2306

Should be able to reach 2nd and R without doing other gears first, however R occasionally grinds a little on mine. Since they're both forward in the shift pattern you may not be getting full forward movement? Check for adequate cable travel at both the gearbox and the shifter lever.
 
seems that the problem has been the cluch master cylinder causing the clutch to drag. the whole master have given up the ghost. Replacemet coming this week.
 

Tim Kay

Lifetime Supporter
Should be able to reach 2nd and R without doing other gears first, however R occasionally grinds a little on mine. Since they're both forward in the shift pattern you may not be getting full forward movement? Check for adequate cable travel at both the gearbox and the shifter lever.
seems that the problem has been the cluch master cylinder causing the clutch to drag. the whole master have given up the ghost. Replacemet coming this week.
Funny, I just replace my clutch master last week, it didn't fail but was leaking. When removed and inspected, the internal walls were corroded and scoured, fluid black (only 1k miles! but 5 years old). My reverse would often needed 1st gear engagement before I shift to reverse otherwise it grinds. After replacing the new m\c the first thing I noticed was no grinding into reverse (only if I'm coasting forward while trying to shift into reverse). BTW, mine is rod shift not cable.

Tim
 
Mine is a rod shift too.
Seems like it was a bad master cylinder, replaced it and car shifts fine, at least so far.
Fluid was black too.If problem reappears then its the slave, but there were no leaks there.

Back to the track maybe this thu.

On another note, maybe its the way my car is setup, with a high rev motor and track baised alignemnt, but this seems a very extreme machine to drive on road, like a rabid dog trying to get off its leash and bite whatever is nearest. Far more apporpriate for the track.

I can see how maybe a softer setup and a 427 with taller gearing would work better on street, but even then its going to be one extreme machine for the road.

Such a good lookign car though, stare at it everytime I pass through the garage.

It also attracts women like flies,maybe its baby blue color, a ferrari in comparison is a prius.
 
Its only appropriate for the road if you are running open megaphones

yep but I lack those big open roads like you have in colorado.
Its either trafficky potholed highways or great backroads which are really tight for a lotus.

The power on my car is such that it wont really loaf along, you are either acclerating or slowing.

Fortunatly it has Monticello motor club to excercise at, which is a 4.2 mile track, or Watkins Glenn to go feed on other cars at, next event there July 7 and will do the open megs.

Meanwhile will try to get to monticello later this week.
 
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Replaced clutch master all shifts well.
Added some compression to front shocks which gave the cR more stability esp u der heavy braking.
Managed 155 so far down main straight at Monticello.
Will prob stiffen front and rear swaybar a for next time out.
It's a pretty impressive handler nice and neutral easy enough to catch.
Brakes which I thought would be a weak link are pretty impressive.

Only barrier is that controls are heavy and it takes a lot of stamina to maintain pace for 40 mins, well that and a prodigious appetite for 100 octane
 
On the megaphone question. I find the mufflers have a more classy sound and the engine is rounder. On track at the glenn ran the megaphones, it was painful in the car till the motor cleared 4k rpm, then epic.

To me the one advanage of megaphones is that they weigh significantly less and save that weight from the rear of the car.
 
Ok so 5 track days now.

The front bake master was bad so its being replaced. lack of front brakes working overheated the rear, despite the bias being ever more dialed to the front. Something was bad with allt he masters, this is the last of 3 (rear and clutch) to be replaced. Maybe they sat on the shelf at the coast in Sa too long.

Been playing with shock settings, still too much power oversteer on corner exits. Reducing rebound ameliorates this but now anythign close to liftoff, like feathering and it spins.

Solutions to try are softening rear compression to ameliorate power on oversteer, Or adding compression to front shocks as a means of stoppign the front pitchign down. Will see.

Alignment sorted and tires heating evenly across. The Hoosiers lasted 4.5 days and about 16 heat cycles. teh reas are gone, possibly all that power on oversteer did them in.

Working with different engine mounting bushings as too much motor movement.
Sorted clutch and shift linkage, its now smooth as butter.

Car is already significanbtly faster, but the front end grip is so tenacious that sorting the rear should enable way higher corner speeds and stability.

Compared to my lotus elise on slicks the GT40 seems more forgiving at the limit, maybe more nervous below the limit. I would say once sorted cornering limits are higher than the lotus. Turn in though is slower and the Gt40 requires a firm hand. Brakes are good, less initial bite than the lotus but more tolerance for repeated use from high speed.
Steering very comunicative.

Power is of course a completly different league. One needs to get used to 150 mph approaches where it was 120 before, etc.

The key for more speed is going to be carrying more though the bends, need to work on getting more rear stability for that.

One last note, its all tremedous fun, whereas other cars may be less challenging but are for some reason more scary. The Gt40 also feels very rugged, like it can be tracked all day every day without suffering. Driving at speed on track requires more intense concentration than other cars and is very physical, but is more fun.

