Bush measurement
Discussion
I'm looking to replace all the bushes on my '79 3000S and looking round at what's available. On the Superflex website they have 2 types for "early" and "late" M-series and imply the change date is around '72 but advise to measure. Quote "for most 'M' Models from Late 72, with Housing ID of 1.030"- 1.035" **Note: will not fit earlier models with housing ID of 0.985", the only way to be certain is to measure"
Being a 79 car, I thought it was a safe bet that mine would be the larger ID but I'm measuring just under the smaller one (0.976") using an internal vernier guage. This is the smallest ID of the bush housing - there seems to be a large chamfer at each end which I am ignoring.
Am I measuring correctly or have I missed the point completely?
GB
Being a 79 car, I thought it was a safe bet that mine would be the larger ID but I'm measuring just under the smaller one (0.976") using an internal vernier guage. This is the smallest ID of the bush housing - there seems to be a large chamfer at each end which I am ignoring.
Am I measuring correctly or have I missed the point completely?
GB
Why not try one of the early TVR specialists, they're not that expensive and your likely to get the right part first time, and even if you dont you'll get it the second time, or if you discover your car/chassis is a hybrid of both types you'll get the right parts third time, but you'll still only pay for the parts you need in the first place. 
ks...i clicked on that just hoping
Back to the topic please; I'm in the same situation as GB, having read the posts on this subject I decided to measure my ID of the bush housing only to find at the narrowest point the size is 0.985 on a 1978 Taimar. NOT the 1.035 as some have stated for cars of this date. But, measuring a new bush before installation I had, its diameter IS 1.035 or there abouts. Looking on the various TR6 supplier's websites non refer to different bush sizes. So, have I miss-understood also? Some clarrification of what is correct and how we can be sure we are putting the right bush into the right housing would be much appreciated.
BP-TVR said:
Back to the topic please; I'm in the same situation as GB, having read the posts on this subject I decided to measure my ID of the bush housing only to find at the narrowest point the size is 0.985 on a 1978 Taimar. NOT the 1.035 as some have stated for cars of this date. But, measuring a new bush before installation I had, its diameter IS 1.035 or there abouts. Looking on the various TR6 supplier's websites non refer to different bush sizes. So, have I miss-understood also? Some clarrification of what is correct and how we can be sure we are putting the right bush into the right housing would be much appreciated.
I did try.... see the link above.Adrian@
From that other thread, I can see how things get confusing.
Both CAD drawings show an ID of 1", whereas polyflex supposedly say there are two different IDs, and there are two cars here that seem to be contradicting everything.
Was the larger chamfer on the later eye to allow for a more robust(larger sleeved) bush (as you say the later bushes internal metal sleeve got larger)? As there is then less of the smallest ID for the bush to be passed through when fitting.
Also, adrian, you said that you have a reamer for the early arms to convert to the later type? How can you ream a larger chamfer onto the early eyelet which has no chamfer (going from the drawings), hence nothing to ream? Or is it the bush you ream?
Both CAD drawings show an ID of 1", whereas polyflex supposedly say there are two different IDs, and there are two cars here that seem to be contradicting everything.
Was the larger chamfer on the later eye to allow for a more robust(larger sleeved) bush (as you say the later bushes internal metal sleeve got larger)? As there is then less of the smallest ID for the bush to be passed through when fitting.
Also, adrian, you said that you have a reamer for the early arms to convert to the later type? How can you ream a larger chamfer onto the early eyelet which has no chamfer (going from the drawings), hence nothing to ream? Or is it the bush you ream?
- edit*
Cerberus90 said:
From that other thread, I can see how things get confusing.
Both CAD drawings show an ID of 1", whereas polyflex supposedly say there are two different IDs, and there are two cars here that seem to be contradicting everything.
Was the larger chamfer on the later eye to allow for a more robust(larger sleeved) bush (as you say the later bushes internal metal sleeve got larger)? As there is then less of the smallest ID for the bush to be passed through when fitting.
