NY98M3's 2017 Build Thread - M52/S52, 6870, AR Designs, E85

[chikinhed]

Install a weak spring on the intake and exhaust valve, assemble with a used head gaskets and measure the piston to valve clearance by depressing the valve until it contacts the piston at all the different crank angles from 30° BTDC to 30° ATDC every 5°. Then you will know.

[someguy2800]

that^^^

Most Ace hardware stores have a selection of small springs

[e30polak]

nah, I got him.




The ZF blew later this day, the new setup is a 420g

What's done to the R8? Supercharged?

[NY98M3]

What's done to the R8? Supercharged?

No idea but its an Underground Racing car so Im sure its boosted up.

- - - Updated - - -

Install a weak spring on the intake and exhaust valve, assemble with a used head gaskets and measure the piston to valve clearance by depressing the valve until it contacts the piston at all the different crank angles from 30° BTDC to 30° ATDC every 5°. Then you will know.

that^^^

Most Ace hardware stores have a selection of small springs

Ill look into that, does the limiter on the vanos not allow it to make all the power?

[chikinhed]

The limiter may reduce the area under the curve.

[Mzfhartge]

The cp pistons were 10.5:1
The new wiseco pistons are 9:1 correct? Valve to piston clearance the least you can do is 13mm on intake and 12.5mm on exhaust

[Da Infammus 1]

What's done to the R8? Supercharged?

It's twin turbo'd.

[someguy2800]

Ill look into that, does the limiter on the vanos not allow it to make all the power?

Top end would be the same. Hard to say if it would loose much of anything on the bottom. Those cams have alot more overlap than stock so its possible it might like the reduced overlap on the vanos with the shim installed better. Its all theory till somebody tests it.

[NOTORIOUS VR]

Dumb question, where does the shim go? Anyone have a picture of a shim (installed or not)?

[Da Infammus 1]

Dumb question, where does the shim go? Anyone have a picture of a shim (installed or not)?

On the shaft of the vanos unit. You have to dismantle it to install it, I've done it a couple of times it isn't really hard.

[NOTORIOUS VR]

On the shaft of the vanos unit. You have to dismantle it to install it, I've done it a couple of times it isn't really hard.

Ahh that makes sense... you literally limit the VANOS shaft length/distance.

Cool thanks.

[NY98M3]

heres the info I got from VAC about the shim and what it does:

it limits the vanos movement so yes it does reduce the torque down low. the vanos retards or advances the timing as needed before 4000 RPM once it hits that RPM the vanos shuts down.

[chikinhed]

heres the info I got from VAC about the shim and what it does:

it limits the vanos movement so yes it does reduce the torque down low. the vanos retards or advances the timing as needed before 4000 RPM once it hits that RPM the vanos shuts down.

Do you even have torque before 4000 rpm with that turbo?

[NY98M3]

Do you even have torque before 4000 rpm with that turbo?

It feels like it spools somewhere around 3800. I thought maybe the shim was to limit the piston to valve clearance somewhere along the line...

[rajicase]

It does limit the piston to valve clearance by limiting the amount of vanos travel.

[NOTORIOUS VR]

It does limit the piston to valve clearance by limiting the amount of vanos travel.

Right, in the end you're limiting the VANOS shaft movement, so you essentially don't get the full intake cam advance. Say 18 deg with the shim vs 22 deg for no shim for instance.

[Da Infammus 1]

heres the info I got from VAC about the shim and what it does:

it limits the vanos movement so yes it does reduce the torque down low. the vanos retards or advances the timing as needed before 4000 RPM once it hits that RPM the vanos shuts down.

VAC's information department is pretty useless from my previous experience. I'm surprised you haven't just run it without the shim or used a dummy spring to see what you can get away with yet.

[NY98M3]

VAC's information department is pretty useless from my previous experience. I'm surprised you haven't just run it without the shim or used a dummy spring to see what you can get away with yet.

I have a few spare cracked heads that I'm going to mock up with soft springs just for this purpose. I compared both the CP and Wiseco pistons and they look identical side by side.

[NY98M3]

progress is slow but at least its moving.



Started assembly last night, file fit the Total Seal gapless top rings, Top rings were set at .026 and the 2nd rings were set at .024
With Total Seal rings, the gaps can be opened up more depending on the fuel and boost level.

Tonight is checking the clearances for the mains

[Da Infammus 1]

I have a few spare cracked heads that I'm going to mock up with soft springs just for this purpose. I compared both the CP and Wiseco pistons and they look identical side by side.

Wise man. Glad to see you moving along!

[NY98M3]

Ive been thinking about the piston the valve clearance...Even with soft springs, how are the hydraulic lifters being "pumped up" while the motor is not running? Is there some sore of simulation that can be done?

[NOTORIOUS VR]

Ive been thinking about the piston the valve clearance...Even with soft springs, how are the hydraulic lifters being "pumped up" while the motor is not running? Is there some sore of simulation that can be done?

Have you seen this: https://sourceforge.net/projects/vanossimulator/

[chikinhed]

You don't need a lifter or cams in there to measure piston to valve clearance, just measure at the valve tip from closed to when it hits the piston at every 5° of crankshaft rotation starting at 30°BTDC to 30°ATDC. When you degree your cams, with lifters and cams installed, you will find out what the lift profile is and can see at what point the valves are closest and by how much.

If you are using a different head to measure piston to valve clearance you should probably compare the head thicknesses and keep in mind that if a valve job has been done on that head the valves my sit into the head a bit more.

[someguy2800]

Ive been thinking about the piston the valve clearance...Even with soft springs, how are the hydraulic lifters being "pumped up" while the motor is not running? Is there some sore of simulation that can be done?

The lifters have a spring inside them that keeps them extended, so your test springs just need to be lighter than the lifter springs. The test springs should be just enough to hold the valves up. If you have some spare junk lifters you can also put some glue on the lifter plunger so they can't move.

[chikinhed]

Does the spare head have the same size valves? That will also contribute an added variable to not using the same head. You should really just check the clearance with the head you intend to use with a used headgasket of the same kind. If it's s cut ring maybe leave the rings out.