Tiga SC81 Newbie Questions

Hi, I just purchased my first S2000, a Tiga SC81. I know some of the previous owners are on this forum. All my racing experience is with Alfas. So, I've got some learning to do.

Here is my first salvo of basic questions I'm hoping you all can answer:

1. The previous owner said they always used race fuel (i.e. 110 octane). Is that recommended? I would have thought these pinto engines could run on 93.... or even less.
2. I noticed that some, but not all, the rotors are loosely bolted in with aircraft lock nuts. Should those bolts be snug (tight?) or should they be loose so that the rotor can float?
3. Any recommendations on engine oil? I don't have any history on the engine build, but it is supposedly fresh with only break-in oil in it now.
4. I'm assuming I should charge the battery - true? Any issues with just hooking it up to a standard battery charger?
5. Does anyone know the wheel size/offset for these? If not, I'll just measure them. I'd like to get a third set of wheels.
6. Before I start writing one myself, does anyone have a good checklist to use to go over the car before the season?
7. The rear brake cooling duct that is mounted to the rear bodywork is melted - too close to an unwrapped header! Any suggestions on what to replace this with... other than the obvious?
8. I've never driven a Hewland box before. Kindly, Hewland has instructions on their website :). Any suggestions for my first time out?
9. Is there anything out there that resembles a "owners manual" for a Tiga?

Thanks! Hope to be out there in the spring.

bob brady
Unionville, PA

Good place to look:

https://www.tapatalk.com/groups/s2racing/

john f

1. The previous owner said they always used race fuel (i.e. 110 octane). Is that recommended? I would have thought these pinto engines could run on 93.... or even less.
- In SCCA spec, Pinto can run forever on 91 pump gas.

2. I noticed that some, but not all, the rotors are loosely bolted in with aircraft lock nuts. Should those bolts be snug (tight?) or should they be loose so that the rotor can float?
- Sorry no experience with Tiga

3. Any recommendations on engine oil? I don't have any history on the engine build, but it is supposedly fresh with only break-in oil in it now.
- Oh no!! Not the dreaded motor oil thread again! Search the forum, there will be a TON of "what motor oil to use" discussions

4. I'm assuming I should charge the battery - true? Any issues with just hooking it up to a standard battery charger?
- Yes you should charge it, what type of battery is it? Many people on the forum use battery tender type chargers.

5. Does anyone know the wheel size/offset for these? If not, I'll just measure them. I'd like to get a third set of wheels.
- Sorry, I do not know.

6. Before I start writing one myself, does anyone have a good checklist to use to go over the car before the season?
- Search the forum, there are many good checklists that have been posted.

7. The rear brake cooling duct that is mounted to the rear bodywork is melted - too close to an unwrapped header! Any suggestions on what to replace this with... other than the obvious?
- Try ceramic coating the header, looks better, last longer, blocks up to 50% of the heat.

8. I've never driven a Hewland box before. Kindly, Hewland has instructions on their website :). Any suggestions for my first time
- Yes, TAKE ALL THE SLOP out of the shift linkage. Cars of your era use borgeson type joints that wear out quickly. Spend the time and money and replace them with Helicopter joints. get them at Pegasus Racing. Buy the special washers as well. You will thank yourself every time you shift.:D

- Take it easy, use the clutch, make sure you match the revs on the downshifts. Over time (and with good linkage) you will get much faster at it and can use the clutch or not. I use the clutch, like gears to last LONG time.

9. Is there anything out there that resembles a "owners manual" for a Tiga?

Thanks! Hope to be out there in the spring.

bob brady
Unionville, PA[/QUOTE]

It will run on lower octane fuel but odds are it was not tuned for it. Ethanol is not friendly to a lot of fuel cells so be careful.

This is a guess, but the front rotors may be floating, I doubt that the rears are but it is possible. You may want to ask Corky Jahn. He is on Apexspeed.


Oil, The thinnest oil that gives you good oil pressure. At idle when hot the oil pressure will be scary low. It's normal. I use 10w-30 synthetic race oil.

Charge the battery for sure, you will probably need to do it between sessions. Type of charger depends on type of battery.

Measure the wheel offset, the bolt pattern is 4x3.75" New wheels will not be the easiest thing to find. You might try Yongbloed.

Dig around on Apexspeed for a checklist. If you get stuck, I can put one together.

Post pictures of the duct. It was added after I had the car, probably by Corky.

If I remember correctly, that car has apex joints in the linkage. Read the Hewland shifting instructions on the Hewland site and follow them. No need to clutch up or down.Takes a bit of practice but you will pick it up quickly.

No owners manual.

100 LL Aviation Fuel is what many of us run in our Pintos. A little lead for the valve seats and can last up to 2 years sitting in A fuel cell or gas can and relatively inexpensive.

Checklist:

http://www.apexspeed.com/forums/showthread.php?73292-Race-weekend-prep-checklist-if-you-need&highlight=Race+checklist

Quote:

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Originally Posted by Fred Michael

It will run on lower octane fuel but odds are it was not tuned for it. Ethanol is not friendly to a lot of fuel cells so be careful.

This is a guess, but the front rotors may be floating, I doubt that the rears are but it is possible. You may want to ask Corky Jahn. He is on Apexspeed.


Oil, The thinnest oil that gives you good oil pressure. At idle when hot the oil pressure will be scary low. It's normal. I use 10w-30 synthetic race oil.

