Tim's 944LS1 track car build!

Lemming wrote:  Fire and ice make installing the pins a breeze.  
What ring gaps are people using?

"Fire ans Ice" raises my heart rate, but it is the easiest and safest way.
chrome moly rings? Rule of thumb is .004 per inch of bore, Hastings says .0035. 005/in for 2nd ring. With fairly open exhaust I'd go tight, .003/inch. I did .012" on 4" bores which is what they usually were out of the box. If the cylinders got honed on a honing machine without boring, their probably on the loose side.

Edit: your stock bore is 3.898

racertomtom wrote:If the cylinders got honed on a honing machine without boring, their probably on the loose side.

Hopefully not a problem, I ordered file to fit rings.  (Sealed Power File-Fit Plasma-Moly Piston Rings)

So Tom, you are running 0.012 top and 0.007 2nd ring gaps?

Lemming wrote:

racertomtom wrote:If the cylinders got honed on a honing machine without boring, their probably on the loose side.

Hopefully not a problem, I ordered file to fit rings.  (Sealed Power File-Fit Plasma-Moly Piston Rings)

So Tom, you are running 0.012 top and 0.007 2nd ring gaps?  

No, .012" top ring and .020" 2nd ring. You might check Sealed Power's site and see what their reccomendations are, seems like the gaps on plasma and chrome are the same with plasma taking a finer cylinder finish, but I don't put much stock in my memory. Be sure and check gap at the bottom of the bore, if there wasn't much wear, your machinist might not have squared it up, I wouldn't have.

racertomtom wrote: Be sure and check gap at the bottom of the bore, if there wasn't much wear, your machinist might not have squared it up, I wouldn't have.

How far down the bore? The machinist did say that there was a small amount of taper, but well within spec, and not worth boring over.

Lemming wrote:

racertomtom wrote:  Be sure and check gap at the bottom of the bore, if there wasn't much wear, your machinist might not have squared it up, I wouldn't have.

How far down the bore?  The machinist did say that there was a small amount of taper, but well within spec, and not worth boring over.  

The bottom 1/3 or the bottom of the ring travel.

Cut the rings today, manufacturer suggested 0.016-0.018 top and 0.02-0.022 for second rings in a street/partial track car. Race was 0.018 - 0.02 for top and it keeps going up with drag/nitrous/SC setup. I ended up cutting them at 0.017 and 0.021.

Lemming wrote:Cut the rings today, manufacturer suggested 0.016-0.018 top and 0.02-0.022 for second rings in a street/partial track car.  Race was 0.018 - 0.02 for top and it keeps going up with drag/nitrous/SC setup.  I ended up cutting them at 0.017 and 0.021.

I think that's a good/wise choice. When you get into drag/Super Comp, compression ratios tend to get progressively higher. There's almost no HP to be seen on an engine dyno from ring gap, but you can see oil consumption and blow-by with too wide a gap. The goal is to achieve all but zero gap during the highest combustion temperatures, which can't be measured.

Lemming wrote:
The only strange issue was that going into T5, I felt like I needed more brake.  I would push harder, but the pedal would not move.  

While the engine was out, I decided to really look into this issue.  It turns out that there was enough of an angle in the input rod, that is was catching on the HB unit and limiting travel.  I welded up a new pedal/clevis joint to get the angle as close as possible.  With no fluid in the system, I was able to push the pedal to the floor, no binding  Cleared the system of all brake fluid and added Castrol SRF and used a power bleeder to fill.  Hopefully this will fix my issue.


Engine is back in the car and the front end is all buttoned up. Just need to install the trans this weekend and I'm back in business.

Been awhile since I posted. The car is still for sale, but to be honest, I've not advertised it much, still worked that I will regret selling.

Rebuilt engine is running well, was at Barber on Friday with Just Track It (i taught the novice classroom sessions and drove all afternoon).

After running a number of weekends, I've decided to ditch the hydra boost system and return to my DMC setup. I just don't like the feel of the HB assist, it's very difficult to modulate the brake effectively. It also feels like it does not want to dissengage quickly when I release the pedal. I'm hoping to have time to pull it this week, before the PCA event next weekend.

I've also determined why my engine was ingesting oil, which has been a problem for some time now. Well, if you didn't know it, there are actually two versions of the LS6 valley cover. The old version does not have an integrated PCV, while the newer one does. Both have a baffle system and look someone similar. It turns out that I've been running the early version, So instead of changing it out, I'm running everything vented to atmosphere and it is working well.

You should just keep it. Unless you really have to sell it for financial reasons.

