Can a cylinder head be removed with a dropped exhaust valve guide?
Just make sure the valves are good and replace the seals. Subaru cylinder head removed with dropped exhaust valve guide, engine ran fine. Side view of valve guide that are okay, no signs of these ones moving. Another valve guide side view, valve guides look okay. Dropped valve guide with the valve removed.
What causes a Subaru exhaust valve to drop?
This causes first the valve to want to stick or hang up in the guide and then under the right conditions as the aluminum head has expanded from heat away from the steel guide the guide will shift a bit, at first and once it has moved will continue to do so until it actually causes a cylinder misfire.
What causes a cylinder head to misfire in a Subaru?
Whenever you remove a Subaru cylinder head you should always look at the valve guides to see if there is any evidence of them moving, particularly the exhaust valve guides. I have seen these guides moves causing misfires or even worse completely drop causing valve to piston interference.
Why is my inboard exhaust valve down on my Forester?
Disassembled the “original” engine and found the valve guide for inboard exhaust valve on Cyl #2 had slid down and held valve open. small indent on piston, not serious. also noted inboard exhaust valve for #1 cylinder is down approx 1/2 the distance of the other. Have not pulled the other cylinder head yet.
How to measure exhaust valve clearance in Subaru Forester?
10) Measure the #1 cylinder valve clearance by using thickness gauge. • Insert the thickness gauge (A) in as horizontal a direction as possible with respect to the valve stem end face. • Measure the exhaust valve clearances while lifting-up the vehicle.
How do you adjust the compression valve on a Subaru Forester?
1) Set the #1 cylinder piston to top dead center of compression stroke by rotating crank pulley clockwise using ST. ST 499977100 CRANK PULLEY WRENCH stroke. 2) Adjust the #1 cylinder valve clearance. (1) Loosen the valve rocker nut and screw. (2) Place suitable thickness gauge.
What causes the valve guide to slide on a Subaru Forester?
The guide whether an alloy or cast iron has less of an expansion at the same temperature then what the aluminum head does. The valve guide only serves to transfer the heat into the aluminum around the guide causing it to expand to the point where the guide can slide. I used to see migrating valve guides a lot working on motorcycles every day.