1990 C4 Engine Rebuild - DIY
10-25-2014, 07:31 PM
#1
Rennlist Member
Thread Starter
1990 C4 Engine Rebuild - DIY
This thread has been a long time coming. I bought my 1990 Carrera 4 in 2007 and it has run fine ever since I bought it. I definitely needs new engine mounts and I built up my skills on the car with a valve adjustment and full hydraulic servicing. It just keeps leaking more and more oil from all the usual points every year. I could live with it but its always bothered my how dirty and leaky the engine is while everything else on the car is in outstanding condition.
I really enjoyed doing the reseal on my 1991 C2 and learned how to drop a motor with the help of fellow rennlister StevePAA (who has moved on to Ferrari after his Tip got rear ended).
First thing I did to start this project was to setup a 1 hour consultation with Steve Weiner at Rennsport Systems. I told him I am pretty much a stock guy, and wanted to "hot rod" my C4 into a reliable street machine with a bit more go, and something to enjoy on driver's events on occasion. He talked to me about a couple of things I could do. This most important thing for me is to take system level approach to this. Not bolt on various go fast parts but rather rely on someone I trust who can deliver a system solution for what I am after. I am still not sure how far I will take this but I don't have to decide that right now.
Since I have a Carrera 4 that means no gearing changes which Steve usually recommends for C2 cars.Steve set me up with a full gasket kit already and I will have him do the heads as well as retrofit the later gaskets into my cylinders. Per Steve's advice he told me step 1 was to do a leak down test to see what we are starting with.
My car is a 1990 C4 with 61,000 miles. I just did my first leak down tests on a 964.
1) start car and get it up to temp, you want to do this hot
2) put car on lift
3) remove secondary muffler and cat as if doing a valve adjust (get access to lower spark plugs)
4) Steve advised I get a Snap On leak down tester and I did. Nice tool and worked flawlessly
5) Put each cylinder at TDC and hook up leak tester via lower spark plug port
6) Dial in left gauge of leak tester to 100psi, read dial on second gauge
7) If leakage is >8% listen if hiss is from intake, exhaust, or past cylinder (oil filler tube)
Here are my results:
Cylinder 1: 3%
Cylinder 2: 10% intake
Cylinder 3: 5%
Cylinder 4: 14% intake
Cylinder 5: 5%
Cylinder 6: 14% intake
Photos of my Cylinder 2 test below. Thankfully no nasty leak past cylinders because I do plan to re-use my pistons and cylinders if everything keeps checking out.
So the journey begins....
I really enjoyed doing the reseal on my 1991 C2 and learned how to drop a motor with the help of fellow rennlister StevePAA (who has moved on to Ferrari after his Tip got rear ended).
First thing I did to start this project was to setup a 1 hour consultation with Steve Weiner at Rennsport Systems. I told him I am pretty much a stock guy, and wanted to "hot rod" my C4 into a reliable street machine with a bit more go, and something to enjoy on driver's events on occasion. He talked to me about a couple of things I could do. This most important thing for me is to take system level approach to this. Not bolt on various go fast parts but rather rely on someone I trust who can deliver a system solution for what I am after. I am still not sure how far I will take this but I don't have to decide that right now.
Since I have a Carrera 4 that means no gearing changes which Steve usually recommends for C2 cars.Steve set me up with a full gasket kit already and I will have him do the heads as well as retrofit the later gaskets into my cylinders. Per Steve's advice he told me step 1 was to do a leak down test to see what we are starting with.
My car is a 1990 C4 with 61,000 miles. I just did my first leak down tests on a 964.
