Macca

Axl911. Spot on. As a pre 1996/7 ROW 993 owner one of the benefits I already have (thank my credit card) is a good set of tighter ratios for street than the US folks. If this were a track car i would look to change to 993 Cup car ratios but suspect it would be a very expensive excerise....

Lastly PMS crank pully vs Factory three belt. You see now the issue with mating them to the crank. One sits more inboard than the other although on the bench they sit aproximately the same depth....

Macca

After much research Id like to add adata point regards the Crank Pulley which future Rennlisters may find of use.

The idea of changing to a smaller lighter crank pulley is possible not a sound one for a road car for three reasons:

1). Smaller diameter wheel may cause issues with power generation
2). Smaller diameter wheels may cause issues with thermal loads (it runs teh fan to cool the cylinder heads)
3). Lighter wheel may caus problems with crank shaft balancing and in a LWFC application could accelerate engine stalling characteristics in an early NVR 993.

The only 993 fitted with a single pulley was the 993 RS Clubsport. This includes the 993 Cup (which apparently has the standard 3 pulley unit too!)! The pulley was single but I believe was the heavier (1100 gram vs 500 gram) unit from the 964. The 964s used a heavier crank pulley to create a "harmonic damper" for the crankshaft which was lighter than the 993s (and has led to subsequent issues of its own). The 993RS Comfort Spec with a/c was fittd with a dual pulley but made of steel not alloy and of only marginally less weight than the standard three pulley wheel. This engine was Varioram and fitted with DMFWC and made up the vast majority of 993s produced.

Basically if you ar NVR running RS LWFC then stick with the three pulley unit regardless.
If you are Variram you could go 2 pulley factory unit (same diameter as 3 pulley unit) for 20% reduced weight buy around $600ud+!

The most interesting datapoint to come to light is that iff you are running NVR and RS LWFC and you are experiencing stalling issues even after chip designed to eliminatethem you should try a 964 3 pulley crank wheel as there is a very good chance the additional mass and vibration eliminating characteristics may solve your stalling issues.

Although I have been lucky in eliminating LWFC stalling issues this information could be of considerable interest to those that do (and read this!).

Unfortunately I have had to pay $335 usd for the privaledge of learning all of this. Let hope Patrick Motorsport are understanding with theor Returns Deprtment! Such is life....

M

Macca

Todays progress is just pictures only as my tech team were too busy working to giv a detailed analysis via email. They hav done well in three days dropping engine and tranny, opening gearbox, fitting LSD, adjusting with shims for lash etc and bolting it all back up then stripping the engine down for installing new cams and springs.

The camshafts with the darker lobes are the DC21-114 supplied by John Dougherty. You can see the new rockers next to the old. So much wor just to get to these parts! The goo news is teh new plugs and wires should be a cinch to fit. The bad news is changing springs is a bitch of a job requiring using air to push the valves up. Shimming them correctly another art. Lets hope it all comes together ok.

Looking at the pictures everything seems to be in good condition without excessive wear...but I clueless....

axl911

Beautiful engine!!!

What's your break-in procedure on the cam? Just run it hard?

Macca

Hi axl911. You know Im not really sure. I understood we could just install, put on dryno and run it hard? Ill have to ask my mechanic. Good question!

Cheers
M

trophy

Looking good Macca, cannot wait for your driving impressions and dyno....

Bill Verburg

here's what a factory RS single sheave pulley setup looks like


these were used on all 993 w/o a/c, could be RS or RS/CS
there is also a 2 sheave for RS w/ AC, but it's not needed as you can use the stock 3 sheave for that too, the weight difference is small between any of these



The RS single sheave looks like this installed on one of my cars

I've got to disagree that this shouldn't be used on a nvr or vram car w/ or w/o a l/w flywheel

the 993 Cups used 964 bottom ends and so all came w/ 3 sheave w/ harmonic balancer
like this, theses are much heavier(~ 2x the mass) than any of the 993 pulleys



the 993 crank is much more robust than a 964 crank, the down side is that the rod journal area is reduced, for this reason the 964 cranks was used in 993Cups, the GT3 crank is derived from the 993 crank but uses the wider 964(and earlier) wider rod journals

Macca

Hi Steve,

You and me alike mate! Ill be relying on the initial dyno numbers (pre having the chip re customised) nd my mechanics bum for initial feedback. Unfortunately I wont beable to give personal feedback with final chip dyno data for another 6-8 weeks myself. Im hoping to get back after the new JICs are recieved and isntalled, car lowered and set up nicely with Rennline rear toe arms.....should be a sweet ride.

