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Now that the cam is installed, we need to get all the rings checked and installed onto the pistons.
Top rings take the most heat and those need the most gap. Forged pistons and hypereutectic cast pistons also take additional ring gap.
Follow the instructions from the piston manufacturer and in my mind, when in doubt, run a little extra ring gap.

You need a feeler gauge (thickness gauge) and a piston in order to square-up the ring in a bore, then measure the gap.



I use to hand file the gaps but I recently got myself a ring gap grinding tool, now i will never hand file rings again, the tool makes the job so much faster and accurate.
If you need to gap rings, beg, borrow or buy one of these tools.




Once the rings are gapped, install them onto the pistons, make sure the top ring is in the top ring groove and that the ring is in the proper position. (follow the instructions that come with the rings)




Installation of the pistons is also straight forward. Be sure to stagger the ring gaps and be sure the con rod caps go on the correct way.... bearing tabs and the stamped number are on the same side.

Here is the short block, assembled.

The cam change has impacted our head choice.
The two race heads we have ready are not a good match with the milder cam.
We double checked the CC numbers on both those heads and re-did the math just to be sure. The 48cc head puts us at 11.6 to 1, the 40cc head at 13.2



Target compression for the selected cam is 10.5 so now what??
Go over to the pile of cylinder heads and start inspecting... that's what.

As much as I hate doing it, we selected a used "street performance" head, broke it down, did some additional porting work to it and added oversize valves. (1.750 / 1.440) Surfaced it .010 just to clean it up and assembled the unit. This head has a 58cc chamber and that puts the engine at 10.2 compression. This has to be one of the fasted performance head rebuilds we have done.

A close look at the short block assembly photo above shows the special windage tray mounting studs on the heads of the center main cap bolts.



The factory SL6 main cap bolt is shorter then the aftermarket bolts supplied with the windage tray kits so there are 2 hardened washers added under the bolt heads to be sure that you do not run out of threads and to make sure that the bolt does not extend into the oil passages leading down to the crankshaft. Yes, if you use a main bolt that is too long, on the cam side of the main cap, the bottom of the bolt will extend into a oil passageway and pinch-off flow.
Knowing this (and being fussy) I always grind the tips of these bolts smooth. Being in a hurry, I just do the two that install on the cam side of the main caps.



Now for the fun part of doing a windage tray installation, a bunch of fit checking!

I like to install the oil scraper along the trailing edge of the windage tray so I do not have to deal with a separate "fitting session" and installation for a oil pan rail mounted oil scraper.
Here is a file photo showing a pan rail mounted scraper:



This photo show an oil scraper welded to the edge of the windage tray. The shot also shows the oil pan with a "anti-slosh" shelf welded across the rear edge of the sump, this keeps the oil in the sump and around the pick-up during a hard acceleration "launch" :





During the scraper welding process, extra tack welds are added to the tray mounting areas to be sure the sheet metal stays attached. The factory spot welds have been known to come loose and things get nasty when the spinning crankshaft get ahold of it.



After mounting the parts, spinning the crank, finding where stuff hits, take it apart and grind, re-install the parts... repeat as needed, (about a dozen times) the assembly is ready for the oil pan installation. We will leave the oil pan off until the head is installed with all it's rocker arm gear. (don't ask me why... )

We are using one of the "big bore" head gaskets on this engine to allow lots of room for intake valve unshrouding.



These gaskets come with a wider "fire ring" and a sticky surface coating so it should seal well. Because of the sticky coating, it is best to leave the gasket wrapped in plastic until you are ready to install it.



Wipe the head gasket mounting surfaces clean, set the gasket in place and then get a helper to help you place the head onto the block. I like to bolt a bare rocker arm shaft onto the head so there is a "handle bar" to hold onto.



I use one standard head bolt to hold the head down while I screw-in the ARP head studs and install the washers and nuts. We torqued this head down to 80 ft lbs. which is the same torque we used on the torque plate (hone plate) during the final cylinder honing operation.

We installed a set of 1.6 ratio, roller tip rocker arms and did some checking.



