120 to 114 to 113 Twin Cam Engine Rebuild
- Thread starter hulkss
- Start date
Yes, I have all the parts including the coated pistons. I'll be putting the top end on pretty soon.
I'm preparing to put the top end together now. I first checked the piston ring end gaps in the refinished cylinders. To my amazement they were factory set right-on where I would have put them: top compression ring .016"; second compression ring .022", oil ring rails .010".
Next I pulled the dowel pins from the cylinders with a screw extractor so I could lap the top faces. They might not be flat and I will be using multi-layer steel (MLS) head gaskets that need good flat mating surfaces.
I lapped the cylinders flat using 180 grit 3M Pro Grade Advanced Sand Paper on a granite surface plate. I rotated them by hand to create a circular finish that will seal properly. One cylinder cleaned up easy. The other was not as flat and needed more work.
They look really good now. The iron liners are perfectly flush with the aluminum castings. I'll press in new dowel pins before assembly.
Next I pulled the dowel pins from the cylinders with a screw extractor so I could lap the top faces. They might not be flat and I will be using multi-layer steel (MLS) head gaskets that need good flat mating surfaces.
I lapped the cylinders flat using 180 grit 3M Pro Grade Advanced Sand Paper on a granite surface plate. I rotated them by hand to create a circular finish that will seal properly. One cylinder cleaned up easy. The other was not as flat and needed more work.
They look really good now. The iron liners are perfectly flush with the aluminum castings. I'll press in new dowel pins before assembly.
For those interested, I like these instructions the best for top end assembly: JIMS Big Bore Kit Instructions
120 to 114 Twin Cam Engine Rebuild
120 to 114 Twin Cam Engine Rebuild
What's your overall rating on the 120 ?
The 120ST a great running motor. Puts out 120 HP and 120 TQ with a nice flat torque curve. Knowing what I know now, I would pull the heads and re-build them when new as I discussed in an earlier post.
120 to 114 Twin Cam Engine Rebuild
What's your overall rating on the 120 ?
The 120ST a great running motor. Puts out 120 HP and 120 TQ with a nice flat torque curve. Knowing what I know now, I would pull the heads and re-build them when new as I discussed in an earlier post.
Here's a look at a piston with Line2Line abradable coating applied (as discussed in an earlier post).
The bore fit should not allow the piston to drop through, but you should be able to push it through with your fingers. Again I am amazed, they fit perfectly. Good work by Line2Line Coatings and Dave Mackie Engineering on the bore sizing.
Now to wash the cylinders with soapy water.
Ugh, this did not get them even close to clean enough. What worked? These microfiber wipes from Amazon soaked with some good old Marvel Mystery Oil (MMO). Wipe over and over until there is no discoloration on the wipes.
Now the cylinders are supposed to pass the "cotton ball test". If you wipe a cotton ball in the bore, it should not snag on the surface finish. If it does, you have folded metal on the edges of the cross hatch surface finish. This folded metal will end up as debris between your cylinder and piston. Test result: PASS
Here is what the bore finish from Dave Mackie Engineering looks like:
The final step was to apply Akerly & Childs AC-9900 assembly lube made for pistons, rings, and cylinders. It is supposed to burn clean and not leave hydro-carbon deposits on parts.
The bore fit should not allow the piston to drop through, but you should be able to push it through with your fingers. Again I am amazed, they fit perfectly. Good work by Line2Line Coatings and Dave Mackie Engineering on the bore sizing.
Now to wash the cylinders with soapy water.
Ugh, this did not get them even close to clean enough. What worked? These microfiber wipes from Amazon soaked with some good old Marvel Mystery Oil (MMO). Wipe over and over until there is no discoloration on the wipes.
Now the cylinders are supposed to pass the "cotton ball test". If you wipe a cotton ball in the bore, it should not snag on the surface finish. If it does, you have folded metal on the edges of the cross hatch surface finish. This folded metal will end up as debris between your cylinder and piston. Test result: PASS
Here is what the bore finish from Dave Mackie Engineering looks like:
The final step was to apply Akerly & Childs AC-9900 assembly lube made for pistons, rings, and cylinders. It is supposed to burn clean and not leave hydro-carbon deposits on parts.
This is fussy detailed work: Clean pistons and rings; Lube rings with assembly lube for rings mentioned earlier; Install left side circlips in pistons; Install piston rings; lube piston skirts; push pistons into cylinder spigots. Everything has a special position and orientation.
