Hello i need some help with my b16a. I did a leakdown test when i got the engine and it showed perfect results on all 4 cyl. 100-90% leakdown. I replaced the timming belt and re did a leakdown test for abits a giggles and it showed that all my exhaust valves were loosing air pressure. So i assumed maybe my exhaust valves were bent (they weren't). So i bought some new valves, measured them, and installed them. So i ran another leak down test and again only the exhaust valves are loosing pressure. The intake valves are completely sealed. I set the timming belt correctly according to the service manual. Ive messed around with the timming just incase the exhaust side camshaft was for some reason pushing down the exhaust valves but nada. I also adjusted the valve clearence .007-.008in on exhaust valves and .006-.007in on the intake valves. So my question is. Should i run the engine with the new valves and let them seat and do another leakdown test later or am i missing something when i replaced the timming belt. I aligned the marks on the camshaft gears and the crank sprocket so everything is well aligned. I just cant figure out why the frigg the exhaust valves keep leaking air pressure if all the valves are new.

 

100%-90% leakdown means its leaking ALL or ALMOST all of the air being pushed into the cyl during the leakdown. I think you're either doing the test wrong, or reading the guage wrong. a proper leakdown tester should show 7% or less leakdown in a healthy motor when done properly.

are you setting the piston to tdc on the compression stroke for each cyl as you test it?

 

Yeah what he said. If your losing 90% past your exhaust valves, something is definitely wrong. Perhaps you mean 10% leakage?

90% leakage and your compression will be crap and the car wont run. You should be able to notice a distinct sound difference when cranking the engine.

There's a chance things will "tighten up" after the engine is run for a bit... I had a gsr head that I had some headwork and a valvejob done by a reputable company (no names) and when I got it back, I did a leakdown also just for ***** and giggles. It had some leakage past the valves, not a ton, but it wasn't perfect. I immediately called the shop to bitch at them. They assured me it would improve and to run it...
I very reluctantly took their advice...Car ran great and after a few weeks of driving I did another leakdown test. Sure enough, things were sealing up almost perfectly (

 

Yes i set the cylinder at tdc at 1st whag i meant was the engine was leakig 10% at 1st then i did it again with the same stock valves as soon as i replaced the timming belt and this time exhaust valves were leaking 30-45 percent. Now with the new valves it leaks 40-50 percent.

 

What was the leakage percentage on the new valves?

 

You lapped your NEW valves before installing these in your cylinder head right?

 

Yes

 

how are the stem to guide clearances?
are the valves a name brand?
after lapping the valves and assembling, did you do any type of liquid leak test in the ports to check the valves for leaks before putting the head on the engine?

 

How do i measure stem to guide clearance?
The valves are dokuro, i measured them and compared them with the oem valves and they are the same size.
No i didnt try to add liquid through the exhaust port.
Im planning on taking the head off again and double check everything.
Can i re use my headgasket? I torqued the bolts to spec but never installed the engine, never even started it. Its a victor reinz hg.

 

This was like 15 years ago, I cant remember but I wanna say it was like 10% or so. Not perfect but more than what I thought to be OK for a brand new head. It tightened up though. I was surprised.