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Re: RE: [T3] engine internal stuff

Hey Toby- 

> P.S. Please keep comments directed to the list and DON"T include me. 
> Obviously, if I get the email then I'm on the list and I don't need the 
> duplicate emails.  Just a heads up, thanks :) 

Sorry about that one, Brian!  I'm used to newsgroups where doing so is 
common... <sigh> 

> >>  Rings  Mahle 
> > 
> >Not bad.  If you want to fork out a little more money, you 
> >could spring for Deves rings, but the benefit, especially on a somewhat 
> >short-lived 2332cc engine, may never be seen :-) 
> What about Total Seal? 

I've never used them personally.  However, some engine builders I've spoken 
with have found that they're difficult to get seated properly. 

> >>  Oil  5-30W winter/30W summer 
> > 
> >...Use a good 20w50 
> >conventional oil or a good synthetic oil.  I've found that 
> >Mobil 1 15w50 actually absorbs heat BETTER than conventional oils.  In 
> fact, 
> >it does so well that your oil temperature rises (I saw about 30F average 
> >increase)... and, if you understand the temperature dependence on oil 
> viscosity, 
> >you realize that this isn't too good! 
> So what are you saying?  Is synthetic good or bad in your opinion?  There is 
> quite the debate about synthetic vs. conventional here so expect flak. 
> Personally, I prefer synthetic :) 

Well, there's more to it than conventional vs. synthetic.  There are different 
formulations.  Heck, even Castrol and Valvoline conventionals use different 
base stocks! (...and Valvoline has less ash in theirs...).  Personally, I like 
synthetic for what it is worth.  In a long-living, full-flow-filtered engine, 
it's a benefit.  Oil change frequency and part wear go down.  In a short-lived 
engine, the benefit of less wear might not be seen.  And, without a filter, 
you'll never see the oil change frequency benefit since it gets too dirty.  
Additionally, there is supposedly less drag with synthetic oil, which means 
more power and better gas mileage.  However, it isn't a significant number.  To 
help oil drag on a Type 1, you're much better off to change that sump setup to 
combat drag (windage trays are cheap, dry sumps are expensive). 

I used Mobil 1 15w50 for awhile.  It gets too hot - I don't like it.  Now, I 
use Valvoline 20w50 - I like it a lot. 

> >...but I'm sceptical of the large viscosity range (i.e. there are 
> >significantly more VI additives added in there that can break down...). 
> But with a pure synthetic oil this ISN"T an issue! 

Not true!  Are there less of them than a conventional oil has?  You bet.  But, 
they aren't entirely immune.  Think about it: how can Mobil 1 and Quaker State 
have a 5w50, 10w50, and 15w50 variety?  Or how about their 0w30 and 5w30?  
Answer: VI additives! 

I like Valvoline's synthetic for two reasons: smallest named viscosity range of 
the 50 oils (only 20w50) and proper operating temperature.  Plus, it is easy to 

> >>  Compression  8.2:1 
> > 
> >...higher compression ratios run COOLER due 
> >to better efficiency and gas mileage.  Less gas burned for a 
> >given amount of power output means a lower temperature... 
> But higher compression creates heat simply due to COMPRESSION.  I'm not sure 
> I fully agree with your thoughts about this.  I would need to investigate 
> more. 

Compression isn't what makes the overall engine all that hot - combustion is. 

And, for that matter, it isn't static compression ratio that matters - it is 
dynamic compression ratio.  This can be seen emperically from a plot of torque. 
 What am I trying to say?  All other things equal, 10:1 with a radical, high 
RPM cam isn't near as harsh as 10:1 with a torquey, low RPM cam. 

And, heck, you aren't riding at WOT all the time, which is all that plot is 
good for.  So, all other things equal, for a given torque output at a given 
speed (i.e. pick a cruising speed...), you need the just about the SAME dynamic 
compression ratio.  Now, you can get that with a lower static compression ratio 
and more of air/fuel mixture, or with a higher static compression ratio and 
less air/fuel mixture.  I prefer the latter - it means that my gas mileage is 
better AND less heat is produced. 

