3.3SS rebuild finally underway..........

[fred cook]

I now have slightly over 100 miles on the new engine. Oil pressure is doing well and I think that I have the timing/tuning/air fuel ratio dialed in now. The engine starts easily from cold or hot and will drop off the cold high idle after about 1/2 mile of driving. For the first 100 miles, I had the ignition interrupter set at 5,000 rpms but have just moved that up to 7,000. I have done some wide open throttle pulls from 2k rpms to 4k rpms and from 3k to 5k. The SS engine seems to really come to life starting at 3k and just pulls harder as the rpms go up. The a/f ratio is running right at stoichiometric levels during normal driving. Under WOT conditions, a/f drops down (richens) into the mid 13s which is where I had hoped it would be. I haven't measured fuel mileage yet, but it seems to be in the 16-17 range for around town driving. AND, so far, no oil leaks! The oil and filter will get changed at 500 miles along with a valve adjustment and a check of the cylinder head nuts. After that, I'll change the oil/filter at 1,000 miles and then go on a 1 yr or 5,000 mile oil change cycle. Life is good!

[fred cook]

Took the SC out for a drive this morning. Once I got on some backroads that are little used, I did a couple of 3/4 gear pulls up to 6k rpms. Just as I expected, once over about 4k, the engine keeps on pulling stronger and stronger. The a/f ratio is running right at 14.5 plus or minus a couple of tenths. On the hard pulls, the a/f goes down into the mid to upper 13s. Once I get another 50 miles or so on the clock, I will push it up to 7 grand. Also, I found a place close to home that has a chassis dyno. Once I get past the 500 mile mark, valve adjustment, head retorque and oil change, I will put it on the dyno and get some hp and torque numbers. More to follow!

[snbush67]

Nice job Fred! Push that baby up to 7k, stop babying her. The sweet spot in mine is 3800.

[IXjamesXI]

Can't wait to see the dyno... enjoy ripping up and down those back roads!!!

[bryant4]

Terrific thread!

sorry, but could someone explain what makes is an "ss" build? or is it 'ss' engine?


3.3ss

[fred cook]

Originally Posted by bryant4

Terrific thread!

sorry, but could someone explain what makes is an "ss" build? or is it 'ss' engine?


3.3ss

Changing from a stock piston diameter to a larger one but leaving the stroke standard makes what is commonly referred to as a "Short Stroke" engine. In this case, I changed from the original 95mm diameter pistons to 100mm diameter pistons which increased the displacement from 3.0 liters to 3.3 liters. At the same time, the Mahle pistons that I used increased the compression ratio from 9.3:1 to 10.1:1. So, now I have a 10% larger engine with about 10% more compression. Cams were upgraded from the stock SC cams to 964 camshafts. The 964 cams have just a bit more lift and duration thus providing a bit more power. When the bore was increased to 100mms, it became necessary (in most opinions) to add dual plug ignition. So, I used a set of Carrera heads that had been slightly ported and had been drilled for the second spark plug. Ignition is by Electomotive XDi direct fire units which replace the distributor and allow for adjustable timing. Sorry to run on, but one thing leads to another, commonly referred to as "the slippery slope"!

[fred cook]

Originally Posted by snbush67

Nice job Fred! Push that baby up to 7k, stop babying her. The sweet spot in mine is 3800.

Yes, mine too. I start feeling the "push" around 3500 but it really comes on at 3800 or thereabouts. I almost wish I could go back for one more drive in the car with the stock engine just to really appreciate the difference. Don't know what the hp and torque is at this point, but will be disappointed if it is under 250hp at the rear wheels! Only the dyno will tell!

[snbush67]

Are you running SSI's? I hope you are harnessing all of your displacement, that CIS should mix the air/fuel nicely. I dont think you are going to be disappointed, I guess you will make 250 and a few more. Overall power is achieved by displacement, compression and stroke. The major contributing factor to where your power band ends up is the cams and the ability to move air through the system, a larger exhaust seems to open up top-end but can eat into low end torque. With the SSI's and CIS you should have a very snappy motor with a low power band. I think if anything is holding you back it could be the flow of the CIS but I dont think it will be an issue. Good luck on the dyno!

[fred cook]

On this engine, I am using the large bore early CIS box and runners. The head ports measured 42mm while the runners are 39mm inside diameter. I opened up the runners to match the phenolic spacers so that there would not be a major interruption of laminar air flow into the cylinder head.



