Engine build prep (2014)

Fast Eddie

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Gents,
Thought I'd share these with you...

Most of my engine components are with 'a man' being balanced, seats cut, vapour blasted, ultra-sonic cleaned, etc. Hopefully engine re-assembly will commence soon. Here are some pics of the various bits n' bobs going into it. I know a lot of you guys already know this stuff, but hopefully it will be interesting to some:

Here's the JS wrist pin compared to the stock pin, its approx. 29% lighter and DLC coated...
image_zps3be89d23.png


JS Carrillo conrods vs stock, the carrillos are simply things of beauty! Overall they are slightly heavier than stock (only slightly), but the little end is lighter. But then, they are approx. 1/2 longer (to suit the short pistons) and are (hopefully) unbreakable (I have broke a stock rod, I'd like to avoid it on this build)...
rods_zpse0e584c9.png


Cam followers, photo doesn't do the difference justice, but the JS supplied BSA followers are approx. 1/3 lighter. Plus, I am convinced, the radius improves cam oiling...
followers_zps0beb5ec6.png


JS stage 1 cam versus stock. The machining of the cam is truly excellent. It doesn't have a huge amount more lift than stock (0.030" ish I think), but does have quite a bit more overlap. I was very tempted to go for 'more' with the stage 2, but repeatedly advised that this is best for road use. I can only hope so...!
cams_zps93ab9b38.png


Pistons. Ah yes, the pistons. The piston on the right, is a stock bore Omega racing piston with a crown raised 0.100" over stock. The piston on the left is a +0.020 JS piston with a crown raised 0.110". Despite this, the JS pistons looks tiny! It is approx. 1/3 lighter than the Omega. Frankly, I think it makes the Omega look like something out of a tractor. These JS pistons are just beautiful...
pistons_zps1df12b77.png


I have to say... and it isn't easy to do so being a Brit... the stuff I've had from you Yanks (that's Jim Comstock, Jim Schmidt, and Matt at CNW) has been pretty bloody impressive. Hopefully, it will all continue to impress once it is all installed and the throttle is pinned to the stop...!
 

grandpaul

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The difference in cam event DURATION is the biggest obvious difference; the overlap isn't nearly as significant.
 
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grandpaul said:
The difference in cam event DURATION is the biggest obvious difference; the overlap isn't nearly as significant.
Being ground for a radius lifter also makes it look a bit different.
 
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Fast Eddie,

Good choices...I'm thinking about the exact same components although my engine runs fine right now.

I really like the reduction in vibration and improved performance.

From everything I've read you will be happy with the Stage 1 cam.

Can't wait to hear the results...please update as you go.

Dennis
 
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Only porn my wife allows me to view and I think she knows gets me-us off better anyway. Keep em coming.
 

DogT

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I always wish I'd put at least the JS pistons and rods in my bike, but at the time it was a lot of $$. But not in the whole cost, I should have done it.

I'm always a bit wary of aftermarket stuff too, it always seems fraught with other issues and it's usually the case. Even the DD clutch rod seal was a 3 day project and required some fettling.

I've actually thought about the copper wire to increase the CR, but then there's the push rod length issue.....

Dave
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Fast Eddie

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dennisgb said:
Fast Eddie,

Good choices...I'm thinking about the exact same components although my engine runs fine right now.

I really like the reduction in vibration and improved performance.

From everything I've read you will be happy with the Stage 1 cam.

Can't wait to hear the results...please update as you go.

Dennis

I will provide updates as I go Dennis.

As to your own motor, not sure I'd go to all this trouble (and cost) if I was happy with how my motor was running!

My own story is that I stripped the top end of my newly acquired '74 850 to see how to raise the CR from the 7.6:1 that it was. Then I took the barrels off 'just to have a look' it was then I found that my cam followers and the cam follower bores in the barrel were very, very, deeply scored and totally shot. I estimated that even + 0.020 followers would not clean up the bores. Debris from the scoring, falling down onto the cam, had also marked that. So fitting JS cam kit, with the bronze bushes for the followers, was just a no-brainer.

