112. Repsolroger390: '69 390. I will be installing a hydraulic roller cam and Edelbrock heads.
I will also use AutoTec pistons which I had specifically ordered to work in either a 69 or 70 390.
If I wouldn't have had these on the shelf, I would have ordered a set to get zero deck clearance.
BORE = 4.205"
STROKE = 3.574"
CTR. TO CTR OF CONNECTING ROD = 5.79"
HEAD GASKET BORE DIA. = 4.250"
COMPRESSED GASKET THICKNESS = .043"
CENTER OF MAIN BEARING BORE TO TOP OF BLOCK = 9.165"
TOP OF TOP RING TO TOP OF PISTON = .200"
CYLINDER HEAD VOLUME IN CC = 54cc
DISH VOLUME = 27 cc
PISTON TO DECK CLEARANCE =.038"
COMPRESSION HEIGHT = 1.550"
Compression Ratio = 9.1:1
Additional prep work to the block before it goes to the Machine Shop:
I de-burr all of the oil return hole in the center of valley area and drill additional holes through opposite of every lifter bore. I use a 3/16" drill and angle it towards the center of the block and then I chamfer the holes on top. The ones at the back of the block are 5/16" and I make a little oil trough to help direct the oil to the holes. I can't take credit for either of these ideas. I saw the small ones in a magazine way back when and Mr. Jim Landis get credit for the ones in the back.
I also drill and tap the holes for the internal oil line and smooth out the tops of the lifter bores. Some blocks have a really nasty flash up there and needs to be knocked down so that there is no chance of interfering with the roller rocker arm links.
This is a 360 block pictured but I did the same exact thing to the 390 block.
IMG_4319 by
Rick Jones, on Flickr
Back from the Machine Shop:
I do the normal cleaning as I do on any engine before I start to assemble.
Core plugs all go in first followed by the Cam Bearings. It is critical to fit the cam before anything else is done incase you have to resize the bearings.
This one goes in nice and can easily be spun by hand.
Next thing is to install the internal oil line.
I make my own steel line but here is some more detail on how I do it.
rebsamcandjeep.proboards.com/thread/480/amc-internal-oil-line-installIMG_4028 by
Rick Jones, on Flickr
IMG_4030 by
Rick Jones, on Flickr
On the performance engines I drill out the main bearing feed holes to match the 5/16" oil feed hole below it and carefully chamfer and deburr the hole.
I am using Clevite Rod and Main Bearings on this one. The Clevite brand seem to give us the best clearances but of course, they are more expensive than the rest. The rest seem to run a little on the big side up to a half a thousants. The clearances on both the rod and mains are right at .002".
IMG_4322 by
Rick Jones, on Flickr
Then a little Lubriplate 105 on the bearings and Assemblee Goo on the rear main seal.
IMG_5127 by
Rick Jones, on Flickr
Crank, Piston & Rod Assembly:
I am using forged AutoTec pistons by RaceTec. If you order a set from RaceTec be sure to inpsect them to make sure that they sent you 4 left hand pistons and 4 right hand pistons.
Twice now they have sent me 8 of one side.
I draw a arrow on them to designate the front of the engine because they don't note it on the piston anywhere. This helps me when I orient the rings.
IMG_5132 by
Rick Jones, on Flickr
The machinist installed new ARP bolts in the rods for me which requires a little machining on the rod nut to work.
The flange head has to have a little chamfer ground on it to clear the pocket in the connecting rod. These get torqued to 50 #/ft.
IMG_3495 by
Rick Jones, on Flickr
Hydraulic Roller Cam:
The cam choice was simple.. This was the only hydraulic roller cam that we could find anywhere so that pretty much narrowed it down.
IMG_5156 by
Rick Jones, on Flickr
We had to really look over the early Comp roller cams because they machined the center bearing journal too wide.
It would actually hold the lifter up and wouldn't let it contact the lobe. They probably have the issue fixed now but I always check to make sure.
IMG_5159 by
Rick Jones, on Flickr
I am going to try to use a Milodon #15000 double roller timing chain and gear which is a SA Gear unit in a Milodon box.
The oil slot misses by half a slot so, I will move it over and I will braze the slots shut on the front side as well.
I may elongate the feed hole in the cam as well.
IMG_5158 by
Rick Jones, on Flickr
I am going to use Crane Hydraulic Roller Lifters. The trouble is, they don't make them any more.
IMG_5157 by
Rick Jones, on Flickr