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Project Marina, Torsion Bar Twiddling

Finally, something other than bodywork. You’re sick of reading about it, I’m sick of doing and writing about it. In a change of scenery, I moved to the front suspension to sort out an issue this Marina had.

Say what you will about the Marina suspension, well no not that; it’s not been pulled from the Minor, but anyway, it’s very simple.

This simplicity works both ways. It’s easy to work on and adjust, but it’s also simple in how it operates which can cause some compromises in ride comfort and handling.

One way it’s delightfully simple is that it uses a pair of torsion bars in the front suspension instead of traditional springs. These operate as a spring by twisting a spring steel rod along its length. As it always wants to try to unwind, it causes a springing effect.

These have one simple benefit for car weirdos like me; they can be adjusted without special tools, on the car (for the most part), and without any legal headaches. This makes the ride height adjustable.

At the back of the torsion bar, which is about half way down the length of the car, is a trim adjuster. This is used to adjust the fine height of the car. These are usually set about half way in their travel, so the ride can be altered higher or lower by a certain amount (usually an inch or two either way). Coarse adjustment is done by moving the arm by one or more splines on the shaft, one spline is one inch in adjustment.

Mine is pretty ugly because it’s 50 years old, and covered in thick underseal, but the basics can be seen. The orange arrow is the torsion bar, this is heading off towards the front of the car to meet the lower front suspension arm. The blue arrow is a locking bolt, this will need to be loosened (not removed) to adjust the arm, and the green arrow is the actual adjuster (which presses against a thick steel “bucket” so it doesn’t dig into the floor pan). The adjuster works but moving the lever up and down, causing more or less twist in the torsion bar.

So, the issue the Marina had. Well, just look at it

It was very nose-up. As it turns out, according to the workshop manual, it should be 14.6-15″ (37-38cm) when measured from the center of the front wheel dust cap to the arch lip.

This is how mine was sitting, up to a full inch too high. I noticed this when I reassembled the front suspension after its rebuild. I was careful not to move the lower arm on the splines, so it wasn’t me that threw it out of whack, but the suspension was so high that the top arm was pressed firmly against the droop stop when at rest. This is not good for ride quality.

It’s quite a large gap

It’s visible in the delivery photos too, even if the tire is a bit flat on the top.

To correct this was quite simple really. Well, mostly. To actually fix the issue I would ideally need to disassemble the suspension and turn the lower arm one spline on the torsion bar to set the adjuster in the middle again, but because I don’t want to do that all over again, I wire brushed off the adjuster, loosened the locking bolt and wound the adjuster bolt out. Loosening the bolt lowers the car as it takes tension off the torsion bar.

I started with the RH side due to easier access and lowered it until the bucket on the top of the adjuster bolt was no longer captive, and wound it back in until it was.

It got it about spot on for what I had in mind, about an inch lower than the lowest stock spec.

It looked pretty good, so I moved to the other side.

Unfortunately this adjuster wasn’t in the middle of its travel, so it bottomed out about here. A smidge more than half an inch lower than stock.

To be fair, this actually looked really good too, even though it wasn’t quite as low. I wound the RH side up to level it out and ended up with this

Compared to what it was, it’s a decent difference. Should improve handling too, both by being lower, but also not having the top arm resting on the droop stop anymore.

Pretty good result on the front. I do have a set of one-inch lowering blocks for the rear, but I want to see what it looks like on the ground again before I decide to lower the rear or not. I think I will, but we’ll see.

I’m hoping to get through a lot more work over the coming holiday period and have the car ready for a WOF early next year. It’s way behind schedule, but it’s slowly getting there.

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