Nothing has changed except the tach is now reading correctly. I would imagine 4500 is about max torque and was wondering if the coil was breaking down at full throttle/max VE, but OK at part throttle with a less dense charge to ignite. But since the tach is MSD driven and not coil driven I figure it is the MSD that is playing up. As I said I am re-routing some of the wires and will try disconnecting tacho, fit 3000 chip, recheck timing, etc, etc next time I am testing. Could be a week or so, got other fettling to do also before going out again.
Kiwi scratchbuilt
- Thread starter Russ Noble
- Start date
Russell
My car is sitting in Crown Relocations Bond store awaiting Adelaide Customs clearance.
I had to fill in a VIP (Vehicle Import Permit ) and waiting for that to clear. - Didn't think I would need permit for a bunch of parts but there you go.
I'm in the process of joining Cobra car club over here. It seems there is around 20 GT40s being built in Adealaide area so have the bug again after long spell of not a lot of enthusiasm. There's a mix of DBRs, Roaring 40s and a monocoque. The GT40 guys have a sub-group in the club.
Is no trouble to through a dizzy in if you want. The Unilite is a Malloy Comp 9000 set up for 10 cam degress (20 Crank) advance and mid range springs - I used to run about 36 deg total in the boat (16 deg static) so would be OK to sort problems. Not sure but think I still have the Mallory coil somewhere also.
regards
KB
My car is sitting in Crown Relocations Bond store awaiting Adelaide Customs clearance.
I had to fill in a VIP (Vehicle Import Permit ) and waiting for that to clear. - Didn't think I would need permit for a bunch of parts but there you go.
I'm in the process of joining Cobra car club over here. It seems there is around 20 GT40s being built in Adealaide area so have the bug again after long spell of not a lot of enthusiasm. There's a mix of DBRs, Roaring 40s and a monocoque. The GT40 guys have a sub-group in the club.
Is no trouble to through a dizzy in if you want. The Unilite is a Malloy Comp 9000 set up for 10 cam degress (20 Crank) advance and mid range springs - I used to run about 36 deg total in the boat (16 deg static) so would be OK to sort problems. Not sure but think I still have the Mallory coil somewhere also.
regards
KB
Kevin, Thanks for the offer, I guess it wont hurt to have a Plan C, so if you want to send down the Unilite, and coil if you can find it, that would be much appreciated. Good luck with the car.
Hmmm...... I'm surprised that nobody picked up on that wee snippet, particularly after all the discussion in this thread http://www.gt40s.com/forum/gt40-tec...eels/23196-care-feeding-knock-off-wheels.html
It would appear that RHT, RHS is definitely not self tightening. I will swap them over and see what happens. I didn't have them lockwired as we were checking them frequently and also whipping the wheels off to rebleed the brakes from time to time.
The upshot of this was that it was necessary to remove the wheel complete with spindle and actually heat the wheel and press the spindle out as it had galled badly on the locating surfaces. Bit lucky that we were running pretty close tolerances there I feel. That was the right rear wheel which is the one subject to greatest loads on an anticlockwise track.
Current plans are for another test session Tuesday afternoon and, if alls well, racing at Levels (Timaru) the following Sunday 15th.
Hmmm...... I'm surprised that nobody picked up on that wee snippet, particularly after all the discussion in this thread http://www.gt40s.com/forum/gt40-tec...eels/23196-care-feeding-knock-off-wheels.html
It would appear that RHT, RHS is definitely not self tightening. I will swap them over and see what happens. I didn't have them lockwired as we were checking them frequently and also whipping the wheels off to rebleed the brakes from time to time.
The upshot of this was that it was necessary to remove the wheel complete with spindle and actually heat the wheel and press the spindle out as it had galled badly on the locating surfaces. Bit lucky that we were running pretty close tolerances there I feel. That was the right rear wheel which is the one subject to greatest loads on an anticlockwise track.
Current plans are for another test session Tuesday afternoon and, if alls well, racing at Levels (Timaru) the following Sunday 15th.