Also, adrian, you said that you have a reamer for the early arms to convert to the later type? How can you ream a larger chamfer onto the early eyelet which has no chamfer (going from the drawings), hence nothing to ream? Or is it the bush you ream?
GB...Polywho are not TVR experts, and TVR were using stock tube on both versions, the measurement ID are 'as is' on the tube. Both CAD drawings show an ID of 1", whereas polyflex supposedly say there are two different IDs, and there are two cars here that seem to be contradicting everything.
Was the larger chamfer on the later eye to allow for a more robust(larger sleeved) bush (as you say the later bushes internal metal sleeve got larger)? As there is then less of the smallest ID for the bush to be passed through when fitting.
Also, adrian, you said that you have a reamer for the early arms to convert to the later type? How can you ream a larger chamfer onto the early eyelet which has no chamfer (going from the drawings), hence nothing to ream? Or is it the bush you ream?
- edit*
Brian, yes, the chamfer was to allow larger sleeved bushes, and my thoughts are you are not looking it the drawing correctly, the early bush is pure and simple (sharp edges removed, from off the shelf tube, the same as the Vixen eyelets). I offer a taper reamer into both ends.
Adrian@
Before the days of buying in a bespoke reamer (bespoke and 2 piece,as you need this to do the inner top wishbone eyelet)... yes I USED to dress the centres out of a large tube rubber bushes to get then into early eylets.
You will find later AFTERMARKET eyelets are again different ID/OD because ...well, just because it IS considered to be an eyelet to take a rubber bush, as is, and tube is tube, metric or imperial.
Edited by Adrian@ on Wednesday 11th January 09:37
Many thanks Adrian for the explanations; now that my "Boss" (Thomas) has got involved he has explained everything to me with the aid of the two diagrams (early and late)! I now understand fully and can make progress, BUT, I now have another question which is related to this bush issue! Consider the top outer rear wishbone bushes which are fixed to the upright with a single long bolt. What is the design mechanism of movement of these bushes? that is, should the bushes rotate on the bolt when there is up/down movement of the upright i.e. the bush sleeves rotate on the bolt, and if so, do the bushes rotate relative to the washers either side of the bush or do the washers move with the bush? AND, presumably the bolt remains static and fixed relative to the upright. OR, when the bolt has been fully tightened up, are the bush sleeves held rigidly between the two washers and the upright (and are therefore held fixed relative to the bolt also)and rotational movement at the bush occurs purely from the flex (Twist)in the rubber in the bush itself? Understanding this would help me to decide how tight to do the bolt up. My own thoughts are that the bolt has to be done up very tightly to prevent any possibility of rotation of the bolt in the alloy upright which if allowed to happen would wear the bolt holes in the alloy casting. I'm also thinking of using a larger diameter washer on the outside of the bush (the "unsupported" side) to give the bush more support; since the standard 1/2 inch washers are barely as big as the bush itself and tend to "barrel" the exposed piece of rubber when fully tightened. Sorry inadvance for this being so long a post.
Adrian@ said:
GB...Polywho are not TVR experts, and TVR were using stock tube on both versions, the measurement ID are 'as is' on the tube.
Brian, yes, the chamfer was to allow larger sleeved bushes, and my thoughts are you are not looking it the drawing correctly, the early bush is pure and simple (sharp edges removed, from off the shelf tube, the same as the Vixen eyelets). I offer a taper reamer into both ends.
Adrian@
Before the days of buying in a bespoke reamer (bespoke and 2 piece,as you need this to do the inner top wishbone eyelet)... yes I USED to dress the centres out of a large tube rubber bushes to get then into early eylets.
You will find later AFTERMARKET eyelets are again different ID/OD because ...well, just because it IS considered to be an eyelet to take a rubber bush, as is, and tube is tube, metric or imperial.
