race parts

[cyclecyko]

hey guys Im a student over here at the school of automotive machinists and was interested in building an all out autcross engine for my dads 124 spider. If anyone has info on parts supliers( other than internation auto) I would appreciate it. as far as I can tell cam selection is dismal at best, but mabey I just dont know where to look.

thanx

[So Cal Mark]

full race motors usually don't work well in autocross; they're generally lower speed events. Do you have any idea what lift and duration you want? What are your plans for engine specs and operating range? Some thought should be put into a coordinated package for good results

[mdrburchette]

As Mark says, you don't want a full race motor. The suspension is more crucial in autocrossing. With that said it would be nice to know what year Spider you're working with since that'll determine which mods would be beneficial. I have a friend with an 80 fuel injected Spider that has won several events with a stock engine, but his suspension setup is impressive.

[cyclecyko]

I understand the handling is extremely important and for that its a 76 124 spider, any info is appreciated on parts and setup.

As for the motor, I being an engine builder have the option to do a lot of neat stuff. Givin the block deck height, stroke , rod length, and piston compresion distance i can find parts and make them work. Same with the head, blank valves can be cut to lenght and have keeper grooves cut in them. however I can not make my own camshafts, that being said what I really need is a good cam company with good specifications for lift and duration @ .050 this stage 1,2,3 crap isn,t going to cut it.

If you guys have any of the reciprocating specs (rod length ect.) that would be awsome, and if there are different rear diff ratios available that is on my list to.

I know this was a lot to ask from a new guy, so I,m sorry but any help would be great.

Thanx,
R.C.

[mdrburchette]

IAP has new cams (not regrinds) or you can order blanks and have them ground yourself. I'm running the 42/82 cams in my 72 which are their autocross cams. Lift is 10.60 mm, duration at .050" clearance is 260, crank degree overlap is 84. They come in at about 3k rpm and levels off at about 7200 rpm. This is with the dual 40 IDFs and it idles nice and smooth at 800 rpm. I'm also running the stock 4:30/1 differential but there's a 4:10/1 and a 3:90/1 available. I don't have specs on a 1756 motor but I had custom rods and pistons made by sending the companies an original with the changes I wanted. I was able to lose 2.5 lbs of rotating mass with the new pistons and rods. I ported and polished the head and used the original valves but have Guy Croft racing valve springs.

[Curly]

IAP has new cams (not regrinds) or you can order blanks and have them ground yourself. I'm running the 42/82 cams in my 72 which are their autocross cams. Lift is 10.60 mm, duration at .050" clearance is 260, crank degree overlap is 84. They come in at about 3k rpm and levels off at about 7200 rpm. This is with the dual 40 IDFs and it idles nice and smooth at 800 rpm. I'm also running the stock 4:30/1 differential but there's a 4:10/1 and a 3:90/1 available. I don't have specs on a 1756 motor but I had custom rods and pistons made by sending the companies an original with the changes I wanted. I was able to lose 2.5 lbs of rotating mass with the new pistons and rods. I ported and polished the head and used the original valves but have Guy Croft racing valve springs.

That's a very similar cam to the one I'm running in the AC Coupe. Timing 45/75, Duration at 0.050" is 257 degrees, Lobe lift 0.410". The engine, however, is only 1608 but runs 9.75:1 compression and twin 45DCOE sidedraft Webers. Pistons have had to have the valve recesses cut deeper into them, and a set of adjusable cam pulleys were required to get the timing set correctly. Flywheel has been lightened and all the regular bits balanced, Fiat electronic ignition, ceramic coated headers, standard bottom end. She'll do 8000rpm easily, but really doesn't come 'on song' until 4500rpm.Great little motor

[mdrburchette]

Curly, are you running a higher dome piston than original? What kind of header is that? I

[Curly]

Curly, are you running a higher dome piston than original? What kind of header is that? I

Standard Oz/Euro spec hi-comp pistons, but with head shaved to bring compression up a tad. Headers are 4/2/1 and I think, are from Fiatorque in Sydney. I'd love to fit a set of Mark's pipes, but there's no way they'd fit around the powerbooster, master cylinder or steering box . Then again RHD does enable us to fit side-draft Webers

[So Cal Mark]

I wish you could run a set of my headers too, you'd be amazed what it does for a motor

[cyclecyko]

thanx for the replies guys, any one else out there with info on bottom end parts and cams bring it on.

[Daniel]

What Year and Engine size are you running ? as for info here on FS seems many people on the forum prefer the
40/80 cams i think they are ok if you want a mild improvement over stock but can go larger without
giving up much bottom end power to a point, once you go up on Duration you'll lose bottom end power
but gain more top end . The Engine size can be a factor on Cam size if your running a 1438-1608 vs 1800
or 2000 . There is a myth that the 1608 cams were the best stock cams but if anyone checks the profile
its the same as the rest of them . After market Valve Springs seem to be hard to find these days but aren't
really needed if your lift is under 11.2mm and floating the stock springs is pretty hard to do under 8000 RPM .

If your not running A Full Race Engine you can stagger your Cam profiles using a larger intake then Exhaust
end result a broader power band ( some Common Cam Profiles like a 42/82 for intake and a 40/80
exhaust ) I have setup many TC's this way and it works really well .

If your going for Race ? side drafts like what Curly has there is the best way to go but like he pointed out
it was easy to install them in a right hand drive car if your a lefty with the steering wheel on the left side
master brake and booster will be in the way . I used a different master on mine and got rid of the booster
to fit the side drafts . The Simple fit is IDF's Down drafts Carbs they bolt up without mods to the Brakes but
less top end power . IDFs are a good improvement over a carb setup though an instant 20 to 25 HP gain on a
stock engine if your running mods even more .

If you were to lower your gear ratio i think that would be the simple way to gain some performance for auto
cross IMO but doing so wouldn't be simple unless you get a hold of a real early 124 rear end that had 440s or
444s i think it was in 69? or older .

Daniel

[cyclecyko]

you make a good point with the gearing daniel. a lot of people freek out about losing "tourqe" but thats a common missconseption. If you make more power you are making more tourqe, it is simply moved up in the powerband. this is because horsepower = tourqe x RPM. so i say make the power high and put more gear in the car wich will effectivly multiply the tourqe at a higher rate and put more to the ground. people often confuse tourqe with bottem end power. If bottom end power is your concern use a smaller cam. even if I have to retrofit a rear end out of a toyota or a datsun to get the gearing i want I will. unless of course there is an aftermarket solution to this gearing.