Valve shims causing low compression?
Since buying Docwra's 'drop in forged engine' I've not had a chance to drive it the way it's meant to be driven. Yesterday I finally had the ££ to take it to HQ Performance and get it on the rolling road. The mapping was checked over and the boost curve is fine. However once boosted the on WOT and to the redline the car then starts miss firing once back on the throttle, after this the car won't start again. A boost leak test has been done with no problems found.
A compression test was carried out and got 6, 5.5, 5, 4 bar which is very low. The garage suggested they think the valve shims are causing the problem with the car. A leakdown test is getting carried out tomorrow. The engine I was told had only done around 5000 miles since built. Ive not even managed 500 miles in it yet.
Is that most likely the problem and is it a fairly easy fix?