Author Topic: 383 / 432 Mopar stroker for the Challenger (Read 31785 times)

femtnmax · « **Reply #15 on:** December 04, 2013 - 07:19:37 PM »

Quote from: brads70 on December 04, 2013 - 09:08:12 AM

I'd be spending a few hours with a die grinder under those valve seats..... I just couldn't leave them like that.

Yea, isn't it great:) That will be coming up soon.
First photo: cranked #1 piston to TDC, installed the timing cover and crank damper to check the damper timing mark for correct TDC. All was ok, so I stamped a couple punch marks on the inner and outer ring of the damper so it will be easy to see if the outer ring turns later on.

Next two photos show valve lift using OEM stamped rocker arms. Checked both intake and exhaust on #1 cylinder. There was basically NO loss in lift with these two stamped rockers. Heres the measurements:
Intake measured lift: .478, cam card spec: .477
Exhaust measured lift: .484, cam card spec: .486
So two of my 1969 stamped rocker arms are right on the money. I"ll check the rest too.

Last two photos show the rocker arm contact pattern on the valve stem. Not a bad contact width considering OEM stamped rocker pushed to hemi cam valve lift.

femtnmax · « **Reply #16 on:** December 05, 2013 - 07:31:08 PM »

440 OEM stamped rocker arm ratio check

Checked all 16 stamped rocker arms for the correct ratio; these are 1969 OEM Mopar rockers with 1.5 ratio. Measured valve lift at the valve spring retainer.

Intake valve lift cam spec: .478
Measured valve lift ranged from .475 to .480, with average = .477

Exhaust valve lift cam spec: .486
Measured valve lift ranged from .481 to .486, with average = .483

So all 16 rocker arms are within 99% of the correct ratio. That�s real close IMO. Maybe I was lucky but good to know they are not way off like some internet sources suggest.

femtnmax · « **Reply #17 on:** December 10, 2013 - 08:25:52 PM »

First photo shows clay checked piston to valve clearance using .517/.524 intake/exhaust lift. Clay thickness showed over .15 inch clearance between piston & valve at these valve lifts. Spring retainer to guide clearance is enough for valve stem seal and .06 gap between spring retainer and valve seal/guide.

Second photo shows crankshaft rear main seal housing alignment check. The groove in the seal housing easily lined up with the groove in the engine block. Recommended rear main seal install is to have the ends of each seal half not meet at the housing/engine block parting surface, but instead have one end of the rear main seal extend out of the seal housing by about 3/16 to 1/4 inch. The seal half in the block extends out of the block also. That way the seal halves help line up the seal housing during its installation.

Third photo shows inside mic measuring the crank main bearing bore diameter. Then outside micrometer measures the inside mic �length�. Take this measurement and subtract the measured thickness of the two bearing shells, then subtract the crank main journal diameter, and the result is the actual clearance between the crank main journal and the bearings for that journal. Repeat the process for all 5 main journals.

Fourth photo shows checking piston ring end gap. The Mahle rings were file-to-fit type so each ring needs to be placed in �its� cylinder and the ring gap set for that ring/cylinder. The Mahle ring kit included up to date instructions which included setting the ring gap for the 2nd compression ring larger than the top ring. Good to see this info being put out there for use. I would have also had info detailing their ring kits �napier� second ring and the benefits of this ring style over the old no-twisted 2nd ring. The napier ring is twisted, thus the lower edge seats into the cylinder quicker and helps scrape off cylinder wall oil which to me is important with todays full groove main bearings sending oil to the connecting rods during full 360 degree crank rotation. Full rotation rod oiling means full oil pressure volume is thrown off the rods and onto the cylinder walls for the entire 360 degree crank rotation, rather than 180 degrees as the OEM designed the 440. Less oil finding its way into the combustion chamber is less chance for detonation.
Buying a ring kit with Napier second ring is one of the reasons I did not buy a complete rotating assy from one of the vendors, because they did not specify what ring package you were getting. Napier kits cost more.
The flat washer taped to the engine block head gasket surface is my �simulated� head gasket thickness for mocking up the valve train geometry including pushrod length. I have 3 taped-on washer locations, and install two center head bolts and lightly tighten�the head is then ready to go for mock up.

