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Join Date: Jul 2010
Location: Lithia, FL
Posts: 1,265
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Thanks Bill!
If the holes are within spec I'd look at honing them and replacing all bearings and these upgrades: High Comp Pistons hotter cams ported heads with new valves, seals, springs & seats larger injectors race exhaust...no emissions testing here in FL ![]() new chip Will this cost a fortune or is it a worthwhile project? Please let me know whattcha think the resulting Hp & Torque I could expect with these mods. Thanks, RC |
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Location: Lithia, FL
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JE offers 11.5:1 & 12.5:1 slugs for $1100
274636 Product Detail Information - JE Pistons Is there any good reason(s) not to go with 12.5 for a mostly street build if it will run on 93 octane pump gas? I found them on Pelican: http://www.pelicanparts.com/cgi-bin/smart/more_info.cgi?pn=JE-274636&catalog_description=JE%20Pistons%2C%20Set%20of%206 %2C%203.6L%2C%20100mm%20bore%2C%2012.5%3A1%20comp% 2C%20%20911%20%281990-98%29 Last edited by CaptainCalf; 07-09-2010 at 05:54 AM.. Reason: add |
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OS Valves
Looks like RS valves are 51.5mm or 1.5mm larger then stock which are 50mm and cutting a bigger hole should be a big deal since new seats are needed anyways: Pelican Parts - Product Information: 993-105-409-42-M154 |
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Cams
Looks like Webcams has RS profile cams for < $1000 per set. The euro spec is with hydraulic lifters. What are the advantages of hydraulic lifters over mechanical in these motors? Web Cam Inc. - Performance and Racing Camshafts |
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Location: Portland Oregon
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JMHO,
12.5:1 is FAR too high for any street car, even with knock sensors. That requires 110 octane fuel, especially in hot weather. Remember now, you are balancing compression ratio, ignition advance and minimal octane. Add summer weather, and those detonation margins evaporate. 52mm RS valves can be installed without new seats. RS cams are excellent, especially with the RS intake valves. Custom software is needed for this, as you might know. ![]()
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Steve Weiner Rennsport Systems Portland Oregon (503) 244-0990 porsche@rennsportsystems.com www.rennsportsystems.com |
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Quote:
This is gonna be FUN! |
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Formerly known as Syzygy
Join Date: Mar 2008
Location: Calgary, AB
Posts: 4,420
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Hydraulic lifters will eliminate the need for valve adjustments. With mechanical, you need to do that.
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Kevin 1987 ROW coupe, Marine blue, with a couple extra goodies. The cars we love the best are the ones with human traits, warts and all. |
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That's good to know cuz pulling the the engine to do a valve clearence check would be a pain...
Quote:
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Join Date: Jul 2008
Location: Franklin, Tennessee
Posts: 276
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Hey Rick,
I am the OP, and I have not gotten the motor done yet, but it is under way. ![]() I sent my heads to Steve, and he reworked them, and added RS intake valves. I bought a set of RS cams from him. He now has my pistons, and will be enlarging the intake pockets on them to allow for the larger RS intake valves. I will be getting Steve to make a chip for me when the build is complete. Good luck with yours. Emerald
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'88 911 coupe, Laguna Green Metallic (sold)95 993 Aventurine Green(sold) 97 993 C4S Vesuvius |
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Nice progress and please post up pics of the heads when Steve is done unshrowding the intake valves
you'll have a torque monster when you're done ![]() Quote:
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Here you go Captain, a peak at the heads after Steve worked his magic . I'll post a few pics of the pistons when they return.
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'88 911 coupe, Laguna Green Metallic (sold)95 993 Aventurine Green(sold) 97 993 C4S Vesuvius |
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Lookin good and pls keep the pics comin
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Well, the last half of the year did not go as planned, but I am finally able to get back to my engine build. I had gotten my heads back from Steve in the last post, and sent him the pistons to have the intake pockets enlarged. They came back looking great, and I managed to get them bolted up. I will try and find my photo of the pistons, as it has gone missing.
I got the cam housings and cam installed, and reassembled the timing chain assembly. I hit a snag when it was time to check the parallelity of the chain sprokets. I was able to get the left on within tollerance with 4 shims, but the right is off by +1mm, and there are no shims to remove. I am currently stumped and scratching my head. I have checked all measurements 5 times, and still end up at the same conclusion. When I took the engine apart, it had 1 shim on the left, and 3 on the right. I changed to a set of RS cams, so maybe this has thrown something out. I can not go forward till I figure it out. ![]() ![]() ![]() ![]() Happy Holidays to all. Emerald
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Doh..... Well it turned out to be a stupid mistake, as opposed to all of those smart mistakes. I had the right camshaft sprocket on backwards. I need to order a few shims from the dealer, but the measurements now work out, and everything lines up.
