Modification Of Hi Lo Trumpet
#16
Posted 19 January 2021 - 08:21 AM
#17
Posted 19 January 2021 - 08:27 AM
Remember 3:1 ratio on front and 5:1 on rearI have got the Minispares HiLo-Kit and red dot cones for the front. I compared the Hi-Lo's to the original aluminium trumpet and noticed that the HiLo's are 8mm shorter at their lowest setting.
The red-dots have the same unsettled height as the used OE Dunlop cones from the rear.
Would you still machine off some material from the HiLo's as a precautionary measure?
Therefore 8mm = approx 24mm on front and 40mm on rear
Edited by steeley, 19 January 2021 - 08:28 AM.
#18
Posted 19 January 2021 - 12:20 PM
I have some off brand hilo's and red spot cones. I was in a similar spot and my car was sitting like a monster truck in the front. I decided to bottom out the adjustment right before going to a local meet. Not sure if the southern heat helped or not but by the time I got to my destination (about 20+ miles) my car was slammed in the front and scrubbing on everything with the slightest turn of the wheel (I'm on 10 inch wheels too). Not sure how low you are going for but I could drop mine to be almost a finger between the tire and arch if I wanted to.
maybe bottom it out and take it for a drive and see what happens? I would be nervous to start cutting things knowing the cones will eventually settle and then you won't have as much thread to raise it back up.
#19
Posted 19 January 2021 - 12:23 PM
I have some off brand hilo's and red spot cones. I was in a similar spot and my car was sitting like a monster truck in the front. I decided to bottom out the adjustment right before going to a local meet. Not sure if the southern heat helped or not but by the time I got to my destination (about 20+ miles) my car was slammed in the front and scrubbing on everything with the slightest turn of the wheel (I'm on 10 inch wheels too). Not sure how low you are going for but I could drop mine to be almost a finger between the tire and arch if I wanted to.
maybe bottom it out and take it for a drive and see what happens? I would be nervous to start cutting things knowing the cones will eventually settle and then you won't have as much thread to raise it back up.
Thanks, that sounds like a sensible approach - It is still a long way until I will be able to take it out for a drive - restoration is in full progress.
#20
Posted 19 January 2021 - 05:09 PM
Remember 3:1 ratio on front and 5:1 on rear
Therefore 8mm = approx 24mm on front and 40mm on rear
Sorry to jump in here on this.
Yes, the Rear Arm Ratio is 5:1
However, the Fronts are in fact 4.45:1, call it 4.5:1. It seems it was Clive Tricky back in the early 60's who suggested it was 3:1 and that's been carried forward ever since.
For what its worth, after 800-1000 miles, the red dots settled about an inch in the rear; 1/4-3/8” in front. Would’ve expected more in the front because of the engine/gearbox weight. Strange. Plan is to trim the front Hi-Lo trumpets to an overall height of 2”.
The Rears have settled more as when fitted in a full Droop, typically there's next to no pre-load on the Cone where as the Fronts in a stock set up have circa 9 mm Pre-load Compression on them. Granted, you've Hilos fitted however it seems from this thread there's some preload on the Fronts.
#21
Posted 19 January 2021 - 06:38 PM
[quote name="steeley" post="3680875" timestamp="1611044872"]
Remember 3:1 ratio on front and 5:1 on rear
Therefore 8mm = approx 24mm on front and 40mm on rear[/quote]
Sorry to jump in here on this.
Yes, the Rear Arm Ratio is 5:1
However, the Fronts are in fact 4.45:1, call it 4.5:1. It seems it was Clive Tricky back in the early 60's who suggested it was 3:1 and that's been carried forward ever since.
For what its worth, after 800-1000 miles, the red dots settled about an inch in the rear; 1/4-3/8” in front. Would’ve expected more in the front because of the engine/gearbox weight. Strange. Plan is to trim the front Hi-Lo trumpets to an overall height of 2”.
The Rears have settled more as when fitted in a full Droop, typically there's next to no pre-load on the Cone where as the Fronts in a stock set up have circa 9 mm Pre-load Compression on them. Granted, you've Hilos fitted however it seems from this thread there's some preload on the Fronts.