Last photo shows final .017 ring end gap. Filed with a hand file, each file stroke away from the moly ring face so as to not chip the moly coating off. Then debur the finished corners with a small knife sharpening stone (ring in photo not yet debured). There are nice ring gap rotating files with hand crank and such, I don�t have one & not too worried about it.

'Cuda Hunter · « **Reply #18 on:** December 10, 2013 - 09:05:05 PM »

Wow, this is a cool build. Love the detail.

femtnmax · « **Reply #19 on:** December 15, 2013 - 10:34:35 PM »

Cudahunter..I'm glad the details are worth presenting. I think its interesting and worth doing.

First photo shows rounded off sharp edge of crank and rod bearing housing so when inserting the bearing half into the block or connecting rod the sharp edge does not scrape off any of the backing material from the bearing.

Second photo shows plastic gauge measurement to determine oil clearance between crank and main bearing with thickness reading just under .002 inch. 1970 Dodge factory service manual pgs 9-62,63 (383/440 engine) and pgs 9-81,82 (hemi engine) discuss shim stock method to measure bearing clearance, which is similar to plastic gauge method in that a piece of material is fitted between the crank and bearing to determine oil clearance. This is an alternate method to determine oil clearance for main and rod bearings, from what was shown in an earlier post.

Third photo shows crankshaft rear main seal installed with seal end offset from housing parting line. The seal offset helps line up the seal housing to the engine block and helps prevent oil leakage between the seal halves. A drop of black RTV silicone is placed on the seal ends and across the seal housing parting line prior to installing the housing/seal into place.

Fourth photo shows Napier style second compression ring. Note the scoop shape at the bottom of the ring.
Fifth photo shows explanation of Napier compression ring. Ring/scoop will be pressed against the cylinder wall. I should have drawn it with the ring against the cylinder wall.

Sixth photo shows filing the ring end to set the ring gap. Only file one end of the ring so the filed end can be kept parallel to the other untouched end. The small wetstone is shown that will be used to debur the sharp edges of each of the ring ends.
Ring gaps for this engine; 4.28 cylinder bore are .017 (top ring) and .021 (second ring). Must consult piston manufacture info to see what ring gap they require. The KB hyper pistons require special wider ring gaps for the top ring because of material used to make the pistons.

Seventh photos shows number 1 main bearing shell with chamfer filed at one location on the bearing. This location points toward the front of the engine. Oil will flow thru the chamfer to squirt onto the timing chain & gear for lubrication.

Eighth photo shows number 3 main bearing with thrust faces. Adding a chamfer to two of the rear facing edges of the upper bearing half allows oil to flow to the thrust face of the bearing to help lubricate the thrust face. When the clutch pedal is pressed to the floor the crankshaft is pushed forward. The only thing that keeps the crank in place is the number 3 main bearing thrust face, and lubrication is helped by adding the two chamfers.

moparmaniac59 · « **Reply #20 on:** December 15, 2013 - 11:30:31 PM »

I agree with Josh, awesome! I've enjoyed following this thread. Interesting. It should be an awesome motor!

Matt B.

femtnmax · « **Reply #21 on:** December 17, 2013 - 09:30:28 PM »

Checking crankshaft main bearing bore diameter and alignment.
The crankshaft main bearing caps were placed in their correct locations (the caps are all numbered) in the engine block and main bolts torqued to spec. Then the main bearing housing �bores� were measured in two directions (�vertical� crank center to camshaft center, and �horizontal� along main cap parting line). Comparing these measurements to factory specs showed the housing bores in my 1969 block were all within or very close to factory dimensions and tolerances. The OEM main bearings showed no sign of abnormal wear after 80k miles. Some correction was necessary to make the dimensions �near perfect�.

