[racerboy]

No matter how much grinding, I just could not get the motor mount to drop into place. I bought one of the Butler Warpath kits which basically uses the later style motor mount in the early frame. It replaces the frame mount completely, but I still have a question. The instructions state that early year cars do not have the holes drilled for the new style mount, and that only one of the 3 preexisting holes lines up. But the instructions don’t tell you which one of the preexisting holes to use as your baseline. I would think it would be the top one, but am not sure.
Here’s the passenger side with no frame mount. I circled in red the preexisting top frame mount hole.


There are also six holes in the new mount, so not sure which one I use as my initial reference.

Here’s what the mount looks like just loosely installed



I sent these same pics to the Butler tech line, but figured I’d ask here as well.


Sent from my iPhone using Tapatalk

[racerboy]

I put the factory mount back on the frame and marked the location of where the long bolt would go with a paint pen. Then I put the new mount in place to line things up. I think this is a better reference.





Not sure which side of the mount is up vs down. Only difference is one side has a long slot in middle between bolt holes.


Sent from my iPhone using Tapatalk

[unruhjonny]

Originally Posted by racerboy

... I bought one of the Butler Warpath kits which basically uses the later style motor mount in the early frame. ...The instructions state that early year cars do not have the holes drilled for the new style mount, and that only one of the 3 preexisting holes lines up. But the instructions don’t tell you which one of the preexisting holes to use as your baseline. ...

From what I am seeing, I would guess that 1970 is one of the "early cars".

Have you reached out to butler for their guidance?

I would think that they would stand behind their product, and give you instruction.

[racerboy]

I did reach out then on their online tech line. I will try calling them a little later this afternoon.

In this photo, the engine seem a bit too far forward? Only one side has a matching hole in this configuration




Sent from my iPhone using Tapatalk

[Sirrotica]

Originally Posted by racerboy

I did reach out then on their online tech line. I will try calling them a little later this afternoon.

In this photo, the engine seem a bit too far forward? Only one side has a matching hole in this configuration




Sent from my iPhone using Tapatalk

If that is the case you're probably going to have to bolt the mount assemblies to the engine while it's connected to the transmission lower it down on the crossmember to see if in fact one of the preexisting holes lines up, and mark the other holes, remove the engine again and drill the needed holes. This is going to be a lot of extra work putting the engine in twice so you can verify the captured style late mounts location, and drilling the crossmember

I thought you were using the ones made from steel strap iron that use the OEM mounts and provide you with another set of holes moved forward from the early mount location on the side of the block. That is the type of mount adapters I fabricated long before anyone made, and sold them in the aftermarket.

Pictured below is the late 3 bolt block to 2 hole early chassis, same idea to reverse the mounting early block to late chassis:



These are sold by Ames, but are the same as the ones I used to make out of necessity in the mid 70s.

Here is a writeup by Ken Crocie in Motor Trend how to article, explaining those adapters and other types that allow you to use early blocks in later chassis, and the 77 and later blocks in early chassis:

https://www.motortrend.com/how-to/ea...ount-adapters/

From the trouble you're having, I'd say the frame mounts aren't in the correct locations. Unfortunately it entails quite a bit of work to properly locate the 75, and later mount system on early subframes.

[racerboy]

Originally Posted by Sirrotica

If that is the case you're probably going to have to bolt the mount assemblies to the engine while it's connected to the transmission lower it down on the crossmember to see if in fact one of the preexisting holes lines up, and mark the other holes, remove the engine again and drill the needed holes. This is going to be a lot of extra work putting the engine in twice so you can verify the captured style late mounts location, and drilling the crossmember

I thought you were using the ones made from steel strap iron that use the OEM mounts and provide you with another set of holes moved forward from the early mount location on the side of the block. That is the type of mount adapters I fabricated long before anyone made, and sold them in the aftermarket.

Pictured below is the late 3 bolt block to 2 hole early chassis, same idea to reverse the mounting early block to late chassis:



These are sold by Ames, but are the same as the ones I used to make out of necessity in the mid 70s.

Here is a writeup by Ken Crocie in Motor Trend how to article, explaining those adapters and other types that allow you to use early blocks in later chassis, and the 77 and later blocks in early chassis:

https://www.motortrend.com/how-to/ea...ount-adapters/

From the trouble you're having, I'd say the frame mounts aren't in the correct locations. Unfortunately it entails quite a bit of work to properly locate the 75, and later mount system on early subframes.

I was trying to use the Ames strap iron ones, but once I got the driver side installed, it didn’t seem to matter how much I ground off on the passenger side motor mount, it kept getting hung up on the frame mount. I’d happily send the Butler kit back and use the Ames one, if there is just some trick I’m missing.

Here’s how much grinding I’ve already done, to both the rubber and steel core. These are not the original motor mounts, they are aftermarket (Korea) that the previous owner installed. Not sure if that might be compounding the problem.




