AMC's "Rambler Division" V8 Engine '56-'67
RAMBLER V8 SPECIFICATIONS & Engine Building Tips
Weight; (from RV8 TSM)
Engine complete (less transmission) 601 lbs.
Cylinder block 160.9
Crankshaft + 62.8 = 223.7
Cylinder head (each) + 49.5 (x2) = 322.7
Exhaust manifold (including crossover) + 27.9 = 350.6
Intake manifold + 27.8 = 378.4
Front cover + 14.7 = 393.1
Camshaft + 10.2 = 403.3
Connecting-rod assembly + 1.72 (x8)= 417.06
Piston + 1.13 (x8)= 426.1
Valve train (including lifter, push-rod, rocker arm, intake valve, valve spring, retainers) +1.09 (x16)= 443.54
SO... 601 - 443.54 = 157.46 lbs. for all the peripherals such as starter motor, harmonic balancer, carburetor, fuel pump, water manifold, water pump, rocker shafts, engine bolt set, alternator and brackets, distributor, spark plugs, oil pump, oil filter mount & filter, valve covers, oil pan & dipstick assembly... apparently this is for the 250 CID version, because...
NOTE: There are at two basic block castings; 'windowed' and 'non-windowed'.
Explanation: I've owned and thoroughly inspected three 4bbl 327 blocks (two '65s & one '66). They all have/had 'solid' main webs. My newest Rambler V8 is a '64 2bbl 327; the center three main webs are 'windowed'. It can be clearly seen that the iron where the windows are is at least 1/2" thick. This means that the 4bbl 327 blocks are definitely the strongest/'best' for an extreme power type build up. This means that there are two different block weights.
I've weighed my '64 2bbl 327 windowed block on a bathroom scale = 178 lbs. (see pics here)
*I was able to trim three pounds off my 327 2bbl block by carefully removing the older fifties style front engine mounting points and 98% of all factory 'fast build' casting bosses with an assortment of grinding tools to get it's bare weight down to 175 lbs. (this is only about 25 lbs heavier than an aftermarket aluminum Mopar RB V8 block!)
I recently have come to learn from seeing pictures of '57 AMC 327 crankshaft gallery, the block had four machined and tapped mounting bosses on the outer edges of the main web X braces next to the oil pan sealing flange. This looked to be a provision for mounting an oil pump windage baffle similar to certain mid fifties Cadillac V8 engines, but with no pic of the baffle itself I cannot verify the speculation.
Since my current 4bbl 327 solid main block is actively employed for the XRV8 Gremlin project, I plan to weigh it sometime after I swap in the 443 CID XRV8 racing engine, which may happen in a year or so if all goes well.
General Dimensions; (RV8 TSM)
Bore Spacing 4.75"
Deck Height 9.994"?
(measured 10" on my block using simple measuring tools)
(I use 9.973" for custom piston, con. rod & stroker crank calculations)
Crankshaft centerline to carb. flange 14 5/16"
Overall length 27 23/32"
Block length 23.02"
Width (with exhaust manifolds) 24 1/8"
Crank gallery depth (from oil pan sealing flange to cranshaft centerline) 2 3/4"
Crankshaft (forged steel) length 27.2"
journal overlap 3/4"
stroke (all 250, 287 & 327s use the same crank) 3.25"
( 2.5" main journals & 2.25" rod journals )
five main bearing, thrust bearing on #1 (total swept areas: #1 = 2.08", #s 2-5 = 2.20" ea.)
Main Bearing Journal Diameter: 2.499" (Std. size)
grooved upper and lower halves 360 degrees
factory spec. main bearing clearance: .0006" to .0032"
rear main seal surface measured on my '65 crank = 2.625" OD x .615" (5/8") wide (data for possible interchange?)
crank snout distance measured on '65 block = 3.175" -from face of front main journal to end of snout (data for possible adapted SFI rated harmonic damper -need to measure thickness of crank thrust plate + thickness of lower timing gear...)
rear flywheel flange measured on '65 crank = 2.595" OD, auto trans/torque converter button pilot hole = 1.63" ID (1 5/8" t.c. 'button')
NOTE: There are at least two different connecting rod castings; 1) a heavier rod which is visually discerned by it's smaller weight pads -this rod's I-beam section is slightly wider at the big end 2) a lighter rod which is visually discerned by it's larger weight pads -this rod's I-beam section measures slightly more narrow where it tapers out onto the big end.