Final crankshaft to main bearing oil clearance for each of the 5 main bearing locations is .002 inch. For street/strip use .001-.0025 is acceptable. Some racers like more, some say no, keep the clearances at the factory specs.
With the bearings lightly oiled and main bearing caps torqued to spec the crankshaft was rotated and checked for consistent ease of rotation thru 360 degrees (each full revolution). The crank rotated smoothly, no tight spots or binding. The crank required ONE inch pound of torque to start it rotating, which is good IMO considering how heavy the Scat forged crank is.

The first photo shows checking the alignment of the engine block side of the bearing �bores�.
Second photo shows checking the main caps for proper alignment.
Third photo shows placing one drop of engine oil on main cap bolt threads. A second drop or two goes under the head of the bolt. Factory bolt torque specs assume the threads are lightly oiled and the head of the bolt does not bind as the bolt seats itself.

Don�t forget to clean all the threaded bolt holes by running a thread tap down the entire length of each hole; followed by blowing the hole out with compressed air. Also run a die down the bolt threads or clean them on a wire wheel, etc.
I then hand turn each bolt into its hole making sure the bolt can be hand turned in and out the entire depth of the hole. I clean all bolts and holes on the entire engine, the little oil pan bolts too.

There can be a long discussion concerning align honing crankshaft main bearing bores. Smokey Yunick in his book "Power Secrets" points out that poor align hone work by many shops is very common. He suggests leave the bearing bores as-is unless there is a real problem, then find a reputable shop to do the work. He says the block twists as the engine revs so the main bearing bores don't stay in alignment anyway.
I have been an ASE certified mechanic since 1977 and I have seen some real crap align hone jobs, so I have to agree with Smokey.

inviolet · « **Reply #22 on:** December 20, 2013 - 10:16:12 AM »

Quote from: ragtopchally on March 26, 2013 - 04:55:57 PM

If you're going with a stroker kit, why not get one w/a 4.150" crank to get 472"?

472 cu. in. (383-400 Main)
Crank: 4.150" Stroke Rod: 6.760" Rod Length
4-383-4150-6760-2374 2-440-6760-2374-990 PREM.
FORGED
(DISH) 4.280 - - - 1-48083-1 $2010 1-48083 $2212 1-48083BI $2336

440 source makes a kit too:

383 >> 496. (4.250" stroke/6.535" rod) Approximate Bobweight: 2150

Turn that docile factory 383 block into a fire breathing, pavement twisting engine of almost 500 cubic inches, and no one (even the car show judges) will ever be able to tell it's not a 383... until they go for a ride! The time has arrived to dust off those 383 blocks we've been leaving in the back of the garage all those years. Chrysler made 4 times as many 383's as they did 440's, and it's no longer necessary to dig up a 440 block to get almost 500 cubes! The low deck, 4.250" stroke version of our Platinum Series crank used in this kit has the smaller 2.200" (big block Chevy sized) journals, and the counterweights are finished at the smaller "B" engine size, to ensure they will drop right into the block with no counterweight clearancing issues. Depending on the block used, many of customers find this kit drops right in with no modifications whatsoever! We now offer fully chamfered "B" engine main bearings as an available upgrade! We keep all the kits listed below normally on our our shelf and ready to ship, usually within 24 hours!

I have the 440 source 496 Stroker kit. Roughly 14,000 miles on it so far,,, and It runs like a Rapped Ape.

Eddy RPM Heads, EDDY RPM Intake, Holley 833 HP. DYNO'D at the Fly Wheel 555HP and 633 Torque.

femtnmax · « **Reply #23 on:** December 23, 2013 - 09:25:34 PM »

Quote from: inviolet on December 20, 2013 - 10:16:12 AM

I have the 440 source 496 Stroker kit. Roughly 14,000 miles on it so far,,, and It runs like a Rapped Ape.

