Replacement of both cyl head on 5VFZE

jaxinmontana · May 25, 2023

Hi all - I'm looking for some feedback on a cylinder head replacement I did on my 5VF-ZE engine in my 1997 Runner. I replaced the cylinder heads with remanufactured heads from Autozone (NuTech) a few months ago. I would never recommend reman CHs from them, but that's another story.

After getting the new ones in and replacing the timing belt, fuel pump, etc. I was hearing some ticking/knocking that suggested either a valve adjustment is needed or a sudden issue with the flex plate? I drove the engine with the ticking noise for about a month and now the engine is running pretty rough. No codes are present at the moment.

Does anyone think that a poorly adjusted valve clearance could cause the engine to suddenly run rough without a code? I adjusted the valve bucket to cam lobe clearances according to spec since NuTech didn't do it.

diverscale · May 26, 2023

well if it runs rough it isn't the flex plate

adjustment for exhaust is 0.011-0.014 and intake 0.006 to 0.009 IIRC. Did you adjust to these settings?

ticking could be a badly sealed exhaust manifold too

brillo_76 · May 26, 2023

Maybe some valve seats moved. Did these heads got hot?

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mtbtim · May 26, 2023

Valves out of spec on the very loose side could make noise. Valves that are too tight and don't close all the way could cause you to burn up a valve. When you did the valve lash adjustment, were any of them way out of spec?

brillo_76 · May 26, 2023

What kinda odd here is suddenly running rough....Unless a head gasket blew. It's not common for valve train to instantly change.

Ticking etc. It definitely could be a bad valve clearance issue.

I guess a nasty intake leak could occur, but I would think codes be starting to show up.

A quick compression and leak down test should rule out blown head gasket issues. As that would cause an instant rough running engine.

I would hope they have valves in spec, but maybe not, as you probably had to reuse your camshafts on these heads.

Could also be something else unrelated to the head job as well.

Going to have to be a process of elimination project.

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19963.4lsr5 · May 26, 2023

One cause of valve noise on our engines is when you pull the exhaust cam without putting the service bolt in the gear before removal.

If you pulled the cams to change shims and didn’t line up the cam dots before removing the cams there could be an issue with the cam towers.

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mtbtim · May 28, 2023

19963.4lsr5 said:
One cause of valve noise on our engines is when you pull the exhaust cam without putting the service bolt in the gear before removal.

If you pulled the cams to change shims and didn’t line up the cam dots before removing the cams there could be an issue with the cam towers.

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Excellent, excellent point you brought up. If the main gear and sub gear of the exhaust camshaft become unsprung, it can make the engine sound a lot noisier.

brillo_76 · May 28, 2023

19963.4lsr5 said:
One cause of valve noise on our engines is when you pull the exhaust cam without putting the service bolt in the gear before removal.

If you pulled the cams to change shims and didn’t line up the cam dots before removing the cams there could be an issue with the cam towers.

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I have to remember this if I pull the exhaust cams out.

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19963.4lsr5 · May 29, 2023

mtbtim said:
Excellent, excellent point you brought up. If the main gear and sub gear of the exhaust camshaft become unsprung, it can make the engine sound a lot noisier.

Trust me I know this to be true. The one exhaust cam was unsprung on the 96 engine. It drove me nuts figuring it out.

And holy balls was it a workout preloading that spring to get the bolt back in.

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mtbtim · May 29, 2023

19963.4lsr5 said:
Trust me I know this to be true. The one exhaust cam was unsprung on the 96 engine. It drove me nuts figuring it out.

And holy balls was it a workout preloading that spring to get the bolt back in.

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I just preloaded one yesterday but I used a big universal pulley holder tool with a lot of leverage. It was easy to preload the spring. You're only turning it the distance of around one tooth on the gear to get the bolt holes lined up on the main gear and sub gear.

rdruss · May 30, 2023

mtbtim said:
I just preloaded one yesterday but I used a big universal pulley holder tool with a lot of leverage. It was easy to preload the spring. You're only turning it the distance of around one tooth on the gear to get the bolt holes lined up on the main gear and sub gear.

Is this unique to the 3rd gen, or all Toyota V6/V8? Is it part of auto valve timing system? Would be an excellent explain video.

19963.4lsr5 · May 30, 2023

mtbtim said:
I just preloaded one yesterday but I used a big universal pulley holder tool with a lot of leverage. It was easy to preload the spring. You're only turning it the distance of around one tooth on the gear to get the bolt holes lined up on the main gear and sub gear.

Mine was off about 1/3 rotation. And yes the last tooth or two were when it got tight. I used my bench vice and some 12” pump pliers. (Slip locks)

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mtbtim · May 30, 2023

19963.4lsr5 said:
Mine was off about 1/3 rotation. And yes the last tooth or two were when it got tight. I used my bench vice and some 12” pump pliers. (Slip locks)

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Weird. 1/3rd rotation of the sub gear to get it aligned with the main gear doesn't jive with what I witnessed at the Yota1 Performance shop watching one of the exhaust cams getting put back together and it also doesn't jive with my own experience doing it. With the sub gear unsprung, it's literally only one tooth off. A quick twist of the sub gear one tooth clockwise gets the bolt holes lined up and you get the bolt in.

mtbtim · May 30, 2023

rdruss said:
Is this unique to the 3rd gen, or all Toyota V6/V8? Is it part of auto valve timing system? Would be an excellent explain video.

I don't have that much experience with other Toyota engines to know if this sprung exhaust gear is a common design. Our engines don't have VVT (Variable Valve Timing) like the newer years of the 2UZ-FE V8 engine came with. I really think it's a way the Toyota engineers came up with to keep the engine quieter. With the exhaust gears under spring pressure, it keeps the exhaust gear and intake gear mating quieter because the gears can't clatter at all. That's my best guess why they engineered it that way. With the exhaust sub gear and main gear unsprung, the engine runs perfectly fine. It's just going to be a lot noisier.

19963.4lsr5 · May 30, 2023

mtbtim said:
Weird. 1/3rd rotation of the sub gear to get it aligned with the main gear doesn't jive with what I witnessed at the Yota1 Performance shop watching one of the exhaust cams getting put back together and it also doesn't jive with my own experience doing it. With the sub gear unsprung, it's literally only one tooth off. A quick twist of the sub gear one tooth clockwise gets the bolt holes lined up and you get the bolt in.

I get where you’re coming from. I strive to be different and it was three or so years ago.

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Replacement of both cyl head on 5VFZE

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