Connecting Rod; (forged steel) length; 6.375" (RV8 TSM)
weight; 1.72 lbs = 780.179 grams = 27.52 oz.
big end width; smallest measurment using Brown and Sharpe
verneer caliper on used 327 rod still having factory machining marks on sides = .992"
(probably the same as '66-up AMC V8 rod width; .992")
Rod bearing journal diameter: 2.249" (Std. size)
(total swept area of each rod bearing = 1.935")
factory spec. rod bearing clearance: .0007" to .0028"
factory spec. con. rod bearing cap bolts: 46 to 50 ft. lbs.
small groove in big end split around rod bolt to lube opposing cylinder wall areas*
AMRV8 Rod Bearing Advice: Avoid semi-grooved rod bearings!
I wholeheartedly believe this is very important, and any person rebuildinig an American Motors Rambler V8 engine needs to understand why; the aftermarket semi-grooved connecting rod bearings degenerate the precision-engineered registration timing of the oil spurt ,which is specifically designed to send a metered shot of oil to lubricate the wrist pin and cool the underside of the piston.
The semi-grooved aftermarket rod bearings over-extend the duration of the oil spurt feature to spray lubrication onto the sides of the crankcase gallery, where no lubrication or cooling oil is needed.
Moreover, in doing so, excessive oil is released through the grooved slot, functioning to reduce the amount of oil in the most highly stressed center area of the rod bearing surfaces, greatly increasing the chance of metal to metal contact...
Hence, we may conclude to rename them 'suicide rod bearings', made to 'kill your engine' with a catastrophic metal-to-metal spun-rod-bearing scenario. IT MUST BE A CONSPIRACY; THEY ARE ABSOLUTELY WRONG.
Don't simply take my word for it; read about the precision engineered connecting rod oil spurt feature as described in Society of Automotive Engineer's article named "The New American Motors V8". (thank you T.J. for posting the articles)
My advice: For any higher performance Rambler V8 application, use Sealed Power 2230CP; they have no oil spurt provision (not even the notch, like the stock AMC rod bearings) delete the oil spurt feature altogther; at higher rpm levels (basically anything above 1200 rpm) (...my 327 XRV8 engine idles at 1200!) oil sling from the rod journals is already enough to cool and lubricate the undersides of the pistons. (any Chevy Gen 1 engine proves this statement; they have no connecting rod oil spurt feature, they are durable in a grocery getter application ~and~ they are proven to run well in the higher rpm ranges; GO TO ANY DRAGSTRIP IN USA AND WATCH HIGH RPM CHEVY GEN 1 ENGINES WIN RACES.
*NOTE: If you are a highly skilled engine builder, it is not impossible to transposition the semi-grooved rod bearings by cutting new rod bearing notches on the opposite sides of the connecting rods for the location tangs of the bearing inserts.