Sent from my iPhone using Tapatalk

[Sirrotica]

I'm going from memory, first of all the strap pushes both mounts out further from the block the thickness of the iron, so you're already wider than the OEM mounts are. The only solution is deforming the rubber enough to get the bolts in the frame portion of the mount. It's going to require some pushing and pulling to get it all lined up. It's not an easy operation, I remember the first time I did it I spent a bit of time getting the rubber to conform to get the second bolt in, with prybars, tapered drifts, screwdrivers, etc., and a bunch of choice words.

One other solution could be it to slot the holes with a burr, to slide the frame mounts towards the outside of the car the like amount of thickness of the strap iron adapters.

The crappy Korean mounts probably aren't helping your efforts, as I already posted they're precise to within a half and inch, but there isn't a whole lot of alternatives to choose from.

Supposedly Butler had urethane mounts made up, and maybe Ames had some rubber ones made, close to an OEM set. No guarantee that that will solve your problem though. The less compliant urethane mounts would likely work against your efforts.

It's the fun of hot rodding, getting sub par parts to fit your application through re engineering and finding out the combination to fit your application. There is a way to do it, you just have to figure out what works for your combination.

If your intent on using the later captured mount system, you're likely going to install the engine twice to get the frame portion in the right spot to find where the holes should be.

Another fun fact is the solid portion that bolts to the block, of the later system has at least 2 different versions. One for B body, and another for F body. The B body pushes the holes out further because the B body frame and crossmember is wider. I've run into that scenario before trying to use B body engine mounts in a F body chassis. They were marked from the factory with a stamping, but on rusty corroded used parts it's usually hard to see the stamping, unless you wire brush all the crud off. It doesn't bolt up either.

Lots of nuances with the later style mounts in different chassis to further complicate engine changes. I've pretty much ran into all the snags, and have worked past them.

[racerboy]

I went back to try the Ames strap iron mounts. Just as a trial run I put the motor mounts on engine and since I already had the frame mounts, I attached them and lowered the engine on to frame to see how much off I was. With the driver side lined up, you can see the passenger side sits a bit higher. You can see the unpainted area of crossmember that the mount would have to drop down.




Sent from my iPhone using Tapatalk

[Sirrotica]

It's off about the thickness of the strap metal X2, just as I said the adapters push the mounts out from the engine.

Two ways I know to get the bolts in.

1) bolt the frame mounts in and pry the rubber engine mounts in until the large bolt goes in. This is how I've done it every time I've used the strap iron adapters. It's not real easy to do because you have to pry quite hard to get the mounts to deflect enough to get the bolts in. That however is how they were designed to be used. This way is likely the least amount of work because it's not necessary to remove the frame mounts, however you have already commited to unbolting them for the Butler mounts.

2) Slot the holes in the crossmember with a burr so you can slide the frame mount to where it needs to be with the added width from the strap mounts. This is going to take longer, because your going to likely remove the engine to lenghten the holes in the crossmember, then re install it.

If you want to use the Butler ones, you're going to have to lower it down on the crossmember to see if one hole does in fact line up, then if it does, pull the engine out and drill the other holes. If none line up you're going to have to scribe, or mark the ouline, and the holes from the Butler frame mounts.

Your car, and you make the decision how much extra work you want to devote to the conversion. It sucks that you've bought 2 sets of adapters, done a lot of extra work, and still don't have the engine secured in the chassis. I know how you feel, because I devoted 50 years to wrenching on cars as my profession, you run into this stuff all the time. Especially when the engineers make running changes as Pontiac did in 1970 for stronger mounts for the new 455s.

[racerboy]

Thanks sirrotica
I already removed the frame mounts, but I am not committed to using the Butler kit if it requires me to modify the car at all. This 428 install is a temporary replacement until my Milner 4.00” stroker crank arrives. Once that gets here, the original WS block is going back in it (it too will be a 428, sort of). I have no interest in cutting/grinding anything on the car itself. I’ll happily re-install the frame mounts and give the strap irons another shot. Where exactly do you pry to force the block down over the frame mount?


Sent from my iPhone using Tapatalk

[Sirrotica]

Originally Posted by racerboy

Thanks sirrotica
I already removed the frame mounts, but I am not committed to using the Butler kit if it requires me to modify the car at all. This 428 install is a temporary replacement until my Milner 4.00” stroker crank arrives. Once that gets here, the original WS block is going back in it (it too will be a 428, sort of). I have no interest in cutting/grinding anything on the car itself. I’ll happily re-install the frame mounts and give the strap irons another shot. Where exactly do you pry to force the block down over the frame mount?


Sent from my iPhone using Tapatalk

At the edle of the metal that the long 7/16 bolts go through, notice the bolts have a pointed taper if they're the OEM bolts, to help align the holes.



I've had to use the larger phillips screw drivers to get through the holes, then pull them into alignment get the bolt started in the front of the mount push it to the back then again use the screw driver to pull the nut on the rear into alignment. I've used tapered drifts to align mounts. Another tool used is a wrecking bar, 30 inch, to pry the mount into submission. I've had a large wrecking bar in my tools for decades, used many times when engine mounts fail to align during engine changes, and need a little persuassion.