1) start car and get it up to temp, you want to do this hot
2) put car on lift
3) remove secondary muffler and cat as if doing a valve adjust (get access to lower spark plugs)
4) Steve advised I get a Snap On leak down tester and I did. Nice tool and worked flawlessly
5) Put each cylinder at TDC and hook up leak tester via lower spark plug port
6) Dial in left gauge of leak tester to 100psi, read dial on second gauge
7) If leakage is >8% listen if hiss is from intake, exhaust, or past cylinder (oil filler tube)
Here are my results:
Cylinder 1: 3%
Cylinder 2: 10% intake
Cylinder 3: 5%
Cylinder 4: 14% intake
Cylinder 5: 5%
Cylinder 6: 14% intake
Photos of my Cylinder 2 test below. Thankfully no nasty leak past cylinders because I do plan to re-use my pistons and cylinders if everything keeps checking out.
So the journey begins....
10-25-2014, 08:24 PM
#2
Three Wheelin'
I don't know enough about what lean down numbers are acceptable, but would seem to me that it's lots of work for a low mile good running car. The leaks really bother you enough to read it down? How bad are the leaks?
10-25-2014, 09:12 PM
#3
Rennlist Member
Thread Starter
I am committed to dropping the motor just to do all the gasket work, spark plugs wire, coils, new engine insulation, rebuild power steering pump, change distributor belt, etc. Fact is I could just do that, put the motor back, and be done with it. However, as I am sure you figured out by now, I am the kind of guy that will take a step further because I think its fun. I have an email out to Steve to evaluate my leak down numbers.
10-25-2014, 11:26 PM
#4
Rennlist Member
Thread Starter
Here are the BEFORE pictures.
10-26-2014, 12:19 PM
#6
Three Wheelin'
Good luck Ricardo. I always enjoy reading through your, very thorough, threads. You've got the approach of a good scientist.
I don't have near the experience of Steve, but 14% leak down is getting up there. Amazing that the Snap-on gauge says that 70% is in the "moderate" zone!
A couple thoughts from my recent rebuild/reseal-
1. The factory crank pulley and cam gear tools are worth it, as is the Stromski piston circlip tool.
2. I was able to cure all of my through-bolt leaks by replacing the 2x o-rings for each one, and torquing the bolts back up, one at a time. Worked perfectly.
3. Powder-coating my engine tin silver has been one of my favorite ideas. So much easier to look for leaks, dropped nuts, etc.
4. Replace all of the aluminum oil line sealing rings, but use common sense for the torque. The factory numbers are definitely too high for a few of them. Pelican has these for cheap under "washers".
5. The later 964 steel head bolts are only slightly less great than the 993TT and Supertec versions, but they seem to work great and they're much cheaper.
6. Harbor Freight heavy-duty disposable gloves are 100x better than your local auto parts version. They won't constantly rip and they are longer down your wrist. It's the little things...
7. Check the long fuel & power steering steel lines that run the length of the car. For some reason, they can corrode where they bend to go through the tunnel. Both of my fuel lines were one scratch from developing pinholes.
Excluding heads/valves, here is my parts list:
1. 999.270.070.01 clutch guide tube screws
2. 999.075.039.02 m6x12mm engine tin bolts, x12
3. 900.123.141.30, 25x30 sealing ring for oil fitting on bottom of case. I couldn't find this one outside of the dealer.
4. 999.707.293.40, p steering o-ring, 40x4mm, not in p. steering rebuild kit.
5. 999.113.463.40, cam seal on p steering end, not in p. steering rebuild kit.
