post by sigmfsk on Apr 17, 2012 4:34:32 GMT -5
So basically, cbodymopar says it won't work based on his experience, Schumacher says it will work but place engine in a different location, are we to assume they have first hand experience at this? Based on the facts and pictures in this thread I am inclined to believe there will be some challenges to overcome when doing this swap. Regarding putting a big block into a small block subframe, expectations seems to vary. Here's the summary as I understand it. LV says that both a - small block + motor mount - big block + motor mount plug into a 74 small block subframe, but doesn't provide info on how the transmission lines up. Ghostbluesman says that both a - small block + motor mount - big block + motor mount plug into a 75 small block subframe but doesn't provide info on how the transmission lines up. cbodymopar says it will plug in, but thinks the transmission won't line up. schumacher says it will plug in (albeit at a different location), but doesn't talk about the transmission. If ghostbluesman completed his installation with it binding, I'd find that persuasive evidence. But maybe he just trial-fit the motor, found that it plugged in, and never got to the point of checking the transmission mount. your friend in suspense, arthur
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