E: Engine Half Time Pinion Sizes

Bill Thomas

Well Known and Active Forum User
VOC Member
We have had this before, Megacycle have fitted bronze bushes instead of our oilite type,
And they need more clearance ??. Cheers Bill.
 

Cyborg

Well Known and Active Forum User
VOC Member
Yes... not a big fan of punch locking. Much prefer Loctite. Some types of Loctite apparently aren’t bothered by a bit of oil on the threads, but I prefer to make sure they are squeaky clean. Similar to cylinder bores after honing... when you are sure they are absolutely clean, you’re almost done. Seems to me that the small nuts on the valve lifter pivots were punch locked originally. Seems brutal to me, but not sure what was available back then. Loctite appeared in 56 I think.
Someone here will probably ask what bushes you had installed in the cams. Coming from Maughan, I assume they are oilite.
Edit... someone asked while I was writing this.
 

Cyborg

Well Known and Active Forum User
VOC Member
We have had this before, Megacycle have fitted bronze bushes instead of our oilite type,
And they need more clearance ??. Cheers Bill.

Bill, you and I are enter highjack territory again. Is it a question of them needing more clearance or is it a case of folks getting cams from Megacycle and installing their own pinions and not resizing the bushing back to the proper clearance? I have no idea.
Now we can debate the best method for resizing the bushings.
 

Bill Thomas

Well Known and Active Forum User
VOC Member
Sorry, I will have to have a holiday,
I don't think it will be too bad to have a bit of slack H/T/P., The noise comes from the other pinions if too tight.
It depends how slack ?, I think they only go up to plus 10 ?.
 

LoneStar

Well Known and Active Forum User
VOC Member
The cams and bushings were supplied by Megacycle - I sent them the new gears and spindles for fitting. They did install bronze bushings; hopefully they set the clearance to something appropriate for the material.

Questions,

- Why is Oilite preferred over bronze for cam bushes, given that the area is oil-drenched?
- What calamity is likely with bronze bushes?
 

Cyborg

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VOC Member
I’m really not the person to answer those questions. Oilite if I understand completely, has pores filled with lubricant , so they will presumably tolerate interruptions of..or low oil supply better than bearing bronze. Again, I don’t know for sure, but you may be over optimistic when you say oil drenched. I haven’t had any personal experience with Megacycle’s bushings, but understand from comments on the forum that folks have had then seize on the spindles. Whether that is directly related to the bushing material or simply a lack of clearance for oil to get into the bushing in sufficient quantity because the bushings were’t opened back up again after the pinion was pressed on remains a question I have. Just wanted to make sure you were aware of the debate.
 

Bill Thomas

Well Known and Active Forum User
VOC Member
I’m really not the person to answer those questions. Oilite if I understand completely, has pores filled with lubricant , so they will presumably tolerate interruptions of..or low oil supply better than bearing bronze. Again, I don’t know for sure, but you may be over optimistic when you say oil drenched. I haven’t had any personal experience with Megacycle’s bushings, but understand from comments on the forum that folks have had then seize on the spindles. Whether that is directly related to the bushing material or simply a lack of clearance for oil to get into the bushing in sufficient quantity because the bushings were’t opened back up again after the pinion was pressed on remains a question I have. Just wanted to make sure you were aware of the debate.
We have been told, The same can happen in gear boxes, When the wrong bushes have been fitted.
 

rogerphilip

Active Forum User
Non-VOC Member
Hello all,

My current ET49 half time pinion, combined with new cam gears, has backlash in its engagement with the idler gear. I know these pinions are available in various sizes to deal with this situation - but I'm not clear on what exactly "+.004" means, for instance.

Is there any way to determine which size is likely to be needed, based on some measure of the existing backlash?

Thanks,

Dave
Hi Dave
Just a thought, but I have in the distant past measured / checked differences in gear sizes by measuring over drills placed in the gaps using three for odd teeth and four for evens.
I have also used this method to measure a male thread on an otherwise scrap component, thus enabling me to replicate the thread on a replacement component with a reasonable degree of accuracy, without the luxury of modern form tools, a gauge, or the matching female component.
HTHs
Regards
Roger
 

davidd

Well Known and Active Forum User
VOC Member
- Why is Oilite preferred over bronze for cam bushes, given that the area is oil-drenched?
- What calamity is likely with bronze bushes?

Having talked with Megacycle a month ago, they will now supply Oilite bushings, but I think you have to ask. Phosphor bronze is just too quick to pick up metal. The oil supply to the cams is just not steady enough. Using phosphor bronze has cost a few owners thousand of dollars and many hours of time, so the risk/reward calculation is really skewed. Those owners that have made this mistake have had bent valves, damaged pistons and damaged followers. The Oilite bushes are a few dollars.

David
 
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