Charge the battery for sure, you will probably need to do it between sessions. Type of charger depends on type of battery.

Measure the wheel offset, the bolt pattern is 4x3.75" New wheels will not be the easiest thing to find. You might try Yongbloed.

Dig around on Apexspeed for a checklist. If you get stuck, I can put one together.

Post pictures of the duct. It was added after I had the car, probably by Corky.

If I remember correctly, that car has apex joints in the linkage. Read the Hewland shifting instructions on the Hewland site and follow them. No need to clutch up or down.Takes a bit of practice but you will pick it up quickly.

No owners manual.

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Howdy! -

IF this is my old green sublime 81 tiga with a Mariah body....

Rear brake ducts were added to the diffuser to help cooling because I made the full undertray blocking engine airflow for better handling and to feed the diffuser. That system needed further tuning and I have no idea how it was changed in the past years but my next step was to change the calipers from the big old girlings to AP and drilled disks. I don't think any of the prior owners got the rotors as hot as I did. IF the brake ducts are too close to the header, you may be thinking about the one on the tail or someone added external ones? Or it wasn't my car.

Car never had floating rotors as far as I recall unless it was changed back in the day.

I always used Mobil 1 synthetic 20w50. The new formula didn't have the zink content but it always worked well for me. Used Mobil 1 for the trans too. The green stuff while effective hold metal in the waxy buildup. The Syn I ran allowed the fine metal to be captured by the magnetic drain plug.

Don't recall the wheel config. I bought a ton of stuff to service this car but when I sold it to my father he just bought the car and not all the spares. Sold off spares separate. Buyer after that had some really nice new wheels he bought.

I always used an Oddesy Battery from Batteries Plus. Replaced every two years so I could make an entire weekend without recharging. Never want to loose a race or not start because of a simple battery issue. Now I charge between every session even if I have a stator (alternator)

When I had the car (Mind you a LONG time ago), I rebuilt the entire shift linkage including all new high quality joints, bushings, bearings, and even the handle itself with a new bushing. Past owners (Never me) seemed to have an issue where a couple of the joints would come loose. Could just be a simple setscrew or something similar.


IF this was my car, the tunnels under the nose work in conjunction with the diffuser and proper alignment. If you take off the diffuser, the car becomes an animal to drive and you would need to block off the nose diffuser.

While my Lola was faster even after all the development on this car, it wasn't much faster. This car was more planted and less nervous going fast. I could drive it anywhere on the track without an issue.

Hope this helps! Its only my OPINION and background. Your mileage may vary.


Cj - feel free to contact me offline.
ctjahn@courtneyjahn.com

Corkey (?), yes it is your old Tiga/Mariah.

Thanks, everyone, for the input. Keep it coming!

Regarding the brake rotors, they are bolted to the hats, but some of the rotors i.e. the left rear, are just loosely bolted. I'm assuming all the rotor bolts should be snugged up, but just wanted to confirm.

The brake duct I was referring to is located on the top of the rear bodywork. I'll need to look at it more carefully to figure out a suitable replacement that stays away from the exhaust heat.

Thanks again,


bob

Quote:

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Originally Posted by bobbrady

Corkey (?), yes it is your old Tiga/Mariah.

Thanks, everyone, for the input. Keep it coming!

Regarding the brake rotors, they are bolted to the hats, but some of the rotors i.e. the left rear, are just loosely bolted. I'm assuming all the rotor bolts should be snugged up, but just wanted to confirm.

The brake duct I was referring to is located on the top of the rear bodywork. I'll need to look at it more carefully to figure out a suitable replacement that stays away from the exhaust heat.

Thanks again,


bob

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Gotcha!

Loved that car. Spent a lot of time on it and the development of it.

Based upon what I have seen, I would double check all the rod ends and validate the right ones are in the right locations. I spent a small fortune and a lot of time purchasing the right rod ends, replacing orig (cast), putting the exact rod ends appropriate to the location, and matching not only the gap side to side, but also the bar length, exposed thread, Jam nuts, wheel base, distance to centerline, replacing clevis's, and ensuring everything was spot on. I used a number of more specialized rod ends on that car than on others. (Oversized shank, small head, big head, etc... don't have the part numbers handy)

The car had a tendency to have the bolts loosen on the old orig rear hats, they were warped and in bad shape due to age and time, so I had new ones made out of billet aluminum and had high quality fasteners and replaced the rotors thinking that was a cause and put in nice new lightened CV's and axles at the same time for good measure. Never had an issue after that but the car has passed through quite a few hands since then. Also make sure the rotor is centered in the caliper and the caliper mount isn't warped or bent pulling it in a direction it shouldn't...

The brake duct on the top of the bodywork could possibly be removed if the naca ducts in the diffuser are still in good condition with the assembly blowing on each caliper. The whole engine bay got pretty warm due to the entire enclosure (I made the entire sub-floor from scratch laying up fiberglass in a sandwich material for the diffuser mount) which is more sealed than factory. I replaced that Naca duct on the top of the tail once. The exhaust was a custom Greg Welch (not sure spelling) that was fabricated special for the car with a design for the prior Mercer motor which was supposed to produce more torque due to the design.... I will leave it up to sceptics if they believe it. Never had the money at the time to dyno it with the header or validate it other than lap times and the seat of my pants... it WAS JetHot coated flat black in the past.

Good Luck!
Corky!
AKA - Cj; Courtney Jahn, Jahn Autosport (Junior)