Project: 97 6-speed, SC400 supercharged 4.7L V8
02-07-09, 07:19 AM
#122
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Sorry guys, Have not had any updates. Nothing much to show. I have been planning out the fuel system and fabricating parts for the build. More custom parts in the works so stay tuned.
02-11-09, 08:06 PM
#123
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Seems like really slow progress but then again I don’t get seem to get the time I would like to work on this. This Week I have been working on the Cams and buckets. David sent me some cams so I got the long needed scissor gears! Thanks David!
First I went to assemble the gears on the cams, The intake cam gears went on fairly easy. I heated the gears in boiling water and froze the cams to aid in putting them together, it helped a lot. Next I went to install the Exhaust scissor gears, This time it was not so easy. With my slightly increased base circle and the higher lift they would not go on the cams. I threw the gears on my mill and put in a half moon clearance to allow them to fit. After the modification I got them all assembled.
Next I went to the motor, This is where the rubber hits the road. I hoped the hours of planning and measuring would allow for the $400+ worth of Prius lifters to correct the lash. Thus far that looks pretty good, Preliminary measurements show that the lash is .007"-.010" on the first 8. Once all said and done I am sure I will need to order a few more lifters for final adjustments.
The bad news is there is more clearance needed in the heads for the cams. One spot is a no brainer, its on the exhaust cam, it is part of the head casting that looks to be factory cleared. It needs more cleaned out of it. The disturbing part is the edges of the lobes as they enter the bucket hole.
Looks like I have two options.
1. Rotary file the top edges of the bucket holes where the two corners of the lobe will hit. They just barely interfere.
2. I could add a very slight chamfer/radius to the cams outer lobe tips edges. This seems logical because they are rough casting there now and don’t have a really clean edge. I would probably need to add a .030"-.040" chamfer to make them clear well. Somthing seems wrong with modifying $1200 worth of cams but It might be best.
Anyone have any recommendations on what way they would go?
Others may not see a condition as I describe due to I am using the Prius lifters and enlarged base circle. This pushes the lifter deeper in the hole some. My valves stems are longer to correct this some.
One thing I still need to look at is piston to valve clearance. It should be good but I need to make sure.
First I went to assemble the gears on the cams, The intake cam gears went on fairly easy. I heated the gears in boiling water and froze the cams to aid in putting them together, it helped a lot. Next I went to install the Exhaust scissor gears, This time it was not so easy. With my slightly increased base circle and the higher lift they would not go on the cams. I threw the gears on my mill and put in a half moon clearance to allow them to fit. After the modification I got them all assembled.
Next I went to the motor, This is where the rubber hits the road. I hoped the hours of planning and measuring would allow for the $400+ worth of Prius lifters to correct the lash. Thus far that looks pretty good, Preliminary measurements show that the lash is .007"-.010" on the first 8. Once all said and done I am sure I will need to order a few more lifters for final adjustments.
The bad news is there is more clearance needed in the heads for the cams. One spot is a no brainer, its on the exhaust cam, it is part of the head casting that looks to be factory cleared. It needs more cleaned out of it. The disturbing part is the edges of the lobes as they enter the bucket hole.
Looks like I have two options.
1. Rotary file the top edges of the bucket holes where the two corners of the lobe will hit. They just barely interfere.
2. I could add a very slight chamfer/radius to the cams outer lobe tips edges. This seems logical because they are rough casting there now and don’t have a really clean edge. I would probably need to add a .030"-.040" chamfer to make them clear well. Somthing seems wrong with modifying $1200 worth of cams but It might be best.
Anyone have any recommendations on what way they would go?
Others may not see a condition as I describe due to I am using the Prius lifters and enlarged base circle. This pushes the lifter deeper in the hole some. My valves stems are longer to correct this some.
One thing I still need to look at is piston to valve clearance. It should be good but I need to make sure.
03-01-09, 07:25 PM
#124
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For those guys that have not messed with the Prius lifters here is some comparison photos. I found them to be about 3 grams lighter than stock with shim.
First here they are installed.
Here are stock and Prius (Stock have the shim, also they are thicker aluminum)
First here they are installed.
Here are stock and Prius (Stock have the shim, also they are thicker aluminum)
03-01-09, 07:29 PM
#125
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Here are my custom thermostat housing and water brigde. Did this to clear the 8-rib belt and add AN radiator lines. Also welded AN's on the radiator.
03-01-09, 07:51 PM
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Thanks guys, Parts will all get polished before final install. What's cool is the new rerouted upper radiator hose now lines up perfect with the radiator inlet.
03-01-09, 09:58 PM
#131
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Looking good Scott! U gonna have her ready for the drag strip this spring? I got laid off at cessna and was forced to sell the sc300. 
So you'll be the fastest SC in town now for sure! Wish I could have given U a ride with the 66mm turbo all tuned up at 22psi. It pulled like a freight train!
So you'll be the fastest SC in town now for sure! Wish I could have given U a ride with the 66mm turbo all tuned up at 22psi. It pulled like a freight train!
03-02-09, 08:10 AM
#132
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Looking good Scott! U gonna have her ready for the drag strip this spring? I got laid off at cessna and was forced to sell the sc300.
So you'll be the fastest SC in town now for sure! Wish I could have given U a ride with the 66mm turbo all tuned up at 22psi. It pulled like a freight train!
So you'll be the fastest SC in town now for sure! Wish I could have given U a ride with the 66mm turbo all tuned up at 22psi. It pulled like a freight train!
I am still shooting for spring but progress is slow. I would have really like to ride in your SC before it went bye bye, I bet it was crazy!
03-02-09, 10:29 AM
#133
Scott,
I missed your post about the cam interference with the head. What did you decide to do? - cut the head or trim the cam lobe?
Also FWIW, I've been running shimless buckets for almost a year, and they've worked out great. I think you'll be very happy with the results.
-scott
I missed your post about the cam interference with the head. What did you decide to do? - cut the head or trim the cam lobe?
Also FWIW, I've been running shimless buckets for almost a year, and they've worked out great. I think you'll be very happy with the results.
-scott
03-02-09, 11:03 AM
#134
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Scott,
I missed your post about the cam interference with the head. What did you decide to do? - cut the head or trim the cam lobe?
Also FWIW, I've been running shimless buckets for almost a year, and they've worked out great. I think you'll be very happy with the results.
-scott
I missed your post about the cam interference with the head. What did you decide to do? - cut the head or trim the cam lobe?
Also FWIW, I've been running shimless buckets for almost a year, and they've worked out great. I think you'll be very happy with the results.
-scott