Whilst it was down, I just couldn't put it back together with the stock rods. I know they're very good, and they would most probably have been fine, but I totalled an engine before when I broke one. And I don't want to do it again. Plus, I still needed new pistons as the bore was oversize and the CR too low. So then the JS piston and rod kit became a 'no brainer' too !

As Comnoz points out, these pistons may not be ideal for everyone, particularly those who genuinely do very high mileages, but for my likely mileages, I decided that the light weight and reduced stresses were what I wanted.

Whilst I was unkind to the NOS 1976 Omega pistons in my post, I would point out that the JS pistons are very similar in shape and design with regard to overall length, skirt length, pin / ring position etc as forged Omegas for big Nourish engines. I've used these a lot, also in iron barrels, and they have performed faultlessly. I say this as a positive comment re new Omega pistons, and re the JS piston design, all IMHO of course.
 
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Fast Eddie said:
Whilst it was down, I just couldn't put it back together with the stock rods. I know they're very good, and they would most probably have been fine, but I totalled an engine before when I broke one. And I don't want to do it again. Plus, I still needed new pistons as the bore was oversize and the CR too low. So then the JS piston and rod kit became a 'no brainer' too !

Best approach once its apart...time is valuable so doing it right is smart. Back when I was a "kid" I was working on my BSA 650 engine in the shop where I worked as a mechanic. I had the pistons and rods on the bench and the boss came up and picked one up and ran a screwdriver down the side. He said "There, now you can put new pistons in there like you should." I guess that is when I learned saving a few dollars is just not good practice if you end up having to do it over again...or worse.
 

850cmndo

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dennisgb said:
Fast Eddie said:
Whilst it was down, I just couldn't put it back together with the stock rods. I know they're very good, and they would most probably have been fine, but I totalled an engine before when I broke one. And I don't want to do it again. Plus, I still needed new pistons as the bore was oversize and the CR too low. So then the JS piston and rod kit became a 'no brainer' too !

Best approach once its apart...time is valuable so doing it right is smart. Back when I was a "kid" I was working on my BSA 650 engine in the shop where I worked as a mechanic. I had the pistons and rods on the bench and the boss came up and picked one up and ran a screwdriver down the side. He said "There, now you can put new pistons in there like you should." I guess that is when I learned saving a few dollars is just not good practice if you end up having to do it over again...or worse.

What shop might that have been?
 
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850cmndo said:
dennisgb said:
Fast Eddie said:
Whilst it was down, I just couldn't put it back together with the stock rods. I know they're very good, and they would most probably have been fine, but I totalled an engine before when I broke one. And I don't want to do it again. Plus, I still needed new pistons as the bore was oversize and the CR too low. So then the JS piston and rod kit became a 'no brainer' too !

Best approach once its apart...time is valuable so doing it right is smart. Back when I was a "kid" I was working on my BSA 650 engine in the shop where I worked as a mechanic. I had the pistons and rods on the bench and the boss came up and picked one up and ran a screwdriver down the side. He said "There, now you can put new pistons in there like you should." I guess that is when I learned saving a few dollars is just not good practice if you end up having to do it over again...or worse.

What shop might that have been?

Actually was auto repair shop on Grand and Fairview in St. Paul. D & D Unlimited. I worked on the bike on off hours. This was a long time ago :D
 

Fast Eddie

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Thought I'd share some more updates with y'all

Had the crank dynamically balanced. When fitting JS rods and pistons onto a sock crank, the static balance will be correct for a 66% factor according to Jim. Even so, mine needed a lot of new drillings to get it dynamically correct:
image_zpsa1a81521.png


And the alternator rotor also needed a couple of drillings to bring into balance:
image_zps45197875.png


The head cleaned up very nicely, the seats had a very mild cut, I'm pretty sure they've not been cut before:
image_zps976fc12c.png


The inlet ports are slightly under 30mm, so, fortunately haven't been hacked out by a butcher (RH10 head) which is good news as it will be going to Mr Comstock for his treatment in the autumn (fall), all I'll do now is radius the inlets by hand to match the 31.5mm CNW inlet manifold:
image_zpsd67d9c1a.png


And here is a shot of the radiused PTO:
image_zps49ee2c6a.png
 

Fast Eddie

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For those who like looking at nice pics of engines n stuff... Here's some more (slow) progress on my motor:

