MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

TR parts and Triumph parts, TR bits, Triumph Car Spares and accessories are available for TR2, TR3, TR3A, TR4, TR4A, TR5, TR6, TR7, TR8, Spitfire and Stag and other TR models are available from British car spares and parts company LBCarCo.

Triumph TR6 - Ignition Timing with Crane Electronic Ignition



I have a very late production 1976 TR-6 (July '76 build date) with twin Stromberg Carbs and Lucas 22D distributor. It's most likely a low compression engine, as it checks out at 120# across all 6 cylinders. I use 94 octane Chevron gas in it.

I recently replaced the points & condensor ignition with a Crane XR3000 electronic ignition. I replaced the advance springs in the distributor at the same time.

In order to make the car run properly, I have had to advance the timing a very long way. It's now at about 26 degrees BTDC at idle with the vacuum retard disconnected. I say about, because it's off the scale on the flywheel when checked with a timing light. It runs well, but I have never known a car to require so much advance before, and it didn't need it with the points ignition.

Anyone have similir experiences, or insights?

Cris Hemingway

The very low compression on this engine - 7.75 if standard- will result in slower burn of the mixture , hence the need to advance the ignition. This dependence of ignition timing on CR is well known- it applies to all petrol engines. I continue to be puzzled why the official timing data show no significantly differnet timing changes for the various TR6 engines. My supercharged motor has 8.5 CR and I use a static timing of 18 BTDC. (Idle is similar as centrifugal advance does not start at 600 rpm tickover.) rising to maximum 38 BTDC at 2400rpm.
Peter Cobbold

Peter, I noticed your car is supercharged. What type do you run and any comments re power, reliability and cost?
Chris, how do you like the electronic ignition vs points? I have had various opinions that say that the points are just as good?
Mike Strong

Mike,
Mike,
Details of blown TR5 are at:
http://www.pil.net/~felix/supercharger/cobbold.html
I used a 'period' Wade blower, but Kai Radicke who hosts this web site has information on an Eaton based kit, available in US. The biggest benefit of supercharging is the large increase in torque- better accelaration, or lazier higher gear driving. The blown TR6 seems like driving a V8. Cost was around £2000. Reliability is acceptable for a DIY attempt- a home made blower drive shaft keyway failed, otherwise little over about 4 years and 10,000miles. Beacuase supercharging releases more power at normal engine revs, you avoid the excessive loadings of high revs and high compressions. The highr temperature in the combustion chamber has not been a problem. And the low CR US-specification heads are ideal for supercharging, without the need to make low conpression pistons or thick head gaskets.
Peter Cobbold

Peter, bit off topic but, I seem to recall on a past thread for caliper conversion that you stated you had done a four wheel disc brake conversion on your car. Could you supply some details on the rears? What calipers, how was the parking/emergency braking handled, what discs, etcetera? I have been playing with this off and on and keep running into a problem with the parking brake. Does you set up use a caliper with a built in parking brake or are you running a second spot caliper? I have been trying to avoid a second spot caliper, but all the calipers that I have played withy so far that have built in parking brake mechanisms have fitment/clearance problems.

I went to the URL for your SC install and tried backing up to get more information by deleting bits of the URL. Whenever I got a 404, I could not help but notice the ISP was "PlantageNet." Good play on history with the name there.
SteveP

Steve

Due to problems with our server i will send this reply in stages


I have carried out a rear disc conversion using nissan primera rear discs,there is a slight lip on the inside edge of the disc but once grinded out the disc fits onto the 4 stud hud.iused rear brake calipers from a ford sierra scorpio {british car mid 1980's).yhese calipers incorparate a parking handbrake, i used the ford scorpio hanbrake cable,the was one length i cut the handbrake in two at the handbrake lever endso now you have two : live ends: i had two adjusters crimped onto the live ends. Speedy cables of N London did this for me
Simon

Fabrication

I made up a plate it is sandwiched between the hub and trailing arm.the plate is where the caliper bolts to.I bought the trailing arm and hub from a scrapyard so that i could experimemt with.I first made the from plywood and then from steel.Imade the bracket so that the caliper sits on the top side of the hub,the handbrake cable is connected as normal at the caliper end, you route the cable through where the tr6 original handbrake cable went through,the outer sheathing of the ford cable has to be secured where the cable grommets were, I have used 2 inch washers for this
Simon

New brake pipe has to made,from the hose on the trailing arm to the caliper,the union to the caliper is metric.I fabricated a connection between the handbrake cable and tr6 hanbrake lever I used existing tr6 handbrake parts and metal studdding for this.I think I have covered everything.

For those people who have e mailed me I am sorry about the delay in posting this

Simon
Simon

This thread was discussed between 22/07/2001 and 02/09/2001

Triumph TR6 index