(...which is a way to use the cheaper, unfortunately more common, aftermarket rod bearings as 'throw away' rod bearings on a race engine which is subject to routine rod bearing analysis and service replacement proceedures ...racing is expensive)
One final note about the mis-engineered semi-grooved rod bearings is that they weigh less, which changes the bobweight factor for precision balancing the crankshaft... causing the stock crankshaft balance calculation to go out of balance... combine the lighter grooved rod bearing with a rod journal that has been turned +.010 undersize & presto; your crank has now lost it's precision balance (which is another debate discussed here by the author of 'Victory Library')
factory spec. con. rod side clearance: .004" to .012"
connecting rod bolt: mine measured .381" thick doweled area, 2.5" UHL
rod bolt has "D" shaped head
(has tapered flat leading down to the curved part of the D made to increase shoulder room)
RV8 TSM states .040" quench spec. from face of head to piston face, including head gasket, for low compression 250 CID '56 version
-head gasket thickness quoted from 'Hot Rodding' forum = .015"
(steel shim type? -needing to measure mine for second example)
*Head Bolt Torque; On my last RV8 build, I torqued my head bolts to 90 ft-lbs & snapped one off. When I unbolted the heads, I found three other stretched bolts -very obvious. So on my latest rebuild, I torqued my headbolts to 60 = no leaks so far. -make sure all head bolt taps are clean; I like to pressure wash my blocks and blow dry with compressed air. Thread in the bolts prior to assembly to find any that might not screw in easy all the way -run a tap in there to clean it again. I like to wire brush my bolts clean, use compressed air, and put a thin line of engine oil down one side of the threads and a few lubrication 'dots' on the shoulders and washers... I use a 5/8" spark plug socket with a 3/4' deep well socket on top of that to torque the two valve cover head bolts (which works good as an extension on some of the other head bolts also, having less flex than a regular socket extension for getting a more accurate reading on the torque wrench)
Pistons; 3 ring conventional, flat tops, no valve notches, cast aluminum alloy, steel inserts,
autothermic, slippered 'divorced' skirts, tin plated, piston pin hole bearingized
*AMC used two different compression distances to effect compression; 8 to 1, or 9.7 to 1
Compression distance; 1.9375" -verified on my AMC 9.7 to 1 4bbl 327
+found 1.9375" quoted on AMC Forum webpages
*compression distance on 327 2bbl versions needs verification to purchase correct aftermarket pistons
part # 3200313 = four barrel high compression piston part # 3202315(B?) = two barrel low compression piston
Piston head thickness; 0.25" (RV8 TSM) Pin offset; 0.0625" (RV8 TSM) finished weight; 511 grams (RV8 TSM 250 V8? & balance lugs allow 31 g weight control)
Pin diameter; .931" (same as '66-up 290/343, 304/360 AMC V8s) press fit
Reciprocating assembly; internally balanced to +/- 1/2 oz. regular production from factory -harmonic balancers, flexiplate/flywheels interchange/independently balanced
Cylinder Sleeves: for Rambler 327 = Enginetech pn# ESL137 3/32" x 4.0" x 6.875"
for overbore experimentals = Enginetech pn#s ESL130, ESL230 & ESL230HP 1/8" x 4.125" x 6.750"
interchanges with Melling pn# CSL261HP (suggesting 'short fill' block filler)
Heads: OHV, 'closed chamber', 'wedge' type, 'as cast' finish, spark plug side 'hump' to induce swirl flow characteristics, pre-emission control design
Note: There are at least three different Rambler V8 head castings; 1) an 'open chamber' that does not have the milled flat on the opposite side of the spark plug (I've never seen one personally, but this is the head shown in the SAE article which I believe was only used on the 250 to have the correct cylinder pressure because of it's smaller bore) 2) the pre-66/7 287/327 65cc (?) chamber head 3) the '66/7 65cc (?) 'smog' head which has the air injection bungs that restrict the exhaust port
I weighed my '64 high compression head on a bathroom scale = 51 lbs.
Mounting bolts; 15 per bank (five bolts per cylinder, perimeter taps into outer water jacket wall)
Chamber cc size: Using Internet comp. ratio calculator shows 65.5 cc with 4" true flat top piston, .015" steel shim gasket, 4.03 gasket diameter, .040" deck & 9.7 to 1 compression (62 cc. quoted from 'Hot Rodding' web forum, -'using cow syringe'...?)
*I encountered no hazzard while using old head gasket in order to gasket match rocker gallery drain back passageway to lifter gallery area, rather there exists an awkward interuption of oil return at that particular point which is caused in part by the mis cut replacement head gasket shape itself... (check this on your engine and you'll see what I mean)
Intake ports; similar to '49-'67 OHV Cadillac design having very similar intake port gasket pattern/flanged areas, slight 'hook' shape at end of port just under valve seat to induce swirl flow, only slight taper from port entrance to valve (?), minimal 'choke'/venturi shape in valve pocket
Intake valve; 1.787" head diameter, 4.899" overall length, w/4 grooves, 0.372" stem diameter
(seat = .094" larger OD) stem clearance; 0.0013-0.0028" (RV8 TSM) angles; valve 29, seat 30 degrees
Rambler V8 valves look identical to AMC 304 valves at first glance but the RV8's 4 groove keeper location is cut one row closer to the tip of the stem (whereas AMV8's 4 groove keeper location on the stem is one groove further down the stem than RV8) Hence, the RV8 valves could be used in 304 AMV8 to fit a taller spring (or dual springs) to make room for a higher lift cam.