Getting to the point where the car would run reliably and strongly has taken effort. Lots of things needed to be tightened after the first two days. The brake issue is a master cylinder issue, they were both bad, why is this.

The car itself is just so adjustable and sensitive to adjustments, it took a professional team approach to baseline what it was doing and then measure very change in terms of feedback and temps to get to a workable base point.

In other words no different to any other race car. But compared to a production car its not plug and play.

Still even now it will eat a turboed winged and slick shod cayman, especialy on the corners.

My guess is a Hoosier shod SPF is going to be hard to beat with pretty much any street based car on track, unless maybe its a 918.
 
That is a great perspective thanks
More to come. Should be back at the track next friday with fresh rubber and
new master cylinder. Hopefully we are close on the suspension setup and I am getting used to the car. So maybe there will be some good comparative data to other cars at the same track.

My best guess is a pro could set a really spectacular laptime in one of these.
They are light, stiff and handle really well. brakes are Ok and modern historic rubber pretty good. You just have to know what you are doing. Might take a few years, which is all part of the fun.

BTw mine scaled at 2463 lbs with full gas which is around 20 gallons in the bladders, or about 1 hour of full on hard charging(3-4mpg).
 
Some updates. After runnign stiffer than stock springs we are going harder again 700/750 as the shock stroke was all being used up to the bumpstops.

All master cylinders have now also been replaced so brakes should be good, running carbotech pads.

The engine was hitting the bulkhead on hard LH cornering, we have replaced all urethane mounts with solids as well as milling a billet rear crossmember between the rear uprights. The stock ones are thin and having to hold the transmission on track are known to deform. With 600 miles mine was already showing signs of deformation.

My conclusion is if you really run your GT40 on track, then the softer street setup has a number of flaws. Anecdotaly there seem to be too many master cylinder failures. Perhaps these sit on a shelf too long before being used and get rust int he bore, in any event there is a tilton direct drop in replacement.

The car is fast and handles great, ista race car and they got the susspemsion right back in the 60s. Compared to modern race cars, its a bit heavy, the brakes a bit weak and there is no aero, but its charismatic in contrast to moderns being mere tools, its engaging and probably way faster than most drivers anyway.

Compared to modern street car thats supposedly trackable. The GT40 is lighter, more powerful, better grip and great handling, harder and more crude, yet way more fun on track and less expensive to run.

Probably take another crack at the track a week from friday.
 
Sean, have you added the lower bell housing mount points to your car, that appears to be in the 1% of original GT40 items that did not make it into the SPF cars, there is a thread in the transaxle forum and info from Kirby Schrader on his method of adding them, while your billet x-member helps the shock towers were/are not meant to absorb the extra loads from the engine/transaxle your now asking them to deal with.
 
Jac thanks for the heads up. Makes sense. Fortunatly my bell housing has the ears, and we were planning on that mod too.

There is also the possibility to do an additional pantera style mount to the rear of the transaxle to the subrame.

We were going to go solid mounts on the crossmember to top transaxle , but after your warningn above will maybe put a poly there to be safe. I know the shock towers are weak point, even though the factory now reinforces them.

As it was with the poly mounts and single point holding the transaxle not only was the crossmemeber starting to deform, the bushings holding the tranny were already ovoid, and the alternator would start eating the bulkhead on hard right turns.

My conclusion is that spf cars may be mostly correct, even have rose joint suspension bits, but they are basicaly street cars as come from the factory and are missing a few simple bits which would make them track cars.

Thats before we get onto the brakes. For street probably fine, for a hot rod fine, but not really up to serious track work, but than even in period brakes were a Gt40 weak point.

At some future date will probably go a full tilton master cylinder setup and some different monoblock calipers.

As it was with soft springs 525 fr 600 rear oldish tires and all the other foibles the car ran 2.43 at monticello. For comparison in my lotus elise on full yoko slicks I can run a 2.47. The production car lap record is a viper acr at 2.28, a 400hp track only lotus exige can break 2.30 so there is a long way to go to break 2.30 but I think its doable. Mostly more speed in corners, less braking.

Interesting to see what the solid mounts feel like. Some say terrible others say you cant really feel the difference, well maybe at idle, but then I am not sitting in traffic.

My guess is between the right springs, fresh rubber, lower ride height and the motor not swinging around its going to be a different ball game.
 
Back at the track on thursday. With stiffer springs the car is 5 secs per lap quicker, and way more stable. The ride is still softer than my lotus elsie.

The solid mtor mounts, from a vibe perspective felt no different, but the shifting and in a different league, Clutch release is now smooth without all the driveline judder.

IMo SPF softenign the race car for the street made it worse. A Gt40 is alwasy goign to be noisy and less refined, solids and proper springs just make it that much more driveable and useable.
 
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