[Healeys] Choke issues continue
kags at shaw.ca
Sat Feb 15 11:19:58 MST 2020
Hi Fred – I’ll give this a try.
The Healey BJ8 choke system is a pain at the best of times – not very well designed. Works well enough when carefully set up though.
The secondary cables shouldn’t be crimped in any way – the outer sheaths are held in their respective sockets by tension when properly set up. Crimping might create more ‘drag’ in the system, which is exactly what you don’t want. This is accomplished by lifting the carb choke lever a bit when tightening the cables at the carb end. This also enables the levers to move a bit further in order to achieve full choke when needed. There is a sweet spot – too much is not good either – the choke linkage will not return to the full off position. It makes a big difference here if the carb choke levers are perfectly synchronized – the engine runs much better when the choke system is in use.
I have found the use of additional helper return springs useful here – we know that the factory / dealers used them on problem cars back in the day. I have tried ballpoint pen springs on the cables (carb end), as well as a couple of other types of spring. Wound up using a pair of old original throttle return springs hooked around the choke lever cable pins and the brake pipes below – has worked well for me for 30 plus years. The important thing here is to get just enough spring force to pull the levers to their full return position., but not enough force to have a very stiff, hard to pull choke knob, which will eventually screw up the system.
The primary cable uses the same principle – when properly set up, the tension in the system will keep the outer sheath in it’s socket on the inside-the-car face of the firewall bracket. This is set at the cable clamp screw in the splitter bar – no (or very slight) slack in the cable with the choke knob fully in at the dash.
I use a bit of white lithium grease to lube the cables. Try not to think of the proper maintenance procedure every once in a while – take the whole damn thing apart and clean and lube the cables. I found a little cable lubing end for an aerosol can that works reasonably well. I just ignore the cleaning part!
I try and set the system up so that roughly the first 1/2 inch of knob movement activates only the fast idle function – no enrichment – really handy when you’re stuck in traffic on a blistering hot day, and the engine wants to die. Really helps to be able to speed the idle up a bit until you are moving again. Also very useful when at very high altitude on a trip (I’m at sea level). Just deal in a bit of fast idle with the choke knob, instead of jumping out with a screw driver and messing up those perfect mixture settings, which took weeks to achieve!
Another little trick I’ve used: If you have the primary cable out of the car, find a ‘tall’ hut ( I think that they are about 5/8 inch or so) to replace the thin one that is so hard to get to at the back of the dash. Makes tightening the primary cable / knob assembly much easier. (sorry, can’t remember the thread size offhand).
Hope this helps. I’m a bit hobbled for a couple of days, but could try and get you a couple of photos if you think it would help.
BJ8, BT7 tri-carb
From: Fred Wescoe
Sent: Thursday, February 13, 2020 4:31 PM
Subject: [Healeys] Choke issues continue
Last week when I pulled on the choke knob of my BJ8, the whole thing came out of the dash. The choke cable itself as well as the sheath came away from the block on the engine side of the firewall and out of the dash. So, I decided that replacing all three choke cables may solve my current problem of an extremely hard to pull choke knob.
The issue I discovered is that the choke cables from the firewall block to the carbs are not anchored at either end. When I removed the block from the firewall, I found that both ends of the two choke cables to the carbs themselves are loose in the sockets of the actual carb choke fitting as well as on the firewall bracket. It seems to me that for the chokes to work properly, both ends of the two choke cables should be crimped into the carb itself as well as to the block on the firewall. This would allow the cables to lift the chokes off their stops as well as allow them to return to their off positions smoothly. This amy also resolve the difficult to pull choke knob. The cable sheathing is much smaller than the socket it fits into at both ends and so there is plenty of slop at the ends right now.
The choke knob is securely anchored to knob on the dash and that tells me the other end, at the firewall block, should also be secured to the block.
Am I correct in my belief that all the cable ends need to be crimped securly for the chokes to work properly and freely?
As I resolve all my choke issues, I will relate what I did from the dash to the carbs.
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