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Hi Russ. Just looking at your up right, are you running a single straight roller bearing or is it just the photo. It doesn't look like a tapper bearing or is there a second inner bearing that I can't see in the photo and are you runing the same set up on the front hubs. I'm just curious as I was thinking down that track with my uprights until I came across the Skyline hubs and it was just easier to use a ready made part. I have now machined one of the front uprights and cut off the unwanted steering arm and pressed in the bearing. Back to your's, that twisting of the upright was only a result of braking ?? I'm guessing it wouldn't have been an issue if you had inboard brakes or would the fact that the mass was still pushing the top and bottom pickups forward while the wheel was pulling the centre back still cause the damage and uder acceleration the opposite afect may have fatigued in the long term as well ???. Any way I know you will get it soughted and look forward to seeing a video of it at speed
Cheers leonmac.
Cheers leonmac.
That would be a major concern since the exhaust mount/bracket is attached to the transaxle which one would hope is firmly attached to the engine block & therefore any movement should only be heat expansion related apart from deflection etc in an accident.
I think in this case Russ has simply underestimated mount strength requirement needed to support that heavy muffler assy.
The engine mount deflection that allowed the pump to touch the f/wall is a concern, but I believe clearance is minimal at that point, but with the engine mounted on vertical flat plates some fwd/aft horizontal deflection can occur.
With regard to the upright failure it appears that with rear brake application, the caliper mounted on the brg tube has simply tried to rotate with the rotor/wheel & 'wrap' the upright around it, a very graphic example of the forces at work! Deflection was probably minimal until the rotor hat bolts made contact to complete the job. Russ is possibly very lucky that it has occurred now in early testing, later in the SFOS series @ higher speeds would not have been funny.
Hi Leon,
Yes, there is a deep groove ballbearing inboard of the needle roller. The needle roller takes the radial loads, the ball bearing takes the sidethrust.
The upright is subject to torque reaction from the caliper, plus the actual pull on the trailing arms to stop the car. With the tyre contact patch with the 15" wide rear race rubber being so far outboard of the trailing arm pickups there is a significant twisting effect transmitted through the lower half of the upright as well. And, as you say, a similar load also under acceleration in the lower gears. Throttle on/off steering corrections in the lower gears through the sweeper and the carousel may not have helped either.
Jac Mac has hit the nail pretty much on the head with his diagnosis, however the block is solid mounted front and rear on 11 mm 7075 aluminium tooling plate and forms an integral part of the rear structure. There is no flex, and the motor will not move!
However I have concerns, not related to the exhaust issue, that the trans may be flexing up and down due to torque reaction, since I noticed that there is some movement if I jack the car up using the tail of the trans. Occasionally, something doesn't feel quite right in the back of the car and I think it could be that. Some fit a brace from the bottom of the bellhousing back up to the engine mount bosses. This is not an option for me, but as soon as I get a chance I will triangulate a frame that is a simple and lightweight addition to the removable rear subframe and connect it into the back of the trans which will be an even better support.
After the failure of the lighter rubber muffler mount setup, I decided to beef up the supports and solid mount the rear of the muffler. I have used 4mm angle iron for the bracket on the muffler and also for the mount on the gearbox and these will have a 5/16 UNF screw clamping them together. I just hate using agricultural angle iron on a race car, but then I guess I AM running a tractor muffler! The muffler IS heavy and the G forces ARE high but it sounds good at idle and is very quiet on the track, and I'm fairly confident that it's not hurting power. Perfect from that point of view!
On the subject of the water pump, I had to see what was happening, so the options were to pull the motor or chop a hole in the firewall. After much debate, (for a full two seconds!) out came the step drill and the tinsnips... It was immediately obvious that the pulley had moved forward on the shaft and the belt had slipped off the back. The cause was probably excessive rearwards cantilever on the pulley. So a couple of recesses were machined into the shaft and two grub screws were set into the pulley to engage in these, and they will stop any future forward movement. Didn't get a photo of the shaft mods due to time constraints, it really is full on just at present! The first pic shows how far the pulley had moved. Subsequent ones show the correct position and the additional grubscrew placement. Machining, of course, courtesy of Lim.
Yes, there is a deep groove ballbearing inboard of the needle roller. The needle roller takes the radial loads, the ball bearing takes the sidethrust.
