For those of us who like to read how/why,,
Eagle Specialty Products, Inc.
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For those of us who like to read how/why,,
Eagle Specialty Products, Inc.
Well you guys asked.... so....
Attached is an abbreviated form of a build presentation I did a couple of years back.
Below is my build sheet. The camshaft is a custom grind from Competition Cams based on their newer XE profiles.
***** However I'll reiterate in the strongest possible terms that I overdid it and great results can be had from 'merely' optimising properly a 3.9 or 4.6 (or any other variant). The factory build is VERY conservative and leaves huge gobs of everything (power, torque, fuel economy, etc) on the table to allow the engine's to cope with just about anything, anywhere, anytime. The more you optimise, the narrower the band becomes of how far you can step outside perfect operating conditions before you run into problems. If I did this all again I would not stroke the motor nor port the heads. I'd likely find a tidy 3.9 or 4.6 and tighten the quench and bump up the compression ratio, give it a tidy up and enjoy it and get most of the benefit for a fraction of the outlay. The ripple effect of this overkill has been expensive and time-consuming and isn't done yet. It has also meant that the vehicle has been off the road a lot and therefore hasn't been used for its intended purpose. I love it to bits, and it drives beautifully, but it has been bittersweet.
Rover 4.9 Stroker Build Specifications
Bore: 94.6 mm ( 3.736 in. )
Stroke: 86.4 mm ( 3.412 in. )
Displacement: 4.904 L ( 299.20 c.i. )
Compression ratio: 10.1:1 (static) 8.6:1 (dynamic)
Valve timing @ 0.050" lobe lift
Intake: 206 degrees, lobe CL - 108 ATDC, opens 5 ATDC, closes 31 ABDC
Exhaust: 212 degrees, lobe CL - 116 BTDC, opens 42 BBDC, closes 10 BTDC
Lobe Separation Angle: 112 degrees
Installed @ 4 ATDC ( intake opening )
Gross (advertised) Duration @ 0.006": intake 249deg, exhaust 263deg.
Lobe lift: intake 0.277", exhaust 0.280"
Valve lift w/- 1.6:1 rocker ratio: intake - 0.443", exhaust - 0.448"
Pistons: Custom forged with high silicone 4032 alloy
Piston Dish: 29 cc's
Pin: 0.927" diameter, full floating
Rings: 1/16" barrel-faced, moly-filled top ring, 1/16" reverse-twist 2nd ring, 3/16" low tension, oil control ring.
Clearances: ( inch )
Main bearings: 0.0023 to 0.0025
Rod bearings: 0.0018 to 0.0020
Crankshaft end-play ( float ): 0.004
Rod side clearance: 0.010 to 0.012
Camshaft end-play ( w/- thrust plate ): 0.005
Piston skirt to cylinder wall: 0.0025
Piston ring end gaps: top, 0.015 to 0.016, 2nd , 0.020 to 0.021, oil control, 0.012 minimum.
Piston crown to deck: 0.003 to 0.005 (Block deck skimmed minimally to true)
Cylinder head
Valve spring installed height: 1.685 to 1.695"
Spring tension @ installed height: 100 to 105 lbs.
Spring tension over-the-nose: 245 lbs.
Lifter preload: Zero lash + 1/2 turn
Push rods: dia 5/16" x 8.4" L
Intake valve** diameter: 1.710" on bigger seats
Exhaust valve** diameter: 1.425" on modified standard seats
** Buick V6 90deg MPFI valves (intake: 231&252ci '79-95, exhaust: 231ci '75-'78)
Torque Settings ( lb.ft )
Main bearing studs; 100 ( ARP lube )
Rod bolts: 50 ( ARP lube )
Cylinder head studs: 70 ( ARP lube )
Camshaft gear bolt: 60 ( Locktite )
Harmonic Balancer: 140 ( engine oil )
Crankshaft to flex-plate adaptor ( socket head bolts ): 65 ( Locktite )
Flex-plate to crankshaft adaptor ( 4 hex bolts ) 40 ( Locktite )
Rocker stud adaptor plate counter-sunk screws: 35 ( Locktite, oil counter-sinks )
Rocker studs: 60 ( ARP lube )
Ignition timing recommendation
Static (at idle) 14 +/- 2 degrees.
Total centrifugal (all-in) @ 2500 to 2800 RPM: 34 +/- 2 degrees depending on octane of fuel and the ambient temperature.
Vac advance 10-12 degrees, to be verified on-road in-vehicle.
That PDF is a fascinating read. Bet that lot wasn't, how shall I put this, cheap.Quote:
Originally Posted by DiscoClax
Ha, ha, ha... no. * sobs quietly * :(
If done again at today's exchange rate it'd top $10k. I did it at better than parity. That's just the engine. Not including the auto upgrades, etc. Hence my stern warning to not get carried away... unless you want to :)
But the basics of getting the quench right, comp, and general good practices would deliver 75%+ of that for maybe 25% the cost. I just didn't know when to stop... and the bigger it got the more I had to do and so the snowball grew.
Sent from my SM-G900I using AULRO mobile app
All cheap compared to a D4 or Storm...
Would much rather the storm though😊Quote:
Originally Posted by ozscott
and the cheapest way of getting the quench right?
* sings * Deck the block with lots of milling, fa-la-la-la-lah, lah-lah, lah, lah. :P Christmas in July?
Measure your TDC piston height below the top of the block (typically around 60thou give or take on a 3.5/3.9). Remove this amount from top of block (assuming you are running a 40thou gasket). Adjust rest of engine if or as required to suit. Assemble. Enjoy :)
Or suck it and see like I did on a 2.25,milled 1/8'' off the head,stuck it back on and started it. Pat
Beer. Obviously.Quote:
Originally Posted by Pedro_The_Swift