| [ Total Views: 1789 | Total Replies: 14 | Thread Id: 93074 ] |
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 deadkombi
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| posted on October 7th, 2011 at 08:09 PM |
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valve spring pressure and valve length
G'day all, I'm new to this site but am in need of some expert advice if possible. I'm from Perth and have a 56 oval with a 2276 in it. It dropped a
valve at the drags on Wednesday night and I think it could be because the valve spring pressure is too high or maybe the combo not right. It has 140
pounds of seat pressure and 370 pounds at full lift at the valve. Currenetly running an Engle 130 with 1.25 ratio rockers. What pressures to you guys
run?
I put valve length, because the guy at the head shop said to try and get valves .100 thou longer and drop the pressures to 100 pounds on the seat and
300 pounds on the nose. Currently running VW650 valve springs.
Sorry I don't have a photo, but there is a great shot from wednesday on the quit motorplex home page photo gallery smokin the rears. Thanks Paul.
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ian.mezz
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| posted on October 7th, 2011 at 08:22 PM |
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try Dangerous
http://www.motorplex.com.au/gallery.php?mode=gall&gid=221
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dangerous
A.k.a.: Dave Butler Muffin Man
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| posted on October 7th, 2011 at 09:09 PM |
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Did you have a rev limiter fitted?
I would not use the W130 with 1.25s.
It is designed for 1.1 rockers, so if used with 1.25's you may have issues.
Where did the valve break?
Those pressures should be fine with the right cam/rocker combo, and a rev limiter.
| Quote: | Originally
posted by westi
That's mad Alan.
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deadkombi
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| posted on October 8th, 2011 at 12:12 AM |
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Thanks for the reply. No rev limiter, but am going to fit one. The valve broke off at the collett. I have read conflicting things about the 130. The
engle website now says that 1.25 rockers can be used, but it used to say that 1.1's where it.
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coletrickle
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| posted on October 8th, 2011 at 09:27 AM |
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130 and ratio rockers will do that but I've usually seen broken springs not valves when things go wrong.
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fish26
A.k.a.: benito
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| posted on October 8th, 2011 at 01:25 PM |
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I totally agree with Dave and Cole, W130, ratio rockers and high revs are a cocktail for problems.
A thick valve lash cap will give your valves a bit of length and you will need to adjust your rocker geometry to suit.
bitten by the bug..........several times
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deadkombi
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| posted on October 8th, 2011 at 07:49 PM |
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Thanks for the feedback. The longer valves were to drop the seat pressure, the geometry is all good. Do you guys know what sort of seat pressure and
nose pressure to aim for? Turning about 7000rpm.
Definately over revving didn't help, the track was slippery and it hit 8000 a couple of times. Will definately fit a rev limiter.
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dangerous
A.k.a.: Dave Butler Muffin Man
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| posted on October 9th, 2011 at 08:08 AM |
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In the past I have used 140 seat pressure with the W130 and 1.1 ratio stock rockers.
Back then, the springs i used did not have as a high a spring rate as yours,
so my guess is the nose tension was only about 320 or so.
It is important that the springs you choose are installed close to .060" from bind.
Apparently if a spring is not operating this way it can cause its own problems like surge(do a search).
I currently am running only .040" on my own set up to avoid this surge, but this is an extreme measure.
This will likely be more tension than you need for your application and 7000 rpm,
so you may like to choose a spring better suited.
Once you have your rev limiter set, you should no longer have any problems,
but I would** replace all those valves now,**
and **make sure that the collets were made/ground in such a way as to grip the stem correctly.**
Then when you set up your springs, make sure you have around .530 travel to bind.
This is approximately .060" more than what lift you should have.
Naturally you MUST check what lift YOU have before final spring shimming, and add that .060".
| Quote: | Originally
posted by westi
That's mad Alan.
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dangerous
A.k.a.: Dave Butler Muffin Man
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| posted on October 9th, 2011 at 08:12 AM |
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Just to be adamant,
YOU SHOULD REPLACE THE OTHER VALVES
YOU SHOULD USE COLLETS THAT DONT BUT TOGETHER
(your pic above shows that the collets are not gripping the stem correctly)
You can buy collets already modified, (bergs for VW style),
or if you want to use VW ones they need to be ground a their parting face.
| Quote: | Originally
posted by westi
That's mad Alan.
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dragvw2180
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| posted on October 9th, 2011 at 10:13 PM |
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I agree with everything Dave said, I have seen more damage done by too little spring pressure than too much. Mike
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gbaker770
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| posted on October 10th, 2011 at 01:51 AM |
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A buddy of mine just had the same exact thing happen. He's replacing them all. |
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deadkombi
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| posted on October 10th, 2011 at 05:07 PM |
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Once again thanks for the help. Any idea of a supplier for stainless valves, 37mm exhaust and 42 inlet, and also a good set of springs that will give
me the lift and pressures required to do the job. I have looked at the WEB springs on VEEDUBPARTS.NET and they offer the right lift, but pressure is
another story, also CB valves, but would prefer Manley if I can get hold of them. Any advice or someone here with them and rough cost.
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dangerous
A.k.a.: Dave Butler Muffin Man
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| posted on October 11th, 2011 at 11:29 AM |
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Fabre are the Australian importer of Manley products.
Try them first.
Vintage used to stock manley valves to.
Bergs were a good source of manley stuff,
and if they have them in stock you will have them within a couple of weeks depending on freight method.
But ring them, they are slow with email.
They can supply you with a whole package: springs retainers collets and shims.
| Quote: | Originally
posted by westi
That's mad Alan.
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deadkombi
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| posted on October 11th, 2011 at 11:56 AM |
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Cheers Dave, thanks for the help.
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 matberry
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| posted on October 11th, 2011 at 12:14 PM |
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x 2 with DB and others above
I get my Manleys from Berg's
Don't use 1.25:1 rockers IMO
Matt Berry Motorsports...air cooled advice, repairs and mods Ph 0408 704 662
OFF-ROAD,CIRCUIT,DRAG,STREET,ENDURANCE
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