I am now looking forward to finishing up when the new shims get here, and then I can start setting the cam timing.... Emerald
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'88 911 coupe, Laguna Green Metallic (sold)95 993 Aventurine Green(sold) 97 993 C4S Vesuvius |
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Emerald:
Hang in there....and continue on your present course. You'll be happy in the end. Rothsport (and Steve Weiner) built me a 3.6 RS Vram motor last winter, and it's a beast. 310 hp w/ 271 ft-lbs of torque. I have RS cams and intakes, racing springs w/ Ti retainers, Vram induction w/ reflashed ECU. 993 heat exchangers and sport exhaust. The end result will be worth it. Great around town drivability coupled with incredibly strong acceleration when you call on it. Enjoy! ![]()
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"Are you out of your Vulcan mind?" Doug 2022 Carrera 4S, 1989 Delta Integrale, 1973 911T CIS |
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Doug,
Thanks for the encouragement. It is a fun project, and it feels good to be getting back into it. I am looking forward to the final result. It sounds like you have the engine I am building. My next hurdle will be setting the timing. I can't say enough about Steve Weiner and his knowledge and dedication to our community. I sent my heads to him because of his great reputation, and then was amazed at his friendliness. He is a true gentleman. What do you have your engine in? Emerald
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'88 911 coupe, Laguna Green Metallic (sold)95 993 Aventurine Green(sold) 97 993 C4S Vesuvius |
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Hi Emerald,
How did you figure out you had a sprocket on backwards? Is the parallel measurement the only way? I have asked this questions before but has not been answered: are there any markings on the sprockets to identify which way they go? Thanks, and keep up the good work. ![]() |
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Good question. I actually stumbled upon it, but the answer was there all along. The easiest answer would be to read Wayne's book on rebuilding Porsche engines. (page 158 figure 6.7) He gives a photo of the sprockets. It is the same sprocket for either side, it is just that one is flipped. I was using the 993 shop manual, and it states to make sure the right side sprocket is facing forward, and forward would be toward the front of the car, not towards the builder. I made the mistake after a long day, and it simply perplexed me, because yes, if the sprockets are backwards, the chains will be out of line and will be off the guide rails.
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Thanks a lot!! I have Wayne's book and will study it.
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Well, the new year is off to a good start, as I just finished timing the cams. Thanks to Steve Weiner for input and guidance, Wayne's book, and Anthony (Axl911 on Rennlist)
I used Anthony's write up because he condensed it into easy to follow steps. I installed a mechanical lifter on #1 and gapped it to .1mm. I then installed a Z block from Pellican, and installed a digital dial gauge and pre loaded it, then zeroed it. I did not have enough shaft to preload a full 10mm, but figured it was the initial few mm's that were important. When the digital dial is zeroed, it will show the deflection of the intake valve as a negative, which makes sense. I then proceeded to follow these steps... To set timing for Cylinder 1. 1. Rotate the pulley so Z1 mark is lined up with the case parting line. 2. Install cylinder 1 intake rocker. 3. Make sure both cams have the dots pointed straight UP. Draw a line from the dot through the center of the cam will make it easier to see the dot is pointed straight up. 4. Put the pin into the cam sprocket where the holes line up. Do this for both sides. You can put the cam sprocket bolt in or not. Leaving it out makes it easier to see how the dot moves. 5. Adjust the cylinder #1 intake valve clearance to .1mm like you normally do in valve adjustment. 6. Mount your dial gauge on cylinder #1 intake. And set it to zero value. 7. Rotate the crank pulley clockwise almost 360 degrees. As you approach the Z1 again you will notice the dial begin to move. 8. Continue to rotate clockwise until the gauge moved 1.26mm or .05 inch. STOP. 9. Is the Z1 mark lined up with the case parting line? If not, use a small screw to remove the pin on the left side cam. Rotate the crank pulley until the Z1 mark is lined up with the case parting line. 10. Now put the pin back into the cam sprocket where the holes line up. 11. Double check by rotating the crank pulley 720 degrees. By the time the Z1 comes around for the second time, when the Z1 is lined up with the crank pulley, your dial gauge should have moved 1.26mm or .05 inch. 12. You are done with cylinder #1. Don’t move anything. 13. If it takes more than 360 degrees to get the dial gauge to move 1.26mm, then you either don’t have the cam dot pointed straight up at the beginning or you did not adjust your cylinder 1 valve clearance properly. Now to set timing for Cylinder 4. 1. After completing the last step in setting timing for cylinder 1, the dot on the right cam should be pointed straight DOWN. 2. Install cylinder 4 intake rocker. 3. Adjust the cylinder 4 intake valve clearance to .1mm like you normally do in valve adjustment. 4. Mount your dial gauge on cylinder 4 intake. And set it to zero value. 5. Rotate the crank pulley clockwise almost 360 degrees. As you approach the Z1 again you will notice the dial begin to move. 6. Continue to rotate clockwise until the gauge moved 1.26mm or .05 inch. STOP. 7. Is the Z1 mark lined up with the case parting line? If not, use a small screw to remove the pin on the RIGHT side cam. Rotate the crank pulley until the Z1 mark is lined up with the case parting line. 8. Put the pin back into the cam sprocket where the holes line up. 9. Double check by rotating the crank pulley 720 degrees. By the time the Z1 comes around for the second time, when the Z1 is lined up with the crank pulley, your dial gauge should have moved 1.26mm or .05 inch. 10. You are done!!! 11. If it takes more than 360 degrees to get the dial gauge to move 1.26mm, then you either don’t have the cam dot pointed straight up at the beginning or you did not adjust your cylinder 4 valve properly. I used a Stomski top dead center tool to verify my Z1. I also found that when I determined which way the pin needed to be moved, I had to turn the crank so the valve closes, otherwise when the pin is removed, the valve spring will cause the cam to rotate. ![]() I also used two Z blocks and two dial gauges so I could verify both sides. I can now start at Z1, turn the crank 360, and the gauge on #1 reads 1.25, and the one on #4 is 0. I turn it another 360, and the gauge on #4 reads 1.23, and #1 is 0. I can repeat this continualy and read the value from 1 then 4. Here are a couple of photos, and am I missing anything? I had heard that the cam timing was one of the trickiest steps, so now that I have done it, I am a bit paranoid that I missed something. ![]() ![]() ![]() Emerald
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