The upright is subject to torque reaction from the caliper, plus the actual pull on the trailing arms to stop the car. With the tyre contact patch with the 15" wide rear race rubber being so far outboard of the trailing arm pickups there is a significant twisting effect transmitted through the lower half of the upright as well. And, as you say, a similar load also under acceleration in the lower gears. Throttle on/off steering corrections in the lower gears through the sweeper and the carousel may not have helped either.
Jac Mac has hit the nail pretty much on the head with his diagnosis, however the block is solid mounted front and rear on 11 mm 7075 aluminium tooling plate and forms an integral part of the rear structure. There is no flex, and the motor will not move!
However I have concerns, not related to the exhaust issue, that the trans may be flexing up and down due to torque reaction, since I noticed that there is some movement if I jack the car up using the tail of the trans. Occasionally, something doesn't feel quite right in the back of the car and I think it could be that. Some fit a brace from the bottom of the bellhousing back up to the engine mount bosses. This is not an option for me, but as soon as I get a chance I will triangulate a frame that is a simple and lightweight addition to the removable rear subframe and connect it into the back of the trans which will be an even better support.
After the failure of the lighter rubber muffler mount setup, I decided to beef up the supports and solid mount the rear of the muffler. I have used 4mm angle iron for the bracket on the muffler and also for the mount on the gearbox and these will have a 5/16 UNF screw clamping them together. I just hate using agricultural angle iron on a race car, but then I guess I AM running a tractor muffler! The muffler IS heavy and the G forces ARE high but it sounds good at idle and is very quiet on the track, and I'm fairly confident that it's not hurting power. Perfect from that point of view!
On the subject of the water pump, I had to see what was happening, so the options were to pull the motor or chop a hole in the firewall. After much debate, (for a full two seconds!) out came the step drill and the tinsnips... It was immediately obvious that the pulley had moved forward on the shaft and the belt had slipped off the back. The cause was probably excessive rearwards cantilever on the pulley. So a couple of recesses were machined into the shaft and two grub screws were set into the pulley to engage in these, and they will stop any future forward movement. Didn't get a photo of the shaft mods due to time constraints, it really is full on just at present! The first pic shows how far the pulley had moved. Subsequent ones show the correct position and the additional grubscrew placement. Machining, of course, courtesy of Lim.
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I was wondering how you were dealing with the side thrust, and the ball bearing would do the trick. As I said before the Skyline hub uses a nice little double tapper bearing thats only 50mm wide and at the rear the Patrol hub has BIG tapper bearings.
Going back to an earlier post, you said you couldn't run in a 1hr race because your car wasn't legal for that race. The question is, what class will you be running in, will it be the same class as you ran your TR7 in which I think was "Prodution Sports and GT Cars" and of course you know that I'm going to ask if a Can-Am style car could run in that class???? Cheers Leonmac
Going back to an earlier post, you said you couldn't run in a 1hr race because your car wasn't legal for that race. The question is, what class will you be running in, will it be the same class as you ran your TR7 in which I think was "Prodution Sports and GT Cars" and of course you know that I'm going to ask if a Can-Am style car could run in that class???? Cheers Leonmac
Russ,
If the problem is with the end of the muffler, you should be able to add a couple of tabs to hold it steady. The trans support That I made came from a local Ace hardware from hollow round stock. It uses the trans bolts and is rigid to the frame as is the motor mounts. Simple and light weight. Don't know if that meets the requirements you are putting on the hardware.
This one shows the tabs and the mount.
If the problem is with the end of the muffler, you should be able to add a couple of tabs to hold it steady. The trans support That I made came from a local Ace hardware from hollow round stock. It uses the trans bolts and is rigid to the frame as is the motor mounts. Simple and light weight. Don't know if that meets the requirements you are putting on the hardware.
This one shows the tabs and the mount.
The rifle bolt is absobloodylutely marvellous! The change is virtually instantaneous, just like a dog box! I had a concern that, because of the speed of engagement, the porsche syncros would baulk it and I would miss gears. But this is not happening.
I'm not sure how hard all this is on the syncros though, time will tell. It could be rapidly destroying them, who knows. There again the change is that slick and effortless that there's not much time or force to cause any wear. Maybe?
Been flat stick all week getting the car ready for Timaru tomorrow. Missed Tuesday testing due to finding a wee gremlin that I had to attend to instead.
