Well, sort of. Except that by "green" we mean "saving a buck by tearing into a blown-up crate motor and using it as the basis for a Super Stock race engine build."
Yes, that is a mouthful, but it's the truth. And it's one of the more fun race engine builds we've undertaken. We started this project by purchasing a no-longer-running Chevrolet 604 crate engine that had been pulled after blowing a head gasket. In the first installment we machined the block and installed the rotating assembly. Last month we moved on to the cylinder heads and started on the valvetrain.
We hit a bit of a speed bump in the last installment when we discovered the 1.7 ratio rocker arms from Comp Cams caused the pushrods to contact the inside of the pushrod guideplates. This month we'll correct that little oversight and finish up the valvetrain.
It's the valvetrain, along with the lightweight rotating assembly, that should give this engine a leg up on the competition. If you remember, the idea behind this project is to reuse as many components as possible from the discarded 604 crate engine we purchased on the cheap and invest the money saved in places where we can find an advantage. Next month we'll finish buttoning up the engine and put our ideas to the test on the engine dyno.
3 Guideplates are made from...
3 Guideplates are made from some seriously hard stuff. The easiest way to create the clearance needed is with a small diameter carbide burr in a die grinder, as you can see here. Make sure not to widen the guide slot any. We used a small grinding stone in a Dremel tool to clean up any rough or sharp edges left over.
4 Here’s the same setup after...
4 Here’s the same setup after the additional clearance has been cut in.
5 Special precautions have...
5 Special precautions have to be taken when using flat tappet lifters in an aggressive racing valvetrain or you run the very real risk of grinding off the nose of the cam lobes or the crown of the lifter during engine break-in. After cleaning the Comp solid lifters, we sprayed them with four coats of graphite spray and allowed it to dry.
The rebuilt 604 Chevy crate...
The rebuilt 604 Chevy crate engine is coming along nicely with an interesting mix of recycled and new parts. We just need to add a few finishing touches before we are ready to head to the dyno.
1 We showed you this photo...
1 We showed you this photo last month. We ran into an issue when we discovered the 3/8-inch diameter pushrods were contacting the end of the pushrod guideplates when matched with the 1.7:1 ratio Comp Cams Ultra Pro Magnum rocker arms we used on the intake valves.
2 The easiest solution turned...
2 The easiest solution turned out to be simply to grind the guideplates to create a bit more clearance. We didn’t need much. Since the guideplates are designed to work with larger 3/8 pushrods, the side-to-side clearance is already correct. The area to be cut is marked with a silver Sharpie.
6 After the graphite spray...
6 After the graphite spray dried, the ends of the lifters were then coated with Comp’s lifter assembly lube. Besides being a good lubricant that protects the vital contact points between the cam lobes and lifters, the stuff is also thick enough so even if your engine sits for a few weeks before cranking for the first time, you know it will still be in place.
7 Finally, before dropping...
7 Finally, before dropping the lifters in place, the bodies are covered with a standard assembly lube.
8 Pushrod flex can be a real...
8 Pushrod flex can be a real issue with high rpm racing engines. We’ve upgraded from the standard 5/16-inch diameter pushrod (bottom) to these 3/8-inch diameter units from Comp Cams to help eliminate flex and accurately transmit the instructions from the cam to the valves.
9 Before final assembly,...
9 Before final assembly, the pushrod tips as well as the threads of the ARP rocker studs are given a light coat of extreme pressure lube. The lube will help protect the area between the tip of the pushrod and the pushrod cup in the rocker arm during the first few revolutions when the engine is cranked. The reason for the lube on the threads of the rocker studs is simply to keep the adjuster nut from galling to the threads after several heat cycles.
10 Here’s another look at...
10 Here’s another look at the new Ultra Pro rocker arms from Comp Cams. These chrome-moly steel rockers have a unique webbed design that makes them both light and extremely strong. They are also full roller for maximum efficiency.
11 Don’t forget to use a...
11 Don’t forget to use a spring compressor to check pistons-to-valve clearance. Check exhaust valve clearance at 10 degrees before TDC and intake valve clearance at 10 degrees after TDC. You want at least 0.060- to 0.075-inch of clearance for the exhaust and 0.050 for the intake. If it is close, set up a dial indicator on the valve to help you measure more precisely.
12 We did our setup and testing...
12 We did our setup and testing with the standard adjuster nuts but these are the units being used for final assembly. They are part of a rocker stud girdle kit from Comp Cams and have been precisely ground to be centered in the girdles and keep everything properly aligned.
13 We’ll perform lash loops...
13 We’ll perform lash loops on the dyno to dial in the best lash settings for the intake and exhaust valves, but for now the lash is set to the manufacturer’s specs of 0.018-inch for the intakes and 0.020 for the exhausts, which will be good for break-in.
14 Comp cuts grooves into...
14 Comp cuts grooves into four of the adjusters for C-clips. These go on the four corners of the engine and act as a shoulder to control the installed height of the aluminum girdles.
15 The girdles are solid...
15 The girdles are solid one-piece units for maximum strength. They lock down onto the adjusters with bolts that pull the center gap closed.
16 Here’s another look at...
16 Here’s another look at the rocker stud girdles. As you can see, they lock all the rocker studs together into one unit to drastically reduce flex of any individual rocker stud.
17 We’re sticking with Cometic...
17 We’re sticking with Cometic for all the gaskets. Notice how precisely the intake gaskets match the intake ports on the RHS heads. No need for cutting gaskets here.
18 The rules where we plan...
18 The rules where we plan to race this engine require a box stock Edelbrock 5001 intake manifold, which you can see here. It’s no Victor Jr, but the single-plane design should still help make good power.
19 All Chevrolet intake manifolds...
19 All Chevrolet intake manifolds can have some tight spots around the center four bolts. Investing in some high quality fasteners with 12-point heads can make your life a lot easier when installing your intake.
20 Rocker stud girdles require...
20 Rocker stud girdles require extra clearance. These valve covers from RHS fit well and provide plenty of clearance for the rockers. We’ll just need to upgrade the breathers later.
21 Street Stock racing requires...
21 Street Stock racing requires either a stock or a “stock style” ignition. For Chevrolets, that means an HEI distributor. A stock HEI can be limiting with a high-compression race engine and create a miss as the rpms increase. We’ll avoid that issue altogether with a high-power DUI HEI from Performance Distributors, which we’ve seen in previous tests take an engine capably to 8,000 rpm and beyond. Plus, Performance Distributors offers this stealth version with a plain black cap so it looks quite stock.
22 Here’s a closer look at...
22 Here’s a closer look at the guts of the DUI unit. Performance Distributors set up the unit to match our engine specs, and included a block-off plate to eliminate the annoying vacuum advance. Also notice the use of nylon screws in the rotor. This is a nice touch to eliminate the chance of sparking inside the cap. Tune in next month for the final button up of our recycled 604.