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Does anyone sell the piston end cap for HPFPs?

D

dmfracer

Ready to race!
Location
Williams Bay, Wisconsin
I think you are asking about what the timing chain is driving? It's driving the cam that is not driven by the timing belt. :)

The timing belt only drives one cam, on the other end of the head there's the chain which connects the driven cam to the non-driven one.

edit: I'm late to the party - VWEngineer already answered.

edit 2: VWEngineer, isn't the exhaust cam driven by belt and intake cam driven by exhaust cam and chain?

Tungaloy said:
I've got an oil leak that appears to be coming from around the vacuum pump too. Thanks for cluing me in about the chain. I may change if I can budget it in. What is it driving?
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T

Tungaloy

New member
Location
USA
vwengineer said:
The intake cam drives the exhaust cam through this chain.
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I think you are asking about what the timing chain is driving? It's driving the cam that is not driven by the timing belt. :)

The timing belt only drives one cam, on the other end of the head there's the chain which connects the driven cam to the non-driven one.
Click to expand...

That's a weird setup. I wonder why they didn't just run the timing belt across both camshafts?
 
clockwise33

clockwise33

New York Giants Fanatic
Location
NJ
Tungaloy said:
That's a weird setup. I wonder why they didn't just run the timing belt across both camshafts?
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VW has used this design going back to at least the MK1 16v GTI.

I suspect its mostly due to outside dimensions of the head for packaging. Having two belt sprockets makes for a big lump in the valve cover (the reason for the hood bulge on the old Eclipses). I assume they were also able to get the 2 camshafts a little closer together without two sprockets twice the size of the crank sprocket.
 
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ROH ECHT

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
Yes...the exhaust cam is driven at the front by the belt and drives the intake cam at the back with the chain and allows 42° adjustment, via the tensioner, of variable valve timing. ←Why the two aren't connected by the belt.

The TSI has an INA camshaft adjustment system and a hydraulic vane cell attached to the front of the intake cam for 60° of variable valve timing with a chain connecting the two cams. ←the TSI(chain driven CXXX engines) way for variable valve timing.


All is explained in the FSI and TSI pdf's;
http://www.golfmkv.com/forums/golfgoodies/mk5golfengine.pdf
http://www.tyrolsport.com/files/forumpics1/PDF/20tsi.pdf
 
clockwise33

clockwise33

New York Giants Fanatic
Location
NJ
ROH ECHT said:
Yes...the exhaust cam is driven at the front by the belt and drives the intake cam at the back with the chain and allows 42° adjustment, via the tensioner, of variable valve timing. ←Why the two aren't connected by the belt.

The TSI has an INA camshaft adjustment system and a hydraulic vane cell attached to the front of the intake cam for 60° of variable valve timing with a chain connecting the two cams. ←the new way for variable valve timing.


All is explained in the FSI and TSI pdf's;
http://www.golfmkv.com/forums/golfgoodies/mk5golfengine.pdf
http://www.tyrolsport.com/files/forumpics1/PDF/20tsi.pdf
Click to expand...

VVT would have also been possible with two belt sprockets (See Nissan RB25)

Another good reason for only 1 belt sprocket on the head is it allows for a larger crank sprocket because it has to be 1/2 diameter of the cam sprocket. Having a larger crank sprocket is better for timing belt lifespan because it lessens circular pitch.
 
T

Tungaloy

New member
Location
USA
Thanks for clearing up about the chain. I got the retainer cap in from JH Motorsports. Swapping it out was alot easier than I thought it would be.
 

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T

Tungaloy

New member
Location
USA
vwengineer said:
Looks good ! :)
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Thanks. Hopefully I can get $45 worth of use out of this pump before I have to replace it. Thanks to the good advice I've received from you and everyone else on this thread I'm putting more money into this repair than I was originally planning to. The used camshaft is enroute. I'll post pics up of it and well see if that's a was a good purchase. I'm about to order a new chain and tensioner too. I'm guess I'm going to have to buy a timing belt without the tensioner and idlers to get by with for now. That'll free up the money for the chain and it's tensioner.
 
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