6. 900.123.131.30 16x20 sealing rings chain guide bolt, x4
7. 900.123.139.30 26x32 sealing ring, oil tstat unions, x3
8. 900.123.106.30 18x24 sealing ring, oil pressure relief L case, also valve on bottom R case, x2
9. 911.602.102.01 distributor shaft o-ring seal
10. 999.707.315.40 intermediate shaft o-ring 33.3x2.4, below front crank seal
11. 999.707.152.40 cylinder base o-rings, x6
12. 999.701.006.40 through-bolt o-rings 8x2mm, x24, blue silicone
13. 964.104.115.20 headgasket/sealing ring x6, steel
14. 993.110.713.01 rubber gaskets for intake stacks x6
15. 999.510.015.02 clutch pressure plate bolts x9, m8x40
16. 999.113.326.41 transmission input shaft seal
17. 999.113.290.41 front crankshaft seal 30x50x8mm
18. 999.707.285.40 front crank o-ring seal 51x4.5mm
19. 964.207.327.00 breather hose
20. 964.105.043.02 left upper chain guide
21. 964.105.043.02 right lower chain guide
22. 930.107.791.02 breather gasket
23. 901.107.351.01 oil return tubes, x4
24. 999.707.112.40 return tube o-rings, 25x6mm, x8
25. 999.085.001.02 heat exchanger barrel nuts x6
26. 993.111.195.00 exhaust manifold sealing ring x6
27. 964.572.785.00 320mm heat exchanger to diverter flaps flex hose, x2
28. 999.201.365.00 needle bearing, in bellhousing for shaft inner, '91 C4
29. 999.201.339.00 needle bearing, in bellhousing for shaft outer, '91 C4
30. 950.116.725.00 cap, on fork shaft
31. 999.113.418.40 gasket on shaft x2
32. 999.113.426.41 crankshaft rear main seal, flywheel end
33. 964.147.187.03 p. steering belt
34. 900.123.118.30 t-stat/engine drain/trans drain aluminum sealing rings, 22x27mm, x6 including trans & diff
35. 928.332.051.02 C4 transverse lock inner rubber seal/bellows
36. 928.332.776.00 C4 paper gasket, transverse lock
37. 964.301.051.01 longitudinal lock inner rubber seal/bellows
38. 900.123.042.20 sealing ring, ps pump side x2
39. 964.111.198.00 gasket exchanger-cat
40. 964.111.192.05 gasket between exchangers
41. 930.105.197.05 timing chain round paper gasket, cam box x2
42. 999.707.313.40 timing chain o-ring behind cam box x2
43. 964.105.193.02 timing chain square gasket behind housing boxes x2
44. 964-105-181-98-INT Pelican# for Wrightwood Racing timing cover gasket kit
45. 964.105.173.01 upper valve cover gasket x6
46. 964.105.135.01 lower valve cover gasket x2
Some tools that may not be in your toolbox:
1. Impact screwdriver and a #3 (I think, or maybe a #2) philips bit for clutch guide tube screws.
2. Ring compressor and ring expander for piston rings.
3. Torque angle gauge/tool for factory head bolt torque.
4. Cheap digital scale that measures to 0.1 grams. If you want to balance your piston weights.
5. 8mm 1/2" drive triple square socket. For pressure plate bolts.
6. Clutch alignment plastic tool. It's a generic Ford clutch disk tool. I had to file mine slightly to fit the clutch disk.
7. Sir tools P207 z-block, and dial indicator for cam timing.
8. 13mm flex/u-joint 3/8" sockets. For the heat exchanger nuts (the only way to get to some of them)
9. 8mm ⅜” drive 5.5” long allen/hex socket for heat exchanger barrel nuts.
10. M12 triple square *long* socket 1/2" drive for head nuts.
11. M12 triple square socket 1/2" drive for flywheel-crank bolts.
12. 5mm 1/4" drive allen socket to torque rocker shafts.
13. 5mm 3/8" drive allen socket to remove rocker shafts.
14. 1/2", 3/8", and 1/4" drive torque wrenches. I used all three.
15. Stomski piston circlip installer tool.
16. Timing chain tensioner- drill two holes in a cheap brake pad spreader
17. Sir tool P237, Porsche P9191 camshaft sprocket holding tool.
18. Deep 19mm socket for cam sprocket bolts, use with P237
19. Old spark plug- use thread to pull out cam sprocket dowel
20. 000.721.928.51 special tool/bolt to remove crank pulley
21. 000.721.929.00 enormous pulley holding tool to remove/replace crank bolt, Sir tools P9280