[/quote]
[quote name="steeley" post="3680875" timestamp="1611044872"]
Remember 3:1 ratio on front and 5:1 on rear
Therefore 8mm = approx 24mm on front and 40mm on rear
Sorry to jump in here on this.
Yes, the Rear Arm Ratio is 5:1
However, the Fronts are in fact 4.45:1, call it 4.5:1. It seems it was Clive Tricky back in the early 60's who suggested it was 3:1 and that's been carried forward ever since
Everyday’s a school day thanks
Edited by steeley, 19 January 2021 - 06:40 PM.
#22
Posted 19 January 2021 - 09:33 PM
I have some off brand hilo's and red spot cones. I was in a similar spot and my car was sitting like a monster truck in the front. I decided to bottom out the adjustment right before going to a local meet. Not sure if the southern heat helped or not but by the time I got to my destination (about 20+ miles) my car was slammed in the front and scrubbing on everything with the slightest turn of the wheel (I'm on 10 inch wheels too). Not sure how low you are going for but I could drop mine to be almost a finger between the tire and arch if I wanted to.
maybe bottom it out and take it for a drive and see what happens? I would be nervous to start cutting things knowing the cones will eventually settle and then you won't have as much thread to raise it back up.
The front Hi Lo trumpets are bottomed out-can't turn them in more without hitting the plate inside of the cone. I'm not concerned with trimming the Hi Lo, there is plenty of thread length for adjustment later if needed.
#23
Posted 19 January 2021 - 09:49 PM
Shorten the male thread as per my initial post on this thread and the MiniSpares instructions.
Easy to do with basic tools and doesn’t potentially weaken the HiLo, which shortening the thread engagement in the alloy body could do.
#24
Posted 20 January 2021 - 02:44 AM
Shorten the male thread as per my initial post on this thread and the MiniSpares instructions.
Easy to do with basic tools and doesn’t potentially weaken the HiLo, which shortening the thread engagement in the alloy body could do.
Will shorten the overall height of the Hi Lo by .3" and lose only 1/4" of thread, leaving just short of 200mm engagement. Will still have the large locknut to support the trumpet, should be fine. Thanks for the concern.
#25
Posted 20 January 2021 - 09:35 AM
200mm of engagement - if your HiLo is that big no wonder you've got problems
I really can't see why you're hell bent on making a 30 second hacksaw/dremel fix into a machining job. Barking.
#26
Posted 20 January 2021 - 06:39 PM
200mm of engagement - if your HiLo is that big no wonder you've got problems
I really can't see why you're hell bent on making a 30 second hacksaw/dremel fix into a machining job. Barking.
200mm?? Don't know where that came from. Good example of why we still use fractions here in the colonies. As for the hacksaw/dremel fix-OCD I guess and WWSD (What would Spider Do).
#27
Posted 20 January 2021 - 06:47 PM
200mm of engagement - if your HiLo is that big no wonder you've got problems
I really can't see why you're hell bent on making a 30 second hacksaw/dremel fix into a machining job. Barking.
Croc's issue isn't the top of the bolt hitting the Cone, but simply that when wound all the way in, the height from the Bolt Head Face to the Flange of the Hilo Body is too high. Machining some off the Hilo Body will allow that to become shorter. It's likely after this he'll also need to shorten the bolt too though.
#28
Posted 20 January 2021 - 07:33 PM
#29
Posted 20 January 2021 - 08:37 PM
200mm of engagement - if your HiLo is that big no wonder you've got problems
I really can't see why you're hell bent on making a 30 second hacksaw/dremel fix into a machining job. Barking.
Croc's issue isn't the top of the bolt hitting the Cone, but simply that when wound all the way in, the height from the Bolt Head Face to the Flange of the Hilo Body is too high. Machining some off the Hilo Body will allow that to become shorter. It's likely after this he'll also need to shorten the bolt too though.
That’s not what he says in #22!
Edited by GraemeC, 20 January 2021 - 08:37 PM.
#30
Posted 20 January 2021 - 09:14 PM
My hilos are the early allen key only adjustment type with a circlip on the bottom of the adjuster bolt. I didn't think this was supposed to be a problem on later genuine hilos with adjusting nut and locknut.
Edited by imack, 20 January 2021 - 09:14 PM.
0 user(s) are reading this topic
0 members, 0 guests, 0 anonymous users