Cases going back together, I'm using Wellseal, I like to apply it with a small paint brush and wait until its quite tacky:

image_zps24b785cf.png


New crank bolts etc and JS Carrillo rods in situ:

image_zps73edbe7b.png


Timing case all plugged up according to Mr Comstock's instructions, along with new oil drain hole just below pump face. All to suit Jim's reed valve PCV:

image_zps79246254.png


Tappet blocks in place in the barrels for JS BSA lightweight cam followers:

image_zps1356e39c.png


Rockers after being lightened and polished by Pete Lovell, they are a million times better than the stock horrid lumps, without being wasted away to the point of causing worry about breakage:

image_zps5226e02d.png


Top end mocked up, i asked the Mrs's advice on barrel colour and he insisted that silver was the only choice, so, having asked her, im stuck with silver now! I've checked the piston height and squish clearance etc and by using a JS copper base gasket and stock flame ring head gasket, I will have .050 squish and almost exactly 10:1 CR:

image_zps5fb8cad4.png




Cam timing next...
 
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Nice work Nigel.
That engine will be so smooooooth when you've finished that it'll embarrass a Honda four :lol: :lol: :lol:

I am just a little bit envious :mrgreen:
 
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Fast Eddie said:
Cam timing next...

I have the stage 1 cam and BSA lifter kit. Not that you need to be anymore geeked (excited) about this, but you are going to love it.

Although I had no clash, my bike would not run to 5000rpm with the stock setting of the cam timing. 10 degrees advanced put it on the money. I will be interested to see what your setting end up to be.

Awesome photo blog. Can't wait for the next go round.
 
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Very nice. I have more or less the same bits to go into my engine. Crank is being balanced, hope to have it back next week.
Keep us updated.
Dan
 
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Progress looks awesome so far...love engines going together with new parts...sweet!
 

Fast Eddie

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Glad you like the pics n stuff chaps, will update again soon.

Reggie, I'm hoping so! And I'm hoping it'll be pretty quick too, although I can't see it matching the brute force of your 'big one'!

Pete, I know you've got the stage one too, your earlier words on the subject partially inspired me! My gut feel was to go with the stage 2, but pretty much everyone advised against it, so I crumbled and went with the stage 1! I know Jim said some earlier cams had the keyway slightly out, I'm hoping mine needs less 'adjusting' than yours, we'll see.

Dantriumph, tell us more about yours... and pics too please!
 
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All good stuff going in there Eddie. Other than the lack of dome, the lightweight pistons look remarkably similar to the 92 mm forged CP Carillos I have here. Almost jewel like finishing on the al, they must have some magnificent machinery.
Will Jim be doing the big valve conversion or just a re& re of the head?
Did you ride the stock bike much before tear down? It will be interesting to see how this engine compares to the stocker.

Glen
 

Fast Eddie

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worntorn said:
All good stuff going in there Eddie. Other than the lack of dome, the lightweight pistons look remarkably similar to the 92 mm forged CP Carillos I have here. Almost jewel like finishing on the al, they must have some magnificent machinery.
Will Jim be doing the big valve conversion or just a re& re of the head?
Did you ride the stock bike much before tear down? It will be interesting to see how this engine compares to the stocker.

Glen

Hi Glen,
Thanks, and I'm glad you like it so far.
The JS pistons are really very similar to the Omega pistons I ran in big Nourish motors too! I know not everyone is a fan of them, from a high mileage perspective, but I'm impressed so far, and can't wait to try them and the rest of the package.
The plan (at the moment) is to get the bike done and dialled in and enjoy over the summer, and dyno it. Then Mr Comstock will do the head, I'm not specifying anything at all to him, I shall leave it entirely in his hands. Then re-fit and re-visit the dyno!
I say 'at the moment' cos... I'm also keeping a close eye on Mr Comstocks 920 billet barrels... and you know what its like... whilst you've got the head off...!
Yes I rode the bike quite a bit before teardown, on some familiar roads too, so I can compare when done, which I can't wait to do! Sadly, and much to my annoyance, and without any reasonable excuse... I did not dyno it before teardown, which makes me :cry: and :oops: and even rather :evil: ... :!:
 
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