(Topic changed) My 2017 ccm rebuild

[karmi]

Look für "corrugated washer" 

Motul 300V 15W50 is a very good idea.

[Martin S.]

So as i am rebuilding my engine and I wanna make it to the highest possible standards i thought about opening this topic.
I have a std size original VW case , measured and found ok !
I gonna install a set of Silverline Main Bearings .
As far as i heard some of the best aftermarket currently available.
Oil is going to be Motul 300v 15w50

When setting up the clearance , what to pay attention for ?  What is your recommended clearance?
For street use , for strip use .
Do you put an oil groove into the split bearings ?
How deep and how large ?
How do you measure the clearance?
With a gauge or do you use plasticgauge ?
The split bearing obviously needs to be checked with the case bolted together , what about the circle ones ? Do they change installed or laying on the bench ? Do they crush ?

How to prepare the conrod bearings ?
  

Bearing clearance was a critical part of my engine build, according to the engine builder. He said it was super important to have enough clearance to allow the oil to flow thru the bearing on an air-cooled engine.
To size the bearings he told me he used paper towel rubbing by hand, using WD40 with the paper towel, and it took like an hour of rubbing to increase one bearing clearance by a thou.

Watch this video where at around the 2:00 minute mark, Steve explains the clearances and how important they are, and unfortunately someone interrupts him just as he says what the end clearance is, but I think it was 5 thou, and the cam clearance 1 to 1-1/2 thou. When he mentions what he did with "his own car" he wasn't talking about a VW, more likely his street-driven 2500hp Mazda RX7 

https://youtu.be/K7djBcHGKYg

As for the oil weight, watch your oil pressure when driving and try to keep 10psi pressure for each 1000rpm as a rule of thumb.
For my hot-running turbo, it needs 10w60 to keep the pressure up while at speed on the highway, otherwise the pressure drops as the oil gets hot and you can clearly see that with your gauge.

[Mike]

I bought washer and bolts . They fit perfect!
Thank you

[Bruce]

To size the bearings he told me he used paper towel rubbing by hand, using WD40 with the paper towel, and it took like an hour of rubbing to increase one bearing clearance by a thou.

I don't think I've ever heard of a dumber way to increase the ID of a bearing. Especially when you have a lathe right there.  I guarantee, the ID isn't round using that method.

[Martin S.]

To size the bearings he told me he used paper towel rubbing by hand, using WD40 with the paper towel, and it took like an hour of rubbing to increase one bearing clearance by a thou.

I don't think I've ever heard of a dumber way to increase the ID of a bearing. Especially when you have a lathe right there.  I guarantee, the ID isn't round using that method.

I agree! Not sure how you'd use a lathe to hold half a bearing, but I'm sure there are other ways to increase bearing clearance.

[samotorsport]

I did myself this tool to hold the bearing in the lathe to cut the groove for example .


In the meantime i did the deck height .
0,57 mm plus a 1,48 copper ring in the head brings me to 2,05 mm over all .
This results in a 9,4/1 static C/R
I only run 98 octane fuel and gonna put the ignition to 29 degree max advance .
This should be on the safe side with a Pauter F8E8 cam .
Next will be installing the heads which got new Gene Berg Valve Keeper Locks as the previous Locks where too tight . Now they got a nice little gap



After that i will modify my rocker shaft to get rid of the springs and put the rocker arms into a better position to make sure the valves turn nicely.
I know i could build ready to use ones , but where is the fun on buying stuff you can do yourself .


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[Garrick Clark]

Those head studs look long .

[samotorsport]

This picture was taken yesterday , today they look different already


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[Mike]

2mm deck height is too much ..... keep it less than 1.5mm.
What heads do you use?
Maybe you can rework the chamber to lower compression a little then...
Regards
Michael

[samotorsport]

I know 2 mm is a lot , but my heads have only 47 ccm volume .
To keep they heat as much as possible out of the cylinders i chose the way i did with the rings inside the head.
Due to this the combustion mostly happens in the head and only 0,57-0,58 in the cylinders .
My heads come from Udo , he did the ports and valve springs etc.
Anyhow the heads are on now , so i will give it a try this way .
On my other engine i usually aimed for 1,3 mm deck height . In this case i have to go this way now , try it and “hope” it works but i suspect with 9,4 C/R this is sufficent to compress enough to make it run smooth

[Mike]

Ok , i understand .
But if the copper rings are part off the heads or the cylinder is like splitting hair 
In the end of the day you will have  no "perfect" quench.
Well and you can try later easy 1mm copper rings if you like
And never touch Udo heads ... there are always very good.

[Martin S.]

