Monday 20 May 2013

Engine Assembly & Header Build

I've been waiting a long time to get to this point.
I finally collected sufficient engine components to justify actual engine assembly. I have run into one last (self-inflicted) hurdle though that I explain at the end of this post, but for now, here is what's been happening for the last few months.
First off, check out the very nice induction setup (below) that was the result of a heap of preparation work by myself and then some great help from Robbie out at Flexicut Engineering. I thought up the original design and had it created in a CAD/CAM program. Robbie then adjusted it to make it more practical to cut on the CNC machines to save a heap of time (= money).
I can't thank you enough Robbie for the "extra mile" you went to in helping out with the coolant exits, the engine valley plate, the throttle linkages, throttle rail mounts, various spacers, etc.
The picture below shows how nice it finished up.















 
I was originally going to anodize parts of it - but it looks good as is (my opinion). So it will remain as a natural finish (natural for T6 alloy).
In case anyone thinks the above was straight-forward or easy to do, there are a heap of design tweaks implemented to get it all to work (fits like a glove actually). And then there are some mod's I would add in hindsight as well - now that it is all bolted up. But regardless, the results are fantastic.
As you can see, i've gone for short & straight runners. Ideally i would include some wedges to position the trumpets more upright (and minimise the potential for cylinders to rob air from each other), but i think this will work ok. The motor will have plenty of natural torque at low rev's to compensate for the short runners at low RPM's.

Now for the engine build.
Firstly, here is the crank and cam being degreed-in, so i can fly-cut another set of pistons.... I sold the last set to a guy that needed them sooner than me. You can see the yellow plasticine being applied again for this task (to measure valve to piston clearance).














And here is the result. I took another 100 thou off the pistons to ensure plenty of clearance for the intake valves. The exhausts had heaps of room by default. What this process doesn't show however - is the time spent making another jig so each piston could be cut exactly the same, as well as the effort that goes into making sure each piston weighs the same to 1/10th of a gram.......














And below you can see the conrods having been prepared and numbered.














This photo just shows my routine for gapping piston rings. I make sure I don't mix them up by leaving them in the bore. And then I..........














....place them back in the box in the position the pistons came out of so I can minimize any chance of putting them in the wrong bore.














Here I finally have the short-block complete.
Things to note are:
  • I am running a Canton main-girdle as a stroker engine needs all the bottom-end help it can get. This is a cheap investment, but in this case it needed mod's to give it the minimum 60 thou' clearance (in a few spots).
  • Degree-ing the cam showed it was 2 degrees advanced compared to advertised spec's. So I've retarded it by this amount to install it "straight up".
  • The mechanical roller-cam has +.700" lift with "reasonable" duration by the way.This should work well with the induction setup i have i believe (but the dyno will prove this one way or the other).














And below you can see I've bolted the heads and valley plate down. I had to build my own "crows foot" socket to allow the torque wrench to reach the nuts (on the head studs) running down the middle of the heads. The big valve springs simply would not allow a standard 11/32" socket to be used.
My "crows foot" socket was made by cutting as standard socket in half so i had the half-inch drive end separated from the socket end.
I then welded them back together, but "offset" by welding a short length of "chopped up old spanner" between them.
I made the center-to-center distance of my new crows-foot exactly 1/10th the length of my torque wrench. This made it easier to calculate the revised torque wrench settings to use as i just needed to take 10% off any recommended settings (as my new torque wrench + crows foot length was 10% longer overall).














Because of the high-lift roller cam and associated heavy-duty valve springs, I went for a stud-girdle as well. I think this is even more important with alloy heads as they do move more than cast iron units. Again, this is just my opinion.














And below you can see the valve covers have been put on and the ports all masked up for yet another trial fit. But this time in order to fabricate the headers. This picture does tell a thousand words (for anyone contemplating this engine/chassis combo.........
You can see that the RRS shock-tower notching kit gives me heaps of room for the first part of the pipes as they exit the heads. This is good news - but I ended up needing absolutely every inch of space I had seeing my header "weld up" kit has 2-1/4" primary pipes combining into a 4" collector.














The photo below shows that there is plenty of room for the pipes as they exit the heads. A keen eye will even see the 4" collector dummied into position all the way at the lower rear. That is fine, but as my car is converted to right-hand-drive - I then had to contend with both the starter motor and the power rack & pinion linkages on the same side of the car (the side shown below).
I think i did 1000 situps in 2 and a half days building these bloody pipes. I knew it was going to be painful but when you are doing this on your own, you seem to endlessly repeat the following tasks: hand cut and fit some pipe, then tack-weld, then remove he header and fully weld, then re-install, then hand cut and fix the next section...... You do this over and over and over.....And you get under the vehicle then get up again for each step














The result was worth it though. Below are the custom pipes almost done.














Once the headers were done and the oxygen sensor ports welded in, I could start to do final assembly. The photo below shows the engine 90% complete and on a temporary engine stand. I'm going to use this stand to initially fire the motor up before going to the dyno - as I want to be sure it starts and runs first.
Dyno time isn't cheap, so getting it started and idling ok first makes sure the wiring is all fine and that there are no obvious leaks or any other myriad problems there may be when first firing an EFI motor.














The shot below shows the motor as it is now.
I am yet to install the coolant system and alternator/power steering pump, but the cooling system is my next task. I am going to fabricate a small tank to combine the two AN-16 outlets if have on the heads - and then this small tank will have a standard radiator "top hose" outlet. You can most easily see the coolant outlet hose fittings for these in the photo above.














I then only need to fabricate the twin electric pump plumbing to circulate coolant into the two inlets (that you see on either side of the belt-driven cam gear).

Now for the frustrating bit..... I seemed to have lost my crankshaft drive pulley for my dry-sump!
This is a show-stopper in regards to strarting the motor. So I need to order another one in before I can start the dam thing. This will take a couple of weeks.
Once back from the dyno, I will update the blog.