Pushed for time so will do an update after the racing.
I'm not sure how hard all this is on the syncros though, time will tell. It could be rapidly destroying them, who knows. There again the change is that slick and effortless that there's not much time or force to cause any wear. Maybe?
Been flat stick all week getting the car ready for Timaru tomorrow. Missed Tuesday testing due to finding a wee gremlin that I had to attend to instead.
Pushed for time so will do an update after the racing.
Thanks Dave, the luck didn't hold. It was one of those weekends......!
I was hoping to do some testing last Tuesday to check the re-routing of the MSD wiring that I had done to try to combat any possible interference issues causing the miss, also to further progress the suspension/handling department, and also to check the security of the wheel nuts now that I had swapped the spindles from side to side.
Swapping the spindles revealed an unexpected gremlin in so far as I discovered the inner sleeve on the front RHS needle roller had moved. This is an interference fit on the spindle and is not subject to side loads and it was still very tight on the spindle. So that was a real surprise. Easy enough to prevent the movement just by placing a cap screw inboard of the sleeve. However the sleeve had moved far enough to contact and knacker the seal and cage of the roller bearing, so new bearings were required. They had to come from out of town and didn't arrive in time for the Tuesday test session.
Test days ($90 per day) at Ruapuna are Tuesdays and Fridays, but this Friday was a local holiday so the track was not available. It never rains but it pours!
Well, I wasn't convinced that re-routing the MSD wires was going to cure the miss, and I didn't want to arrive at Timaru with it still playing up so I then decided to fit the proven ex-TR7 optical pickup into the Motocraft dizzie, and utilise the Crane XR700 and the coil that went with it. No rev limiter and had to swap the wires on the tach back to the way they were originally! Also had to attend to a couple of minor items that for the previous meeting the local scrutineers, knowing we were time challenged, had been lenient about. At an out of town track I didn't want to push my luck.
Nevertheless, after a couple of weeks of late nights, by 11pm Saturday we were loaded up and ready for a good sleep before our 5:30 departure for Timaru the next morning. Except the good sleep didn't happen, my normally sedate and quiet neighbours had a party in full swing that went into the wee small hours. Bloody typical!! Never mind, them's the breaks.....
The schedule for Timaru was one qualifying session and three races. Rain was threatening and the track was cold. I managed to make a complete dick of myself by doing a 360 coming out on to the track for the qualifying session. Caused I think by that missfire at 4500, just at the wrong time, that I hoped I had cured. No such luck. Anyway no damage, so on with the business.
Levels is a completely different circuit to Ruapuna, shorter and generally tighter and the car was twitchy and still had the miss and was not good off the line, so I decided to treat the day as a test session and asked Race Control to start me off the back of the grid in all races.
In between races we progressively reduced tyre pressures and camber, which improved the handling and times and tried closing up the plug gaps to see if that would get rid of the miss. No such luck!
During the last race I developed cramp in both hands which locked the gearchange hand onto the steering wheel thus unable to change gears. Time to call it quits and DNFed. The cramp was probably caused by the long hours put in on the car and not having decent meals over the last couple of weeks. The things we do......
All in all an inauspicious weekend with an uncompetitive car, I guess it can only get better....
Nevertheless, apart from the results, it was an enjoyable and relatively relaxed weekend. Lim was with me and my other best mate, John, made the trip over from the Coast again specially to help out. Great guys both.
The car attracted a lot of attention and favourable comment, so that was quite pleasing. Sunday showed we are heading in the right direction with the suspension setup and revealed that I will have to look further for that miss. Not difficult, it's just a matter of working through everything. Will make further suspension and electrical changes and do some testing Tuesday week. We have now done about 60 laps in the car. Next race is Dec 13 at Ruapuna.
Ironically, in the North Island spaceframes are eligible for the NI Endurance races! Yes, I will be running in Classics, in the 'Sports and GT' class
I think you will run in the class for open top cars. 'Racing and Sports-Racing'
I was hoping to do some testing last Tuesday to check the re-routing of the MSD wiring that I had done to try to combat any possible interference issues causing the miss, also to further progress the suspension/handling department, and also to check the security of the wheel nuts now that I had swapped the spindles from side to side.
