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759NRNG
759NRNG Dork
12/16/17 8:52 a.m.

Mom, the 'SKI', Limerock...........Scoreboard!!!!

TED_fiestaHP
TED_fiestaHP Reader
12/16/17 5:23 p.m.

   I could be wrong, but every time I hear about someone doing something exotic with the head/valves, it doesn't end well.

       These engines have a simple valve train, just use the uprated springs that are available and use the fiat valves and fiat shims.  The OEM valve train is simple and lighter than most.   I used to run my fiesta push-rod motor to 8,000 RPM.   The fiat single cam motor starts out with a much simpler and lighter valve train.

         I am sure Bayless will be able to help you out, always next season.

   At least the failure was somewhat minor, when racing it is easy to ruin a lot of good parts quickly.  I once lost a motor, and about the only good part left was the fancy valve cover.

 

     Hard to make plans with racing.....   

 

   Do you plan to return to lime rock?   Another event to consider  VIR, production class festival (with GTL), big turnout, great track, near end of Oct.

 

 

BrokenYugo
BrokenYugo MegaDork
12/16/17 6:44 p.m.

In reply to TED_fiestaHP :

IIRC the problem with the stock stuff is the Fiat shims are too thin if you have a reground cam, I think there's a shim from something else with a thickness range that makes it work, Volvo redblock? 

LMGill
LMGill New Reader
12/16/17 8:58 p.m.

Ted,

 The issue is, this was done in the mid 70's when all the experience of what was sufficient, was kept among the factory teams in Europe. In addition, when you have a 20,000 sq. ft. aerospace shop at your disposal, it's difficult not to do what seems reasonable or "easy" when compared with a Pratt & Whitney fighter jet engine. Now of course, it's easy to "Google" what everyone is using. 

As for Lime Rock, yes. I plan on being there next year. Being on the West coast, I'll run local events and time permitting, travel the country hitting different historic events. I'd like to race at Sebring, because that was another track we went too often.

Broken,

The Alfa valve train was adopted because it was lighter. Given the "shims" were 8mm in diameter, not 25. But, I'm sure the oldman didn't count on the valves being too short, and he didn't want to manufacture his own valves for the what would be the test sessions. I'm sure getting cancer didn't factor into his plans. I know he had some other development plans for the motor, including some titanium  venturi fan blade units from a jet fighter fuel system, configured to fit between the carbs and the manifold, he was keen to try. The plan was to get the chassis sorted out, then spend some time developing the motor with some additional ideas. Unfortunately, he never got the chance. So now I'm picking up where he left off. 

TED_fiestaHP
TED_fiestaHP Reader
12/17/17 11:12 a.m.

   I do admire the work you have doe and this will be a great historic car to run.

        Using shims under the lifter will create lighter shims, but might not really be needed.  Compar the fiat valve train to many others and the fiat stuff is actually very light and simple.  Also keeping the shim on top sure makes valve adjustment a lot easier, ever adjust the valves on a Maserati biturbo....  3 valves, 2 of them operated with one lifter.

       One common way to use a ground cam, is to mill the bottom of the cam box.  If all the shims are onn the thick side of the range, could take a tiny bit off the bottom of the cam box to all using shims on the thinner side of the adjustment range.  There are cams available that are not re-grinds.

    I didn't make it to Lime Rock, but hope to see you next year.

        Now that the car is basically built, now you have some time to get it all working, then it will be more fun than work.

          I haven't done much with my fiat 128 lately to many other things going on, eventually will get that done, would be fun to get both of them on the track at the same time.

 

128racecar
128racecar Reader
2/17/18 11:14 p.m.

Great build thread! I used to race a 72 128 sedan with VSCDA from 1998 to 2005. Great high revving race car that was forgiving to drive at the limit. Absolutely dominant in the rain with Hoosier Dirt Stockers. Car went to California in 2005. Still trying to relive those days with a 1st Gen Civic, but it's not the same. Your car is way more sophisticated than mine was. Drop me a line if you want to pick my brain, even better yet, come race with us this summer with the VSCDA. Have fun!

Marc in Indy

LMGill
LMGill New Reader
2/22/18 2:23 p.m.

In reply to 128racecar :

I'm working on my Colotti 4 speed and managed to pick up a 5 speed as well that need a taller final drive. This in addition to repairing the valve issue. Turns out I'll need to fabricate a new front suspension arm to clear the 5 speed. Luckily it's the simple bar side to the Fiats suspension and I only need to move one end .6" to clear the bump for the 5th gear.

Then I'll race it out here in the Southern California area and see how much track time I can get. I am planning to go back to Lime Rock for their historics event later in the year, So I may be in that area of the country for your September event.

iceracer
iceracer UltimaDork
2/23/18 11:13 a.m.

On the gearing thing.   110/115 mph at Lime Rock.  Take into consideration the speed in Big Bend which I found to be around 60 mph, the slowest turn.  Will you need to down shift ?

The key to handling with FWD is to prevent roll.  A stiffer rear bar/ suspension is the answer.

 At LR I could trail brake into BB.   All other turns were brake before the turn then power thru.  The power on/off handling of FWD as mentioned earlier is true.   It really shows up on the ice.

 

LMGill
LMGill New Reader
2/24/18 9:07 a.m.

In reply to iceracer :

The car first ran at Lime Rock in 1977 and at the time the Colotti gearbox had a tall final drive, so I don't think the car ever got out of 3rd gear. But to get down to 60, the car does have 10 1/2" discs with Girling AR calipers all around. So as long as the tires stick..... 

Here is how close I came to sucking a valve into the #2 cylinder:

 

And here are a couple of shots from Lime Rock's 60th. Turns out, my brother still had the Old Man's "Auto world" drivers suit. (Blue, hanging on the trailer) I added a couple of pivoting hooks to the side of the trailer in order to hang the FRP hood out of the way.

Welded up the new gearbox case yesterday (closed off the speedo hole and added a fitting for the oil temp sender) so this weekend is reassembling the Colotti 4speed in it's new home.

I was planning to test the car in February and March, and run at the VARA event in March. But unfortunately, Midwest was unable to complete the required head work, so the head is on it's way back to me and I have sourced a local shop to complete the work. I've got 4 weeks, perhaps I can still make the VARA event.

LMGill
LMGill New Reader
3/1/18 1:01 p.m.

Sorry folks, I moved some files on our server and didn't check for broken links here. Corrected now.

I forgot to mention, that while at Lime Rocks 60th, Polish Eagle Racing bought lunch for the Flag & Communications team on Saturday. Lime Rocks catering team was fantastic and provided a nice box lunch with our label on them.

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