So, with that in mind, what is wrong with insanely high compression ratios?  
Well, a couple things.  First of all, the anti-knock rating of the fuel.  The 
hotter the fuel becomes, the more likely to auto-ignite it becomes.  For this 
number, compression temperature and pressure IS important.  That's one reason 
why we aircooled folk call 8.5:1 high and everyone else calls it low: we run 
hotter!  Gasoline is 87-92 or so, right?  LPG is 130 - they get higher 
compression ratios.  Methanol is somewhere up there, too.  If the compression 
ratio is too high, it becomes increasingly likely to predetonate - a surefire 
way to screw everything up and overheat like crazy.  Diesel is a special case 
since their fuel isn't injected until ignition time, so they run with 
compression ratios well over 20:1.  Second of all, the engine may be too weak 
to hold together all that well under extreme pressures.  20:1 will blow our 
engines apart after awhile :-) 

> >>  Ignition Bosch 050 dizzy, Blue coil, 8mm wires, W8ac plugs 
> .... 
> >But, you should use a dual-advance distributor.  Either fork 
> >out $250-300 for a fully-adjustable Mallory unit (aircooled.net is the only 
> one 
> >that carries them) or make your own from old Bosch parts for cheap.  You 
> can 
> >obtain a fully adjustable canister from a 36hp engine... or from me - I 
> have 
> >over 10 of them stockpiled :-) 
> So, how is such a dual-advance dizzy cheaply made?  Care to share? :) 

I already did :-)  Check out March, April, and May 2001 VW Trends - there's a 
three-part article sequence in there I wrote.  I made mine for about $20 in 
junkyard/swapmeet parts.  If I had more available at that time (like I do now), 
I could have done it for less. 

(although, admittingly, I made some people mad at me because I flamed the Bosch 
009 and 050... <sigh>) 

> >Coil is nice.  If you add a CDI module of some sort (Universal 
> >Tiger 581, MSD, Mallory, Jacobs, etc.), you can increase your gap and give 
> >yourself a slight boost in gas mileage and a pretty big one in cold-morning 
> starting. 
> Not to mention more torque. 
> >Whose wires are you using?... 
> I talked to one of the Berg boys about two/three years back and he was 
> running STOCK Bosch spark plug wires on his dragster.  Claimed the size 
> didn't matter, were readily available, and did the job perfectly.  Go 
> figure! 

That's true to an extent.  The only real problem with stock wires is that 
they're designed to be replaced.  For a dragster, who cares?  It never runs 
long enough.  But, for a daily driver, a decent aftermarket set can last 
forever and won't deteriorate performance if they start to die... 

For an EXCELLENT read on wires, check out Magnecor's site. 

> >>  Carburetion Dual 40mm Dellorto 
> > 
> >Perhaps a bit small.  Consider 45 Dells or 44 Webers.  Also, 
> >what RPM band are you shooting for?  That'll determine your venturi size... 
> Well, thanks to the super short intake manifolds we gotta use under our 
> decklids, having large throats ain't always good since the intake velocity 
> goes down, reducing atomization of the mixture as well as the amount.  True 
> on the rpm band vs. venturi.  Of course, going FI would be a FAR BETTER 
> route ;) 

In the end, what really matters in venturi size.  THAT is what you size to your 
engine - you size them so that at your maximum desired RPM, you can still pull 
the amount of air you need through it without too much restriction.  Precise 
formulae are fun, but emperical observations by dyno guys are easier :-)  Hell, 
it's a carburetion system - if you want to use precise formulae, don't waste 
them on carbs... 

Here's one I use for a rough IR carburetion calculation: 
VenturiMM=SQRT(RPM*CylCC/2800).  For a 2332cc engine (583cc cylinder) at 
6000rpm, that's about 35.33mm.  From what I've seen, typically VW people tend 
to stay on the liberal side of this estimate. 

Then, as for throat size, you have a catch 22.  Big throat size for the same 
venturi size means better atomization on the main circuit, but an overly 
sensitive throttle response at your foot (can you say gas mileage killer?  :-) 
and poorer atomization on the idle and progressive circuits.  Smaller throat 
size for the same venturi size means the opposite of above.  Keeping the ratio 
of venturi area to throat area (VenturiMM/ThroatMM)^2 around 65-80% is good 

Now, Weber 44IDFs come out of the box with 36mm venturis.  Sounds good to me! 

As a sidenote, Weber 48IDFs come with a 40mm venturi.  But, Weber 40IDFs come 
with a 28mm venturi.  Too small!!! 

> >>  Flywheel 200mm Stock VW 
> > 
> >Consider lightening the flywheel, especially considering the added weight 
> on 
> >the counterweighted crank.  It won't change a dyno reading, but it'll help 
> you 
> >to accelerate quicker (kinda like getting alloy wheels over steel)... 
> But if it's gonna be on the street more than the strip then shifting will be 
> a PITA if it's lightened!  I know from experience (however, my 
> double-clutching techinque was greatly improved :) 

Yah, it is a bit trickier.  I've done it before with a stock crank - it's not 
an absolute PITA, but it wasn't perfect.  But it was fun to chirp the tires 
when shifting into 2nd or 3rd gear when you dumped the clutch if you screwed up 
:-)  However, with a heavier, counterweighted crank, it's not as bad... 

Take care, 

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