Grecian White/Apache Red 225

[Harv]

Part throttle, a little bit of extra vacuum but not enough extra force to overcome the piston/damper friction.

The ported vacuum is clever.

I wonder if a slightly lighter damper oil (less viscous, easier to move with that little bit of extra force) would do the trick?

Damper oil viscosity is often viewed as a dark art though

Cheers,
Harv

[Craig Allardyce]

The problem still exists with the damper removed. Just screwing up the idle see's it go rich.

[Craig Allardyce]

The ported vacuum trial didn't work that well. On deceleration it sucked the piston to the top of its travel lol. I should have thought of that happening.
Anyway, one thing got the better of me. It stuck in my mind that it always takes more force to initially move something than to keep it moving. These carbs (HIF type SU) were always spec'd with ball bearing suction chambers. I never fitted them, and stayed with the old style. They looked better, and you could run large or small diameter piston springs, which gives you more options with combinations of the two types. These older ones always had a slight drag due to oil/fuel film on the piston tube and the suction chamber (very close tolerance).
As my initial problem was going rich during the first part of the piston lifting, I decided to try the ball bearing chambers. Low and behold, it has dramatically improved. I'm now going to go with running the low pressure suction restrictor on the float bowl vent line. Using the manometer tubes, and with the vacuum line fitted to the float bowl vent tube, I can see and control the amount of fuel drop in the main jet. I just have to get the restrictor the right size so excessive fuel isn't leaned out at higher airflow through the carby. Good thing I have one to measure with some jet drills.
Point to note, the fuel bowls are still vented normally to atmosphere. The vacuum via the restrictor is teed into this line. I was quite suprised how little negative pressure you need to alter the fuel level in the jet. It's not even readable on analogue vacuum gauge at idle, but drops the fuel level an inch or so.
It also look like I have to polish up another set of vacuum chambers now!

e6b5e690-ece7-4642-8f3f-da7871df7aa3.jpg (154.09 KiB) Viewed 1235 times

67a0aa65-8b77-4f39-a013-3a4a70f83e47.jpg (127.91 KiB) Viewed 1235 times

2add9bae-5ba4-4695-9818-0a5c3f268157.jpg (111.8 KiB) Viewed 1235 times

[Blacky]

I’m not sure what language you’re speaking but I certainly admire your persistence

[ed.harris]

Hi Craig,

What sort of Oil Pressure is the Engine making with the 308 Oil pump gears?

I have some 308 gears coming for my build if I feel like doing the same with my current grey build.

Do you have any spare spacer plate lying around that you want to Sell?

Cheer Ed.

[Craig Allardyce]

Pump now makes 30 psi at idle, 40 psi at 4000. Relief is shimmed but I'm also running hydraulic lifters with oil being fed up the pushrods to the adjuster cup (inverted now).
I don't have any spare spacers as they are hand made and exactly finished to each pump. No two pumps are the same and any miss alignment will cause damage.

[Errol62]

The ported vacuum trial didn't work that well. On deceleration it sucked the piston to the top of its travel lol. I should have thought of that happening.
Anyway, one thing got the better of me. It stuck in my mind that it always takes more force to initially move something than to keep it moving. These carbs (HIF type SU) were always spec'd with ball bearing suction chambers. I never fitted them, and stayed with the old style. They looked better, and you could run large or small diameter piston springs, which gives you more options with combinations of the two types. These older ones always had a slight drag due to oil/fuel film on the piston tube and the suction chamber (very close tolerance).
As my initial problem was going rich during the first part of the piston lifting, I decided to try the ball bearing chambers. Low and behold, it has dramatically improved. I'm now going to go with running the low pressure suction restrictor on the float bowl vent line. Using the manometer tubes, and with the vacuum line fitted to the float bowl vent tube, I can see and control the amount of fuel drop in the main jet. I just have to get the restrictor the right size so excessive fuel isn't leaned out at higher airflow through the carby. Good thing I have one to measure with some jet drills.
Point to note, the fuel bowls are still vented normally to atmosphere. The vacuum via the restrictor is teed into this line. I was quite suprised how little negative pressure you need to alter the fuel level in the jet. It's not even readable on analogue vacuum gauge at idle, but drops the fuel level an inch or so.
It also look like I have to polish up another set of vacuum chambers now!


e6b5e690-ece7-4642-8f3f-da7871df7aa3.jpg
67a0aa65-8b77-4f39-a013-3a4a70f83e47.jpg2add9bae-5ba4-4695-9818-0a5c3f268157.jpg

Hi Craig,
Looking at the vacuum chamber photos, I see they have a tall style cap on the damper piston ends. Does this differentiate the ball bearing type chambers? The ones I have have the same style caps as HS6, and I’ve been told this probably means they are HIF6 rather than HIF44.

