What's Everyone Using for Engine Mount Shims?
 

Title is basically it. What is everyone using to shim their engines?

I have mighty mounts that when installed last year sat too low. The oil pan can pass the width of a piece of paper, that's it. So while technically not touching, still too close for comfort.

I also found that the factory motor mount bolts bottom out before providing a clamp load with these mounts. As a result I used large washers under the mounts.

Can I move these washers above the chassis side mount to give a bit more clearance? I don't have any flat stock and don't really have the tools to fabricate a flat stock mount. I also don't see that there's anything specific made for the first gen firebird's in this regard.

I'm aiming to have my engine back in the car this weekend. It doesn't need to be fancy, I just need a quick, safe and effective solution.

Thanks!

Like you I have a 69 Firebird and had the same problem. In my opinion a washer especially a small one that does not support the entire surface area of the rubber mount is not good enough. Maybe you could find a large washer maybe 1.5 inches in diameter that could work. It would need to be at least .125 thick to raise the motor enough. I decided to use a steel plate that I cut to be the same size as the mount and drilled a hole in the correct location. I know that’s not what you want to hear but it’s the best way. You could get by with a hack saw, drill bit and a round file and get it done or maybe a steel shop could fabricate it for you for a small fee.

Yeah the washers I used were grade 8 stuff that is the same size as the harmonic balancer washer.

U shaped shims for frontend alighnment.Tom

Do you have a Sawzall, a bench vise, a 3/8 drill and some hand files or an angle grinder?

If so then it’s not difficult to use some 1/8” or 3/16” mild steel plate that you can probably get for next to nothing from the scrap pile at a steel yard and make up some proper shims in a few hours or less.

If a large OD washer can suffice then I’m sure any hardware store should have something you could use.

For the 69 Firebird style mounts with the 1/2 inch bolt you could do it 3 ways.

1) Stack fender washers between the mount and the frame.

2) Find some front end shims with 1/2 inch opening to slide in the gap between the mount and frame.

3) Find some flat plate and fabricate shims that can be slid into the gap without removing the bolt. Since this option would provide the most surface area for the engine to sit on, it would probably be my choice.

The mity mounts use the bottom of the barrel Korean junk mounts as their basis. I'm fairly certain with proper mounts and a chain or turn buckle on the driver's side of the engine you would have better results.

FYI, there have been some members on PY that have reported breaking the mity mounts under severe usage. No matter what MM claims, their product leaves a lot to be desired. $100 for adding a bolt as a limiting device to a $5 mount is crazy pricing, IMO.

These poly mounts would likely solve the sagging problems, not sure if I'd use them without a turnbuckle though.

https://butlerperformance.com/i-2445...tegory:1393552

This type of mount is not known for standing up to abuse. my 69 GP race car used the same mounts as the early F bodies, and I needed to add a turnbuckle to keep them from breaking. New mounts would last a couple of weeks before tearing and separating. This was back in the late 70s when there were still decent mounts available.

Adding a turnbuckle attached to the cylinder head also takes a lot of strain off of the oil pan rail area of the block. There have been more than a few documented engines that have broken up the main webs using stock style motor mount systems. In the stock mount application, all the torque is concentrated on the #3 main web. This tends to start cracks in this area. Adding a limiter attached to the cylinder head stops the stress being concentrated on a small area of the block, as well as only the #3 main bulkhead.

In 1970 Pontiac engineers redesigned the 455 mounts to have 3 attachment points as well as external stiffening ribs, and the new mount straddles the #2 and #3 main bulkheads.

It's your car, and your choices..............:thumbup:

Obviously I was treed by other posters as I formulated a post that covered all advantages, and drawbacks of the stock F body mounts.

I had the same issue- A little expensive but I used the JBP polyurethane motor mounts Sirrotica posted above and now have adequate clearance on my 69 bird. They are noticeably thicker than the crap rubber mounts.

Same thing here.

Thanks this is good information. Having a 73 455, I'd love to take advantage of the full mount. Chassis Works makes a pretty slick modern tube style mount that utilizes all three mounting holes. I'd have to look to see what would be needed chassis side for fabrication.

I agree that the mighty mounts are kind of a bogus product. I wasn't thrilled with them when I received them. I should have gone with the Poly mounts to begin with, but I was worried about damaging them with the headers on the car. I've got ceramic coated headers now that may be better in that regard.

We have similar setups, have you had any heat related issues with these mounts on your 69?

Yes. A small area on the passenger side mount is close to the Long Branch manifold and sustained minimal damage to the mount as it self-clearanced.

Best to use steel/shims , polyurethane melts if near heat .

This is what I did. Flat plate, Size I wanted with hole in center. No U-shape shims for me. lol

I used a 1/8" thick aluminum plate for my '67 FB. Easier to work with than steel and is the full size of the mount.

I've used U shaped fender washers without issue.

Originally I used some grade 8 washers that I cut a slot in, but more recently I bought thich U shaped alignment shims made for 1/2 bolts.

I've used Grade 8 washers, or body alignment shims with no issues.

I forgot I had a set of transmission mount shims laying around. They fit just about perfect on the mounts.

I’m going to use those for now and probably pick up a set of the Butler poly mounts in the spring.

I appreciate everyone’s feedback!

Well...this thread quickly became moot. I ordered up the Butler poly interlocking mounts this morning after the passenger side mount failed on installation yesterday. While torqueing the mount bolt, the passenger side mount gave up it's threads.

Lesson learned, stay away from anything made with the off-shore mounts, including the nearly new mighty mounts that I tried to use.

Hopefully I'll have the butler mounts in hand this week and can finish my engine install next weekend.

I bought some motor mount shims from butler along with the mighty mounts. I don't have the engine in yet but I figured it was easy insurance.

There was a guy selling 1 piece CNC cut black shims on here a while back. I used on one side only.