The push rod angles and the tip to stem contact point are both "spot-on. This is the nice thing about using a high compression piston and not having a lot of material milled off the head and block surface, the valve gear geometry ends-up as the factory designed it!





We bolted things down and flipped the engine over and installed the timing chain cover and oil pan. I held my breath as we spun the crank around for the first time and guess what, nothing hit inside!



Note the oil slinger, this needs to be installed, especially if you are oiling the chain and gears by using the chamfer on the front main bearing. (shown earlier)

This race engine will use an aftermarket Fischer vibration dampener.
The one I have uses a center hub that the inertia ring bolts onto.
I have a special installation tool which makes factory dampener / dampener hub installation easy.



If you do not have this type of tool, a bolt with a stack of large washers will also work but you will have to draw the unit down some, add washers and go the rest of the way.
DO NOT pound the dampener on with a hammer. Doing that will smash the #3 main bearing thrust surface, resulting in excess crankshaft end play.

The inertia ring bolts-on with 6 socket cap bolts:



There are a couple of problems with using aftermarket dampeners on a SL6. Most of the units I have seen, place the inertia ring inches away from the timing chain cover and there is no pulley groove in the ring.
We machined an inch off the mounting hub of the Fischer dampener shown here, in order to get it to fit closer to the cover. We then used a flat pulley, (GM) bolted to the front face of the dampener, to drive a "V" belt. This new spacing made us move the waterpump pulley and the alternator forward so everything now lines-up.

We are in the final assembly stages with a few more things to bolt-on before we install this new engine into the car.

The oil pump is installed with-out any special tricks, outside of gluing the gasket to the engine block and using a light coat of grease on the pump face. Doing this allow you to remove the pump later, with-out destroying the gasket.

Next we installed all the freeze plugs.
Give the holes a sanding to be sure there is no rust or burrs that would prevent a good seal.



Apply some "sticky" sealer, we use super weather strip adhesive... do not use RTV.



It is now a matter of pounding-in the plug. Use a socket that just fits the ID of the freeze plug and give it a few firm taps. Stop when the plug is flush with the block's surface. Wipe-up excess sealer and you are done.

If there was ever a moment were I really wanted a "magic wand" it is now. There is something about swapping the manifold set off of one engine and onto the new one that makes me grumble...



Once I get moving on this task, it is not that hard. It did not take long to pull the manifolds off the old engine and lucky for me, the gasket stayed on the head and the manifolds "broke away" clean so they did not need much to prep the manifold surfaces.

The manifold mounting surface on the cylinder head was remachined so it was already clean and flat. We applied some high temp sealer and stuck-down the gasket.
NOTE: the following photos are not up-side down, I find it easier and get better results when we install the manifold set with the engine turned up-side, down.



A lighter coat of sealer is used on the manifold side, this helps sealing and helps the manifolds separate cleanly if removed later.



Start by installing the center washers / nuts and lightly snug them down.
Check the end to end alignment of the manifolds as you install the remaining fasteners. Some light taps on the manifolds insures that the manifolds ports are up as far as possible.



Once everything is in position and all the hardware is installed, tighten the manifold set, starting from the center and working out to both ends in an alternating pattern. A bracket here and a water pump there.... this engine is ready to get installed into the car.

My son Allen was busy pulling the engine out of the race car while I finished-up the new engine build.



We put a bone-stock 71 225 1 bbl into the race car to make the last race of the 2007 season, we ran 18.20 on this 1bbl engine and 15.40 with a 50 horse shot.
It was nice to have a stock engine in the car over the Winter months, it would start right-up on the automatic choke and drive around with-out any 'fuss'... when ever we had to move cars around.
If anyone needs a good running stock SL6, this engine runs well and is available.

We are pretty well practriced on swapping engines in the race car, we only un-hook the minimum amount of items. Note how the starter is hanging on a hook, so we do not have to remove the wires.



We had to spend 20 minutes swapping parts from one engine to the other but after that, the new engine goes-in with-out much trouble.