22. Large open ended wrenches for engine oil lines - 36mm, 32mm, 30mm, 27mm
23. Sir tool P246 offset flare 36mm wrench - for oil lines. Not neccesary, but very helpful.
Chemicals and sealants:
1. DC 55 (Molykote) is your friend, slather it on all rubber o-rings.
2. 000.043.024.00 Olista Longtime 3EP, lube for clutch parts, between metal and metal surfaces
3. 999.917.788.00 Optimol MPO, lube for clutch parts, between metal and plastic surfaces
4. Liquimoly LM 48 assembly lube for the cams, moving engine parts.
5. Liquimoly LM 508 copper anti-sieze. For high-temp parts, exhaust nuts & bolts, etc.
6. Pentosin CHF202 or 11S for power steering. System takes exactly 1 liter in my experience.
7. Loctite 574 flange sealant, orange, for timing chain boxes.
8. Threebond 1194, and a rubber roller (art supplies store) to apply it. For cam tower surface.
I don't have near the experience of Steve, but 14% leak down is getting up there. Amazing that the Snap-on gauge says that 70% is in the "moderate" zone!
A couple thoughts from my recent rebuild/reseal-
1. The factory crank pulley and cam gear tools are worth it, as is the Stromski piston circlip tool.
2. I was able to cure all of my through-bolt leaks by replacing the 2x o-rings for each one, and torquing the bolts back up, one at a time. Worked perfectly.
3. Powder-coating my engine tin silver has been one of my favorite ideas. So much easier to look for leaks, dropped nuts, etc.
4. Replace all of the aluminum oil line sealing rings, but use common sense for the torque. The factory numbers are definitely too high for a few of them. Pelican has these for cheap under "washers".
5. The later 964 steel head bolts are only slightly less great than the 993TT and Supertec versions, but they seem to work great and they're much cheaper.
6. Harbor Freight heavy-duty disposable gloves are 100x better than your local auto parts version. They won't constantly rip and they are longer down your wrist. It's the little things...
7. Check the long fuel & power steering steel lines that run the length of the car. For some reason, they can corrode where they bend to go through the tunnel. Both of my fuel lines were one scratch from developing pinholes.
Excluding heads/valves, here is my parts list:
1. 999.270.070.01 clutch guide tube screws
2. 999.075.039.02 m6x12mm engine tin bolts, x12
3. 900.123.141.30, 25x30 sealing ring for oil fitting on bottom of case. I couldn't find this one outside of the dealer.
4. 999.707.293.40, p steering o-ring, 40x4mm, not in p. steering rebuild kit.
5. 999.113.463.40, cam seal on p steering end, not in p. steering rebuild kit.
6. 900.123.131.30 16x20 sealing rings chain guide bolt, x4
7. 900.123.139.30 26x32 sealing ring, oil tstat unions, x3
8. 900.123.106.30 18x24 sealing ring, oil pressure relief L case, also valve on bottom R case, x2
9. 911.602.102.01 distributor shaft o-ring seal
10. 999.707.315.40 intermediate shaft o-ring 33.3x2.4, below front crank seal
11. 999.707.152.40 cylinder base o-rings, x6
12. 999.701.006.40 through-bolt o-rings 8x2mm, x24, blue silicone
13. 964.104.115.20 headgasket/sealing ring x6, steel
14. 993.110.713.01 rubber gaskets for intake stacks x6
15. 999.510.015.02 clutch pressure plate bolts x9, m8x40
16. 999.113.326.41 transmission input shaft seal
17. 999.113.290.41 front crankshaft seal 30x50x8mm
18. 999.707.285.40 front crank o-ring seal 51x4.5mm
19. 964.207.327.00 breather hose
20. 964.105.043.02 left upper chain guide
21. 964.105.043.02 right lower chain guide
22. 930.107.791.02 breather gasket
23. 901.107.351.01 oil return tubes, x4
24. 999.707.112.40 return tube o-rings, 25x6mm, x8
25. 999.085.001.02 heat exchanger barrel nuts x6
26. 993.111.195.00 exhaust manifold sealing ring x6
27. 964.572.785.00 320mm heat exchanger to diverter flaps flex hose, x2