I would love to take your 496 for a spin.
Why did I not go for 470 or 496 cubes?
The 470 needs a Mopar 400 block. Did not find one locally. I was looking for a 400 block when the 383 came along.
According to 440Source both the 470 and 496 need 6.535 rod length, and the 470 and for sure the 496 really need some good flowing cylinder heads. I�m doing a budget build and don�t have the $$ to buy the parts. I�m using the rods that came with the 383, which some say will help avoid detonation with the OEM open chamber heads.
The short piston pin height of the 496 means short piston skirts. Any rocking of the piston will hurt ring seal. The cylinders need to be carefully cut/honed to final shape, and cylinder head torque plates would help a lot to make true/round cylinders. There is no machine shop in my area that has Mopar torque plates/ does quality work. I did not want to chance early ring seal blowby/failure knowing that my cylinders are not as round as I would wish.

First photo shows installing the oil pump drive bushing. With a file chamfered the outer circumference �edge� of the new bushing and tapped it into place using a brass drift and the pump drive shaft to push the bushing into place. Easy install with no issues.

Second photo shows cylinder head on the block, not much room to unshroud the valves by enlarging the combustion chamber. Unshrouding the valves improves mixture flow past the valves. Lots of porting articles show large amounts of unshrouding on Mopar big block heads and big flow increases to go with it, but I don�t see much room for doing so on the 383, and a 440 and 400 each only increases the cylinder diameter by the thickness of the black felt tip lines shown on the next photo. So figure two felt tip lines for the 400. I did what I could to unshroud by chamfering the top of the cylinders and will unshroud the valves and blend to the cylinder chamfers.

Third photos shows chamfers at the top of the cylinders. The black felt tip lines are a trace of the head gasket combustion chamber. I chamfer only up to a little less than the felt tip lines so the head gasket will seal properly.

Fourth photos shows felt tip lines tracing the head gasket shape on the cyl head gasket surface. Not a whole lot of unshrouding to be had, but I�ll do what I can to improve port flow.

A note on the Napier piston rings. Some like Mahle have the scoop shape as shown in the photo I posted, some don't, but they all have a bevel to the 'face' of the ring so only the lower edge of the ring contacts the cylinder wall. I drew the bevel on the face of the ring in the pencil drawing I posted, just forgot to label it. As the engine has miles put on it the ring contact will increase to include the full face of the Napier ring. During engine break in the 'edge' only contact helps the ring quickly seat to the cylinder wall to reduce oil blow by into the combustion chamber.

femtnmax · « **Reply #24 on:** December 24, 2013 - 08:28:28 PM »

Merry Christmas to everyone and their families.

First photo shows installing the rear camshaft plug. Clean the engine block recess and cam plug with brake cleaner. The engine block required several wipes to properly clean it. Coat the block recess and outer circumference of the plug with Permatex aviation gasket sealer or other high quality oil resistant sealer. Start the cam plug into the engine block with a socket that fits the outer rim of the plug and light hammer taps keeping the rim of the plug parallel with the engine block rear machined face. Pushing the plug into the block by exerting pressure on the plug�s outer rim keeps the rim �out� and firmly seated against the engine block hole. I have never had a plug leak when installed this way for cam plugs or engine block freeze plugs.
Some installers just find a socket that fits into the recess in the plug, but installing the plug this way may cause a leak. I have had freeze plugs leak when installed this way so I quit using this second method.

Second photo shows installed cam plug with rim of plug flush with machined face of engine block.

Third photo shows parts fit check of the Scat forged crankshaft, and the rest from Brewers Performance: steel flywheel, 8 hemi flywheel bolts, and bell housing. All parts fit together well.
The alignment of the crankshaft center of rotation and bell housing hole that the transmission input shaft bearing retainer is centered on needs to be checked; the rotation of the trans input shaft needs to be on the same line, or very close to, the crankshaft center of rotation.. Attach magnetic dial indicator base on the flywheel with indicator contacting the hole in the bell housing as shown in the photo. Rotate the crankshaft and note the indicator readings. The photo shows my notes, I'm half way thru the process. Find the max reading +/-, rotate the crank so indicator needle is at this max point, reset the indicator to zero and rotate the crank again to find max �out of alignment�. My final measurement (.007 inch) showed the bell housing needs to be �lowered� vertically by half the dial indicator measurement, thus lowered by .0035 inch. That is less than the .005 offset which is considered acceptable; so no offset pins are required for my assembly.