I used a one piece tapered ring compressor from ARP. This worked great.
Here you can see the piston rings. Don't get an end gap in these cut-outs or you might ruin a ring trying to push the piston into the bore. This is all the further the pistons can go and still let me get the wrist pins in. The spigot cut out is not for wrist pin assembly, it's there to clear the piston oiling jets.
Here's some photos of the blueprinted heads. You can see the AV&V beehive valve springs and the cleaned-up combustion chamber with re-ground valves.
Here you can see the intake and exhaust AV&V manganese bronze guides and the nice CNC factory porting in the MVA heads. Looks great when blasted clean. That little hole in the exhaust port is where the automatic compression release vents to.
Next step: put the cylinders & pistons back on the cases.
I used a one piece tapered ring compressor from ARP. This worked great.
Here you can see the piston rings. Don't get an end gap in these cut-outs or you might ruin a ring trying to push the piston into the bore. This is all the further the pistons can go and still let me get the wrist pins in. The spigot cut out is not for wrist pin assembly, it's there to clear the piston oiling jets.
Here's some photos of the blueprinted heads. You can see the AV&V beehive valve springs and the cleaned-up combustion chamber with re-ground valves.
Here you can see the intake and exhaust AV&V manganese bronze guides and the nice CNC factory porting in the MVA heads. Looks great when blasted clean. That little hole in the exhaust port is where the automatic compression release vents to.
Next step: put the cylinders & pistons back on the cases.
I made some split 4" long spacers from some flexible plastic water pipe. I put them on the cylinder studs. I pushed the piston up in the bore and set the rear cylinder in place. I pushed the piston down so I could see through the wrist pin bore and pushed in the wrist pin.
Now for the dreaded circlip. From doing one side on the bench, I knew just how to do it. Just use a little screwdriver in the notch as shown in this video.
Here's a photo showing the front cylinder ready to have the orange spacers removed.
And here's the finished job. The white PVC pipe spacers are holding the cylinders in place so I can rotate the engine and check the piston deck height.
Now for the dreaded circlip. From doing one side on the bench, I knew just how to do it. Just use a little screwdriver in the notch as shown in this video.
Here's a photo showing the front cylinder ready to have the orange spacers removed.
And here's the finished job. The white PVC pipe spacers are holding the cylinders in place so I can rotate the engine and check the piston deck height.
Glad to hear that you didn't have any trouble with the wrist pin clips. From looking at the Vertex video, it appears as if the clips used were just like the stock clips. If so, those are a more flexible and a whole lot easier to install using the method shown in the video. Now the FM clips that come with the CP pistons and have the little tangs on them are a hell of a lot harder to install. I'm excited for you brother. The process will move much more quickly now.
Those are called Kramm-Lox and there is a special hollow tipped tool for them. Makes them the easiest of all.
I'm using SE forged rocker arm supports and S&S forged standard rocker arms. With the cam I have (.579 valve lift), I don't need or want roller rockers as they are less stiff than normal rocker arms. Stiffness the the key to good valve train dynamics.
Note the larger oil drain holes for the breather valves in the center of the forged support. I also Installed S&S rocker shafts and Rockout inserts to prevent rocker shaft rotation and noise. Here you can see the difference between stock and the new parts.
I followed the advice of NGOT8R to adjust the new Fuel Moto push rods.
Do not install the push rod cover tubes. I did make an attempt with one cover tube and deemed it for self torture only. With different tubes or softer springs it might be possible. The tube holder tool proved futile.
Just torque the rocker arm assemblies into place, adjust the pushrods per instructions (with no cover tubes), then disassemble and reassemble to install the cover tubes like you were working with fixed push rods. Simple and easy.
Now it almost looks like an engine again!
Note the larger oil drain holes for the breather valves in the center of the forged support. I also Installed S&S rocker shafts and Rockout inserts to prevent rocker shaft rotation and noise. Here you can see the difference between stock and the new parts.
I followed the advice of NGOT8R to adjust the new Fuel Moto push rods.
Do not install the push rod cover tubes. I did make an attempt with one cover tube and deemed it for self torture only. With different tubes or softer springs it might be possible. The tube holder tool proved futile.
Just torque the rocker arm assemblies into place, adjust the pushrods per instructions (with no cover tubes), then disassemble and reassemble to install the cover tubes like you were working with fixed push rods. Simple and easy.
