My Samurai

[ScottieJ]

The bogging will be that you’ve dropped it to 8*, that’s what the book says but as mentioned in my previous post most of us run 10* as they run better.

[Larry]

Cheers Scottie, I guessed that might have been the case but thought I would try it just in case. I'll stick it back to 10 and go from there.

[maxaret]

Hi Larry
Do you mean that the piston 'flutters' up and down slightly ?
10w40 should stop piston flutter unless the damper/damper spring is worn or perhaps the incorrect damper/spring for that particular SU carb is fitted ,I believe there are different types of damper and spring for different models of SU ?

[Larry]

Yes, flutters up and down but like you say, only slightly. Give me a day or so and I'll get a video to show you what I mean. Thanks

As it happens I have a spare SU belonging to a friend, I'll compare and see if they have similar play.

[Larry]

So I've compared the pistons and mine looks to be ok wear wise, compared with another used one at least. I'll get a video later.

I've also bought a pressure gauge for checking fuel and vacuum. Fuel pressure measuring at just over 4psi at 12.6v and as high as 5 when engine on and blipping throttle. I'm gonna buy a regulator to trim it back to between 2 and 3 psi, see if that makes a difference.

Also gonna whip the cam cover off and double check valve clearances, as I've noticed it's a little tappety.

[donkeychomp]

If you are checking the tappets it might be worth getting some Loctite. Those screws get loose very easily!

[Larry]

Valve clearances checked and all ok. I haven't added locktite as I didn't need to change any, but point noted for next time. Thanks

[Larry]

Doing some googling and came across this forum thread, same engine and same issues, unfortunately the guy never confirmed if he found a fix.

https://forum.retro-rides.org/thread/20 ... p-su-hif44

Rather than order a pressure regulator to go with the cheap pump I have, I've decided to buy a better quality pump that puts out a slightly lower pressure.
https://www.ebay.co.uk/itm/FUEL-PUMP-EL ... 890.l49292

Should have it by the weekend, will wait and see what that does.

Have also put timing back to 10 btdc now.

**Edit**:
I forgot to mention, I've now added the proper SU dashpot oil also

[Larry]

Huco fuel pump fitted. Made a bracket to hang it off the back of the intake manifold so it's tucked in out of the way against the bulkhead.

Only had time to give it a very quick run but it looks to be an improvement. Need to get it proper hot to be certain.

Pump seems like a good quality unit. It must have a built in regulator as it only kicks in when it needs to. It barely runs at idle but ticks away much faster when holding the throttle open.

[donkeychomp]

Hopefully that's cured it. Very tidy engine bay there!