Triac Auto Clinic
The home of
Flaming Imps Racing
Seat Arosa with a 1.6 AVY GTi engine swap
After being brought in for mapping with a mild built engine built by another engine builder running an Emerald K6 ECU the calibration process was started and unfortunately didn't go to plan. The engine lasted a while before trying to put a valve through the piston. After letting the owner know we decided between us to take strip the engine and find out what went wrong. Pulling the engine apart we found that some of the hydraulic lifters had lost their oil pressure while others had kept it. Pulling the head off it was easy to see what had happened straight away, the exhaust valves had been kissing the pistons before the inevitable happened and a valve head snapped off. The cylinder head is now scrap and the block needs a bore to rectify the internal damage. Further investigation found that the key way on the exhaust cam gear was partially butchered suggesting that it had not been installed correctly and moved whilst being run on the dyno. We also picked up that the intake valves had started to touch the pistons. We had a chat with the owner who decided to use us to build up a fresh forged engine. The owner supplied a spare AVY engine that was stripped for the head and any other items needed. It was decided to use the block from the spare engine as getting hold of pistons for this engine became a bit of a nightmare. We managed to drop lucky with a 0.25mm oversize piston from a UK seller meaning that we could freshen the bore up and start fully fresh. The build was going well until we found that the manufacturer of the rods and pistons stopped supplying the shims for the little end. The original rods are guided by the big end journal, the new rods are narrower on the big end meaning that they needed to be guided by the little end. The new rods how ever had around 3mm of float in the little end meaning that I needed to machine up some shims in aluminium and get them hard annodised to remove the little end float. After getting the end float on the rods sorted it was time to check the valve clearance with the race cams that were previously installed. The issues we have here are the engine runs on hydraulic lifters meaning that under normal circumstances you won't get full lift as the oil pressure isn't holding the lifter at full height. Back to the lath and two solid lifters were made to be used temporarily to check the valve clearances. With the head gasket removed we had 0.7mm of clearance on the exhaust side and 1.5mm on the intake, so with the head,gasket installed (0.6mm thick) and crushed up we will be over the 1mm clearance required. The engine was finally fully assembled and reinstalled into the car and put back on the dyno. This time all went according to plan and the calibration was completed with the engine making 140bhp and 130lbft at the hubs. The car was then taken out to complete the over run and low down take off. This was all dialed in and the car taken on a track day and beaten on by the owner for a full day without any issues.
Next on the plan is an AVY/AFH hybrid to push the peak RPM to 9000 and aim for 200bhp.
Watch this space....