Rover v8 3.9 valve springs & boost?

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Pxr5
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Re: Rover v8 3.9 valve springs & boost?

Post by Pxr5 »

When I did the cross bolting I used shim stock & carefully milled the caps on one side so that there was no distortion of the main tunnels.
When the crank was installed the crank span freely with no tight spots .



DEVONMAN
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Re: Rover v8 3.9 valve springs & boost?

Post by DEVONMAN »

Pxr5 wrote:
Wed May 22, 2019 12:04 pm
When I did the cross bolting I used shim stock & carefully milled the caps on one side so that there was no distortion of the main tunnels.
When the crank was installed the crank span freely with no tight spots .
When I did it I just used shims on the starter side of the caps. (3-4 thou) I didn't do any milling. What did you mill ?
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Pxr5
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Re: Rover v8 3.9 valve springs & boost?

Post by Pxr5 »

I milled one side of some of the caps, ( only slighty) so I could use one thickness of shim stock, that gave me a nice snug fit.

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Re: Rover v8 3.9 valve springs & boost?

Post by SuperV8 »

Pxr5 wrote:
Mon May 20, 2019 10:46 am
The question is though, at what level do you need rods, pistons & springs?
The First limiting factor will be the pistons.
I think it's generally considered standard pistons are ok to 10 - 12 psi.
I think it's generally considered standard rods are ok for boost - just not so good at high RPM's.
Springs don't care what the boost is - only concern for springs is what valves and cam they are being used with.

Tom.
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stevieturbo
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Re: Rover v8 3.9 valve springs & boost?

Post by stevieturbo »

SuperV8 wrote:
Tue Jun 18, 2019 7:53 am
Pxr5 wrote:
Mon May 20, 2019 10:46 am
The question is though, at what level do you need rods, pistons & springs?
The First limiting factor will be the pistons.
I think it's generally considered standard pistons are ok to 10 - 12 psi.
I think it's generally considered standard rods are ok for boost - just not so good at high RPM's.
Springs don't care what the boost is - only concern for springs is what valves and cam they are being used with.

Tom.
To a point.....try running 30psi boost with very weak springs...and you will have very poor valve control as in theory you could overcome seat pressure from air pressure alone. Both on inlet side and exhaust side.

But on a low boost, low rpm setup....no real concern.
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