Cause of ticking

[immortality]

I think it's a 5/16" unc bolt? 18tpi so the thread pitch is about 1.4mm or (0.056") per turn. so 2 full turns of pre-load would be about 2.8mm or 0.112" pre-load which is to much. Have you checked with Crow to see what the recommended pre-load is to suit there lifters?

From hand tight it's probably another 1/4 - 1/2 turn before the bolt is torqued to spec' so the pre-load would be even more

[maldotcom2]

By hand tight I mean nipping it up with a short handle Allen key. But it 2 turns sounds excessive, i'll have to recheck the exact amount of turns because I wasn't sure what the torque specification is on YT ultralites. Does anyone know?

I have noticed that the engine is now very smooth while cruising. No vibration, idle is much less lumpy, no popping on deceleration. Although top end power seems to have dropped off.

[immortality]

the torque required is based on the fastener, so in this case i think MACE recommends 23Nm for there 5/16" cap screw bolts so the YT items would be much the same

[MACE]

We recommend 23 ft/lbs for the fasteners.

In regards to lifter crush 1.5-2 turns is what we aim for with these street engines.

In saying this though, if you feel that power output has dropped off top end you would have to log how that car is running, as you may be getting more effective lift (changing AFR's) or the valves might not be seating properly at higher RPM.

Regardless though that ticking is likely coming from your extractors, it seems

[maldotcom2]

Well as long as 2 turns is not risking bottoming out the lifters i'll just leave it and send the bastard to the exhaust shop. The car has landed on the extractors going over speed humps so maybe there's a crack that they could find.

[MACE]

Well as long as 2 turns is not risking bottoming out the lifters i'll just leave it and send the bastard to the exhaust shop. The car has landed on the extractors going over speed humps so maybe there's a crack that they could find.

Lifters have around 180thou of travel from memory so you'll be right

Please keep us posted

[immortality]

I have heard of someone who set there hydraulic lifters much like solid lifters using adjustable rockers, prevents any lifter collapse but you need to be careful with lifter pump up. Also makes the valve train a little more noisy.

[MACE]

I have heard of someone who set there hydraulic lifters much like solid lifters using adjustable rockers, prevents any lifter collapse but you need to be careful with lifter pump up. Also makes the valve train a little more noisy.

I'm tipping he had a lot of lifter crush!

[maldotcom2]

I just had a reputable exhaust shop have a listen. He thinks the top end sounds great and the tick is the sound of the gasses in the extractors. He gave me a number of a guy who does ceramic insulation on the inside of the pipes. Apparently it makes a world of difference. If I get that done i'll post back with results.

[MACE]

I just had a reputable exhaust shop have a listen. He thinks the top end sounds great and the tick is the sound of the gasses in the extractors. He gave me a number of a guy who does ceramic insulation on the inside of the pipes. Apparently it makes a world of difference. If I get that done i'll post back with results.

Ah excellent

In regards to the tick, I'm a little skeptical that ceramic coating will help considerably with the sound.

Before ripping anything off please consider what I've written previously

"Ok I just shot 100 PSI up the exhaust pipe and got under the car with soapy water. I found some leaks around the flanges which I have repaired with new gaskets, bolts and high temp silicone. The noise is still identical so it wasn't that. MACE, if I buy your CROW lifters do you have the specs for preload so I can determine whether or not I need longer/shorter pushrods?"
Yes that's not a problem

"Does anyone else have tuned length extractors? I'm wondering if this is amplified valve noise"
Before changing lifters I would try somehow physically mount this material to each header (or use exhaust wrap to a lesser degree)

ACL Race Series Heat Shield Material

This will dampen help in dampening the sound.

Please keep us posted

Cheers,
Steve

[maldotcom2]

This is different to normal ceramic coating. Some sort of insulation applied to the inside of the pipes apparently. I've never heard of it personally. He also mentioned that internal modifications exacerbate the problem, which sounds logical.

[MACE]

This is different to normal ceramic coating. Some sort of insulation applied to the inside of the pipes apparently. I've never heard of it personally. He also mentioned that internal modifications exacerbate the problem, which sounds logical.

The internal mods sides of things is correct. As for the coating I'm still skeptical, I suppose there is only one way to find out I guess