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Old 05-29-2022, 07:28 AM   #1
RicardoB
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Member#: 529973
Join Date: May 2022
Default Valve Lash question for EJ255 engine

Hello,

I am working on a swap from EJ205 to EJ255 in a GC8 classic.

When preparing the engine i have checked the Valve Clearance.

Intake

Cyl 1 Left 0.008"
Cyl 1 Right 0.008"
Cyl 3 Left 0.008"
Cyl 3 Right 0.008"

Cyl 2 Left 0.008 "
Cyl 2 Right 0.008"
Cyl 4 Left 0.008"
Cyl 4 Right 0.007"

Exhaust

Cyl 1 Left 0.011"
Cyl 1 Right 0.011"
Cyl 3 Left 0.012"
Cyl 3 Right 0.012"

Cyl 2 Left 0.011"
Cyl 2 Right 0.011"
Cyl 4 Left 0.012"
Cyl 4 Right 0.011"


I have read different valve clearance specs,

Intake 0.007" with a range from 0.005 to 0.009"
Exhaust 0.009" with a range from 0.007 to 0.011"

Or

Intake the same as above
Exhaust 0.013" with a range of 0.011 to 0.015"

I am a little confused about this, i have read many stories on different sites and forums.

Engine is a EU EJ255 from 2005-2007

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Old 05-29-2022, 07:31 AM   #2
rtv900
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Vehicle:
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Default

what is it you are confused about?

the lash is so that when everything heats up the valves don't end up being stuck cracked open.
You need something and that's why they provide a spec
just follow the spec
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Old 05-29-2022, 08:45 AM   #3
benflynn
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They look fine. A lil loose is ok, they wear tighter usually.
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Old 05-29-2022, 10:29 AM   #4
RicardoB
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Default

Quote:
Originally Posted by rtv900 View Post
what is it you are confused about?

the lash is so that when everything heats up the valves don't end up being stuck cracked open.
You need something and that's why they provide a spec
just follow the spec
Do i need to follow the 0.25mm spec or the 0.35mm spec for the exhaust side, thats for me an open question.

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Old 05-29-2022, 12:54 PM   #5
motorbykemike
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if you are checking the lash on a worn in motor just leave them as is
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Old 05-30-2022, 10:18 PM   #6
cproo12
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Location: Michigan, USA
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Crystal Grey Metallic

Default

Sounds good to me. I can see why you would be worried since they are at the looser side for the first spec you found.

Let's assume worst case scenario, tolerance for exhaust lash is 7-11 thou. You only have 3 valves out of tolerance and even then, are only 1 thou out each. I guarantee you there are tons of 200k mile subies driving around in way worse shape than that.

In addition to this, the valvetrain components are only going to heat up while driving and expand, thus reducing the gap while you're driving. If your tolerances were SMALLER than they should be, you would be at a risk of your buckets grinding on your camshaft lobes.

When you are out of tolerance, the engine will sound clicky, and potentially damage your valvestems, but 1 thou isn't enough to worry.

Although, if you are going to take heads off and refresh the top end, you might want to consider having a machine shop grind the valve seats and tip the valves to tighten everything up. Costs vary, but for me a whole valve job was only like 300 bucks.

Happy building!
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Old 05-31-2022, 03:16 AM   #7
RicardoB
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Ok, so does this mean that the engine can run on 0.25 exhaust clearance?

Because when i maintain the 0.25 mm or 0.009" everything looks fine.

But when i compare this to the 0.35mm or 0.0138" i see different results meaning they are all out of spec on exhaust side.

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Old 05-31-2022, 03:19 AM   #8
RicardoB
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Quote:
Originally Posted by cproo12 View Post
Sounds good to me. I can see why you would be worried since they are at the looser side for the first spec you found.

Let's assume worst case scenario, tolerance for exhaust lash is 7-11 thou. You only have 3 valves out of tolerance and even then, are only 1 thou out each. I guarantee you there are tons of 200k mile subies driving around in way worse shape than that.

In addition to this, the valvetrain components are only going to heat up while driving and expand, thus reducing the gap while you're driving. If your tolerances were SMALLER than they should be, you would be at a risk of your buckets grinding on your camshaft lobes.

When you are out of tolerance, the engine will sound clicky, and potentially damage your valvestems, but 1 thou isn't enough to worry.

Although, if you are going to take heads off and refresh the top end, you might want to consider having a machine shop grind the valve seats and tip the valves to tighten everything up. Costs vary, but for me a whole valve job was only like 300 bucks.

Happy building!
Thank you!

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