On the other end, the exhaust ports measured 39mm and the SSI tubing extension that goes thru the flange measured about 36mm. So, using a variety of tools, I flared the flanges out so that they would just slip into the exhaust port recesses. Sorry, but I don't have a picture of this.

Right now, I feel like the only significant restriction in the system is the air plate. The only thing that I can do about that would be to switch to one off of a 3.3 turbo motor. Before I drop $3-400 on that, I want to see what numbers the engine is making now. At this point, I have the engine tuned so that it is running right at stoichiometric (14.7+-) while cruising and then it drops to about 13.5 under wide open throttle. I got it to do this by using the cold start valve as a 7th injector by wiring in a momentary contact switch that only opens at about 99% throttle. The cold start valve sprays fuel thru a small aluminum manifold that directs fuel to each intake runner. It may not be perfectly balanced, but seems to work ok. The system starts, idles and runs quite well. Don't know how much more I could ask of it!

[Kemo]

anxiously awaiting the dyno results... great thread! interesting use of the cold start valve. I have heard of people doing this but this is the first thread ive actually seen. any more info on this?

[KTL]

Be sure to check the timing with a light when you dyno it. The long steady time it takes to pull the engine thru the rpm range in 3rd or 4th gear is the best opportunity to see if your XDi has timing float

[fred cook]

Took the SC out for it's longest drive to date. Put about 65 miles on it running in the 50-60 mph range or around 3k in 4th gear. When I got almost home, my a/f gauge decided to take a powder and went out. So, I get to trouble shoot that issue tomorrow. I talked to a tech at the Innovate plant and he gave me some things to check. Probably nothing major. So, the new engine has right at 200 miles on it now. Starts good, runs good and so far, no leaks! Temps run between 190 and 200 F. while cruising. Pushing it harder, I have seen the temps up to almost 210. Ambient temps are in the low to mid 80s. The oil lines to the wheel well oil cooler are getting hot so the internal and external thermostats are working properly. I have a switched fan on the front oil cooler, but haven't needed it yet. On a cold startup, I am seeing a little smoke, but can't tell if it is gas or oil smoke. I'm guessing gas as it is more white than blue. It goes away very quickly and doesn't happen on warm starts.

[bryant4]

Many thanks for the good "SS" explanation, Fred!

Also, would love to see more of your custom plumbing for your CIS-lite

[soren.911]

Any updates?

[fred cook]

Originally Posted by soren.911

Any updates?

Sorry about the long delay. My project has been shoved aside because of some family health issues. Also, the A/F gauge that I installed quit working properly so I am in the process of rewiring it. Once the gauge rewire is done, the car will go back on the road. At the present time, the new engine has about 200 miles on it with everything working well and (so far), no oil leaks. Over the last couple of months, I have been starting the engine and let it run for 10 minutes or so. Even after sitting for a week or more, it will fire right up! One of the last things that I did before the "interruption" was to adjust the timing and ignition interrupt to it's final setting. Now the engine should rev to a bit over 7k rpms and get up where the real power happens! I'm really anxious to see how that works. Thanks for the interest!

[fred cook]

I finally found time to finish rewiring the a/f ratio gauge only to discover that my red top gel cell battery had gone bad. Fortunately it was still within the 3 year warranty period so I got it replaced at no cost to me. Meanwhile, back at the shop, installed the new battery, re-calibrated the a/f gauge and fired the engine up. Let it run for a few minutes and took it for a short drive of about 10 miles. This is the first time that I have had the ignition interrupt set all the way up to 7500 rpms. Once the engine was up to full operating temps (190 F), I did some 2nd and 3rd gear pulls up to between 6500 and 7000 rpms. Very pleased with the way it runs, it seems to get stronger as the revs build. I do have a small glitch with the oil pressure gauge in that it follows the engine rpm up to just over 3 bars of pressure and then the needle sticks. I replaced the sender unit and checked the wiring so the problem almost certainly is in the gauge itself. I also will need to adjust the a/f ratio as it is now running just a bit richer than I would like it to be. All of the thermostats seem to be working properly as warm/hot oil is getting to the front oil cooler. When I moved the car out of the garage, I noticed a couple of very small oil spots that appear to be from the tranny. So far, no engine leaks! Once I get up to 500 miles, I will change the oil and filter, check the valve adjustments and then it should be ready for the road.