Swapping the spindles revealed an unexpected gremlin in so far as I discovered the inner sleeve on the front RHS needle roller had moved. This is an interference fit on the spindle and is not subject to side loads and it was still very tight on the spindle. So that was a real surprise. Easy enough to prevent the movement just by placing a cap screw inboard of the sleeve. However the sleeve had moved far enough to contact and knacker the seal and cage of the roller bearing, so new bearings were required. They had to come from out of town and didn't arrive in time for the Tuesday test session.
Test days ($90 per day) at Ruapuna are Tuesdays and Fridays, but this Friday was a local holiday so the track was not available. It never rains but it pours!
Well, I wasn't convinced that re-routing the MSD wires was going to cure the miss, and I didn't want to arrive at Timaru with it still playing up so I then decided to fit the proven ex-TR7 optical pickup into the Motocraft dizzie, and utilise the Crane XR700 and the coil that went with it. No rev limiter and had to swap the wires on the tach back to the way they were originally! Also had to attend to a couple of minor items that for the previous meeting the local scrutineers, knowing we were time challenged, had been lenient about. At an out of town track I didn't want to push my luck.
Nevertheless, after a couple of weeks of late nights, by 11pm Saturday we were loaded up and ready for a good sleep before our 5:30 departure for Timaru the next morning. Except the good sleep didn't happen, my normally sedate and quiet neighbours had a party in full swing that went into the wee small hours. Bloody typical!! Never mind, them's the breaks.....
The schedule for Timaru was one qualifying session and three races. Rain was threatening and the track was cold. I managed to make a complete dick of myself by doing a 360 coming out on to the track for the qualifying session. Caused I think by that missfire at 4500, just at the wrong time, that I hoped I had cured. No such luck. Anyway no damage, so on with the business.
Levels is a completely different circuit to Ruapuna, shorter and generally tighter and the car was twitchy and still had the miss and was not good off the line, so I decided to treat the day as a test session and asked Race Control to start me off the back of the grid in all races.
In between races we progressively reduced tyre pressures and camber, which improved the handling and times and tried closing up the plug gaps to see if that would get rid of the miss. No such luck!
During the last race I developed cramp in both hands which locked the gearchange hand onto the steering wheel thus unable to change gears. Time to call it quits and DNFed. The cramp was probably caused by the long hours put in on the car and not having decent meals over the last couple of weeks. The things we do......
All in all an inauspicious weekend with an uncompetitive car, I guess it can only get better....
Nevertheless, apart from the results, it was an enjoyable and relatively relaxed weekend. Lim was with me and my other best mate, John, made the trip over from the Coast again specially to help out. Great guys both.
The car attracted a lot of attention and favourable comment, so that was quite pleasing. Sunday showed we are heading in the right direction with the suspension setup and revealed that I will have to look further for that miss. Not difficult, it's just a matter of working through everything. Will make further suspension and electrical changes and do some testing Tuesday week. We have now done about 60 laps in the car. Next race is Dec 13 at Ruapuna.
Ironically, in the North Island spaceframes are eligible for the NI Endurance races! Yes, I will be running in Classics, in the 'Sports and GT' class
I think you will run in the class for open top cars. 'Racing and Sports-Racing'
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The cramping was probably caused by dehydration. For at least 2 to 3 days before an event you should be hydrating. A in car drink system would also go towards aleviating the problem. I ride motocross for fun and solved a lot of my cramping issues with these suggestions.
You know how you have the carb mounted backwards, have you compensated for this in the float settings? We discussed this ages ago when you or someone else asked the question.
Basicly a Holley runs a higher primary bowl fuel level than the secondary--- I cannot remember if your Demon also has this feature---- now if you have not allowed for this you could be getting starvation on one end & or flooding in the other under acceleration.
P.S. Found that old thread & see the Demon fuel sights are matched in height.
Oh well back to the dwg board.... love to have been standing on the spectator bank at levels for the 360°.... Red mist 1...Russ 0.:stunned:
I would remove the alt/w-pump belt & hook the ignition system up to a seperate 12v battery to eliminate everything for a start, then work from there...
Basicly a Holley runs a higher primary bowl fuel level than the secondary--- I cannot remember if your Demon also has this feature---- now if you have not allowed for this you could be getting starvation on one end & or flooding in the other under acceleration.
