Discussion
Stunned Monkey said:
Who is Andy?
http://www.pistonheads.com/gassing/profile.asp?nam...Did my bodies, too
Very pleased with his work !
Hi all
Very kind comments (from most anyway.)
Could I please point out the gaskets advertised on ebay on the link crypto gave are nothing to do with me but another seller by the name of pc928t.
My eBay throttle body advert can be found at:
http://m.ebay.co.uk/itm/251922807669?nav=SEARCH
as well as the Pistonheads one.
My thermo gaskets form part of the same advert. The gaskets advertised by this seller are just gasket paper.
Very kind comments (from most anyway.)
Could I please point out the gaskets advertised on ebay on the link crypto gave are nothing to do with me but another seller by the name of pc928t.
My eBay throttle body advert can be found at:
http://m.ebay.co.uk/itm/251922807669?nav=SEARCH
as well as the Pistonheads one.
My thermo gaskets form part of the same advert. The gaskets advertised by this seller are just gasket paper.
Ok, but we'e talking about throttle butterflies, not i.e. half time bearing, where you have real loads.
Most important is that they are sealed against air soak.
As said, i'm very pleased with the results. I fitted new body gaskets from power (Andys will do it though) and new throttle springs and i have absolutely no shuttering or shunting. Throttle is very smooth and more direct than before.
Most important is that they are sealed against air soak.
As said, i'm very pleased with the results. I fitted new body gaskets from power (Andys will do it though) and new throttle springs and i have absolutely no shuttering or shunting. Throttle is very smooth and more direct than before.
Apologies I've not been on here much to respond to this. I've been dragged down to the south of France by my better half for a few days. Spent yesterday around the Millau bridge. Civil engineering at its best.
Martin following your recent comments on this thread and others you made in November last year about my TB mod I will explain my actions. Yes roller bearings can take more load; they also produce more friction due to the larger surface area touching. I have tried to have the spindles moving as freely and easily as possible. You also suggested using a bushing instead of a bearing. I stayed away from this because metal rubbing metal can cause electrical interference on what is already border line circuitry. The bearings I use are more than adequate to support the loads put on the butterfly spindle. The way they are sealed and mounted means there is no chance the grease will be sucked out by the induction pressures as you suggested while air cannot be drawn through them altering the balancing.
Regarding brinneling, you sited the case where cars needed their wheel bearings replaced after a long transport on a trailer. This is a completely different situation. The cars are stationary while putting loads on the same spot on the bearings through vibration, road conditions etc. as ball bearings are moved through their travel, they naturally creep and move so when they return to idle, the balls will not always be in the same place. When the car is stationary at idle with the engine off, there will not be the same vibrations as when it is on a transporter. Maybe your car spends quite a time on the back of a transporter? How much of your cars hours of use is spent at idle with the engine running? It would take many, many hours of being in this position to start marking the bearings. As I said earlier ball bearings creep during use so the chances of the balls getting marked is minimal to nothing. IF you ever felt the bearings wear or getting notchy they can easily and cheaply be replaced with no further machining required. In fact if I was in a good mood and you sent the bodies back to me I would do this as a good will gesture.
I hope this essay clears some points up and explains the reasoning behind my methods.
Andy
Martin following your recent comments on this thread and others you made in November last year about my TB mod I will explain my actions. Yes roller bearings can take more load; they also produce more friction due to the larger surface area touching. I have tried to have the spindles moving as freely and easily as possible. You also suggested using a bushing instead of a bearing. I stayed away from this because metal rubbing metal can cause electrical interference on what is already border line circuitry. The bearings I use are more than adequate to support the loads put on the butterfly spindle. The way they are sealed and mounted means there is no chance the grease will be sucked out by the induction pressures as you suggested while air cannot be drawn through them altering the balancing.
Regarding brinneling, you sited the case where cars needed their wheel bearings replaced after a long transport on a trailer. This is a completely different situation. The cars are stationary while putting loads on the same spot on the bearings through vibration, road conditions etc. as ball bearings are moved through their travel, they naturally creep and move so when they return to idle, the balls will not always be in the same place. When the car is stationary at idle with the engine off, there will not be the same vibrations as when it is on a transporter. Maybe your car spends quite a time on the back of a transporter? How much of your cars hours of use is spent at idle with the engine running? It would take many, many hours of being in this position to start marking the bearings. As I said earlier ball bearings creep during use so the chances of the balls getting marked is minimal to nothing. IF you ever felt the bearings wear or getting notchy they can easily and cheaply be replaced with no further machining required. In fact if I was in a good mood and you sent the bodies back to me I would do this as a good will gesture.
I hope this essay clears some points up and explains the reasoning behind my methods.
Andy
Andy_mr2sc said:
Martin following your recent comments on this thread and others you made in November last year about my TB mod I will explain my actions.
I'm not trying to attack you or the service you offer - just to get answers in the engineering terms I too work with on a day to day basis.
As I said, I'm not convinced my TB's are healthy and at 50k miles, probably need this problem addressed, and I want to satisfy myself that the options I'm looking at are indeed the best ones.
