Beware Cheap Door Solenoids - Minimum 20mm Stroke Required

[ChimpOnGas]

A quick note of warning and advice to those looking to replace their worn out door solenoids.

I needed to replace my original 5 wire door solenoid recently on my late 1996 Chimaera, the car has the brushed ally door plungers on the rear wing so uses one solenoid per side to perform both the lock and un-lock functions. My original was making a nasty noise when I locked the car, while it still worked it was clearly about to fail at some point soon so I purchased a 5 wire door solenoid from a reputable seller of auto alarms.

Unfortunately while the solenoid functioned perfectly, it's stroke was a fraction too short, just 5mm too short to be precise, to ensure the lock can be fully pulled all the way into lock mode the solenoid rod must fully retract and also have a fully extended unlock stroke of 20mm.

I only wasted £4.00 on the fractionally shorter stoke version so it's not the end of the world, and I clawed more than the £4.00 back by collecting the real deal high torque SPAL solenoid with the full 20mm of travel from Andy at Powers Performance, thus saving the postage. In the end I decided to buy their last two so I've got a spare, sadly SPAL have stopped production of this excellent quality solenoid.


Here's the noisy original solenoid I've now replaced, shown in the fully extended un-lock position:




And here's the same in the fully retracted lock position:




And here's those real deal SPAL solenoids before fitting:




Even though these were pretty much the last two SPAL solenoids in the country I'm sure there are plenty of good alternatives out there, just make sure what you buy retracts the rod close to the end of the solenoid and it has the full 20mm of stroke required


Here's a short YouTube clip of the noisy (sounds like a duck!) original solenoid:

https://www.youtube.com/edit?o=U&video_id=4D26...


And here's the lovely new quiet SPAL solenoid in action:

https://www.youtube.com/edit?o=U&video_id=d3pX...


I hope this helps someone?

Dave.

[MKnight702]

If the 20mm ones are no longer available can't you just make a cam to extend the throw?

[ChimpOnGas]

MKnight702 said:

If the 20mm ones are no longer available can't you just make a cam to extend the throw?

As the YouTube clips show I've already fixed the problem by using one of the two quality SPAL solenoids I purchased on Monday from Powers Performance. These were the last two SPAL solenoids Powers had and SPAL have stopped production so they wont be getting any more, but as I was clear to point out in my post that doesn't mean other solenoids won't work.

I just wanted to warn others that there are solenoids out there with a stroke that's slightly too short to fully pull the lock into the locked position. The mounting holes on the first one I purchased were correct, even the wiring colours were the same as the original, but it's stroke was just 5mm too short to lock the car.

There's a possibility the issue could have been helped by extending the rod that's fixed to the door lock itself, but this requires some fabrication work, and the closed to open stroke of the problematic new solenoid would still remain 15mm not the full 20mm required. Trying to fudge the lock itself or fit cams is not the way to fix the problem, the proper and permanent correct functioning solution is simply to find a solenoid that has the full 20mm of closed to open travel to match the lock itself.

If you start fudging and fabricating changes to the lock you're still only working with a 15mm stroke solenoid you'll probably find you can now lock the car but be unable to unlock it at the other end of it's range of operation, because no matter what you do a solenoid with a stroke that's 5mm too short for proper lock operation... is always going to be 5mm too short!

The whole point of this post to to inform people they need a solenoid with the full 20mm of stroke, any less and you're going to run into trouble

These automotive solenoids do have standard mounting hole centres, and on the whole, the stroke should be a standardised 20mm too, but as I discovered to my cost not all door solenoids are created equal, some fall fractionally short in their stroke and only operate over 15mm instead of the full 20mm. Buying such a short stroke solenoid should be avoided as it simply won't be capable of activating both the lock and the unlock functions as this is ultimately governed by the full working range of the lock itself.

I hope this helps?

Dave.