Marc's 1990 4.2L V8 Twin Turbo Coupe Quattro

Post by **Marc** » Mon Mar 17, 2008 7:24 am

I had the tranny in and out at least 7 times. That tranny jack BTW is friggin perfect for this type of work. If you're stuck without a lift doing a job like this, it makes life much, much, easier.

I almost contemplated building a jig to locate the position where the shift linkage bolts to the body relative to the tranny so I could get the linkage right off the car.

cuatrokoop · Post by **cuatrokoop** » Mon Mar 17, 2008 7:40 am

a4kquattro wrote:You should have seen it when it had a 1/2" of mig snot all over it from tacking it in place from underneath the car till I got the position right

Ah, I don't think I should have seen that....I don't think anyone should have seen that!

WAUG0806 · Post by **WAUG0806** » Mon Mar 17, 2008 8:50 am

Now that you have the "test mule" prototypes, you should get somebody to do 3d cad drawings so the next guys can do it the ez way and/or some capable vendor can make a conversion kit from chromoly with delrin bushings, etc.

Maybe they will make you the beta tester!

mean time have fun with your beautifully effective shifter! 8)

Post by **Marc** » Mon Mar 17, 2008 9:19 am

WAUG0806 wrote:Now that you have the "test mule" prototypes, you should get somebody to do 3d cad drawings so the next guys can do it the ez way and/or some capable vendor can make a conversion kit from chromoly with delrin bushings, etc.

Maybe they will make you the beta tester!

mean time have fun with your beautifully effective shifter! 8)

I'm not sure beauty really belongs in the same sentence with the shifter, but effective I'll take

Thanks Doug.

Derracuda · Post by **Derracuda** » Mon Mar 17, 2008 9:33 am

i'm skeptical Marc... you haven't powdercoated it red yet.. so i don't think it will match your car or work properly

Post by **Marc** » Mon Mar 17, 2008 9:49 am

derracuda wrote:i'm skeptical Marc... you haven't powdercoated it red yet.. so i don't think it will match your car or work properly

Maybe I should powdercoat it wrinkle to hide the fug factor

Toxcheap · Post by **Toxcheap** » Mon Mar 17, 2008 9:51 am

"ah..I think it'll be fine"

pkw · Post by **pkw** » Mon Mar 17, 2008 10:27 am

what is plan for increasing combustion chamber size? going to give us a step by step? going to cc it when it is done to show how much difference it made?

pkw · Post by **pkw** » Mon Mar 17, 2008 10:29 am

would 4.2 heads and intake fit on a 3.6? that would probably lower compression by a bit.

Post by **Marc** » Mon Mar 17, 2008 10:39 am

plan is to go through a normal port and polish procedure and see how much material is removed without drastically altering the profile of the combustion chamber. I'll re-cc the heads along the process and if I can manage 5ccs I wont be stacking the gaskets.

Post by **HT Motorsport** » Mon Mar 17, 2008 11:03 am

a4kquattro wrote:
derracuda wrote:i'm skeptical Marc... you haven't powdercoated it red yet.. so i don't think it will match your car or work properly

Maybe I should powdercoat it wrinkle to hide the fug factor

Do they make 1/2" wrinkle?

Have you thought about using that one as a jig and making up a nice version for a kit for others to buy?

H

Post by **HT Motorsport** » Mon Mar 17, 2008 11:04 am

a4kquattro wrote:plan is to go through a normal port and polish procedure and see how much material is removed without drastically altering the profile of the combustion chamber. I'll re-cc the heads along the process and if I can manage 5ccs I wont be stacking the gaskets.

Hey mark,

for interest sake do you fancy sharing your mathematics on the CR vs CC thing?

H

Post by **Marc** » Mon Mar 17, 2008 11:27 am

timmmy wrote:
a4kquattro wrote:
derracuda wrote:i'm skeptical Marc... you haven't powdercoated it red yet.. so i don't think it will match your car or work properly

Maybe I should powdercoat it wrinkle to hide the fug factor

Do they make 1/2" wrinkle?

hehe, apparently I need it. Tough crowd here on MG

Have you thought about using that one as a jig and making up a nice version for a kit for others to buy?

H

not really, trouble is that its more than just a simple rod, it has a ball socket on one end and would require a fair amount of machining to make one from scratch. I suppose I could mold the rod or something so that someone could use it as a template to figure out where to cut the b5 s4 rods, but that sounds like work..

Post by **Marc** » Mon Mar 17, 2008 11:54 am

timmmy wrote:
a4kquattro wrote:plan is to go through a normal port and polish procedure and see how much material is removed without drastically altering the profile of the combustion chamber. I'll re-cc the heads along the process and if I can manage 5ccs I wont be stacking the gaskets.