Bill,

Glad you chipped in mate. I wasnt clear in my email but my findings were same as your other than the fact somewhere I read that the heavier 964 3 belt pully wheel (1100 gram approx vs 470 gram approx for 993) was used on some 993 LWFC appliations. Perhaps that was wrong. Its good to have your inputs and pictures. Your always a man of facts which weall appeciate! :-)


Cheers
M

Macca

Update. Patrick Motosports have responded saying this part is for a backdate project where a 993 engine is installed in an earlier car with earlier a/c pump. Unfortunately their advertising (see their weboste) wasnt overly clear in this regard at all. Thy will change it.

They have offered a refund of parts price if the goods are returned "as new" and havent been "bolted up" onto the crank? Im not sure how we were supposed to know it was the wrong part till it was bolted down? Oh well...well see where this goes. I hope they do the honourable thing...

This is one of the downsides of long distance parts transactions.

Cheers
M

boman993

This project thread is so awesome!!! Thanks for keeping it updated Macca!

Macca

Thanks Jakob. Stay tuned over the next few months. After phase 4 there will be a final phase 5 :-)

M

MarkD

Things are coming along nicely Mark...
Glad everything arrived in time!

Macca

Thanks Mark. Yip everything arrived perfectly - just days before the work began. Parcels from Germany, US East and West coasts converged up little old downunder a week ago like synchronised swimmers! Without your help this wouldnt have happened.....

Cheers

M

Macca

Ok Gents. Further updates today.

The good news is the cams are in. Timing has been completed on one bank. The bad news was the Eibach high lift spring I was shipped did not mate with the factory valve seats. No eibach seats were available with the springs and I was assured by eibah these would fit. As you can see from the pictures this wasnt the case. The springs look very similar outside diameter but inside diameter varies a fraction and makes it impossible to seat. Unfortunately compressed air was used and all springs removed befre this was discovered....

Im working with Eibach now and Ultrarev (good guys) the suppliers to get a refund. Only one spring was oulled form the box and never fitted.....Ill update all on that later....

The factory springs like everything else so far encountered in the engine seemed in very good condition so we decided to go ahead and reuse them. The opportunity was taken at this time to install new valve guide seals. This was precautionary but apparently these are a common issue once the guides themselves start to wear. My seals were going hard but still intact. I dont believe there was any evidence of excessive valve guide wear (although the valves werent pulled so difficult to tell for certain) so we left the guides in place. The 993 wasnt using excessive oil as far as I recall - maybe 500mls for 1500-2000 miles. The OEM springs were re shimmed to ensure equal performance so not all was lost although there was around 5-6 hrs labour here we needednt have paid if we had have known the outcome....

So data point for those in the future. Dont opt for eibach high lift valve set at $175 usd unless you have a machine shop that can re profile the seats or can buy the matching seats. Alternatively opt instead for Aasco springs with titanium retainers and custom seats for $700+ usd - although in full fairness Camlob and others have also experienced issues with exact fitment for these too! This is a street engine so given this cam change and solid rocker update was intended as a moderate cost vs bhp upgrade my wallet didnt stretch that far!

The only question we have outstanding is the rockers made by John Dougherty. The mechanic says the holes are larger than the 993 hydrallic rockers and questions if there will be oiling issues. Im awaiting Johns response but in earlier correspondence he did not indicate any issues or the need to backdate the 993 rocker arms....

If Johns response confirms this then tommorow the second bank will be timed and the box mated to the engine and the work starts on putting it all back together. There are a number of smaller items of unrelated work being performed via thrid parties so it will still be a matter of 3-4 days beforee the 993 is ready for teh road. At this time fingers crossed it will run well. Then it needs booking in for Dyno and AFRs to Steve Wong for chip mapping....

Update = John Ds rockers are bushed and this blocks the oiling hole found on the earlier rockers....allgood there! You can go ahead and use the standard rocker shafts and bolts too!

PS - in pictures below sorter spring = eibach...
PPS. For DC21-114 cam standard springs can handle lift fine. Remember this isnt a super aggressive race cam - more a hot roadsports cam with a 6800rpm limiter designed for driveability.

Cheers
M

camlob

I opted for the aasco springs and retainers. Apparently, I have to machine some material off the retainers. I dont know why. It should have come already machined in my opinion!

I sold the steve wong chip to a friend and surprisingly it pulls good! We are going to the dyno tom.

Really amazing how things change. I recall you didnt want to install a cam before!

My car will take some time since so much work is being done to it.