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340 Engine mounts

Started by 7212Mopar, August 19, 2017, 12:52:00 AM

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7212Mopar

I finally lowered my engine (340 LA) to the K frame use Mag mounts from Mancini. There is about a 1/4" gap between the bottom of the mount to the K frame on the DS and slightly more by the PS. If I let the mounts all the way down to the k frame, the cross bolts cannot get through. Is this normal or did I do something wrong?
1973 Challenger Rallye, 416 AT
2012 Challenger SRT8 6 speed Yellow Jacket

Brads70

No, Something is wrong.  Not sure what though. Sounds like the mount is out?

303 Mopar

Is your K-member or frame rail bent?


Shane Kelley

I can't see what's going on real good on my phone. But have you loosened all your motor mount brackets bolts and tried to line everything up while your setting it in place? You might just have everything tighten and be a little off.   It looks like the centering pin is out of position on the mounts and holding everything up.

7212Mopar

K-frame was stich welded slowly that I doubt the heat wrapped it. The brackets was refinished and engine rebuilt and has  a new Milodon road race pan. The engine mounts are new. I will try to losen everything and see if the pins can go in. I hope the engine mounts are not defected.
1973 Challenger Rallye, 416 AT
2012 Challenger SRT8 6 speed Yellow Jacket

Cuda Cody

Like Shane said, loosen everything up and see if you can wiggle it in place.  :yes:

Brads70

Quote from: 7212Mopar on August 19, 2017, 07:51:14 AM
and has  a new Milodon road race pan.

Check to see if the kickouts at the front corners are hitting the k-frame preventing it from sitting down. Mine was but on a BB , small block might have similar issues?


7212Mopar

Thanks everyone.

I spent a good part of the day working on getting the engine to sit correctly. I had previously trimmed the K frame mounting pads to clear the road race oil pan. It mostly clear except still a bit tight. So I took the grinder out again and made some bigger cuts. The PS had a small plate welded to the cut that is parallel to the oil pan. Unfortunately after all this works, it still sit high with the cross bolts inserted. No change whatsoever and nothing is touching.  :angry:

I compared the new mounts with the old rubber mounts and the new one appears to be thinner. The old compressed and worn rubber mount is thicker by about the same amount as the gap. Time to order some Schumacher Poly-Loc mounts and try again next week.
1973 Challenger Rallye, 416 AT
2012 Challenger SRT8 6 speed Yellow Jacket

Cuda Cody

Man, that sucks.  I've not had any problems like you are having.  Let us know how the new mounts work.

ScottSmith_Harms

Are you using a vintage 340 block or a later "resto" or R3 block?

303 Mopar

Quote from: Cuda Cody on August 19, 2017, 11:26:56 PM
Man, that sucks.  I've not had any problems like you are having.  Let us know how the new mounts work.

:iagree:  I've installed a few sets of the Mag Mounts and have never had a problem.  It's got to be something with the k-member or block as @ScottSmith_Harms is asking.


7212Mopar

It is a 1971 340 block that was in the car when I purchased it back in 2012. I believe the motor mount brackets are from the original 318. I am using washers at the driver side rear bolt. Everything were refurbished and reused except the mag mounts are new. I am going to take it apart soon and put a caliber or scale to the old and new mounts to measure the thickness.

There is nothing hitting and I can lower the engine all the way sitting on the pads. The problem is the bolt holes no longer line up and I cannot insert the through bolts. I tilted front and back, side to side and same problem, other than I pulled my shoulder muscle that I discovered this morning.
1973 Challenger Rallye, 416 AT
2012 Challenger SRT8 6 speed Yellow Jacket

7212Mopar

I think I found the problem. The bolt holes at the new mount were indexed differently from the stock mounts. The holes are located further away from the engine so when lowered all the way sitting to the K Frame, holes no longer line up with the holes at the K Frame. Despite the factory designed with the oversize holes, the differences were too much.

The pictures show the new on the left and the factory original on the right (passenger side, same issue at the driver side). The holes of the new Magnum mounts are further away from the flat part of the mount. The thickness of the rubber are the same but the factory steel is thicker heavier materials. The factory nuts welded to the mount is also heavy duty.

I am kind of mad about this badly made product and wasted two days of my time. No progress and more money to be spent. How the heck they be off by so much?   :verymad:
1973 Challenger Rallye, 416 AT
2012 Challenger SRT8 6 speed Yellow Jacket

7212Mopar

After some readings on the issue, I am thinking to go with the Schumacher rubber mounts with the torque strap.
1973 Challenger Rallye, 416 AT
2012 Challenger SRT8 6 speed Yellow Jacket

Shane Kelley

I would knock that welded nut off and slot those holes until the mount sits flat. Use a nice flat washer on both sides and just put a nut and lock washer on the bolt. Done.