The smallest offset dowel pins have a .007 offset. Offset dowel pins:
http://www.brewersperformance.com/proddetail.asp?prod=DP007A

If you need to remove the dowel pins, here are a couple of suggested methods that I found on the internet.
IQ52: I've found that the easiest way for me to remove the bellhousing alignment dowels is to drill the center of the dowel with a letter F drill and tap the stud with a 5/16 course tap. Screw a 5/16 bolt through the stud and push the dowel out. It works so easy that I now drill through the offset bellhousing dowels from the back (the part that pushes into the block), BEFORE I install them, so I can easily tap them while they are in the block and push them out if I have to change the dowel rotation.
Arco440: Here is a little trick I have used in the past. Use a small propane torch heat up the area around the pins not real hot just hot enough to melt some candle wax on the pins let cool repeat a couple times watching for wax flare up. Once it cools the wax is sucked in and now vise grips can remove the pins ....This works well for exhaust studs and lower control arm bushings and most things that get stuck.

femtnmax · « **Reply #25 on:** December 26, 2013 - 10:06:56 PM »

Doing the final rocker arm check, experimenting with lash caps to correct the rocker tip to valve stem contact pattern.
For non-roller tip rocker arms the rocker tip contact on the valve stem begins on the intake manifold side of the valve stem when the valve is closed. As the valve opens the rocker contact �rolls� across the valve stem with the rocker tip contact ending on the exhaust manifold side of the valve stem. The movement is like a rocking chair rocking back and forth across the floor. Smokey Yunick says the contact pattern needs to stay .02 inch away from the outer diameter of the valve stem.
I checked the rocker tip contact with no valve stem lash cap. The tip contact started at an acceptable location on the valve stem; but near full valve lift the tip contact rolled near the exhaust side, then began to scrub/rub back toward the center of the valve stem. This type of motion is ok for roller tip rocker arms, but not for non-roller tip rockers. I experimented with .06 and .08 inch thick �lash caps� which extend the length of the valve stem thus moving the rocker tip contact (both open and closed) toward the intake manifold side of the valve stem. The .08 thick cap moved the contact too near the OD of the valve stem at valve closed. The .06 thick cap had an acceptable valve closed contact and at valve max lift the rocker tip did not scrub across the valve stem.

First photo shows rocker tip to valve contact with valve closed, .06 thick simulated lash cap.
Second photo shows rocker contact valve maximum lift.

Third and fourth photos show pushrod angle to rocker arm adjuster valve closed then open. Note the pushrod angle sweeps from toward the rocker arm shaft to away from the shaft. This is acceptable, no radical angles are created valve open or closed. The pushrods easily cleared the cylinder head casting with no clearance grinding required.

The pushrod length is 8.0 inches for the setup in the photos. Crane iron rocker arm with two threads of the adjuster showing, .06 inch thick lash cap, and hydraulic lifter cam with lifter piston depressed .05 inch into lifter body. Engine block head gasket deck surface has been cut .026 inch; cylinder heads cut .012 inch.

Fifth photo shows copper colored valve spring shims used to center the rocker arm tip over the center of the valve stem. Shims are .06 inch thick, VSI part #201.