Exhaust ports; flange pattern similar to '49 OHV Cadillac and Studebaker V8 but rectangular outlets instead of rounded, two outer end ports with one single center (siamesed) port outlet -the high pressure area where the exhaust leaves the combustion chamber under the valve is almost 'straight down' from valve seat, then exhaust gas exits the pocket through a horizontal rectangular area (very similar to Cadillac's '49-'67 OHV V8 exhaust port design) from there, as the exhaust gases proceed past the water jacket above (on the 'roof') the horizontal rectangular area transitions into a verticle rectangular area, then to exit. Upon close inspection, the exhaust ports have obvious taper from valve seats to larger sized outlets. The 'floor' is fully waterjacketed, the 'roof' only about 50% -thermal physics to speed up flow on the roof side.
port outlet sizes = 1 5/8" tubing end ports, 2 1/16" tubing for center siamesed port = very similar to '53-'67 Cadillac design having the widened center siamese exhaust port
the two center siamesed ports both have exhaust crossover passageways beginning just under the valve seat 1/4" deep and are 'mirrored' to form a substantial crossover assembly which appears to be tuned for equalization of both cylinder banks? -I believe this a component part of the siamesed center outlet design ('66-up AMC V8 heads have crossover passageway under intake running diagonally from one single exhaust port to a single port on the other bank)
NOTE: There are at least four different exhaust manifold combinations 1) '56-'62 Rambler V8 exhaust manifolds, front exit 2) '63-65 Rambler cars with 287 & 327 have the best 'high flow' rear exit exhaust manifold 3) Jeep 2bbl 327 front exit 4) Gray Marine water cooled exhaust manifolds
Exhaust valve: 1.406" head diameter, 4.892" overall length, w/4 grooves, chrome plated stem 0.372" diameter, stem clearance 0.0018-0.0033" (RV8 TSM) angles; valve 44, seat 45 degrees
RV8 exhaust valve has same head size as AMC 304 but has it's 4 groove keeper location cut one row closer to the tip of the stem, whereas AM 304 V8 has it's 4 groove keeper location cut one row closer to the valve stem seal. Hence, the RV8 exhaust valve could be used in a 304 in order to fit a taller spring (or dual springs) in order to use a higher lift cam.
Valve stem center to center spacing (minimum width measured on my '64 heads with pressed in iron guides) total width = 2.187", both guide IDs = .3765" so 2.187" - .3765" = 1.8105" center to center (compares to 1.74" lifter bore spacing)
Valve guide OD for valve stem seal location (measured on '66 327 head having pressed in guides) = .6"
Oversize Valve Size: because of the 1.8105" center to center distance, 2.02/1.60" valves are slightly too large. Since they have the same stem size, 4groove locks and are the same length, I have found that AMC 360/401 2.02/1.65" can be cut down to 1.95/1.60" = this mod definitely improves both port pockets when the larger cut seats are blended in & there is no worry to 'break through' into the water jacket with a common sense throat cut below the seat. (my 440 XRV8 heads have their bowls rounded well beyond a simple throat cut with no break through into the water jacket -only one example though)
Valve Springs; (from Elgin Catalog) Elgin pn# RV863S Valve Springs; (from RV8 TSM)
Outside Diameter: 1.322"/1.342"
Inside Diameter: .948"/.968" Inside Diameter: 0.938" - 0.953"
Closed: 95-105 lbs. @ 1.812" Closed: 85-91 lbs. @ 1.13/16" (1.8125")
Open: 188-202 lbs. @ 1.437" Open: 150-160 lbs. @ 1 7/16" (1.4375")
Coil Bind @ 1.356" Free Length: 2.20"
Spring Type: Single
NOTE: '56-'67 Rambler V8 valve lift is limited by the stock spring specifications: 1.812" installed height - 1.356" coil bind spec. = .456" - .060" (for .010" proper clearance spaces on 6 coil spring) = .396" max. 'safe' lift allowed by stock spring for reground cam.
