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strange OD question.

Country flag
My original OD solenoid (BJ8 phase 1) has been acting wankie recently. It works fine 95% of the time then won kick in. I found that if I remove the rubber boot and give it a tap with a wood dowel it is fine for days. It may just be hanging up on dirt or something. I purchased a replacement from some third world country but haven't installed it yet. I'm thinking the original may just need the "piston" lubricated with some white grease. I am running mostly original and would like to keep it that way. Has anyone experienced a problem like this and solved it with just servicing it?
Country flag
There's two sets of points in there, one to provide current to pull the piston up and one to hold it up (something like 15A or so momentarily to pull up, less than an amp to hold, IIRC). It's more likely a problem with the points. Note there's a relay in the circuit--in addition to the 'kick-down' relay--and if it's flakey you'll get intermittent operation.


Great Pumpkin
Country flag
:iagree:---With Bob.
tahoe healey
Country flag
I checked and cleaned the points in the relay a few weeks ago. I went through all the wiring and connections and switches. The mystery is why it works when it is tapped.

Healey 100

Jedi Warrior
The problem with those little tiny little points inside the solenoid is that only a few ohms of resistance across them are enough to seriously reduce the pull in force needed to engage the OD. The contact resistance across old, worn points varies quite a bit from time to time. This makes OD engagement frustratingly intermittent.

I have found cleaning or filing the points or tapping on the solenoid only offers temporary relief. The ultimate solution is to install a new solenoid or find a decent old one.

The contacts inside the relay(s) can also affect the OD, but my own experience is that the difficulty usually lies with those little points inside the solenoid.

Good luck!


Great Pumpkin
Country flag
"I purchased a replacement from some third world country but haven't installed it yet."
Swap it in for the present one and see if that solves the problem.

"I'm thinking the original may just need the "piston" lubricated with some white grease."
I'm thinking give it a good cleaning up sans any lubricating grease and see if that solves your problem.


Darth Vader
Hi TH,

Although I do agree with the comments previously made, I would also suggest checking to make sure the rubber button is in place and in good condition below the piston. If missing or deformed, the piston could extend beyond the pull of the solenoid and not respond. If only partially deformed, it may reflect the hit-and-miss action you are experiencing. Since it is one of the more inexpensive components of the OD, it may be a good just-in-case candidate for replacement.

Ray (64BJ8P1)


Jedi Knight
Change the solenoid with the reproduction , they work just fine. The operating coil loses its strength and ability to snap the piston up to the hold position. I just messed around with my TR4 's OD solenoid ( and the box of old Lucas solenoids ) for hours before changing it, glad I did.

Marvin Gruber

Country flag
I've found if you have the solenoid screwed down in a bit of bind the piston sticks i finally loosed one side just 1/4 turn and its working well.

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