[Craig Allardyce]

Yes, and a fatter neck on the suction chamber, BUT, HIF 4,6, & 7 carbs ran either normal or ball bearing suction chambers. Metric versions, HIF 38 & 44 ran only ball bearing chambers.

[Errol62]

Thanks Craig

[Craig Allardyce]

Well that's a wrap on the engine and box. I completed what I hope is the final solution to a leak free grey motor being a screw in dipstick. For those that know, the crank rotation at higher rpms tends to push oil up the dipstick and past the crappy felt seal.
Previously I had also repaired an external leak at the layshaft section within the bellhousing. This area is where the layshaft is pushed into the gearbox and is held in place by the input shaft retaining housing. The shaft is only sealed by its interference fit. Luckily I decided to leave the box inverted for a while to see if anything was leaking! It was. A bit of loctite wick in, and a custom gasket with retainer plate that is sandwiched under the input shaft housing fixed it.
Now onto refitting the steering box as I pulled it to check the internals again. I have an annoying amount of steering play and wander in comparison to what my EK ute was like to drive. Nothing was found and I'm suspecting the radial tyres with their sidewall flex is the issue. My EK was fitted with the latest Bridgestone crossply's and it steered and tracked really well.
I have two more mods to do with regards to the new crank vibration damper. One is a 1/2 fan spacer that I'll have to knock up so the fan has clearance to the larger diameter damper. The other is removing the two crossmember splash guards as they will need to be slotted for the damper (slightly).

fa7ed65b-5e17-43e4-af69-60c929a34db4.jpg (218.15 KiB) Viewed 80 times

98d47786-5229-484d-8a0a-20f4dc60646e.jpg (256.91 KiB) Viewed 80 times

b9f3be64-6a5a-4bc5-88b1-2f18d98cfc44.jpg (279.8 KiB) Viewed 80 times

0232ce95-092c-4a9b-9348-e6bd7e082cb2.jpg (231.01 KiB) Viewed 80 times

[Blacky]

Thats purty

How much rooting around is the hydraulic lifter conversion mate ??? I would be real interested in doing that

[Harv]

Did you tap the dipstick port to 1/8 NPT? Curious, as the factory port size is near perfect for tapping that thread.

Cheers,
Harv

[Craig Allardyce]

Did you tap the dipstick port to 1/8 NPT? Curious, as the factory port size is near perfect for tapping that thread.

Cheers,
Harv

Yes mate. 1/8npt. No drilling required.

[Craig Allardyce]

Thats purty

How much rooting around is the hydraulic lifter conversion mate ??? I would be real interested in doing that

You need to make a jig that supports the drill bit in the lifter bore due to the angle. You also have to calculate the angle required vs the hole position in the lifter bore. This will also depend on what your cam lift is. This is to ensure the hole is within the oil groove of the lifter proximity. You will also need different pushrods as the cup type and size in the lifter is different, as well as the tappet adjusters. I needed to run oil up the pushrods as I could not source the same pushrod and adjuster set up. My adjusters are cupped downwards. Camshaft closing rates are important if you want to run hydraulics with out them pumping up. I had to run heavier springs due to my high lift and low duration cam. So no, not much dicking around

[Craig Allardyce]

Knocked up the 1/2" fan spacer and fitted it today. Fan clears the vibration damper nicely.
Have now fitted the steering box and got things ready so I can fit the engine and box tomorrow.

cd9d37ba-56cd-4c33-abdc-16c171d603da.jpg (135.63 KiB) Viewed 21 times

3a00f8c3-3343-47c9-86a4-a7ca9a9ca602.jpg (132.32 KiB) Viewed 21 times

adefd682-2e44-4bc8-8fd2-97a4f3de5c85.jpg (321.1 KiB) Viewed 21 times