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Big Block Motor Mount Confusion...

I wonder if poly bushings from Energy would work for you vs. the Prothane ones?

Maybe it's time to just get a set of mounts from DIY4X or ORD.
 
i always been a energy suspension guy my self .

only thing I got from prothane was the 4 core rad isolators that energy dosnt show.

and last pic go middle #2
 
Maybe I'll call Energy tomorrow and get the dimensions of theirs. I'm wondering if the mounts that came out of my k30 are aftermarket and thus part of my fitment issue.

Is there a problem with having the space on the sides like shown in pic 2?
 
Is that gap just on the one side?

If the gap is on the top side it seems like it would be ok, if it is on the lower end I would worry about the engine wobbling around.

Either way that stuff would always be in the back of my mind lol.

Are you against competition motor mounts? Just trying to keep everything stock for the most part.

I had DIY4X motor mounts before (now I have TNA ones) they both use the same poly bushing that goes in your spring. The bushings are cheap and plentiful.
 
The gap is on both sides. I'm concerned as well that it would shift side to side (or actually up and down at that point since that is how it would be oriented). I assume it is supposed to be snug side to side as well as top to bottom. I haven't even looked at the DIY mounts, but not against them. This was supposed to be a simple "I need new poly motor mounts" thing and it has evolved into this. It really should be as simple as ordering new mounts and slapping them in, but unfortunately it has not been.
 
That's how I expect the dang thing to fit!!!! Any chance you have (or can get) a measurement of the internal clearance of those clamshells? I see those pics are old, so it's unlikely but thought I would ask anyway. No worries if not.

What kind of bolts did you use to hold them together?
 
bolts are old school for snow mobile metal cleat to rubber track replacments when rivits pop . or elevator bolts . https://www.mcmaster.com/#elevator-bolts/=15v8un2 these just have a square hex like a carriage bolt .

mine are #10 size screw . just what I had around . and the flat fits in the stamped recess like the rivet and not push off frame stand when bolted down .

looks like around 1 3/4" if you have them bolted to frame stands and go to top of opening the replacement half sticks out.

anymore measurements I have to unbolt them from the project truck there in . still no motor yet so would be easy .
 
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Thanks. How about the side to side measurement? Just trying to figure out why one of my Prothane mounts is too wide to fit in the smaller clamshell I have and the smaller Prothane is too narrow to fit in the other mount. I'm not 100% sure the SBC mount I pulled out of the grey dually is a factory original.

I talked to Prothane tech support and they said I could cut the larger humps down a bit on the 7-507 mount to get the clamshell to close, or I could just use the 7-506 mount in the larger clamshell I have which leaves that slight gap on the sides. They said since the two large humps on top are wedged in place it should be OK. I'm actually leaning towards cutting down the 7-506 mount to fit in my smaller clam shell since that is the one that will bolt right to my frame side bracket.

sweetk30 said:
bolts are old school for snow mobile metal cleat to rubber track replacments when rivits pop . or elevator bolts . https://www.mcmaster.com/#elevator-bolts/=15v8un2 these just have a square hex like a carriage bolt .

looks like around 1 3/4" if you have them bolted to frame stands and go to top of opening the replacement half sticks out.

anymore measurements I have to unbolt them from the project truck there in . still no motor yet so would be easy .
Click to expand...
 
I'd cut it down a little, I remember my energy suspension inserts fit pretty tight, I had to crank the supplied zipties down to pull the shell together.
 
just removed and measured .

bolted together mount on flat bench tape measure flat on bench to top of insert hole were clam shell starts to make the humps = 1 3/4"

un bolted sitting by its self all parts loose on bench = 1 7/8"

clamb shell body width across middle were bolt would pass threw = 3 3/8"

top row of bolts to frame bracket to bottom row in the insert hole . the hole is 3 1/2" opening .

insert energy suspension 3-1116 mount by its self is 2 1/4" tall and 4" threw bolt hole center side to side and 3 1/2" top/bottom .


just mount insert
0111171419a.jpg


just mount insert
0111171419b.jpg


unbolted together free floating
0111171420a.jpg


shell width
0111171420b.jpg


bolted together
0111171421a.jpg
 
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Thanks a bunch for taking all those pics and measurements. Unfortunately I'm not sure you got me the one I need! Haha! Here is the one I was looking for (pic below). Don't go to a bunch of trouble again though. I think I have this kind of figured out at this point. My plan is to shave down the large humps on the 7-506 mount (SBC) since they fit inside my SBC clamshell the best and those clamshells fit my frame mount already. That being said, I've got the Energy mounts on the way to see how they fit compared to the Prothane. Should be here Friday. I'll return whatever doesn't fit.

IMG_1832.JPG
 
I've copied this from my other thread since it is pertinent to this conversation. That way if someone else happens along this thread when searching for info at a later date they will have a conclusion, or at least additional info. Here is what I found today:

The BBC clam shell is about 1/2" to 3/4" wider than the SBC, so the two parts won't go together without excessive slop. What I failed to take into consideration (and had assumed since a BBC was previously installed using SBC mounts) is that the BBC spacing center to center of the through bolts (that hook the clam shell to the poly mount) is a little over 1" wider than the SBC. The measurement I came up with center eye to center eye is 17-1/8". The SBC center to center when mounted on the SBC frame brackets is right at about 16". I'm not really sure how in the heck they managed to get the original BBC into these SBC mounts unless maybe they somehow cut the rubber down in the original mount to give them some room to work. I have the old BBC mounted to a stand we made using new poly mounts and it too is at 17-1/8" eye to eye. I thought for a minute that the two blocks were maybe different and that was my issue, but that turned out not to be the case.

So, what I have now is the SBC mounts (frame, poly, and clam shell), but I've had to drill the frame to account for the wider width of the big block. Hopefully I'll have it fully installed tomorrow or the next day and I'll post some pics of the final solution.
 
So that is why the BBC frame brackets have the top 2 holes up higher than a SBC.
 
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