It's hard to sell one of these cars, they have so much of us wrapped up into them. Nobody really understands whats involved in building one and certainly won't pay the proper amount for it...

Interesting stuff, Tim. Too bad the HB didn't work out. I run that same early LS6 valley cover with a PCV valve on the catch can exit. Works great. And I agree with Doc. Keep it!

Rich

Tim, have you noticed the pedal travel is extremely short between no and full brake? I think the cause is the Mustang master cylinder bore is too large (1" bore). I spent some time last month looking for another master cylinder with comparable mounting that would fit on the hydroboost unit but didnt turn anything up. The only options were from Ford and Dodge diesel trucks (which use a similar hydroboost) but they all use larger master cylinder bores.

I am going to continue running the setup to see if i can get used to it but the more i think about it i will likely eventually put in a Tilton pedal box. It sort of pains me to pull the system out though because i think getting all of the parts installed was one of the hardest parts of the entire swap .

Honestly I think the best hydroboost setup is the early BMW or Porsche 965 setups that reuse our factory Porsche master cylinder.

Then there's no brake bias issues, but those systems are more complicated and expensive vs the Mustang unit...

Techno Duck wrote:Tim, have you noticed the pedal travel is extremely short between no and full brake? I think the cause is the Mustang master cylinder bore is too large (1" bore).

Agree completely, not nearly enough throw. I also looked for a dual 3/4 setup and could not find it. I should have time to finish pulling the HB tonight and reinstalling my DMC.

Car has been running well until yesterday, looks like I threw the #6 rod bearing at the track. Still have to take it apart to determine actual problem. Once again I'm looking at a friends LSA blocked engine that pushes greater than 500 to the wheels. He's had it for sale for quite some time, fresh rebuild. I'm waiting on the build spec to determine how easy a detune is as I want to run pump gas, not race gas $$$$$$$$.

I asked in another thread, but will ask here as well, how much TQ/HP are people putting through their turbo S trannys?

Currently running 422rwhp and 410 wheel ft lbs through mine. No issues.

Sorry to hear of your motor issues again. I'd think that just putting a street fuel tune on your friends motor would be enough for it to run fine on pump gas.

Bummer about you engine. Mine's making 389 hp, 407 lbft at the wheels. Turbo S trans in it's 3rd season going strong. Just changed fluid, the old MT-90 that came out looked good, no metal shavings on the magnet.

Rich

My tuner says a detune is easily done, will likely use a restrictor to keep tq up at the expense of high RPM HP. Will also be able to run pump gas :-)

I'll likely shoot for a few tunes running from 350 - 400.

I just got done building mine, and will debut it at Mid-Ohio next weekend. I have a Tilton triple pedal set, and really like it - easy to adjust the bias with a balance bar, and really good modulation. Effort is very reasonable, if a bit higher that OEM. I adjusted very quickly, and it's not fatiguing. A friend of mine has old #16 (bought here) that he added hydroboost onto - and I'd agree modulation is tough.

Now that I have some time, I'll have to post up more about the car!

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Adding the Boxster ABS to the Mustang hydroboost helps a lot. Lets you crush the brake pedal and let the ABS sort it out...

docwyte wrote:Adding the Boxster ABS to the Mustang hydroboost helps a lot.  Lets you crush the brake pedal and let the ABS sort it out...

I'm not a big fan of allowing ABS to slow the car, threshold braking and modulation work best in the dry. In the rain, well that's another matter.

The 6.2L LSA engine in sitting in the garage waiting to be installed. Everything is disconnected in the car and I'll pull the old LS1 out tonight.

^^^ Agree. So much of braking effectively is being able to modulate braking with turning, and manage weight transfer. ABS is a pretty crude way to do this in the dry, though nice to prevent falt spots! Motorsports ABS systems at are another level, and I've seen that doen in a 944 once.

First glitch with the LSA install, turns out that my one-off oil pan for my LS1 does not fit. It was a close fitting pan for the LS1, with the LSA, the oil pick up tube was hanging way too low. So, I cut and welded it, fixed. Then bolted it up just to find the the rod bolts are hitting the pan at the front of the engine. Guess I'll have to have it cut and welded, wish I was set up to weld AL I was really hoping to have it installed this weekend. Now I'm wondering if there's anything else that will be problematic with the swap?

Bummer. Is the stroke of the LSA longer making the pan need more clearance? Will this cause a problem with your crossmember/rack clearance?

Rich

Everytime my steering has bound it's because the motor mount has collapsed.

Stroke won't matter, I have a 383 stroker in my car now and I'm using the same oil pan and have the same steering rack clearance. I did have to clearance my windage tray tho.