It's gonna be more of a challenge if you're laying on your back. Ideally you'd be working on a lift. It might take 2 people to get the bolt in, it's no picnic getting the rubber to twist enough to get the last bolt in. Once it is in the rubber will start to conform. The second time I had to put mount bolts in that car, the mounts had taken a set, and it was much easier.

As I said in my earlier post, I've put OEM style mounts in a dodge truck that I had to use a come along to pull it enough to get the stud through the hole in the frame mount. Sometime mounts line right up, and other times you have to use brute force to get them in. Once they're in and bolted down there's no problems with them. We already know in this case, because of the thickness of the strap iron, they're moved out 1/8 to 3/16 of an inch on ether side, total of 1/4 to 3/8 inch.

[racerboy]

Thanks! Question about using a lift. I do have a lift in my shop. Would you suggest bolting in one side (eg, driver side), and then lifting gar and using pry bar from underneath? The reason o ask is that I was trying to install engine w/o the transmission and if I disconnect it from the hoist to get it up in the air, it seems like it wants to ‘lean back’. Can one motor mount hold it in place?

I do have the original motor mount bolts with the tapered end.


Sent from my iPhone using Tapatalk

[Sirrotica]

It's heavy on the rear of the engine brcause the newer mount location was moved forward. If your concerned, use a ratchet strap on the rear to suspend it level, it might help when you're trying to get the bolt in too if it's level.

One mount should be sufficient, but lifting the rear close to the correct plane is going to help align the holes also. As you pry the mount over it's also going to try to compress the opposite mount you put the first bolt into. It's not simple, but it's definitely possible to pull off.

Hopefully you're going to have the engine connected to the chassis here shortly...................

[racerboy]

Another question. On the driver side, the strap iron does not sit flush. The welded nut that the motor mount bolts to hits a casting rib on the block. As a result, the strap is twisted a bit. Am I able to grind the protrusion on the block? Or will that weaken it?


Here’s where it hits the welded nut


Not sure if you can see it in this photo, but the rear of the strap is bowed out a little.


There is no interference on passenger side. That mounts flush.

[racerboy]

Instead of slotting the crossmember, could I just shim the frame mounts. I messed around with a couple of thick washers (0.100”). If I thought this would work, I would just fabricate a plate to raise the frame mounts the same thickness as the strap adapters. Not sure if you can see the washers between crossmember and frame mount. The straps are about 0.129” thick



Sent from my iPhone using Tapatalk

[Sirrotica]

That little bit of cast iron isn't going to make a difference, Pontiac stock blocks break in the #3 bulkheads on the oil galley hole from the main bearing to the cam bearing, usually when you're over 600 HP. That was the reason for the motor mount redesign, was to spread the stress over (#2, and 3) bulkheads rather than just #3.

From your pictures the difference is about 3/8 of an inch, just what I said in my previous posts. Push the engine over that amount, and each mount will deflect about 3/16 of an inch .1875

If stacking washers makes a difference feel free. I really don't see how it's going to make your situation better, as the 45 degree slope mount on the cross memberis going to move the mounts further towards the center of the car taking it in the wrong direction, at least that's how I see it.

I'd just set the engine in there, flex the rubber on the mounts with pry bars, and put the bolt in, been there done that. It works just fine. I first did it in 1978, done it many times since then. When you swap back to the engine you're having built it should drop right back in.

I've seen brand new mounts in a stock application that matched up worse than what your pictures show. I flexed the mount, and bolted them in, and sent it down the road. Motor mounts are designed to flex, hence the rubber construction. You're overthinking this.

[racerboy]

Ok. Thanks. I’m going to re-install the frame mounts tomorrow(no washers) and have a go at it.


Sent from my iPhone using Tapatalk

[racerboy]

Was able to get the engine in today. By ‘in’ I mean get the bolt through the passenger side mount. Did it with the car on the lift and a friend of mine used a pry bar to pull down on mount while I put the bolt in. The mount still seems like it sits too high (on top of the frame mount). Maybe once it starts up and torques it will settle down a bit.



Sent from my iPhone using Tapatalk

[racerboy]

Made a little progress over weekend with getting the flywheel and clutch installed. Of course I couldn’t find out where I put the clutch fork (how the heck do you lose a clutch fork?!) so that’s about as far as I got. I did get the oil filter adapter in. I don’t think you can see it from the photo, but the passenger exhaust isn’t going to bolt up until the motor mount settles down. The driver side exhaust will bolt right up because that mount is in the right place.




Sent from my iPhone using Tapatalk

[racerboy]

I noticed that the Z-bar fitting that screws into the block on the ‘69 428 that was in my GTO is longer than the firing that was on my ‘70 400 in my TA. I am assuming that the Z-bars are a little different between the A and F body cars, and that I should install the shorter fitting (the one I’m pointing to) on the 428:



Sent from my iPhone using Tapatalk