I know 2 mm is a lot , but my heads have only 47 ccm volume .
To keep they heat as much as possible out of the cylinders i chose the way i did with the rings inside the head.
Due to this the combustion mostly happens in the head and only 0,57-0,58 in the cylinders .
My heads come from Udo , he did the ports and valve springs etc.
Anyhow the heads are on now , so i will give it a try this way .
On my other engine i usually aimed for 1,3 mm deck height . In this case i have to go this way now , try it and “hope” it works but i suspect with 9,4 C/R this is sufficent to compress enough to make it run smooth

Dish your pistons 

[samotorsport]

In case of , this would have been my choice .
I actually thought about this .
Next time i have a unserviceable piston i will give it a try on the lathe


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[samotorsport]

So here they are , my first selfmade rocker arm shafts, still need shimming and adjustment, an domehead M8 bolts to clear the heads .





This was just a mock up on an old head .


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[karmi]

Looks good. I always have discs in between, because I think it turns easier.

[samotorsport]

Yes , the discs or shims are going to be done on the real head , i also plan to groove the shaft for improved oilflow to the adjustment screw .
This will all be done next


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[Martin S.]

Why not use a new ratio rocker set? More lift and a better design. 

[samotorsport]

Yes i know , for the moment i wanna stick with the stock ones , maybe one day i gomma uprade but you can t do everything at ones
Maybee 1,25 one day , but the engine was actually really fine with good torque in my Bus .


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[Martin S.]

Yes i know , for the moment i wanna stick with the stock ones , maybe one day i gomma uprade but you can t do everything at ones
Maybee 1,25 one day , but the engine was actually really fine with good torque in my Bus .


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Ask Udo what he recommends for his heads. It's a cheap upgrade worth doing first time around for free lift if your heads will appreciate it. Free power! 

[samotorsport]

So my solid rocker arms are done ,


But now i am facing a problem i had already before . When checking the valve geometry i found while sitting on half valve travel i fits perfect in line with the bolt . So far so good .
But the adjustment bolt is almost bottomed out


Lick the stock length pushrods are too short .
So my first idea was to put lash caps on .
By taking a mm of the block away i destroy the angle I guess . Or maybe using swivel feet adjusters ?
What do you recommend in this case ?
Or getting longer pushrods ?
Greets
Sam 


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[samotorsport]

I just spotted , the pushrods are 277 mm so not the full 280 stock length . I guess they where shortened somewhere a while back .
So i guess i go for 280 mm rods .
This should fix the issue I guess

[brewsy]

Sam,
Im not an engine builder but... Are the stock adjusters going to be strong/tough enough to handle the increased load from the new cam and springs?
Also are you not going to run lash caps anyway to stop the ends of the valves from wearing??

Cheers
Marc

[Martin S.]

With stronger springs, HD pushrods are recommended. If the pushrods are not perfectly straight, the stress with more spring starts to bend them a bit at a time, until they fail. Same thing with the swivel feet adjusters, they are recommended when the adjust screw is on the valve tip. I used the Smith Bros. style of (the cheaper non-tapered ones) aluminum pushrods that are ground straight, and give you the strength of cromo without the noise. Someone just posted a vid of how to set up the geometry and I thought it was great! https://youtu.be/eTWXzYWieeg

[samotorsport]

Thanks for the video , looks very interesting !
I will give this a try to make sure everything is correct.


No if not needed i dont plan on putting lashcaps on . I ve got hardened valve tips and pretty mild cam . So it is not really needed .


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[samotorsport]

As you can see the geometry is not yet where it is supposed to be .
The rocker arm is standing on the right spot on the valve but i don’t like to have the adjuster screwed in this far .
So either milling of the the shaft block about 1-2 mm or putting on lashcaps .
Not yet sure which way to go


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[mikko k]

Lashcaps.

[Martin S.]

I've heard people say they like having lash caps because if there's any damage, you can easily replace the lash cap without pulling the motor.
But what about longer pushrods? That's the other variable in the geometry equation. Adjustable pushrod for checking 

[samotorsport]

I have an adjustable rod installed
I ve tried to adjust it to a longer value, but in that case , adjuster bolt somewhere in the middle range, longer rod, the geometry is way of , it is not even close to follow the valve in a straight line.
so to me the center of the rocker shaft and the top of the valves are not in the right relation , so either the valve should be longer , ( in case of a lash cap that is the case) or the center of the rocker shaft should get closer to the valves .
I will get a set of lash caps tomorrow and will try how it fits .
If I am happy with it I keep it , otherwise I will mill down the blocks.

[Bruce]

I would never ever use stock adjuster set-screws on an engine like yours.
If you get swivel foot adjuster screws, you don't need lash caps, and your slightly shorter pushrods will work perfectly.

[Martin S.]

Ok so swivel foot adjusters are longer than stock ones, interesting. Is the added length of a swivel adjuster similar to the added height of a lash cap? So there are two options to make the effective installed height of the valve stem taller.

When heads are rebuilt, I wonder if there is an established valve stem height as part of the blueprinting of the head or is it take what you get.