As an alternative I sometimes just buy jag based 1" OD poly bushes with a 3/4 ID. I then buy 3/4 stainless bar and I bore and ream it to a fitted size for the Bolt, Then machine to length. This gives less comppliance in the bush and a fatter "sized" sleeve for a fast road / Race application.Brian, yes, the chamfer was to allow larger sleeved bushes, and my thoughts are you are not looking it the drawing correctly, the early bush is pure and simple (sharp edges removed, from off the shelf tube, the same as the Vixen eyelets). I offer a taper reamer into both ends.
Adrian@
Before the days of buying in a bespoke reamer (bespoke and 2 piece,as you need this to do the inner top wishbone eyelet)... yes I USED to dress the centres out of a large tube rubber bushes to get then into early eylets.
You will find later AFTERMARKET eyelets are again different ID/OD because ...well, just because it IS considered to be an eyelet to take a rubber bush, as is, and tube is tube, metric or imperial.
Edited by Adrian@ on Wednesday 11th January 09:37
But I am talking vixen / griff here rather than M, The principles however are the same..
N.
N.
Brian, the bolt head needs to be nearest the shocker, it is a fully locked up joint, I always use poly in this position, BUT if you use rubber then a better support AND set at ride height (poly do not have attached parts).
Slow M - Bernard gave a coherent explanation with what is happening...hopefully he will be along soon as my search could not find it, oldgeebee- Graham, recently posted a picture of his old bushes and my explanation of washer chopping off ringlets of rubber after a while an the need for better support IE a washer.
Adrian@
also read ..perhaps re read this
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Bernards previous..
Ms are set up with rear toe in. The mountings on the chassis side are parallel. That means that as the lower arm articulates up, the upright starts to pivot forward at the top. As the top arm is also set for toe in, the effect is that it wants to pivot the bottom of the upright back, as it (the arm) swings up. The two effects are cumulative. The harder the durometer of the bushings you use, the more the rear suspension binds in that motion. The increase in effort required in its motion isn't particularly horrible, but has to be taken into consideration in the same was as if you would, were you to add a progressive rate spring to the system, or an anti roll bar.
And from Graham
http://thumbsnap.com/xXa05ySE
Slow M - Bernard gave a coherent explanation with what is happening...hopefully he will be along soon as my search could not find it, oldgeebee- Graham, recently posted a picture of his old bushes and my explanation of washer chopping off ringlets of rubber after a while an the need for better support IE a washer.
Adrian@
also read ..perhaps re read this
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Bernards previous..
Ms are set up with rear toe in. The mountings on the chassis side are parallel. That means that as the lower arm articulates up, the upright starts to pivot forward at the top. As the top arm is also set for toe in, the effect is that it wants to pivot the bottom of the upright back, as it (the arm) swings up. The two effects are cumulative. The harder the durometer of the bushings you use, the more the rear suspension binds in that motion. The increase in effort required in its motion isn't particularly horrible, but has to be taken into consideration in the same was as if you would, were you to add a progressive rate spring to the system, or an anti roll bar.
And from Graham
http://thumbsnap.com/xXa05ySE
Edited by Adrian@ on Wednesday 11th January 20:10
heightswitch said:
As an alternative I sometimes just buy jag based 1" OD poly bushes with a 3/4 ID. I then buy 3/4 stainless bar and I bore and ream it to a fitted size for the Bolt, Then machine to length. This gives less comppliance in the bush and a fatter "sized" sleeve for a fast road / Race application.
But I am talking vixen / griff here rather than M, The principles however are the same..
N.
N.
http://www.mcmaster.com/#standard-titanium-tubing/...But I am talking vixen / griff here rather than M, The principles however are the same..
N.
N.
N,
Have a look at the very last item on the page. Kind of pricey, though. Good for a 5/8" bolt, with a .625" reamer. Or, might be a snug fit, considering most bolts are slightly undersized.
Also
http://www.mcmaster.com/#steel-hollow-rods/=frex6x
Best,
B.
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