Hey mark,

for interest sake do you fancy sharing your mathematics on the CR vs CC thing?

H

certainly. To calculate CR you use BDC cylinder volume divided by TDC cylinder volume. Borrowing some of the math from one of my previous threads (goin' 20v on the cheap: http://www.motorgeek.com/phpBB2/viewtopic.php?t=84 ):

bore = 8.46cm
stroke = 9.27cm
stock CR = 10.6:1

CR = cylinder volume @ BDC / cylinder volume @ TDC

Cylinder volume @tdc = Vo = combustion chamber volume, area between piston face and top ring, gasket area....)

Cylinder volume @bdc = Vo + (volume create by bore * stroke) = Vo + ((pi * (bore / 2)^2) * stroke) = Vo + ((3.14 * (8.46 / 2)^2) * 9.27) = Vo + 520.58cc

knowing the CR is 10.6:1 we can solve for the unknown Vo:

10.6 = (520.58 + Vo) / Vo

10.6 * Vo = 520.58 + Vo

9.6 Vo = 520.58

Vo = 520.58 / 9.6

Vo = 54.23cc (which actually checks out pretty damn close to my measurement, since the extra 4.23ccs would be for gasket area, etc).

So to figure out the area created by a gasket, I assumed 1mm compressed thickness (which might be a little off by my above calculation, eg it would seem to be a little less than 1mm):

Gasket Volume = Gv = (pi * (bore / 2)^2 * thickness) = (3.14 * (8.46 / 2)^2 * 0.1) = 5.6cc

but just for the sake of argument, adding 5.6cc of volume we get the following cr:

CR = BDC volume / TDC volume
CR = (574.81 + 5.6) / (54.23 + 5.6) = 580.41 / 59.83 = 9.7:1

high, but still turboable. My calculations were closer to 9:1 on the 3.6 as I recall, I never actually went through all the math on the 4.2,thanks for the prod

Post by **Marc** » Tue Mar 18, 2008 9:44 am

I measured the gasket thickness today and I think I'm underestimating the volume a bit. I measured a used gasket at 1.8mm so I'd have to imagine fully compressed thickness cant be much less than 1.6mm. Using that, volume from a 1.6mm thick gasket would be almost 9ccs with the following affect on CR:

CR = (574.81 + 8.985) / (54.23 + 8.985) = 583.795 / 63.215 = 9.24:1

that might be more than I can take out of the combustion chamber safely, we'll see. This also brings into question the factory's compression ratio numbers. I almost want to CC the actual BDC volume to see how the measured numbers compare with the calculated numbers...

a_CQ · Post by **a_CQ** » Tue Mar 18, 2008 9:54 am

This also brings into question the factory's compression ratio numbers. I almost want to CC the actual BDC volume to see how the measured numbers compare with the calculated numbers...

Probably a good idea before you start grinding.

Post by **HT Motorsport** » Tue Mar 18, 2008 4:37 pm

You will need a big pipette for that measurement

Derracuda · Post by **Derracuda** » Tue Mar 18, 2008 4:42 pm

timmmy wrote:You will need a big pipette for that measurement

haha, yeah!!

Derracuda · Post by **Derracuda** » Tue Mar 18, 2008 6:02 pm

JB Weld!!! just a thin layer though

Post by **Marc** » Thu Mar 20, 2008 9:02 pm

got the tranny bolted up for hopefully the last time today. Although I realized after everything was in that I had forgotten to put the rubber boot over the shift rods (the big one that attaches to the shifter box). Hopefully I can slide that on there from the top after disconnecting the rods and maybe dislodging the box, we'll see. Doh!

AudiSport4000 · Post by **AudiSport4000** » Fri Mar 21, 2008 6:37 am

:woowoo:

Post by **Marc** » Sat Mar 22, 2008 2:03 pm

Got the rubber boot onto the box ok, installed the axles, and fitted my KW struts up front.

255/40/17 RA1s now fit

just waiting on some gaskets for the driveshaft flanges and I'll be able to finish the job and go for a spin. :woowoo:

Post by **HT Motorsport** » Sat Mar 22, 2008 2:19 pm

Ill just go to the bathroom for a few minutes....Very nice

Now I see why you were tied up today

Nice job.

H

Derracuda · Post by **Derracuda** » Sat Mar 22, 2008 2:20 pm

so the ol' 3.6 is still in there and running then? when's the 4.2 swap happening?

Post by **Marc** » Sat Mar 22, 2008 8:23 pm

Yep, 3.6 is still in until I'm ready to fit the 4.2 (gotta flow bench the untouched head first, then port work, then assembly). The tranny had to be done anyway so I opted to do that first.

On another note, Can anybody recommend shops in the Southern NH / Northern MA area that can do corner balancing?