(stock cam provides .375" (3/8") lift, allowing .080" coil spring clearance)
*AM supplied a special 'two step' valve spring retainer on 327 4bbl engines having higher rate valve springs with dampers (technically a dual spring) -these have a 'shorter' overall height for increased retainer to valve stem seal clearance.
*AM supplied thicker 'single step' valve spring retainers for use on all other 2bbl RV8 engines which will most likely cause retainer to valve seal interference when used with higher lift reground cam -this retainer to seal clearance needs to be double checked when using any non-stock cam on 2bbl engines.
XRV8 Race Parts valve spring kit is made to allow .480" 'safe' lift.
This, along with XRV8 RP radiused tip rocker arms is how to hop up your Rambler V8 engine.
Melling's chart showing stock Rambler V8 2bbl pn# VS-500 spring (no damper) (VS-360 & VS 970 are similar)
On my '64 and '66 heads with pressed in iron guides, the base of the valve guide measures .916".
On same heads (pressed in guides) the valve stem seal area's diameter is .600" (and typically uses Sealed Power SP2011 type seal)
See Crane for tech theory on higher performance valve spring selection (originally supplied some AMC Group 19 parts)
Rocker arm assembly; shaft mounted Nash style rockers: AMC RV8 TSM quotes; 'rocker arms are made of cast pearlitic malleable iron' (right and left/two rocker castings)
*As of May 2016, I have measured and verified that that stock RV8 non-adjustable rocker arm have an approximate 1.55 ratio (measured my stock '64 rockers; 1.4625" / .9125" = 1.598 ratio)
250 CID came with adjustable rockers for solid lifter cam (look for gray? painted engine?)
287/327s have non-adjustable rockers for hydraulic lifter cam (287 = blue, 327 = red painted engine)
*apparently all Gray Marine AM RV8s came with adjustable rocker arms. The additional weight caused by the adjustment provison increases the weight of the rocker arm, thus requiring a stronger valve spring and pushrod to negotiate higher rpm levels without causing undesirable valve float. The adjustable rockers are nevertheless 1.5 ratio, hence there is no benefit because when using either type (non-adjustable or adjustable) the 1.5 ratio rocker arm tips will need to be custom radiused anyway for use with higher lift re-ground cam. Since 1.5 ratio rocker arm tips are obviously become overworked to handle cam cut for more than .500" lift (too much scrub on valve stem tips) I would strongly advise custom made/adapted roller tip rocker arms instead.
It does appear that Crower makes right and left offset stainless steel or aluminum roller tip rocker arms with .25" offset. The p#s for the individual stainless unit is #74510 and for the lower cost aluminum is #75510 (pg. 12 & 21 in catalog ...either type could be bushed to fit AMRV8 rocker shaft diameter?)... however, I think these high quality units are even more expensive than having a custom roller tip set made by Harland Sharpe...
shaft diameter; 0.858-0.8585" OD (RV8 TSM) *measured .858" on my '64 shafts
*one possible option to have Rambler V8 rocker arm shafts restored to spec. (or to repair scored/galled pivot points) by using 'hard chrome' plating process... possibly even 'built up' .016" to use Mopar RB 7/8" rockers?
rocker arm ID; 0.860-0.861", clearance 0.002" (RV8 TSM)
(My RV8 rockers, individually weighed on a postal scale, averaged from 4 to 4.5 oz.)
*for sake of comparison; Ford FE V8 shaft = .840"? 'straight' style
Mopar LA/B/RB V8s = .875"? (7/8") offset right and left style (similar to RV8)
Since most RV8 rocker arms have accumulated fatigue stress from many hours of run time (?) For higher performance application I would suggest three stage polishing process; 1 grind to weight match, 2 sanding rolls to smooth irregularities, 3 wire wheel and felt buff for mirror shine.
(questionable benefit to 'lightly shot peen' rockers after polishing? plausibly not because may damage pearlitic grain structure?)
Since stock RV8 rocker arms are 'cast pearlitic malleable iron' of unspecified alloy with unknown carbon and silicon content, they should not be heat treated; the product outcome is dubious at best without knowledge of the critical temperatures and quench rates of this particular rocker arm material. (we don't know the details) ~Therefore~ Heat treatment is at best 'a shot in the dark' & will most likely depreciate the desired quality of the otherwise AMC engineer specified product.
