I have a 1.5 DOHC engine. After my son drove the car with no water and blew the gasket, i had the heads resurfaced and put a new gasket on. I did all the work possible since this was a major overhaul (timing belt, seals, gaskets, plugs, mounts,etc...) to get the engine to as best shape as possible. I could not find a head locally so i got one online atjisengine.com which camewith the cams, chain, valves and lifters all installed. After i installed everythingand got the car started, i noticed a ticking or tapping sound quite loud. I checked the valve clearances and noticed that they averaged .008" with some even as tight as .006". Most Mazdas don't have adjustable valves but mine do. I have shims (metal discs) that sit in the hydraulic lifters that sit ontop of the valve. the manual states the correct specs to be between .010" - .012" on both the intake and exhaust valves. Some are measured at TDC and the balance are measured at BDC. I corrected the shims accordingly so that now ten of the sixteen read .012" and eight of them read .010".

With the shims corrected, i thoroughly expected the tapping sound to disappear. It got alot better, but it's still noticeable. At first i thought that it was just normal, but my wife(it's her car and it's her daily driver) mentioned that she can still hear a slight tapping sound. If my wife notices it, then it is not acceptable. Now should i adjust the valves to .012" - .014" to make up for the resurfacing? I'm hoping this is a familiar symptom that folks are already familiar with. Any help is greatly appreciated.

 

Resurfacing a head on an overhead cam engine changes the cam timing since the slack is taken off 1 side so you can't go by the crank timing marks. That said i always go a bit tight on valveclearance myself.

 

just to be sure i'm correct, i turned the crank to TDC and did my first set of adjustments and then to BDC and finished my second set of adjustments. the thing that puzzled me was that on other motors i worked on, when i did valve adjustments, the cam lobes were always opposite the adjustment and i checked the maximum clearance of the lobe for the specs but if you follow the manual for the protege and adjust at TDC and BDC, the cams are not being checked at the maximum clearance. The lobes are actually facing more sideways than away from the adjustment and looks as if the gap would be different if checked . Is this the correct manner of checking and adjusting these valves?

In addition, what do you mean that the timing changes because the slack is taken off one side??? hmmmm...

 

When you shave a head on an overhead cam engine it brings the cam closer to the crank. One side of the timing belt/chain is kept tight by the tensioner resulting in the cam being out of time a few degrees depending on how much was shaved from the head. If you set the cams perfect at TDC then look at your crank timing it will be off. To adjust the valves by the book you will have to disregard the crank timing pointer and go by the cam timing marks. I would still go .002 tighter on intake and exhaust.

 

please tell me what you mean by going tighter by .002"? When i first started the car after reassembly, the valves were very loud and they averaged at .006-.008". I adjusted the shims so that they are as the specs in the manual, intake and exhaust both between .010-.012". the valves are still tappingnoticeably, but with great improvement. It seems that if i was to go to a bit more, like .012-.014" the tapping would improve even more. I want to make sure i'm heading in the right direction. By going tighter do you mean to add .002 and go to .012-.014".

Am i understanding you correctly, because to me that seems like i'm not tightening the gap, but widening it to make up for the loss of the resurface. Or do you actually mean that instead of using .010-.012 I should go to something tighter like .008-.010".

 

.008 - .010 . Less clearance means less noise and better performance.