Lash caps that fit the .371 valve stem diameter, with pad thickness of .06 thick, and less than .14 inch total thickness so they don�t contact the valve spring retainer locks:
Crower Cams 86122D-16

femtnmax · « **Reply #26 on:** December 27, 2013 - 07:16:27 PM »

Photo shows rod bearing to crankshaft journal oil clearance check. Torqued the rod bolts to ARP spec of 50 ftlb. Then measured the rod big end housing bore diameter with inside mic. Then measure the inside mic with outside mic. The same outside mic is used to measure the crankshaft rod journal diameters. A ball mic measures the two bearing shell thickness, then subtract the two shells from the rod housing and compare that number to the crank journal diameter. The difference is the oil clearance.
The crank main and rod journal diameters were all at or near the minimum spec, so the main bearing and connecting rod housing bore diameters were all finished to their minimum diameters too to keep the oil clearances within factory specifications. The result is .002 inch oil clearance for both the main and rod bearings. This is a good clearance for my street use.

femtnmax · « **Reply #27 on:** December 27, 2013 - 07:18:28 PM »

Here is the 383/432 short block build cost.

Complete engine, 1969 383 oil pan to intake manifold $250
Stroker crank, Scat forged crank, 3.75 stroke, OEM rod journals, Flatlander Racing $886
#4-383-3750-6760-2374
Forged flat top pistons, Diamond #51910, Flatlander Racing $640
Moly piston rings w/ napier 2nd ring, Mahle #315-0035.035 $120
Connecting rod bolts&nuts to fit OEM rods, ARP #145-6002 $67
Timing chain & gear set, 9 keyway, Engine Pro #08-2010-9 $96
Crankshaft main bearings, Sealed Power #4094M $70
Crank rod bearings, Sealed Power 8-2320CP $68
Cam bearings, Durabond #PDP-17, cam rear plug $27
Engine gasket set, Felpro #KS2110 $46
Head gaskets .039 thick, Felpro #1009 $76
Intake manifold valley pan gasket, Felpro #MS96007 $13
Intake valve stem seals, positive PFT, Sealed Power #ST-2004 $48
Oil pump, Melling #M63 $80
Oil pump drive bushing, Dura-Bond AD-584 $2
Oil pump drive shaft, Melling IS-63 $56
Camshaft, Crower #32241 $157
Lifters, Crower #66031-16 $87
Engine block freeze plugs, Sealed Power #381-8011 $13
PARTS TOTAL: $2802

Bore & hone block $200
Cut block head gasket surfaces .026 inch for zero deck $185
R&R cam bearings $55
Resize OEM 383 connecting rod big ends w/ ARP bolts $120
Heat connecting rods, install pistons/pins onto rods $48
Cut .10 inch off crankshaft counterweights (could cut 0.2 off and still balance w/above parts) $85
Doing this leaves .06 inch clearance between crank counterweight and piston pin boss
Balance rotating assy $250
LABOR TOTAL: $943

Short Block Total: $3745

femtnmax · « **Reply #28 on:** December 29, 2013 - 07:57:45 PM »

Camshaft install:
First photo. I clean each lobe and bearing journal of the cam with paper towels sprayed with brake cleaner. Then the cam lobes are coated with thick grey assembly grease specifically for flat tappet cam lobes. I rub the grease back and forth onto each entire lobe, working it into the lobe. I like the thick grey grease because it will stay there for months. Cam lobe lube is Lunati cam lobe grey grease, or Joe Gibbs assembly grease.
Comp Cams sells a thin red cam lobe lube that is plenty sticky, but thin viscosity. It is probably ok if the engine will be running in a couple days; but for me I need a grease that will �stick around� for awhile. Then the cam bearings and journals are coated with engine oil and the cam is installed in the engine block. Also shown in the photo is special engine oil with zinc additive that helps to break in the flat tappet cams. There are several brands to choose from.

