1971 Single sided swingarm fastback (2011)

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cjandme said:
That Is one slick, tricked out Norton........keep up the good work.......what am I missing with regards to the lifters ...both pictures seem to show them oriented the same way?
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Look at the pictures prior to engine assembly and you will see two clues (that I missed too) one, the gap between each pair of lifters, as seen above the retainers, is different, on set has almost no gap, and they are offset for and aft, whereas the anonymous picture shows a far more symetrical set up even ngaps and no for/aft offset.

Probably the lifters are paired wrong.....at least he has a good picture to sort the puzzle....not clear how much potential damage there might be, I think it unlikely anything would hit what it should not....but I suspect a degree wheel timing check would show odd figures....and I guess it is possible that the lifter edge on one of them might hit the cam lobe at a damaging angle....hard to tell that....but having seen it I am sure none of us would test the theory....just lift the barrels...not the end of the world....just more time!

It takes a bit of looking to see how these lifters work with their retainers anyway....it must have made the barrels easier to make....as well as potentially reducing lifter weight....
 
I would think the fore/aft misplacement would result in totally incorrect valve timing, and probable cam damage at least...
 
grandpaul said:
I would think the fore/aft misplacement would result in totally incorrect valve timing, and probable cam damage at least...
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grandpaul, I can see you are not so used to the British way of understating things.......

What you said is pretty much what I said! :wink:

But until we see how it assembles orhe measures the misplacement I think that 'probable' is no more than 'possible'.....but I would not 'run it up and listen' either.... :eek:
 
Hey, so I went out to garage and got my boroscope out and looked in cylinders...sure enough I am a few degrees from TDC and all four valves are open. I just hope I havent damaged anything. it doesnt appear that the valves have touched.

Im calling in sick today to deal with this immediately, gunna open her up right now


dam, this is so stupid, I cant believe I did this, Its not like this is my first norton engine build
 
Well, engine tear down is amazinly quicker than build up. There has been some damage , barrel studs pulled out, valve is bent and lfters were jammed. But i do not feel as bad because I think the problem was not my assembly ....but a lifter that missed a step in manufacturing,

this first pic is a shot of the lifters, if you look at the left one youll see that the clearance below friction surface has not been machined out...this would not let thelifter seat all the way,

1971 Single sided swingarm fastback (2011)


here you can see the bent valve
1971 Single sided swingarm fastback (2011)


lucky the guide has not been effected and the other valves appear to be unscathed.
 
here you can see the lifter stuck in a position higher that the rest, not allowing valve to retract all the way

1971 Single sided swingarm fastback (2011)
 
The Dunstall lifters are not the prettiest machined parts.

Here is a shot of my 810 barrel with the lifters propped up. Note the uneven transition from the round shaft to the foot.
1971 Single sided swingarm fastback (2011)
 
It looks like the lifters on the right aren't plumb Bob? Lol Or is it an optical contusion?

M.A. -This too shall pass.
 
I have never seen a decent looking Dunstall part. It's like low end parts from India. It's amazing that stuff even worked.
 
I have to agree in some respect. I have a Dunstall 850 and some of the parts I love, the 2-1-2 exhaust for instance, and the overall look and stance of the bike. I love the tank and front fender but the seat being attched with velcro to the fiberglas isn't great and the play in the shifting could be less. I don't suspect that he was designing for off-in-the-misty-future but originally for racing. I remember the original early Shelby Cobras being a bit crude, having visited the factory in Venice back in the day as a young lad, but current restored Cobras are better than new ones ever were. Paul I still like your bikes. Perhaps "low end parts from India" is a bit harsh.
 
Well, I did kinda thing these lifters looked a bit budget. Bt this is my first commando engine build that is not with factory parts. so I was willing to give it a shot.
Anyway, Ive already got a friend installing new studs in the cylinders with his bridgeport.

meant to post earlier, but this is a pic of the forwars cylinder studs that pulled when I tourqed the nuts....I kinda thought something felt funny, but nothing looked wrong

1971 Single sided swingarm fastback (2011)
 
motoalchemist said:
here you can see the lifter stuck in a position higher that the rest, not allowing valve to retract all the way

1971 Single sided swingarm fastback (2011)
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It is obvious when you know its there, but these barrels and lifters don't give you the clues the standard set up does.....