For examples to support NOT heat treating these rocker arms study 'malleable cast iron' engineering articles, there are more than a few articles currently on the Internet such as this one posted by "Machine Design"
-it is questionable as to whether or not having RV8 rocker arms bronze bushed will improve their durability whereas this process would necessarily remove some 'as cast' material, thinning the stressed pivot area, plausibly reducing it's mass and already low resistence to tensile forces (ability to stretch) But cast pearlitic malleable iron shows competent fatigue strength under compressive loading, which then makes it an acceptable material for making a rocker arm which generally operates under compressive load imposed from the valve spring.
*It may be do-able to make custom 7/8" molybdenum or stainless steel shafts & bore RV8 pedastals
(stainless steel expansion rate is closer to expansion rate of cast iron)
*When I learn stock Rambler V8 rocker offset specification will add data for reference specification:
*Now, as of May 2016, I have measured an approximate RV8 rocker arm offset of .3", which is less than Mopar RB's std. spec. of .475"... so this plausible source for adapted rockers will need further analysis
Push rod length; 8.687" x .275" diameter, but I have found 5/16" pushrods in some RV8 engines) 'ball & ball, no oil hole' type
*this chart says 8.687" and shows comparison to other engine pushrod lengths
Lifter bore diameter; 0.904" (same as '66-uo AMC V8)
Lifter bore spacing measured on '65 block = 1.714" center to center (measured .810" + diameter of one lifter) -compares to 1.8105" valve stem spacing (data for possible roller lifter install on custom ground roller cam... (*lifter bores can be 'keyed', not to use a tie bar)
*apparently Mopar B/RB V8 has 1.80" lifter bore spacing which should work to use those pre-existing roller lifter systems (this will need to be double checked because I have no actual evidence or experience with this plausible swap potential) ... link bar would need to be narrowed .05" on each side? & would need to check lifter to oil gallery registration to ensure there is no loss of oil pressure due to misalignment of the lube passageways)
Camshaft; .375" lift (3/8"), 244 degrees duration, single pattern
lobe taper; .001-.002 per inch (RV8 TSM)
bearings; housing bore length max wall
#1; 2.1560" 0.750" .0620
#2; 2.1460" 0.750" .0620
#3; 2.1360 0.750" .0620"
#4; 2.1260" 0.750" .0620"
#5; 1.620" 1.060" ,0620'
Rambler V8 camshafts has a large shaft diameter similar to '66-up AMC V8s (not a weird looking cam/no skinny shaft surprise like some of their competitors) whereby it makes a good candidate for using a re-grind service in order to get a more aggressive cam lobe profile cut...
Timing Chain & Gear Set; Center Distance = 4.965" -same chain and lower gear pn#s as '66-up AMC V8 -both have 23 tooth lower & 46 tooth upper gear sets. However I've compared and measured both upper timing sprockets and there is no easy way to make an adapter for interchange; The stock cam snout diameter specification on '66-'91 AMV8 is 1.016", but I've measured 1.019" on SA Gear's aftermarket unit, whereas my Rambler V8 upper timing sprocket bore diameters measure 1.00" exactly = the later AMC V8 upper timing sprockets have a .019" larger bore = TOO LOOSE/won't work. Rambler V8 use a 3/16" woodruf key and later AM V8s use an 1/8" woodruf key = upper timing sprocket alignment key doesn't match either.
I've completed my first 'XRV8 Parts' roller chain timing set for '56-'67 AM RV8 by transplanting an RV8 hub into an AMV8 upper sprocket using my homemade precision benchtop lathe.
If interested, here's a link to view my product: "XRV8 Roller Timing Set" -I guarantee greater precision than any other 'fast build unit & my 'slow build' unit will be precision beam balanced on parallel bars, detail polished and have it's sprocket teeth carefully wire brushed to improve the service life of the chain
Oil Pump: factory spec. end gear clearance; .004" & gear to wall .008"
MORE DATA AS RESEARCH CONTINUES...
For info on purchasing "XRV8 Race Parts" for your vintage Rambler V8 engine: