Thunda Babe

[WoodRay]

Some more progress this week. Its very annoying to say the least at the shoddy work some engine builders do. My head was already "rebuilt" prior to me buying it. Two issues I've found of late are the installed heights of the valve springs are way too high, and the spring pockets in the head are grooved from previous wear. I ended up making some shims to get the valves back down to the correct height. Previously the seat pressures were about the same as a standard grey spring!
Yesterdays testing went well with the reversion all but gone and some gains made. Airflow through the head is improved again and now my carbs are fully opened with the heaviest spring fitted. Time for more induction ability!

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[Alan]

What seat pressure did you end up with? what rpm were you getting the reversion Craig?

[WoodRay]

65lb and 5000rpm. Still not enough but an improvement. I have gained 800rpm.

[Alan]

Crikey, what were they before? surely they must have forgot to put the shims in. How's the new bottom end coming along ? could be needed soon.

[WoodRay]

I didn't measure them at the wrong height. It was below 65lbs by the specs for the springs fitted.
Bottom end has hit a big hurdle. Auscrank is going out of business (retiring). Will know this next week if the new owners are continuing with billet cranks.

[WoodRay]

Onto the next change for the engine. I have obtained a set of triple 2" Su's after handing over my first born and one testicle.
I'm currently boring out the adapters and manifold for fit up.

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[WoodRay]

The new carbs fit so the fuel tank will live for another day. I have a new Alloy tank to fit at a later date.
Reversed the alternator and it increased it's output. Contrary to popular belief it shouldn't have made a difference apart from the fan. Andy maybe able to help: Its a 55 amp Bosch BXH1236. Not sure if it's star or delta wound.

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[WoodRay]

Started on some plank repairs as the bilge pumps are just keeping up. Did a quick plug check with pleasing results finally as they are now getting a good brown tinge. New carby needles arrived in one day from Sydney, go figure. Looking forward to the next run. The last one was good with the cav plate pulled up and now powering through the porpoising. No rich misfire at full throttle and now slightly lean up top hence the new needles.
I'd really love to know what the average speed of 155ci skiffs was in the day if anyone has an idea.

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[Wildwoody1]

Woodray, the following figures listed by APBA ,
1972 Records across States ranged from 78.49 , 73.46, 67.08, 58.09 , 51.10 for Skiffs
With the fastest Runabouts being 70.90 NSW and 68.73 Vic
Ian Harvey at 78 + was done with the Grey Repco. from competition experience against the Repco Brabham he was in the 80,s without a doubt. This engine made about 50hp more than any of the modified Car engines being run.

[WoodRay]

Thanks mate. I tip my hat to them. Such a great achievement to get to the speeds that they did back in the day. I'm certainly finding out how hard it is to replicate even in these times.

On the flip side I've had to do some temp repairs on a plank that is splitting along the rivet line and grain angles. This has amounted to some more leakage that I need to fix. All problem spots have had the rivets removed and have been dowel plugged. Sections between the ribs have some pieces laminated over the areas. All grain openings have been cleaned and filled with a sawdust and adhesive mix. Now waiting for laminates to dry before some paint and riveting to go.

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