Crankshaft install:
Second photo shows crankshaft rear main seal installed at �clocked� position to help prevent seal leaks.
Third photo shows engine assembly lube for crank bearings. Again there are several brands to choose from. This lube is thicker than engine oil, and will provide lube until the oil system is primed or the engine started for the first time. I always prime the oil and fuel systems before first start. Bearing lube used is Goodson AL-22-8 "first lube". Engine oil is Joe Gibbs "BR" break in oil.
Last photo shows aligning the crankshaft #3 main bearing rear thrust faces. You want the rear facing thrust faces of both bearing halves to be flush with each other by pressing the crankshaft forward and the bearing/cap rearward. The end result is the upper and lower bearing thrust faces equally contact the crankshaft thrust face.
I torqued the main bearing cap bolts in 3 steps. Then one at a time loosened each bolt and torqued to final torque in one sweep.

Even though all the parts have been cleaned before, during final assembly I wipe every contact surface of each part down again with clean paper towels sprayed with brake clean. I use 1/3 or � a towel at a time. As soon as the towel shows much sign of �dirty� I replace it with a fresh one. Dirty may mean removing the engine oil that was used during mockup.

femtnmax · « **Reply #29 on:** December 31, 2013 - 07:03:12 PM »

Piston rings onto pistons. Timing chain gear set install.
First photo shows two mfg sheets that recommend using ring expander tool to install the top two rings onto piston, as shown in the 2nd photo. For the bottom oil ring they say spiraling the two oil rings onto the expander is acceptable.
Clean the piston ring grooves thoroughly then installed the rings starting with oil rings/expander, then middle ring and top compression ring. Make double sure the �dots� on each of the top two rings face �up�. All the rings should slide around easily in the grooves once installed.

Third photo shows timing chain gear set install. Degree checking the cam intake centerline had the centerline at 2deg retarded; so keyway is at 2R, and 2R tooth points toward dot on large gear. Don�t forget to slip the oil slinger tin washer onto the end of the crank. The slinger fits between the timing crank gear shown and the harmonic damper not yet shown. Timing bolt was installed with 2 rows (not drops) of blue locktite and torqued to spec, then loosened and retorqued a second time.

Last photo shows ring end gap alignment. Correct piston ring end gap locations help promote ring seal and cylinder wall life. Main details to be considered include the following.

*** No ring gaps aligned with either of the two piston skirts, and not aligned with piston pin centerline. There are 4 vertical edges of the two piston skirts. These 4 locations are good locations for the 4 ring end gaps (2 oil rings, and 2 compression rings), just keep the ring ends at edge of skirt or OFF the skirts.
*** No two ring gaps at same location. Keep each ring gap away from other end gaps.
*** Spiral wound ring compressors can catch on ring ends and rotate the rings as the compressor is tightened. The end result is some ring ends may end up aligned with each other. Some folks say they have never had a problem, others say they have seen the bad results with slightly weaker compression and visually on engine tear downs.

The last pic is a suggestion for ring end gap locations. There are several ways the end gaps can be located and have good results.
The first piece to be installed is the oil ring expander with its butt joint aligned with the piston pin centerline. Next is the lower oil ring, which can be spiral wound over the piston, starting with the end near the expander butt joint, and wind the oil ring immediately over the butt joint which keeps the expander ends from moving and stepping over each other. Then the upper oil ring is wound in place with its end gap opposite the lower ring ends. Do not want either oil ring end gap aligned with the oil ring expander butt joint. The complete 3 piece oil ring assembly should rotate easily all together as a group in the piston groove.
Next the two compression rings should be installed using a ring expander tool, starting with the lower ring which goes in just above the oil rings. Most all compression rings have round �dots� stamped into the top side of the ring so its easy to verify the correct side of the ring is facing �up�. The end gaps of each compression ring are placed opposite from each other, and not in alignment with either oil ring end gap. The end result is all four ring ends are approximately 90 degrees apart from each other.
I locate the top most compression ring end gap facing 'up' toward the intake manifold. That way any raw fuel that makes its way into the combustion chamber does not run down thru the top ring gap. This detail is a must-do for flat boxer-type engines like VW, Porsche, or Subaru.

Author Topic: 383 / 432 Mopar stroker for the Challenger (Read 31785 times)

femtnmax

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'Cuda Hunter

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inviolet

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