P.S. Found that old thread & see the Demon fuel sights are matched in height.
Oh well back to the dwg board.... love to have been standing on the spectator bank at levels for the 360°.... Red mist 1...Russ 0.:stunned:
I would remove the alt/w-pump belt & hook the ignition system up to a seperate 12v battery to eliminate everything for a start, then work from there...
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Thanks Kevin, the dizzie arrived yesterday morning. All good.
Timaru wasn't too bad.... Because of rain or cramp in other races, Race 2 was the only session that was meaningful. My times consistently dropped in this race as I explored the handling vagaries of the car. See here MYLAPS
Decidedly nervous handling on some of the undulations/bumps on the Timaru track and there's not a lot of runoff area if it all turns to custard..... Basically a bump steer problem which I am attending to now.
Jac Mac. Can't remove the alt/wp belt as I have removed the elec wp!!
This was the result of yet another minor drama in the week before Timaru. It's been a pretty fraught time trying to meet the race dates! The Davies Craig pump started weeing all over the floor, and after making sure that it wasn't external connections etc I removed the pump and stripped it down. The shaft in the critical area where the seal seats had not been fully machined around half of it's circumference so after very little use it became unable to hold back the water. See pics showing the good side and bad side of the shaft. The critical area is just below the circlip groove that is just below the machined flat. Fortunately the car is running cold at present so there is no need to combat heat sink when it is switched off. Maybe I should start a thread, "Quality Control In Oz" :lipsrsealed:
However that now leaves an unused stand alone relay in the system, nice and handy to the ignition components, so I am going to try temporarily wiring the coil through this. I will also try disconnecting the tach, and fitting a new cap and rotor. One thing at a time on Tuesday. If that doesn't help then I'll try your suggestion of a totally isolated seperate battery power source. Good idea! I am becoming increasingly convinced that it is a tach or wiring issue.
Timaru wasn't too bad.... Because of rain or cramp in other races, Race 2 was the only session that was meaningful. My times consistently dropped in this race as I explored the handling vagaries of the car. See here MYLAPS
Decidedly nervous handling on some of the undulations/bumps on the Timaru track and there's not a lot of runoff area if it all turns to custard..... Basically a bump steer problem which I am attending to now.
Jac Mac. Can't remove the alt/wp belt as I have removed the elec wp!!
This was the result of yet another minor drama in the week before Timaru. It's been a pretty fraught time trying to meet the race dates! The Davies Craig pump started weeing all over the floor, and after making sure that it wasn't external connections etc I removed the pump and stripped it down. The shaft in the critical area where the seal seats had not been fully machined around half of it's circumference so after very little use it became unable to hold back the water. See pics showing the good side and bad side of the shaft. The critical area is just below the circlip groove that is just below the machined flat. Fortunately the car is running cold at present so there is no need to combat heat sink when it is switched off. Maybe I should start a thread, "Quality Control In Oz" :lipsrsealed:
However that now leaves an unused stand alone relay in the system, nice and handy to the ignition components, so I am going to try temporarily wiring the coil through this. I will also try disconnecting the tach, and fitting a new cap and rotor. One thing at a time on Tuesday. If that doesn't help then I'll try your suggestion of a totally isolated seperate battery power source. Good idea! I am becoming increasingly convinced that it is a tach or wiring issue.
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I meant just take the belt off after warming it up & run it a couple of quick runs up thru the rev range to see if that helps... if it does then you have a problem with the alternator or related wiring circuits etc, or possibly that gilmer belt drive causing an issue. Got some fresh super secret Nascar pics from a mate just back from TX on tuesday, only place they appear to use tooth belts is on the oil pump, all the P/Steer, W/Pump, Alt are flat Poly Vee or normal Vee belts, there has got to be a reason for that, even the new FR 9 & front dizzy Chev nascar motors are done like that.
Looks like you have to be logged into My Laps for the individual lap times to be accessed. Anyway the five flying laps of the six lapper went like this...
1:19.892
1:19.090
1:17.914
1:17.577
1:16.614
By comparison the fastest lap of the race, set by the winner, was 1:09.738 so there's a long way to go yet!
