Hi Folks
Well, I finally broke in my fresh 1971 340 build after 4 months. This engine is going into my Cruiser 1971 340 Demon this spring (hopefully).
Here's the rundown on the build........
.040 Cast Silvolite pistons .018 out of the hole. Piston clearance .00075
Hastings moly rings
Compression rings .017 gap
Oil rings .037 gap
OEM Re conditioned 340 rods with ARP bolts. .0017 clearance
OEM steel crank .002 main clearance, .003 end play.
Melling HV oil pump with hardened shaft.
Cast "O" heads with 2.02 valves and 70 cc Chambers. Comp 942 springs with installed height 1.7 inches.
OEM hydraulic 340 rocker gear with .035 preload and .040 shaft shims. Comp Hydraulic Lifters.
OEM 340 HP Manifolds
Comp XE 262 Camshaft, .0025 endplay.
OEM Cast intake with 6139 Thermoquad (stock).
MP adjustable distributor (Mallory)
Champion RN 12Y plugs
Hi flow water pump with Robert Shaw 180* stat.
This combo started and ran like a champ on the run stand. 20 minutes at 2000RPM using Comp Cams break in oil and a WIX oil filter. Then 20 more minutes varying the RPM from 1500 to 2500 RPM. Timing at 34* during the entire break in. Shut her down, drained the oil and changed the filter. Re filled with Lucas Hot Rod oil 10w30. Let it cool, then fired it up for another 15 minutes varying the RPM as well. Shut her down, let it cool off during lunch....and then a compression test.
Observations...............
#1 Holy crap, not a single leak anywhere!
#2 Hot idling oil pressure is 60 lbs.
#3 Compression is 180 lbs across the board.
#4 16 inches of vacuum (rock steady needle) idling at 850 rpm with 20* idle advance.
#5 20 inches of vacuum at 2000 rpm with 34* advance.
#6 The break in oil looked really good after being drained. A couple of barely distinguishable silver streaks in the oil when scrutinized. LOL....No chunks!
For a Comp Cam's flat tappet break in, I feel that it went well. Time will tell. Here are a couple of pictures.........
Thanks for looking