289 build

[allan horsfall]

Clive
I've got to ask, if thats your usual route to Silverstone, how come you've still gpt a license??? With the cameras on that road you can loose your license in one trip.

Regards

[clive]

Quite simple Allan, the road is so fantastic and quiet you don't want to speed to enjoy it. I have travelled it many times and I know where the cameras are. Back in the day when they were introduced and used the old film type cameras, there were 16 between Edinburgh and the border but only one had film in it at any time. You never knew which one it was so it was like Russian Roulette! Nowadays with sat navs, most of the traffic uses the A1 or A74 leaving the A98 almost deserted.

[KevinW]

I would point out that the Hawk petrol tank is narrower at the bottom than the top, so a swing arm sender will never be 100% accurate.

well, if my model was correct, it doesn't matter whether it tapers or not - you still have a non-linear response curve, however you set up the ball cock, or whether you have a vertical level meter. If its square-ish compared to wedge shaped, it'll just have a response thats a bit less of a curvy 'S' on a 289 tank compared to a 427 tank!

[amulheirn]

Ball cocks and response curves - you've blown my mind Kevin.

Good news is that I took out the tank, put in a new sender, sealed it all up and the gauge works again! Went for a socially-distanced road trip with a couple of friends last wednesday and it was a success all round. The old sender had a sticking point in it, and was stiff - wasn't sure how it had become so defective, but maybe I damaged it during installation somehow. Was so pre-occupied with concerns about the wheels coming off my newly-built 289 that I had no time to notice whether the fuel gauge was working.

I now need to resolve the next concern about driving the car, which is the sparks my rear-most exhaust clamp emits when I go over a big depression in the road.

I think Gerry told me once that he thought many Hawk 289s sit too low. The Hawk build manual isn't specific about it, but I wondered if the two 'packers' that go between leaf spring and axle are optional. They are of different thicknesses from memory. Why supply two of different thicknesses when one would be ok? Does this mean they are some kind of adjustment?

I asked him once on Facebook if I could remove them and he said I could, but I could have done with a proper conversation about it - a few questions arose in my brain:

• Could I remove one to get an extra 0.5" clearance?
• Could I remove both?
• Why did I replace the original bolt through the leaf springs with a 'special Hawk' one? Was that to locate the packers so they don't slip out?
• If I remove a packer (or both packers) will I have to change the special bolt?

Anyway - hopefully I'll get on with that tomorrow night - if the urge for lockdown beer drinking doesn't overcome me again...

[StewbieC]

Hi Andy,
I took both spacers out and ran without them for ages. I even toyed with the idea of fitting an extra leaf to the spring or even some helper springs as in coilovers on the rear gas struts.
In the end I fitted the IRS with modified exhaust which sits higher and now no more grimacing when you hit the dips

[StewbieC]

I would point out that the Hawk petrol tank is narrower at the bottom than the top, so a swing arm sender will never be 100% accurate.

well, if my model was correct, it doesn't matter whether it tapers or not - you still have a non-linear response curve, however you set up the ball cock, or whether you have a vertical level meter. If its square-ish compared to wedge shaped, it'll just have a response thats a bit less of a curvy 'S' on a 289 tank compared to a 427 tank!

You notice that the tank empties very slowly at first (on the gauge) and gets alarmingly quick as you get closer to the bottom. I know I have 30 miles when it is totally empty on the gauge, I haven't ever risked any more

[Dave Woodward]

Mine empties rapidly for the first quarter, very slowly through the middle of the tank, and then quickly again through the last quarter?? Make sense of that if you can

I was instructed on installation to put a bend in the arm to prevent the 'ball' from hitting the bottom of the tank which I did. I would now think though that would mean the tank never reads full (which isn't true).

[peterc]

Dave, your description of the gauge read out and it’s speed of dropping is what how Kev has described. Mine is similar as i’m sure are most Hawks.
Depending how much bend you made in the arm it could be possible that you have merely changed the avoidance of hitting tank bottom with a premature full reading when the tank isn’t really 100% full.
I remember my arm being adjustable for length but it’s all a bit hit and miss to get it correct. The main thing is getting empty to read some where near correct so you know when to fill up.
I think I will still try the Spiyda box of tricks.
Peter C

[peterc]

Andy. I think everyone has the grinding of the exhaust clamps where it passes under the rear axle. That’s why I rerouted mine along inside the cills and then over the axle rather than under.
Certainly try removing one or both of the axle spacers to raise the car. Just check what the wheel to wheel arch clearance looks like to avoid over doing it.
Yes, Gerry says we all have our cars too low.
Peter C

[clive]

No bother for me with the exhaust under the rear axle, but the middle silencers under the seat are a problem if the sleeping policemen are too high. If the road calming measures are the single square type they are a real problem if you drive over the middle of them.