Now it almost looks like an engine again!
Thanks for the vote of confidence. I feel that I may be able to participate in a conversation about late model twin cam engines now.
I've been working on the drive train. Here's a view of the completed primary case internals including: new compensator (OEM) with GMR "Compensaver" oiling tray: the original chain tensioner at the bottom; CVO Clutch with a Rekluse EXP clutch pack; and a new 1.4 kW high performance starter from H-D.
I put a light coating Molykote G-N on the clutch and compensator splines where they were fretting before.
The new starter has a significantly bigger motor. The old starter was not enough for the big motor.
The Rekluse EXP centrifugal clutch was easy to install.
I also got my wheels back together with new Dunlop American Elite Tires and chrome steel valve stems. I'm using an 18" front wheel from a 2013 Street Glide. I believe I get a little better ride and grip with the 18 in tire vs the low profile 19 inch tire.
I refurbished the brake rotors with a special Flex-Hone. I also picked up some new EBC high friction certified brake pads.
I put a light coating Molykote G-N on the clutch and compensator splines where they were fretting before.
The new starter has a significantly bigger motor. The old starter was not enough for the big motor.
The Rekluse EXP centrifugal clutch was easy to install.
I also got my wheels back together with new Dunlop American Elite Tires and chrome steel valve stems. I'm using an 18" front wheel from a 2013 Street Glide. I believe I get a little better ride and grip with the 18 in tire vs the low profile 19 inch tire.
I refurbished the brake rotors with a special Flex-Hone. I also picked up some new EBC high friction certified brake pads.
Here's some dimensional specifications on my 114 engine as built. These are standard dimensions from H-D with a +.010 re-bore of the cylinders and a slight cut on the heads to reduce the combustion chamber from 97 cc (after valve job) to 93 cc.
Cylinder Bore = 4.070”
Piston Stroke = 4.375”
Connecting Rod Length = 7.667”
Head Gasket Thickness = 0.030”
Head Gasket Bore = 4.090”
Piston to Cylinder Deck Height = 0.000”
Head Gasket Volume = 6.46 cc
Cylinder Head Volume = 93.00 cc
Deck Height Volume = 0.00 cc
Piston Dome Volume = 5.00 cc
Head Volume Total = 94.46 cc
Single Cylinder Displacement = 932.73 cc (113.84 cubic inches total)
Calculated Compression Ratio =10.87 : 1
Intake Valve Closing 47 deg ABDC (SE 259E cam)
Corrected Compression Ratio 9.68 : 1
Calculated Cranking Compression Pressure 203.4 psig
Cylinder Bore = 4.070”
Piston Stroke = 4.375”
Connecting Rod Length = 7.667”
Head Gasket Thickness = 0.030”
Head Gasket Bore = 4.090”
Piston to Cylinder Deck Height = 0.000”
Head Gasket Volume = 6.46 cc
Cylinder Head Volume = 93.00 cc
Deck Height Volume = 0.00 cc
Piston Dome Volume = 5.00 cc
Head Volume Total = 94.46 cc
Single Cylinder Displacement = 932.73 cc (113.84 cubic inches total)
Calculated Compression Ratio =10.87 : 1
Intake Valve Closing 47 deg ABDC (SE 259E cam)
Corrected Compression Ratio 9.68 : 1
Calculated Cranking Compression Pressure 203.4 psig
Before I go any farther with this engine build (primary still open and no fuel or intake system) I want to test the engine a bit. I connected a mechanical oil pressure gauge where the pressure sensor goes. Then I connected a remote start switch from the starter motor battery terminal to the starter solenoid connector. No spark plugs installed, main fuze out, ignition switch off. I don't have the fuel system installed, however if I did, I do not want fuel to be injected or the the ignition to try to spark.
With no cylinder compression, this starter cranking test should break-in the new starter at light load, prime the oil system, and confirm that valves are not hitting pistons or other gross problems from assembly errors.
Pressing starter button....cringe....
Wow....cranks fast and sounds good. After a few 10 second blasts I get 35 psi on the oil gauge. Cool! I'm good up to this point
With no cylinder compression, this starter cranking test should break-in the new starter at light load, prime the oil system, and confirm that valves are not hitting pistons or other gross problems from assembly errors.
Pressing starter button....cringe....
Wow....cranks fast and sounds good. After a few 10 second blasts I get 35 psi on the oil gauge. Cool! I'm good up to this point
