1967/1969 Bonnie Rebuild Desert Sled Project - Any Advice

You req R inlet and non R exhaust lifters. edit 70-3059R inlet and 70-8801 exhaust.

 

Most dealers in the US should be able to get you a set, i'm lucky that i can get some parts direct from L F H but they sell out as soon as they get a batch in as all the big buyers get it all first :-(

 

while you have all the parts out, go to a hardware store and buy some paint pens. you can paint the tappets, jugs, rod bolts, rods, whatever, with the paint pens so that you never have to remember which way they came out:




my jugs are marked at four corners with four colours. th etappets are marked to the outside with the same colours. rod bolts match their corner and rods are marked individually. things that wear nto one position like tappets and cams can go back like they came out without you having to tape pr label or bag. this is important for me as i have no brain.

i buy all my tappets used from eBay and then have em ground at megacycle

 

new tappets will be fine to go. but them from a reputable supplier so you dont get el cheapos from china. used ones on ebay go for around US$100 for a set right now.

i cant remember what megacycle charges to reface them. i measured once and they had ground 0.010 off. ive never had any trouble getting them on the telephone. barb used to answer and was difficult for some people to talk to-- never me-- but last time i spoke with them her daughter had taken over the phone duties.

the paint stuff is just a way to avoid making mistakes. i already had a lot of them because i was a beekeeper and used them to mark queens. youll end up with similar shortcuts.

 

0.997 and 0.998 is right in there on the camshafts. the last megacycle cams i bought were 0.996 and 1.002. at that time, my new timing side bushes were too long and so i had to stone them down to get endfloat. i ended up with timing side cam bushing lengths of 0.981 and 0.985, giving me 0.015 and 0.017 endfloat. endfloat specs are in the manual at 0.013 to 0.020.



to my knowledge all the timing side bushes are now manufactured too long so as to ensure that they can fit anything. if youre going to be changing bushes, they expect you to hand-fit them too. not a problem except with the solid bronze ones, which were an answer to a question that nobody asked.

i've measured brand new kibblewhite solid bushes at exactly 1.000, and some loose sintered bushes of mine have been 0.993, and other dimensions as well.

the answer is just to measure the bushes and make sure they fit the cams you have.

 

i havent done many of these, but ive never had any where the bush didnt stick out far enough to be clear of the right side of the timing chest crankcase casting. heres the last ones i did.



first, you can see that the bush sticks out a bit from the timing chest casting. whether it sticks out or doesnt is not important. ive never had one so long that just taking metal off the left side of the timing side bush's top hat didnt solve the problem.

second, you can see that the megacycle camshaft bearing surface for the bush (the part of the camshaft between the step on the cam and the right side of the inner thrust flange on the cam) is shorter than the bush. this IS important, because the cam will bind. this bush had to be shortened

 

yes.

yes

yes

yes. here's what one looks like with the pinion rubbing the case:



im thinking there was just a tiny bit not enough clearance. any tighter and the pinion could have messed up the case or sheared the key. or who knows.

you will also find bodges from people who dont know what they are doing. this is a motor i took apart a while back. the intake timing side bush was too long and the pinion was locking up against the bush. so instead of shortening the bush, the DPO dropped a washer under the cam pinion securing nut so that the nut was tight without pushing the pinion all the way on'



there was nothing holding the pinion to the camshaft except the little key.

^^^this is why you should never trust someone you dont know who sells you an assembled motor and says, "fully rebuilt . . ."

 

art is correct. get someone to talk to you who is familiar with how the factory did things. the manufacture of these machines held to a mechanical philosophy that doesnt exist anymore. lots of hand fitting and selection of best-fit parts from a pile on the table, lots of skill as opposed to formal QC, and lots of personality.

the first time i split the cases on my 1972 T120, i discovered that some long lost mechanic at the foundry had scratched his initials into the sand core before pouring the aluminum, and there they were forever, in reverse relief.

ive told you just about all i know about cam bushes, so now you can share it with someone else as long as any of these old beaters are still around..

 

thats where the initals on mine were scratched

 

i would get a better one. it isnt much of a brake , but you want all you have

looks like he hit the brake actuating lever on a kerb or something

you can get em on ebay

https://www.ebay.com/itm/174349932527?hash=item289810d7ef:g:XT0AAOSwqpJe19MN

heres one . a bit dinged but only 40 bucks.

theres another for 20