Thread: My new baby arrived today

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Bob,
It's interesting to me that you say that an open differential keeps a car straighter under heavy acceleration. Now I'll agree that on wet or slick (snow/ice) pavement a locked rear can tend to swing the rear if too much power is applied, but even on slick pavement you get better traction with a healthy posi or TruTrac. On dry pavement the only reason I can see for the car staying straighter with an open differential is that you're over powering the single drive wheel, and basically giving up any traction that you might have with the posi. In short, you're not putting enough power on the ground to push it crooked. A good unit applying equal power to both rear tires is by design going to push straight. Give me a Good Detroit TruTrac, or next best a healthy posi with good clutches any day over an open differential. That's one of those lessons learned many, many years ago, the first time going up against a posi with open.

Roger, that is why I'm seeking feedback from folks that have had both in the same car. My Track-T is very light at 1790 lbs, and the only experience I have with posi have been in heavy cars, a blown 427 '55 Ford and a Corvette. If I would have felt a drop off on the rate of acceleration when the single tire broke loose, I wouldn't be asking the question. Both the '55 and Vette's rate of acceleration dropped off a lot when both tires broke loose, plus on a crowned highway would start to get sideways.

Look at the basic physics. One tire gives traction of X, then two tires fed equally give traction of 2X. Of course, if you exceed the point of traction, your acceleration is going to drop off, but with two tires receiving power your acceleration is going to be near double. It's a matter of learning to deal with the power, and the amount of traction that one has. An open differential is going to lose, every time.

Roger, I just learned something tonight doing some research. My Jag IRS from a 80's sedan is limited slip, and that explains why it still pulled strong even though there was some tire slip. On my heavy hot rods with posi, there never was a minor single tire slip, when they broke loose they both went up in smoke.

Changing gears a bit, the new skid plate...

Attached to the front cross member


Protecting the oil pan and bridging the bell housing


To protect the TKO 600 trans


And a nice taper back to the tail shaft housing. I'm protected and not by Trojan!


Doesn't look too bad as a nudist

I'll chime in.

My 78 firebird with a (healthy) 305 always swung wide when it lost traction, open diff.

Well, I managed to acquire the original limited slip guts from the differential, and installed it.

What I found, was that the rear end popped when entering a turn, ( yes, I used the additive for the oil ) which was annoying, and when I lost traction under acceleration, the rear end broke loose worse than before.

Also, the tires wore badly to the inside

On the plus, it saved me from getting stuck in the mud, somewhere between Cali and GA.

maybe extreme power affects differently from mild power, but my experience mirrors his.

Bob,
Thanks for your encouragement but the motor is still not in. I just got the correct short nose water pump today since the one that was shipped with the motor is a long snout and doesn't line up. I also ordered a heavy duty Tilton starter which now I already have. My Sanderson headers aren't here yet. I ordered a bunch of TH350 upgrade parts that aren't here yet but tracking says arriving end of this week, then we'll rebuild the trans with the new parts. I ordered new heavier duty motor mounts (Energy polyurethane), a couple of Magnaflow oval mufflers, some 2-1/2" stainless mandrel bent piping for a new exhaust. The other day I got a set of M&H drag radials and radial front runners that I think I'll like. It'll probably be a couple weeks before it's running.

Bob, I'm really enjoying your driving impressions! The post you made on the Cobra forum is also something I've wondered about, quite light cars with plenty of power, and made up my mind to one day have a powerful light car. So this '32 is the lightest I've had so far. I had a '67 E-Type roadster years ago but that weighed a bit over 2700 lbs. and only had 260hp. My current sports GT car (quite modified) weighs close to 3500 lbs but has over 700hp, but when I track it on roadcourses the excessive weight is quite noticeable and takes its toll on transient handling and brakes and tires.

Which leads me to another thing I love about your car, that it's a track roadster. One of my near future goals is to build one of these old cars for roadracing, maybe for a historic or vintage class if I can get them to let me into one...still have to research those details.

As far as a posi, my highboy has a new Detroit Truetrac in it now, which is not an overly locked posi like some others (like lockers and more aggressive posi's) since it allows some relative slip between the two rear wheels under certain conditions, such as turning and light loads. I haven't tested it out yet on my car but I have driven another one with it and it's smooth and quiet under all conditions, but locks both when load indicates I want to accelerate. The one I pulled out was an open diff which was OK for such a light car but I just don't like peg legging it on one tire when I hammer the throttle. The sports GT car I mentioned above has a clutch type LSD in it (O.S. Giken SuperLock) and it works so fantastic on street and especially on the track (roadcourse) that I wouldn't believe it if I didn't actually experience it many times. It plants the car much more securely braking into corners and powering out of corners earlier and with better control.

Originally Posted by deckofficer

Roger, I just learned something tonight doing some research. My Jag IRS from a 80's sedan is limited slip, and that explains why it still pulled strong even though there was some tire slip. On my heavy hot rods with posi, there never was a minor single tire slip, when they broke loose they both went up in smoke.

