Valve Guides, Geometry Etc

CastleMGBV8 · Post by **CastleMGBV8** » Wed May 13, 2009 12:34 pm

Tom,

Thats why theyv'e gone up then, I paid £129.00 less discount for Gold card and an extra £18.00 for the additional ball ends but thats a year ago before the pound did a nose dive.

£147 x 2 $294 div. 1.5 = £196 so £180 isn't a rip off, just a pain in the wallet!

Kevin.

topcatcustom · Post by **topcatcustom** » Thu Jun 04, 2009 7:14 pm

Just read a bit of Des' book and just noticed he has said that with good quality anti pump lifters the plunger position doesn't really matter too much and that pre-loads between .020 and .060 are ok up to 6500rpm- which makes sence if they dont pump up!

I might not have to worry so much about every one being 100% spot on then....

Is nice to hear that something doesn't have to be quite perfect in a tuning book!- even though I know one of you is going to burst my bubble

topcatcustom · Post by **topcatcustom** » Tue Jun 09, 2009 7:47 pm

Well due to budget I am going over to the dark side and using shims under my rocker pedestals. I bolted everything up today and preloads vary between 0.020 and 0.040 with 3 that are more like 0.060, going to drop them in to someone tomorrow who should be able to grind them down to bring them back in line, then my pushrod problem is over!

All I was wondering was- due to the amount of movement around the rocker area and the fact they are only held in by 1 bolt, has there ever been a problem with the shims rotating at all? My 2 ideas were to put a nick in each shim so it bites into the ally when done up tight so no rotating, or put something through the shim for the same reason...

Any thoughts?

TC

CastleMGBV8 · Post by **CastleMGBV8** » Tue Jun 09, 2009 9:14 pm

Tom,

Provided you have the shims properly aligned with the oil holes and torqued up correctly, you shoudn't have any problems.

Re the preload, if you have to live with near 60 thou on a few so be it, as your using a blower you should have masses of torque so you may not need to rev over 5800 RPM, where does your cam make power?

Kevin.

topcatcustom · Post by **topcatcustom** » Tue Jun 09, 2009 10:54 pm

Hi Kevin, Real Steel quote the RPM range to be idle-6000, as you know though I would be pushing my luck at 6k so will put a limiter at 5800 to help the rockers and shafts. Main reason though for the rev limit and keeping the lifter preload down is to keep the chance of a backfire (from pump up or valve bounce) at a minimum- my blower set up is effectively a plenum of approx 8 litres of fuel/air mixture, obviously a backfire might upset me a little!!!

TC

mgbv8 · Post by **mgbv8** » Wed Jun 10, 2009 8:02 am

Tom
The shims wont move mate. Trust me!!
And for an engine that is only doing normal RV8 revs 20-60 thou on the pre loads will be ok.
I haven't kept up with this thread, but have you made sure you have enough valve lift available for the cam??

topcatcustom · Post by **topcatcustom** » Wed Jun 10, 2009 9:23 am

Hi Perry, I put a weak spring in and ran the cam through a cycle with no probs, I think there was at least 100thou piston/valve clearance if thats what you mean, I also took 100thou off the guides. I wasn't expecting piston to valve clearance to be an issue as I am using 14 bolt 3.9 (36cc?) heads, 1.2mm composite gaskets and std 9.35 comp pistons which should be about the lowest compression set up using st RV8 parts if I am correct?