Super Street Network

 |   |   |  Intake/Exhaust Valve Check - Tricks Of The Trade

Intake/Exhaust Valve Check - Tricks Of The Trade

Helping you wrench.

Scott Tsuneishi
Feb 3, 2012
SHARE

Cylinder head valves normally will not just bend unless the engine has experienced some sort of trauma. Bent valves can occur as the by-product of a timing belt failure, as the valves strike the pistons. Depending on what bent the valve, there may be damage you can’t see, and won’t until the head is off.

Impp 1202 04 o+tricks of the trade+valve ports Photo 1/4   |   Intake/Exhaust Valve Check - Tricks Of The Trade

Visual Valve Inspection:

- Check valves for smooth movement and good seating
- Check guides for wear
- Check lifters/rocker arms
- Check the top of the valve stem for damage/pancaking
- Check camshaft lobes for damage or excessive wear

If you suspect a faulty valve or recently purchased a used cylinder head and are unsure of its condition, but need to get your car running ASAP, we have a quick and easy setup on how to check for bent valves with the cylinder head(s) off.

One test method that can be performed in your own garage is to do a valve leakdown test. To perform the test, you would need an air compressor that delivers at least 90 psi, a wood block with a 9⁄16-inch hole drilled through the center, and water.

Prepare the cylinder head by removing the cams and lifters. Flip the cylinder head(s) upside down and insert any used spark plug to seal the chamber. Pour water into each of the combustion chambers.

Impp 1202 05 o+tricks of the trade+remove cams and lifters Photo 2/4   |   Intake/Exhaust Valve Check - Tricks Of The Trade

Proceed by taking the wood piece and pressing it up against either the intake or exhaust port to achieve an airtight seal. Using the air hose, insert it into the 9⁄16-inch hole wooden block and release compressed air into the cylinder port.

Impp 1202 05 o+tricks of the trade+wood piece Photo 3/4   |   Intake/Exhaust Valve Check - Tricks Of The Trade

Using the compressed air/water method, you will actually be able to see bubbles forming past a bent valve on the intake or exhaust side—the larger the leak, the bigger the bubbles. If your cylinder head shows symptoms of a bent valve(s), we suggest taking it to a qualified machine shop to fix the problem.

Impp 1202 06 o+tricks of the trade+compressed air Photo 4/4   |   Intake/Exhaust Valve Check - Tricks Of The Trade
SHARE ARTICLE
By Scott Tsuneishi
247 Articles

RELATED ARTICLES

BROWSE CARS BY MARKET

MORE HOW TO

Few production engines before or since are capable of the sort of horsepower the 2JZ-GTE's good for with so few modifications.
Aaron BonkJun 29, 2015
New 2-quart size of A2Z Wheel & Tire Cleaner features cool flexible hose for getting at all those hard-to-reach places
Bob HernandezJun 26, 2015
With its Reference Series for the Scion FR-S and Subaru BRZ, OEM Audio Plus takes the pain out of upgrading car audio
Bob HernandezJun 25, 2015
Turbo two-seater Italian sports car groomed by Pogea Racing to reach 62mph in under 4 seconds
Bob HernandezJun 25, 2015
Forge Motorsport and Litchfield Imports' Dominator intercooler kit takes charge cooling in the Nissan R35 GT-R to the next level
Bob HernandezJun 22, 2015

SEARCH ARTICLES BY MAKE/MODEL

Search
TO TOP