Jack up the rear, both wheels off the ground, tranny in neutral, engine off. Spin your passenger side rear wheel "forward" - if the driver's wheel turns forward you have some form of limited slip, but if it turns in reverse your differential is open. That's the only research that's really going to tell you what you have without opening up the differential and checking the carrier.

Nick, I'm going to stay tuned to this thread as you sound like a guy that is methodical and does things right. I can't wait to hear your first driving impressions. With my engine and trans mounted so low in the frame rails, clearance and oil pans have been a PITA, but for cornering has been worth it. I live in the Sierra foothills and all my local roads are twisty mountain roads. Since I can't induce any body lean, I'm guessing my CG is about spindle height. With no moment-arm above the center of the wheels, it corners flat and acts like a slot car. Good for freaking out a passenger that is not familiar with it, going into a "slow to 35 mph" curve at a constant 70 mph clip.

This is at 8000' and one of the few and far between passing lanes. Typically drivers poke along at 50 mph or less, then speed up in the passing lane, moving into the left lane but unable to over take due to steep grades and loss of power at that elevation. This is with the 383, which the way it was built, I never bother to run it past 4000 rpm because the HP peak was 4050, but it was built for torque and rang the bell at 516 lb/ft at just 2800.
The exhaust on an engine built for torque is quiet and mellow.

Well I won't be driving for awhile. I've kept this to myself until I knew what happened. After that second drive I noticed a bad oil leak coming from an oil pan bolt. Odd thing is it leaked with some pressure behind it, not a simple little drool that tightening the bolt would cure. It is my belief at this time (and I'm looking for input from you folks) that who ever prepped the Dart block, they might have drilled the the block for the oil pan bolts too deep and caught the oil passage to the filter. Mike, who is a tech/salesman for Scott Shafiroff told Ben at Eagle that it isn't his problem. I have emailed Scott to be sure his employee his reflecting his policy. I spent over $11K on this engine, the web page for this engine states a 2 year warranty, as is par for the industry.

Before I bad mouth Shafiroff all over the automotive forums I will wait and see how all this pans out.

Of course it wouldn't hurt if folks that are interested in a pro built engine drop Scott an email saying they are watching the forum to see how this is handled. That sure worked when I had the new but leaking throw out bearing from Mcleod.

Well, that sucks!! I'll see if I can locate a website... Hope it turns out alright, I know I'd be fumin' mad 'bout now..

I'm not mad yet because sometimes employees don't follow the owner's policy. I emailed Scott Shafiroff but he is on the East coast and after business hours. I won't be upset until I hear "not our problem" from the owner's mouth.

This is the ad for the engine. At the bottom "2 Year Warranty"

427 RealStreet Small Block Chevrolet Crate Engine

I would also be highly pissed. But I hope it turns out to be a simpler problem than your theory of drill/tap too deep.

Bob, I hope you get this resolved favorably very soon. I'll leave a message on Shafiroff's "contact us" page since I don't see anyplace else to do such a thing.

Nick, that would be good, thank you.

I have a friend that is doing some research for me on Dart blocks. If anyone here can answer the below questions, jump in. Here is our correspondence....

It is your input that I am interested in, and after seeing the video what do you think? Is the oil passage inside the block that close to the oil pan bolts that if over drilled by Dart could hit the oil passage?

Not much of an expert on Dart Blocks...I have a friend who is a World Head (Dart) distributor...he might know...I'll call him tomorrow. Just wondering....if what you think is the problem IS the problem...what about grinding a screwdriver slot into a stud about 1" long.....drench it with red loc tite and screw it up into the hole.....I know....you SHOULD NOT have to resort to such jury rigging....but, just a thought

My concern is any foreign material I might use to stop the leak leads to the possibility of it entering the oil passage and starving the engine of oil. Then I would have a ruined engine that would be on my dime.

Thank you for touching base with one of your contacts. I have no idea where in the block on the driver's side (the filter side) the oil passage is and how far from the block's oil pan meeting surface. If he knows this distance, which oil pan bolt holes are in line with it, then it is just a matter of me measuring the depth of the bolt threads in the block and confirming how deep.

I have been out in the cold shop looking at blocks-----you can simply remove the oil filter and adapter to get access to that oil feed hole---altho I didn't have a Dart block apart to look at ---all the chev blocks that 2nd pan bolt hole is completely forward of where the passage hole is--the gallery hole is not forward of the front edge of the main bearing #5-----

I believe that after your scraping the pan you have just caused a strain (buckle/distortion) of the pan that happens to concentrate at that spot(narrow curved area between filter and block) causing a leak--it would be a good idea to check all your pan bolts for length/fit as it doesn't look like you have the pan rail support strips installed( that will take up nearly 1/8) also the use of studs would solve the problem there also---------

Jerry,

I'm not sure I followed your explanation. These are all new parts, assembled for the first time by the engine builder, Scott Shafiroff at his New York facility. When that bolt was removed and the engine run, a very fine oil mist that the camera couldn't catch was coming from the thread hole. This indicates to me a very small pin hole in the oil line.