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Note: The cam bores feature sharp edges. To aid in camshaft bearing installation, first deburr the edges with a sharp scraper. Once all block grinding, tapping, and deburring was finished, the block was thoroughly washed, rinsed, and blow-dried, with 5W30 engine oil applied to the cylinder walls to prevent surface-rusting. The camshaft bearings (supplied by Dart) installed with no muss or fuss. By the way, these cam bearings, included with the block, are already coated with an anti-friction material (likely a moly graphite derivative), which is a nice touch by Dart.
With the Crane steel billet roller camshaft coated with 30W engine oil, the cam was carefully inserted, checking for rotational freedom.
NPT PLUGS
The block front features three NPT holes… two 3/8″ NPT and one 1/4″ NPT, all adjacent to the cam tunnel front hole. Since we plan to use the Jesel belt drive timing system, these NPT plugs must sit flush or below the block surface to provide clearance for the belt drive cover. I simply tapped each hole deeper until the installed plugs were a kiss below the surface. With the original rear NPT threaded holes (one 3/8″ NPT and two 1/4″ NPT), plugs will protrude a bit. To gain clearance for a rear motor plate, these holes need to be tapped deeper as well, or you can drill access holes in a motor plate. We opted to leave the threads as-is, and will drill holes in a motor plate at a later date. All NPT steel plugs were installed using Teflon sealing paste.
By the way, before installing the block’s expansion plugs, deburr the edges to aid installation. They’re a tight fit, so be careful to keep them square. I coated the perimeter of ours with a thin coat of Ultracopper RTV before installation. This provides not only additional sealing insurance but serves as a lubricant during installation.
FILE-FITTING & INSTALLING OUR RINGS
Our piston rings are from Perfect Circle, including top rings (plasma moly ductile 4.600″ x 0.043″, P/N 300-0242), second rings (4.600″ x 0.043″, P/N 302-0435), and the 3/16″ oil ring package, P/N 303-0362.
Using our Summit Manufacturing and Engineering “Adjust-A-Bore” ring squaring tool, I positioned one ring at a time squarely in each bore, removing to file-fit, rechecking, etc., until I had a top and second ring precisely sized for each bore (I file-fit each bore’s rings and organized them accordingly, per bore location).
Diamond Racing’s Eric Simone suggested a gap of 0.022″ for the top rings and 0.024″ for the second rings.
Following his advice, I file-fit our top rings to achieve an end gap of 0.022″, and second rings for a gap of 0.024″. I used Summit Racing’s new bench-mount ring filer that features a natural diamond abrasive wheel and crank handle. An adjustable ring position locator and fixed front stop allow consistent filing for the entire ring set. I also used Summit Engineering’s new ring squaring tool, which proved very handy. It’s expandable and features a drop shoulder that pushes the ring squarely into the bore at a depth of 0.500″. I measured an out-of-the-box clearance end gap of 0.021″ on our oil ring rails, which is fine (the acceptable minimum is 0.015″).
With the rings installed on our Diamond pistons, I verified a top ring groove clearance of 0.0008″ and a second ring groove clearance of 0.001″. The top ring features a radial depth of 0.170″ with a back clearance of 0.0075″. The second ring features a radial depth of 0.210″ with a back clearance of 0.005″. Radial depth of the oil ring package is 0.195″. I measured an out-of-the-box clearance end gap of 0.021″ on our oil ring rails.
When installing the oil ring package, I first installed the oil ring support rail (supplied with the Diamond pistons). Because the piston pin bore height location encroaches into the oil ring groove area, the support rail provides a floor, or footprint for the oil ring.
Here Scott Gressman installs the bobweights to our crank. Our bobweights were set up at 2383.5 grams each.
Scott uses a spacer to locate each bobweight in identical left/right locations on each rod journal. The spacer drops over the journal.
With the spacer in place, the bobweight is tucked against the spacer and then tightened. The spacer is removed once the bobweight is secured in place.
Scott pulls a bit of weight from our front counterweight as dictated by his Sunnen Pro-Bal balancer.
The rear counterweight wanted a bit more weight, so Scott drilled a 1″ hole through the rear flange and through the rear counterweight. Here Scott taps a heavy-metal slug into the counterweight hole. A fill-slug was also added to the hole in the flange.
Horizontal installation of heavy metal eliminates the risk of a slug flinging out during operation.
Here Scott fine-tunes the balance by grinding a few thousandths off of the rear counterweight.
A final check of our crank endplay showed an acceptable 0.007″ fore/aft movement.
Double spiral locks secure each end of the piston pin. Here Gressman slips one into place using his fingers. He’s definitely better at this than yours truly. I simply stood by during lock installation, taking photos and sipping coffee.
Squaring up the piston rings (to check end gap) was quick and easy, thanks to this bore-diameter-adjustable Summit Engineering squaring tool.
I file-fit all of the top and second rings using this diamond-wheel ring filer from Summit Engineering. The diamond wheel is very aggressive, so care is required to avoid over-filing.
The oil ring support rails are required because of the location of the pin bore (the bore intersects the oil ring groove). Install the support rail at the bottom of the oil ring groove, with the male dimple facing down, centered at the pin bore.
The gap of the support rail. Gap really isn’t critical for this rail, as long as it doesn’t butt together. It should sit inside the groove and not contact the cylinder wall.
Our steel billet Crane roller cam was inserted, with journals coated with Royal Purple Max Tuff lube and lobes coated with 30W oil.
The Jesel belt drive system looks intimidating at first, but it really wasn’t a big deal to install.
The Jesel cover is installed to the block with a big block Chevy stock-type timing cover gasket. The cover is secured with a series of 1/4″x20 socket head cap screws, which I tightened to 50 in-lbs.
COMPONENT WEIGHTS
Lunati rod big end —619.5 g
Lunati rod small end —275.0 g
Lunati rod total weight —894.5 g
Diamond piston —542.0 g
Diamond piston pin —160.0 g
Diamond oil ring support rail —9.5 g
Clevite rod bearings (1 rod) —49.5 g
Perfect Circle ring pack (1 piston) —46.5 g
1 set spiral locks (4 locks) —4.5 g
Oil allowance —8.0 g
Bobweight total —2,383.5 g
Tags: BOBWEIGHTS, CAM BEARINGS, CAMSHAFT INSTALLATION, CRANKSHAFT BALANCING, DIAMOND PISTONS, FILE FITTING THE RINGS, GRESSMAN POWERSPORTS, LUNATI, NPT PLUGS, SPIRAL LOCKS, SUMMIT RACING
