Gridgway

I think I've finally lost the plot. BD motors run very happily on dizzy ignition with a mechanical advance curve. My BDG produces 293 bhp very simply. So adding knock sensors, tuning with gas analysers is just adding unnecessary complication that is (in my view) extremely unlikely to produce a nice reliable smooth running result. Good luck with it, but please try to get a simple solution running!

What's one of those? And why?

It's pretty easy to do. I would indeed set it to TDC and check that the rotor arm points to where #1 is on the cap. Pull out the dizzy. Watch the spindle move and get it back in in the right place. If it nend up on the wrong place that is visually very easy to spot.

This must the ignition advance version of the Schrödinger's cat thought experiment where observation changes the outcome! Rather bizarrely, the distributors on mine and Jen's FF2000s (pintos) had both massively moved overnight at Silverstone one race weekend between Friday test and saturday quali first thing. Still a mystery. They ran fine all day, then the timing was out overnight. We can only think that someone moved them, but that's nonsense as who on earth would do that? Sorry, not a very helpful comment from me. Other than, once done up dizzys don't move, so the problem must be in the internals. Or a problem of measurement. If it was me, I'd swap another dizzy in (assuming I had one I could swap out or borrow or had a spare) to try and narrow it down.

So purely mechanical then. Excellent. Another basic question. How are you checking the timing?

I may have missed this, but what controls the advance? Is it just mechanical in the dizzy? You've not got an ab14 Lucas module there as well?

There's something not right going on. My BDR starts easy peasy. Doing the dizzy up so it doesn't move is similarly easy. Timing just doesn't move in the normal world! Is there something else going on with fuel or sparks?

And now sold to a very nice man!

I can't imagine not having compressed air and tools in my garage if you have space and resources!

It's got to be a carb problem. The old fuel crud has got in there. I know you've said you don't like the idea, but you can isolate the problem by spraying easy start or brake cleaner into the intakes. If the engine runs and stops it's a carb problem. If it doesn't run then it's a spark or timing problem. No need to be precious about it. When we start the BDG (overblown cross flow) in my F2 race car, we take a water bottle, make a hole in the lid and fill it with petrol to have a big squirt down each throttle body to get it going!

Back to the top, updated price £11,000

Those are very short trumpets!

Needs a good inspection to check for any damage apart from the sheared bolt. Left to my own devices, I'd want to get the DD tube out to get the remains of the bolt out and to check it was all ok.

on the engine starting problem, happy to help there!

On the topic of senders, mine was all rusted up and had to be replaced. All that's available now are the generic ones with the float arm in two bits that you have to cut to length, solder together and bend accordingly. As there is a baffle in the tank the float arm can't be very long. It's extremely hard to know how to get the right length and shape as you can's see it in the tank (obviously). I made a full scale mockup of that section of the tank using foamboard so I could sort it out. Seems to work ok. You'd need to check that the generic sender available is compatible with your gauge. I still have the mockup in the shed if pics of it are any use. Or if I could get it to you you could use it.

There are a few online. Did Silverstone Classic in 2022 in the March... Race 1 Look away at the end if you are of a sensitve nature! Race 2 starting at the back after race 1!

Yes my assertion is that the likely reason for an engine builder to do those things is to get a higher power engine which almost always (if not always) involves higher RPM. I run my BDG up to 9,500 (in racing) although I am told they used to use more rpm back in the day.

From my BDR build sheet it mentions the use of AE Hepolite pistons which I would be tempted to think are cast not forged, but that's just a guess. I can't find a reference to a Hepolite piston for a BD if I google though.

I don't think I see it really like that. The routes to getting more out of a BD engine pretty much have one thing in common - higher revs. You build it to carry on higher up the rev range and function there. More porting and potentially bigger valves - more gas in and out (esp at higher revs). Forged pistons - stronger at higher revs and can work at higher compression. Steel crank and rods - stronger to handle higher revs. More detailed balancing - higher revs. And so on. Lighter steel flywheel - higher revs. Now there are other side effects such as better throttle response with a lighter flywheel. But things like longevity, drivability, fuel efficiency (hehehe) are not normally high priorities of someone building a higher spec BD. Not sure how that helps your quest (mainly because I'm not sure what your quest is), but might be a helpful perspective. Graham PS what are you thinking of doing with a gas analyser? Mapping is normally only concerned with AFR and uses a lambda or wide band lambda for that.

Back to the top again, had some interest but no actual taker yet. I'd really like it to find a new home as I want to use the space and I have also got my BDR project. I would consider lower offers, so if anyone is looking for a fab xflow, but thinks it's just too much money, try me and see - you could be surprised.

I'm fairly sure that they are not long enough. But given what Bob has got is different from mine, my suggestion was going to be too get some appropriate steel strap and make pieces to lengthen those in there. I'd also test fit the new tank to make sure it fits and can be secured as there's no rear lateral support. Also the side supports don't look parallel, but that must be a camera issue

Well I have no data, just a strong suspicion!

Indeed, so we'll give it a miss thanks.

But most people have their harnesses done up quite loosely. I understand that to be more dangerous than inertia reel belts.

If you want, post a picture of the basket that the tank sits in (with the tank not in situ). Then we can see.