Jason Moyle Racing

Just to prove we're not totally 8v biased here's some multi valve action for you....

I was approached by Duncan Brown on here about building a box of bits that he had acquired. Most of the bits were there but although Duncan wasn't chasing a power figure as such he said 215-220hp would be nice and anything more a bonus (I was long for the "more" bit!), though he would prefer decent torque rather than all out numbers. With the parts we had to hand I suggested to Duncan that some of the parts would need upgrading to reach his target, namely the cams...Newman 272 hydro's...and the exhaust manifold...an off the shelf road based 4-1.

Among the parts was a ported cylinder head so I started from there to see what we had to work with. Airflow was decent to be fair but was achieved via ports that were too big and throats that are too small, so my concern was low & mid torque could be hurt, however there was plenty of flow for top end breathing....that wasn't the biggest issues though. At some point in it's past the valves seat's must have been cut by the machine shops tea maker as I doubt someone who knew what they were doing had done them. However the main issue was both the head & inlet manifold faces...the same tea maker must have been asked to clean them up but didn't really understand the job in hand as I'd imagine he used a variety of smooth grit wet 'n' dry to get the finish but with wildly varying hand pressure as there wasn't a straight surface on either!....tarted up for sale springs to mind.

After assessment at my machinists he declared he could true up the faces and re-cut the seats so we went with that to save starting from scratch with another head. Once we knew what we were working with I looked at cam spec's to suit and found exactly what I wanted with Piper's 290 degree race profile. Duncan didn't want to use more than 8000rpm so I wanted to see peak power at around 7500rpm and I had a torque target of 170-175ib/ft. With steel cam buckets and race valve springs added into the mix I built & shimmed the head up to suit.







With the hefty skim needed to true up the head face we had a very shallow chamber, so the forged pistons needed their raised compression crown reducing a fair bit to bring the C.R back in line and the valve pockets deepened to clear the valves at TDC. With the machining done and the block decked to give the required squish I use the bottom end was built up with the steel H section rods and wedged crank as supplied, with ARP studs used to secure the main caps and the head.





Duncan supplied some KMS throttle bodies to go on our JMR inlet manifold, and ventured off to Tony Law Exhausts with the manifold spec I gave him to suit the powerband I wanted to achieve.

After bolting the engine on to the AP Motorsport dyno Alvin set about setting up the Omex management and squeezed all that was possible from what we had....





...which was 229hp @ 7,500rpm (229.99 if we want to be picky!), holding 223.75 @ 8000 and 172ib/ft of torque @ 5,500rpm. With the torque target hit and hp bonus over what Duncan was hoping for it should drag a MK1 Golf around the circuits ok.



...turn it up!.....