28. 999.201.365.00 needle bearing, in bellhousing for shaft inner, '91 C4
29. 999.201.339.00 needle bearing, in bellhousing for shaft outer, '91 C4
30. 950.116.725.00 cap, on fork shaft
31. 999.113.418.40 gasket on shaft x2
32. 999.113.426.41 crankshaft rear main seal, flywheel end
33. 964.147.187.03 p. steering belt
34. 900.123.118.30 t-stat/engine drain/trans drain aluminum sealing rings, 22x27mm, x6 including trans & diff
35. 928.332.051.02 C4 transverse lock inner rubber seal/bellows
36. 928.332.776.00 C4 paper gasket, transverse lock
37. 964.301.051.01 longitudinal lock inner rubber seal/bellows
38. 900.123.042.20 sealing ring, ps pump side x2
39. 964.111.198.00 gasket exchanger-cat
40. 964.111.192.05 gasket between exchangers
41. 930.105.197.05 timing chain round paper gasket, cam box x2
42. 999.707.313.40 timing chain o-ring behind cam box x2
43. 964.105.193.02 timing chain square gasket behind housing boxes x2
44. 964-105-181-98-INT Pelican# for Wrightwood Racing timing cover gasket kit
45. 964.105.173.01 upper valve cover gasket x6
46. 964.105.135.01 lower valve cover gasket x2
Some tools that may not be in your toolbox:
1. Impact screwdriver and a #3 (I think, or maybe a #2) philips bit for clutch guide tube screws.
2. Ring compressor and ring expander for piston rings.
3. Torque angle gauge/tool for factory head bolt torque.
4. Cheap digital scale that measures to 0.1 grams. If you want to balance your piston weights.
5. 8mm 1/2" drive triple square socket. For pressure plate bolts.
6. Clutch alignment plastic tool. It's a generic Ford clutch disk tool. I had to file mine slightly to fit the clutch disk.
7. Sir tools P207 z-block, and dial indicator for cam timing.
8. 13mm flex/u-joint 3/8" sockets. For the heat exchanger nuts (the only way to get to some of them)
9. 8mm ⅜” drive 5.5” long allen/hex socket for heat exchanger barrel nuts.
10. M12 triple square *long* socket 1/2" drive for head nuts.
11. M12 triple square socket 1/2" drive for flywheel-crank bolts.
12. 5mm 1/4" drive allen socket to torque rocker shafts.
13. 5mm 3/8" drive allen socket to remove rocker shafts.
14. 1/2", 3/8", and 1/4" drive torque wrenches. I used all three.
15. Stomski piston circlip installer tool.
16. Timing chain tensioner- drill two holes in a cheap brake pad spreader
17. Sir tool P237, Porsche P9191 camshaft sprocket holding tool.
18. Deep 19mm socket for cam sprocket bolts, use with P237
19. Old spark plug- use thread to pull out cam sprocket dowel
20. 000.721.928.51 special tool/bolt to remove crank pulley
21. 000.721.929.00 enormous pulley holding tool to remove/replace crank bolt, Sir tools P9280
22. Large open ended wrenches for engine oil lines - 36mm, 32mm, 30mm, 27mm
23. Sir tool P246 offset flare 36mm wrench - for oil lines. Not neccesary, but very helpful.
Chemicals and sealants:
1. DC 55 (Molykote) is your friend, slather it on all rubber o-rings.
2. 000.043.024.00 Olista Longtime 3EP, lube for clutch parts, between metal and metal surfaces
3. 999.917.788.00 Optimol MPO, lube for clutch parts, between metal and plastic surfaces
4. Liquimoly LM 48 assembly lube for the cams, moving engine parts.
5. Liquimoly LM 508 copper anti-sieze. For high-temp parts, exhaust nuts & bolts, etc.
6. Pentosin CHF202 or 11S for power steering. System takes exactly 1 liter in my experience.
7. Loctite 574 flange sealant, orange, for timing chain boxes.
8. Threebond 1194, and a rubber roller (art supplies store) to apply it. For cam tower surface.
Last edited by -nick; 04-19-2017 at 04:00 PM. Reason: additional part numbers
10-26-2014, 12:36 PM
#7
Three Wheelin'
I have nothing to really add here other than my amazement of you guys who are willing and able to take on projects like this in your own garage.
