No longer a ''budget" race GTV

Alfa Romeo ONLY please!
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kevin
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No longer a ''budget" race GTV

Post by kevin » Sat Jul 25, 2009 1:48 pm

Thought I would start a new topic as this car has progressed from a stock standard 2.5 track day car to a more serious race car with a wild camm'd 3.0 24v motor.
Looking back on three years of racing , the few problems i have had ,come from 'bad " driving and experimintation in limited testing time.
The really good areas in this car are brakes ,clutch, engine, suspension and very reliable prop set up.
The bad areas are tyres, tyres and tyres - not enough grip even though perfectly balanced car. (MD gonna help out here )
Grey area -The gearbox - pinion failures have been have been due to over eager changedowns in the heat of battle creating a small chip on tooth and then stripping completely on acceleration.
Also starting to prepare a second identical origional GTV 3.0l in this topic removing all first time mistakes.
Pics to follow of duplicate set ups , maintenance areas, and lightening fiberglass parts and new donor 3.7 motor in two races time after more testing in road car.
All input is welcome as this is how I have finally got this car to this stage.
Irony of this car is its still road 'legal' and I still drive it to and from the track. The ride is getting much rougher though!
Check out pics of new light weight boot lid. 3kg
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kevin
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Re: No longer a ''budget" race GTV

Post by kevin » Sat Jul 25, 2009 1:51 pm

New watts set up for 2nd car and plennums
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kevin
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Re: No longer a ''budget" race GTV

Post by kevin » Sat Jul 25, 2009 1:53 pm

Finally starting to replace all glass except front windscreen with 3mm PET.
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Re: No longer a ''budget" race GTV

Post by kevin » Sat Jul 25, 2009 2:03 pm

Stripped clutch out to see what wear is like after year of racing. I experimented with copper one side and standard other. Wear is even 6.3mm. Main reason clutch came out was a vibration and it is caused by a loose insert in bearing housing. This housing came like this so iI will probably have to machine another one with light press fit. Dont want to shatter housing. This is definately an area where a lghtweight clutch should be made - next progression down line.
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Re: No longer a ''budget" race GTV

Post by kevin » Sat Jul 25, 2009 2:05 pm

New sets of headers
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Re: No longer a ''budget" race GTV

Post by kevin » Sat Jul 25, 2009 2:13 pm

With regards to the LS unit in the above pic I have just had the bearing shafts rewelded and ground to correct size. Before in last thread it was oval due to heat from turning bearing. The machinist did a brilliant jod on this part with 0.01 tollerance.
I have now forgotten how to put it back together and will have to search for links. I remember there was on JK's book on 4cyl. He also mentioned increasing lock up by shimming but how do you measure that % and what should be suitable for track .
The race car currently has a GRIPPER unit from UK which is brilliant - thanks Andrew B for putting me in touch with Gripper.
kevin
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Re: No longer a ''budget" race GTV

Post by kevin » Sat Jul 25, 2009 2:20 pm

Ok, last race had hitch ride as fuel rail washer split - not sure how but it was much safer to tow even though it was a minor leak.
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Re: No longer a ''budget" race GTV

Post by Jim K » Sun Jul 26, 2009 3:13 am

This part from the book will help:
First job is to clean everything thoroughly with thinner.
Inspect all parts for abnormal wear especially the two end thrust washers, as they tend to wear excessively and break. Next, inspect the friction plate internal teeth; they should fit perfectly over the driven gear teeth without any sideplay. If the teeth are worn, new plates are required (gears wear out too but at a much slower pace).
Arrange everything in the proper order and get ready for reassembly. This may sound simple in theory but requires quite a few precise measurements and repeated trial-and-error assembly/disassembly cycles on the bench. Put everything inside the housing in the proper sequence (do not lube anything at this time). Fit the cover on with only a couple of the 8 special bolts, placed diametrically opposite each other. Clamp the proper splined stub securely in the vise and slide the LSD on it with the cover on top. This is the first moment of truth, one of many to follow. Fit the other stub on top and try turning with the torque wrench. If you can turn with a steady (not breakaway torque) 3kgm for 25% units and 6kgm for 47% ones…do it again because I for one don’t believe you! If your reading is much lower or nothing at all, take the unit off the vise and disassemble again. Use the dial caliper to measure flat plate thickness and replace them with thicker ones. They originally came in three sizes, 1.9, 2.0 and 2.1mm. If you’re lucky your original ones will be the thin type. Replace them with thick ones and reassemble. If you already have an assortment of steel shim washers as previously mentioned, all the better. Just add one on the end of the pack and put the cover back on. Repeat the test. If this time you get excessive torque, say 10kgm, you have gone too far and will have to fit a thinner shim and/or thinner plates. As you can see I have taken the two extremes, no torque and too much torque to illustrate a general course of action. It all has to do with total plate stack thickness acting as a friction preload within the housing. Having to deal with this sort work often enough, I had my own special assortment of round washers water-jet cut from 0.15, 0.2 and 0.5mm thick steel sheet. Needless to say, these washers are placed at one ends of the pack where they are only subjected to pressure, not friction.
When you finally and hopefully arrive at the target values of 3kgm (25%) and 6kgm (47%) recheck by fitting all cover bolts, tightening to the proper 2.7kgm. If again all is well, disassemble the unit once more so that you can lube all parts with the proper LSD compatible oil. One I have found which works well for me is Valvoline GL5 80-90LS.
You must now reassemble for the last time. Fit the cover and torque all bolts before placing the unit on the vise. Torque testing now should result in values approximately half of what you had when you ‘dry’ tested the unit. So, about 1.5 and 3kgm ‘wet’ readings will place you square-center on what is needed for 25% and 47% respectively.
Good luck!
Jim K.
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Mats
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Re: No longer a ''budget" race GTV