I see there is also a very small nick in the piston....not really consequential...

The question remains I guess, where did the lifters come from because that one cannot have been used......

Looking at the pulled threads etc raises the question.....would you be safer with another set of barrels'?
 
dam, this is so stupid, I cant believe I did this, Its not like this is my first norton engine build
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Unfortunate but unless you had previous experience of Dunstall parts they probably looked ok, though could you not check for full movement before you assembled? Anyway don't feel so bad. I just stripped my top end to try and locate a rattle, found nothing other than bad exh valve tips. I re-assembled engine on bench in a different orientation to usual and managed to fit pistons in wrong bores. Result after a 10 mile Jan 1st run was heavily marked pistons and a dinged exh valve which had imparted slight seat damage, bad enough that valve lapping would not cure. I couldn't even see damage but the valve leaked petrol with both springs installed. And yes the rattle was bad for a few seconds until the valves made their own recesses. I'm putting down to age but that's not your excuse is it? Hope you get it sorted, good thing it didn't fire!
 
just one of the troubles with a junkstall cylinder. you should also do something with the rest of the head bolt holes while your friend has it or better yet put on the shelf where it wont give you any grief.

motoalchemist said:
meant to post earlier, but this is a pic of the forwars cylinder studs that pulled when I tourqed the nuts....I kinda thought something felt funny, but nothing looked wrong

1971 Single sided swingarm fastback (2011)
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Yikes.

Strange how in the last shot, the shoulder on the far right lifter appears to be there, opposite it's mate...
 
L.E.N. said:
Perhaps "low end parts from India" is a bit harsh.
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1971 Single sided swingarm fastback (2011)


You're right, it's probably insulting to low end parts from India...

Crude is being kind when describing Dunstall parts.

TimeSert the shit out of that barrel before putting it together.
 
I went down to Rabers today to buy a new valve and head gasket. for those of you here in the bay area you'll know this is holy grail of Norton Commando shops.
It wasnt real busy so i got to spend a few minutes talking to Bob (raber) about my problem. He noticed right away that i have large over sized valves, and high lift cams. He asked what cam sprocket I was Using. I put the stock sprocket on...Long story short...i needed to install that adjustable sprocket i have. The valve bent because the Ex and In touched. The duration of this cam must be extended so cam timing is going to be crucial.
So I will be mapping out the lift and duration this weekend with my degree wheel and dial indicator.

total cost for new black diamod over sized intake valve, head gasket (flame ring) and base gasket...and a couple of Norton stickers. 83.00 USD

not completly destroying new engine before engine even runs...priceless
 
Ya might have to add a bottle of Patron or Glenlivet for Ken Canaga to that list. Lol. Still pretty cheap, all things considered. Luv the wheels,just the right amount of red.
 
motoalchemist said:
I went down to Rabers today to buy a new valve and head gasket. for those of you here in the bay area you'll know this is holy grail of Norton Commando shops.
It wasnt real busy so i got to spend a few minutes talking to Bob (raber) about my problem. He noticed right away that i have large over sized valves, and high lift cams. He asked what cam sprocket I was Using. I put the stock sprocket on...Long story short...i needed to install that adjustable sprocket i have. The valve bent because the Ex and In touched. The duration of this cam must be extended so cam timing is going to be crucial.
So I will be mapping out the lift and duration this weekend with my degree wheel and dial indicator.

total cost for new black diamod over sized intake valve, head gasket (flame ring) and base gasket...and a couple of Norton stickers. 83.00 USD

not completly destroying new engine before engine even runs...priceless
Click to expand...


Some will say that the vernier adjustable sproket is another disaster waiting to happen.....an avoidable one

Alternatives are described elsewhere in more detail, but you might find that getting the set up you want as a trial with the adjustable item and then repeating the timing you want with a stock sprocket by adjusting the setting of the chain/timing pinion, and maybe an offset key, is a better long term solution....

You might also find that if you identify the cam and valve sizes someone can give you a pointer to likely set up....I assume the valves are not so large that you should consider re-angled inlet guides!
 
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