Here are the measurements for EU needles;
And the stages where the needle is measured;
Your getting there , sounds like it’s just slight adjustments needed now , well worth getting a colour tune , to adjust the mixture , it’s a low cost and easy way to make sure the mixture is right , rather then just guess !
If the air cleaner is off , raise each piston and see if the butterfly’s are seated right , only need to be open a little , for the engine to run too fast . make sure the return springs are strong enough !
It is also really cool to be able to see the flame in the cylinder. It is the most fun tool that I have. Helped me get things sorted out with my ZS carbs when I put adjustable needles in them.
David
68 E-type FHC
Good news but you have a serious air leak somewhere. You said earlier (I think) that the 5 seconds were at 1800 rpm and I just came here to say your butterflies or something were set wrong, now it’s 2500 on different carbs for 3 mins.
An engine is basically an air pump and for this big of an engine to race at 2500 it needs fuel and air. I can’t say I’ve tried it but I am skeptical that an idle screw could pass enough air unless it was screwed out to the limit or missing. That suggests the butterflies or bushes are shot or a gasket/fibre insulator is broken. That’s why it needs choke to keep running
PS: .250” and 6mm are the same thing in this context, give or take a few thou.
Another suggestion, now that you have identified the problem as carb related. I sent my carb out to Joe Curto for a complete overhaul, rebushing the butterflies, etc. They came back and the engine idled beautifully without any further adjustments. I know there are a lot of other Curto fans out there, and considering that your carbs are over 50 years old, they could probably do with a professional overhaul. Not saying you can’t do it right also, but Joe has been doing this well for decades.
2 Likes
Erica, which model is the second one you refer to ? A Pertronix is on my list and
also wouldn’t like that you can’t static time.
It’s the second revision module. I think it is red. It has some advantages and disadvantages. It is self healing and less likely to fail, and has more power at higher revs. But it can’t be timed statically and requires suppression wires.
Regarding the high RPM’s at idle, check to be sure that the throttle link rod is not binding and that it’s properly returning to the lever stop. Maybe you need to adjust it.
And double check your ignition timing.
This was my problem! The return springs on the butterflies were too weak. They provided a nice snap when not running, but didn’t hold the butterflies down when running. I put some stronger springs on and it’s idling at 1000-1200 with choke out.
I still need to dial it in, and check the timing, but I really think it’s down hill from here. I backed the car out of my ( very small) garage and it was great. I’m looking forward to tomorrow when I can get running the way it should be, give it a good washing, and have it ready for cars and coffee on Sunday morning!
I REALLY APPRECIATE all the help and advice from everyone here. Sometimes it can feel pretty isolating when dealing with issues, and having a group of fellow enthusiasts to kick around ideas makes a huge difference. Really.
THANK YOU all.
Robert
3 Likes
great news and well done!
Robin, the HD8’s use UE’s, not EU’s. I’m new to the site, so I haven’t figured how to post a pic of the UE dimensions but if one searches for SU carbs, you can find Speed Sports book which includes the needle charts at the end. The HD8 needles are found under the 0.125 charts.
Welcome to the E-Type rodeo Larry!
Have a look in #user-guides-and-how-tos, there you will find How do I: Add pictures to a post?
Welcome to J-L.
Glad to hear you have it running well now. I have been following this thread with interest as I might run into similar issues in my SU conversion I started last weekend.
Time to go out and enjoy it after all the work.
Jay
Thanks much Andrew! I’ll do so.
Best regards,
Larry Trom
804-677-5090
Doug, see that you’re in the Denver area. Do you run UM’s or a leaner set?
I have a Series 1.5 with Strombergs, so no SU needles. I do have Joe Curto’s adjustable jet system installed though. You in the Denver area as well?
Ah, ok. No I’m two hours north of Santa Fe, NM. In the mountains at 9100’. I’ve had the stock UM’s and they’ve always been too rich. Just swapped for UD’s from Joe (and new jets as they are 20 years since I last replaced them) . Will get around to tuning shortly and see if they help out.
Didn’t think the pics would load, but it worked! Dimensions for the UM and UE needles