Looking forward to another detailed thread. I have an entire memory card full of rebuild pics from my motor and trans. My wallet and i both agree being more hands on would have been great
Looking forward to another detailed thread. I have an entire memory card full of rebuild pics from my motor and trans. My wallet and i both agree being more hands on would have been great
Trending Topics
10-26-2014, 02:14 PM
#9
Burning Brakes
Ricardo's DIY threads are some of the best I've read. My C4 brake/hydraulic bleed went flawlessly by following Ricardo's thread
https://rennlist.com/forums/964-foru...procedure.html
I'm really looking forward to this one.......
Thanks 
Ricardo
The following users liked this post:
kos11-12 (10-30-2020)
10-26-2014, 10:44 PM
#10
Rennlist Member
Thread Starter
Wow, Nick, thanks for the comprehensive list of special tools. I have some of them but will reference your list down the road.
10-26-2014, 11:18 PM
#11
Rennlist Member
Thread Starter
Next step for me to to drop the engine on my C4. I am using Adrian Streather's Porsche 911 (964) Enthusiast's Companion: Carrera 2, Carrera 4, and Turbo 1989-1994 and Garrett's famous C4 engine drop post from 2005 as my guide. I am following Adrian's procedure and then check Garrett's post when I run into trouble or need color photo references.
I will be disconnecting the throttle cable from the engine this time. On my C2 I disconnected at the pedal and ended up damaging the cable during service of the engine.
My list of reference material:
- Adrian Streather's Porsche 911 (964) Enthusiast's Companion: Carrera 2, Carrera 4, and Turbo 1989-1994
- Wayne Dempsey's How to Rebuild and Modify Porsche 911 Engines 1965-1989
- Bentley's Porsche Carrera 964: 1989-1994 Technical Data - Without Guesswork:
- Rennlist 964 Forum of course
- pfixit.com 964 engine rebuild video
- Rennsport System's Steve Weiner to supply my parts and performance consultation
Currently stuck on clutch slave cylinder removal, the top nut is a pain in the butt!
I will be disconnecting the throttle cable from the engine this time. On my C2 I disconnected at the pedal and ended up damaging the cable during service of the engine.
My list of reference material:
- Adrian Streather's Porsche 911 (964) Enthusiast's Companion: Carrera 2, Carrera 4, and Turbo 1989-1994
- Wayne Dempsey's How to Rebuild and Modify Porsche 911 Engines 1965-1989
- Bentley's Porsche Carrera 964: 1989-1994 Technical Data - Without Guesswork:
- Rennlist 964 Forum of course
- pfixit.com 964 engine rebuild video
- Rennsport System's Steve Weiner to supply my parts and performance consultation
Currently stuck on clutch slave cylinder removal, the top nut is a pain in the butt!
10-28-2014, 12:39 PM
#13
With a garage like that, you WILL have fun rebuilding the engine.
Top end rebuild has been one of my favorite task in my 964/993. The amount of knowledge, resource, and support for these 911s is absolutely incredible.
Top end rebuild has been one of my favorite task in my 964/993. The amount of knowledge, resource, and support for these 911s is absolutely incredible.
10-28-2014, 03:35 PM
#14
Three Wheelin'
Go Ricardo. I am a big fan and hope this goes well. I'll be doing it one day myself. The slave cylinder seems like mostly just getting the right elbow position from below. I did mine on jackstands in the driveway. Seems like it helped to remove the plastic duct that blocks some of your access. Wheel off of course.
This looks like a fine thread already. And a very generous contribution from Nick to help fill in some of the blanks.
This looks like a fine thread already. And a very generous contribution from Nick to help fill in some of the blanks.
