Are cylinder heads in the engine block?
The upper part of the engine is called the cylinder head, while the lower part is the engine block. The cylinder head sits on the engine and closes off the combustion chamber. The gap that remains between the cylinder head and the engine is completed by the head gasket.
Why are there two camshafts in an overhead cam engine?
This arrangement was used to provide four valves per cylinder while minimising the valvetrain mass and minimising the overall engine size. A double overhead cam, dual overhead cam, or twin-cam engine has two camshafts per bank of the cylinder head, one for the intake valves and the other for the exhaust valves.
What happens when the cylinder head cracks on a car?
Cylinder head cracking, can result in, catastrophic damage to the engine. In some cases, cylinder head cracking, may be so severe; that replacing the complete engine is the only cure. So, the causes of cylinder head cracking, are all relatively simple and easy to prevent.
What causes aluminum cylinder head to bow up?
If you are rebuilding a late model OHC engine with an aluminum head, it’s not unusual to find a lot of distortion in the head. Overheating tends to bow the cylinder head up in the middle because heat concentrates in the center of the casting.
What causes a cast iron cylinder head to crack?
One of the causes of cracking in cast iron heads is stress created when the valve seats are induction hardened. The concentrated heating process that hardens the valve seats also creates residual stresses in the head that may cause it to crack later – even if the engine has never overheated.
Can a camshaft be removed from a cylinder head?
Warning: When removing the camshaft, you want to make sure that it does not fall, as it can damage the bearings in the cylinder head. Step 15: Remove the camshaft gear. Using your ratchet and socket, remove the center bolt on the camshaft gear and remove the gear from the camshaft.
What makes a dual overhead camshaft a DOHC?
Generally, engines with dual overhead camshafts (DOHC) are higher performance engines, they produce more power, and can run at higher speeds. The camshafts have the job of opening the valves that let air into and exhaust out of the engine. The camshaft uses rotating lobes, called cams, that push against the valves to open them.
What causes the cam to move back in the block?
If the end play is excessive, it will cause the cam to move back in the block, causing the side of the lobe to contact an adjacent lifter. Broken dowel pins or keys. The dowel pin or woodruff key does not drive the cam; the torque of the timing gear bolt, or bolts, against the front of the cam drives the cam.
What does a tappet do in an overhead cam engine?
This is slightly incorrect, as the noise can be down to a multitude of components within an engine’s valvetrain. However, a tappet (also known as a cam follower or lifter) is a small cylindrical mechanism which is attached to the end of the pushrod(in overhead valve engines) or the rocker arm (in overhead cam engines).