mx5-kiwi

Hi Guys

Just working through a few issues pre race season and one was lifter tick with the odd funny clunk when warm...

Normal oil change maintenance is every 2nd - 3rd race meeting (about 2 hours driving per meeting) ...but as recommended to me by two separate racers/mechanics, I have done an oil and filter change and used a Motor up type product that has improved the lifter tick to where I am comfortable but I have ended up with a noise that sounds like a failed or failing lifter, this noise was a little intermittent prior but now pretty regular once warm.

Just one tick/clunk per cycle (it seems). Noises can be hard to locate but this almost seems guaranteed it is from exhaust side of the head/cam/lifter area and not the crank or bore...

So questions are...

Do I just try and track down the one failed or collapsed lifter and replace it?

Do I replace all lifters at the same time to be safe/because that is what you do...?

Do I, as a 90% race motor with 10% street use, move to solid lifters...for and against..?

Look forward to advice, suggestions or otherwise...

EDIT: Not sure if required but in the interests of disclosure motor is a 1600 semi built...with forged pistons, rods and ported and flowed head. Valves, cams etc are stock to my knowledge. Runs 10-15 psi boost on a t28 with 264hp at the wheels at 15psi.

sixshooter

iTrader: (12)

On a 90% track engine you should replace all of the lifters, SUB or hydraulic.

mx5-kiwi

Thanks sixshooter.

Can anyone expand on this...are SUBS even available for the 1600?

how hard is it to keep SUBs gapped correctly...

Do HLA's have a rev ceiling?

m2cupcar

iTrader: (5)

Yes SUBs for 1600 (same lifters as 1800). I actually used Mazdaspeed's (Mazda Competition Parts) SUB kit for the 1600 Production car with minor modifications. SUB will give superior valve action and less valve train load (allowing for softer springs) over HLA and SOB. I checked clearance after every race weekend (4hr race + practice/qualifying) to guarantee proper valve action and sealing. Miata HLA action begins deteriorating at 7k rpm, but a solid lifter will always have better valve action (when tuned) since it lacks the HLA's reaction to the cam/valve movement.

Leafy

iTrader: (1)

Other options.

Kia Hydo lifters. Smaller plunger than the mazda ones, drop right in, theoretically less likely to tick, cheaper than mazda, lighter than mazda.

Ford zetec shimless lifters, even lighter than the supertech SUBs, drop right in, harder to setup cause you have to measure the required height then order the correct ones for each position. I think only that guy with the hill climb locust in the mid atlantic area has done it.

Remember, putting solid lifters on a hydro lifter cam makes the cam more aggressive.