Andy_mr2sc said:
Yes roller bearings can take more load; they also produce more friction due to the larger surface area touching.
It's the grease being forced under the rolling elements that generates the difference in rolling resistance, and will be worse on a roller. Next time I meet with our bearing people, I'll ask this question.
So... you're right, but IMO for the wrong reason - but I stand to be corrected
Andy_mr2sc said:
I have tried to have the spindles moving as freely and easily as possible. You also suggested using a bushing instead of a bearing. I stayed away from this because metal rubbing metal can cause electrical interference on what is already border line circuitry.
I know (now) that Jenvey use PTFE-filled oilite bushes, I myself suggested something like IGUS H1 but someone else (you?) pointed out they'd tried that but had problems with sealing. I would expect a sintered phosphor-bronze bush to provide a better ground path than even a roller bearing.
...I just broke off to go check my facts on the Racing Green offering and b*gger me, they're now getting Jenvey to refurb their exchange throttle sets. This is something I had been thinking of doing, being a satisfied Jenvey customer myself.
Andy_mr2sc said:
The way they are sealed and mounted means there is no chance the grease will be sucked out by the induction pressures as you suggested while air cannot be drawn through them altering the balancing.
Andy_mr2sc said:
Regarding brinneling, you sited the case where cars needed their wheel bearings replaced after a long transport on a trailer. This is a completely different situation.
I totally agree that every movement of the throttle will redistribute the grease and hit reset on the cause, but unlike a wheel bearing of a car on a transporter, the bearings return to the exact same position every time.
Andy_mr2sc said:
How much of your cars hours of use is spent at idle with the engine running? It would take many, many hours of being in this position to start marking the bearings.
My point is that it's actually very difficult to say, and for a bearing manufacturer, very difficult to design for, other than to maximise that which gives them the best possible chance and then to test it - an approach I take every day in my job.
I've done a quick bit of googling and came across articles from NTN and NMB, both manufacturers I have worked with. I really like the look of the needle roller elements NTN feature in this article
www.ntn.co.jp/english/products/review/pdf/NTN_TR73...
In which it also states:
"Ball bearings are narrower than drawn cup bearings, but their built-in seals alone cannot completely prevent air leakage so additional seals must be incorporated"
Interestingly I cannot find any independent corroboration for my assertion about false brinelling, though one or two making reference to needle roller bearings being "resistant" in this applicaiton.
I look forward to reading your reply, and thank you for taking the time to engage, it's nice to deal with doers rather than talkers I'll shut up now.
I must agree I cannot put a time span on the life my parts because to my knowledge none have failed yet. I think it would be fair to say they should last considerably longer than tvr's solution to drill and ream the aluminium casting!
I was considering using a secondary seal when I started looking in to this as like you say some of the other companies do but as the set up works fine without it I didn't see any point in making it more complicated and introducing another component that in time could wear or fail. The idea was to produce a simple solution that solves an on going and well publicised issue for my own personal car that I then decided to offer to fellow enthusiasts for a realistic price. I have my own cad/cam based engineering workshop so I can perform this in house. I have had repeat orders from some greatly respected Tvr specialists in the UK as well as Europe and one set has even gone to Japan. I am now working on improving other areas of tvrs, specifically the Tuscan but the RnD, cad time etc is huge.
As you obviously know from your research there are many different approaches to this problem. One of the highly respected solutions is performed by Dreadnought TVR in Scotland. They use a bronze bushing of some sort and while I don't know the exact details, the last I heard it was a £900 conversion so I would hope a lot more goes in to it than my humble approach. If you are looking for other options it could be worth talking to them or as you say, Jenvey are the top players in this field.
I am not going to continue splitting hairs so to speak about the different methods regarding bearing types, seals etc as I strongly believe that any of the offerings at all levels are a vast improvement on the standard set up. im looking forward to reading about your final decision and the results obtained.
I was considering using a secondary seal when I started looking in to this as like you say some of the other companies do but as the set up works fine without it I didn't see any point in making it more complicated and introducing another component that in time could wear or fail. The idea was to produce a simple solution that solves an on going and well publicised issue for my own personal car that I then decided to offer to fellow enthusiasts for a realistic price. I have my own cad/cam based engineering workshop so I can perform this in house. I have had repeat orders from some greatly respected Tvr specialists in the UK as well as Europe and one set has even gone to Japan. I am now working on improving other areas of tvrs, specifically the Tuscan but the RnD, cad time etc is huge.
As you obviously know from your research there are many different approaches to this problem. One of the highly respected solutions is performed by Dreadnought TVR in Scotland. They use a bronze bushing of some sort and while I don't know the exact details, the last I heard it was a £900 conversion so I would hope a lot more goes in to it than my humble approach. If you are looking for other options it could be worth talking to them or as you say, Jenvey are the top players in this field.
I am not going to continue splitting hairs so to speak about the different methods regarding bearing types, seals etc as I strongly believe that any of the offerings at all levels are a vast improvement on the standard set up. im looking forward to reading about your final decision and the results obtained.
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