Post by Mats » Sun Jul 26, 2009 3:26 am

Good to see you now realized that there is no such thing as a racecar on a "low budget". :wink:
Mats Strandberg
-Scuderia Rosso- Now burned to the ground...
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GTV 2000 -77 - Died in the fire.
155 V6 Sport -96 - Sold!
kevin
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Re: No longer a ''budget" race GTV

Post by kevin » Sun Jul 26, 2009 9:35 am

Jim , thanks a million. Could not have asked for a better reply. Take me a few days to digest and get it sorted.

Mats, to keep budget lowish I try make four sets of everything I make and then between my mates who are starting to race GTV's it hepls keeps costs down...ish.
Here is a pic of some 8 J 15 inch compomotives which I have just rebuilt with new bolts and nuts. These are critical as I have had them snap on me before. Reason is they never get replaced and after tightening them to often they stretch. Actually highly dangerous if a whole bunch suddenly go but thats on on rims that have never been serviced in twenty years. These rims were a standard rim on our South African GTV 3.0l in 1983. You could have also orderd car with the star centres as well.
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Re: No longer a ''budget" race GTV

Post by kevin » Thu Jul 30, 2009 9:34 am

Will start LS this weekend as weather has not been condusive to working in garage at night 4 deg. (thats probably a perfect summer evening for Mats ). Thanks again Jim for reply - free accomodation for world cup if you want to watch Greece try win a match.
Finished off making new insert and re macining housing. The old insert had collapsed probably from loose yoke bolt or overheeated bearing. Kept the housing in cnc mchine the whole time so insert was in correct position. Alfa really did there homework on this material on insert as anything under 3mm on EN3 distorts.
This insert serves as a sliding interference fit while the back bearing(load carrying bearing) is a press fit into housing- fixed interefence fit.
Realised while housing was in cnc machine how easy it would be to make a whole new one .
I took off all the intakes on race motor and plenum setup to put on 3.7 to replicate it . So when I transplant 3.7 into race car all i need to change are the maps on the injection. Maybe might need a bit of dyno work as no two fuel pressure systems are the same.
So far this week the 3.7 has done over 2500km with oil and water levels constant. Total on motor is 4000km. Another week of more testing and monitoring and then I will transplant. I have not used expensive syntheic oil either due to high clearences.
Interesting to see the mild 'porting' alfa did on the 3.2 intake manifold. This is the only place it differs from the 2.5 24v.
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Mats
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Re: No longer a ''budget" race GTV

Post by Mats » Thu Jul 30, 2009 1:11 pm

Plug leads, on a 24v? :P
Mats Strandberg
-Scuderia Rosso- Now burned to the ground...
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GTV 2000 -77 - Died in the fire.
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Re: No longer a ''budget" race GTV

Post by kevin » Fri Jul 31, 2009 1:45 pm

Yeah I would prefer coil packs but when they are no coil packs available you have to make a plan. I could have bought new ones but definately not at the dealer prices. They must be nuts to charge 200$ us a coil pack. (maybe ok if you live in US but not when you live in the jungle).
Took a bad video on cell of 3.7 motor at work today. Sound is bad but you can see how clean the exhaust is. Custom head gaskets have survived with severe dynoing and water is perfectly clean so I think I am safe there. Doing alot of milage in all conditions with high temps in heavy traffic and fast open road. Car is a serious sleeper with everything standard except clutch and box. Should transfer this to engine thread but this is the new race engine.
Check clip
http://www.youtube.com/watch?v=fZFOXzEMQX4
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Re: No longer a ''budget" race GTV

Post by Mats » Fri Jul 31, 2009 2:52 pm

What's the spec on the exhaust? Sounds nice, more 2.5 then 3.0. :)
Mats Strandberg
-Scuderia Rosso- Now burned to the ground...
-onemanracing.com-
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GTV 2000 -77 - Died in the fire.
155 V6 Sport -96 - Sold!
kevin
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Re: No longer a ''budget" race GTV

Post by kevin » Sat Aug 01, 2009 11:18 am

Mats, strange you ask as I had three new rear boxes from 1985 for the GTV 6 2.5 . Which ever car i have put them on over the years its had that similiar sounding 2.5 v6 whine. This car is just deeper though. This rear box was made here in South Africa for Alfa Romeo, its a 63mm ''free flow'' box.
The rest of this 3.7 has 45mm headers into 57mm downpipes converging into 63mm then into first silincer box under gear lever and then 63mm through to end box.
I have found that you can vary the note of these v6 engines if there was a scale from 0 to 100. My 3.2 sounds like another car altogether with one box , but then it does have a different bore.
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