24
votes
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What is a head?
tl dr: Cylinder heads (commonly just called "heads") are the big piece of metal which caps and seals the end of the cylinder bore.
Types of Cylinder Heads:
There are three basic types of cylinder ...
- 148k
12
votes
Why don't cars have a cylinder head with separate barrels?
There are a few factors to consider.
Ease and cost of mass-production. Individual barrels require individual assembly, whereas a cast piece of metal has a lot of things built-in and assembly can be ...
- 12.2k
10
votes
Do Most Common Engines Have A Cylinder Head?
As @rpmerf says, virtually all piston engines have at least one cylinder head.
Most engines will have one head per bank of cylinders, as you suggest, though some have more - IIRC some of the ...
- 28.7k
9
votes
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Cylinder Leak-down vs Compression Test
Compression test is more to test if there is a problem. If your compression is low, it could be a number of different issues. You can test the rings by adding oil to the cylinder and see if the ...
- 8,433
9
votes
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How many times can you go through a torque sequence when installing heads? I'm worried I messed up and should try again but don't wanna make it worse
Considering you have torque to yield (T2Y) bolts, once torqued through the angle sequence, you're done. If you remove the bolts, you have to start over with new bolts. T2Y bolts are one and done, ...
- 148k
8
votes
Should I get 2nd Opinion on head gasket issue?
It is ALWAYS good to get a second opinion. I would highly recommend taking it to another shop and have them tell you what they think it is even if you believe the first shop to be right.
That being ...
- 1,958
7
votes
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Do Most Common Engines Have A Cylinder Head?
All piston engines must have a cylinder head. The head is on top of the block and forms the top of the combustion chamber. The head is also where the valves are. The valves and chambers in the head ...
- 8,433
7
votes
Accepted
Small crack/gap between cylinders on block
It's completely normal, nothing to worry about
It's simply the gap between the sleeves. If you look from above, straight down, you will see a straight edge cut into the outside diameter of the metal ...
- 32.9k
7
votes
Can you run an engine with an acorn shell in one of the cylinders?
You might get away with it, but I sure wouldn't recommend trying. The risks just seem too high.
Instead try either blowing air into the cylinder with a small tube (to leave room for the shell to come ...
- 14.4k
7
votes
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Can i Use The Same Old Bolts On The Same Cylinder Head?
Your Passat uses torque to yield bolts, so they must be replaced. The torque to yield bolts are considered "one and done". This is because during the torquing process, they are stretched beyond ...
- 148k
6
votes
Can I run on 7 cylinders if I shut the injector to that cylinder off?
Yes you can. Obviously you'll be at a reduced power level, but no problems should occur from doing this.
EDIT: While I believe this is a "plug on" application, you'll want to ensure your coil is not ...
- 148k
6
votes
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How to clean cylinder head and engine block contact surface before gasket change?
You shouldn't sand the block at all unless there is existing damage of some kind - but it really doesn't take much to damage, even a fine scratch can ruin the seal for the gasket. If you have to sand ...
6
votes
Why don't cars have a cylinder head with separate barrels?
Most modern car engines have overhead camshafts. Overhead camshafts pretty much oblige the use of a one-piece cylinder head. Imagine the difficulties of aligning the camshaft if each cylinder had a ...
- 797
6
votes
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Is this cylinder head junk?
This, in and of itself, is nothing to be worried about. The reason I say this is, it is not part of the sealing surface for a cylinder. There is more than enough meat there to seal the cooling port, ...
- 148k
5
votes
Accepted
Hand turned the crankshaft while in gear. Clutch damage?
It's fine
I did a similar job on a 2003 model recently. I kid car. Luckily, I didn't have any bent valves to deal with.
Turning the engine over with the head off and the car in gear won't hurt ...
- 32.9k
5
votes
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How can head port volume affect the power curve of an engine?
What exactly is meant by cylinder head intake/exhaust port volume?
The amount of air that can pass through the intake or exhaust ports as well as the amount of resistance (back pressure) that is ...
- 32.9k
5
votes
Why do manufacturers use different bolt types on cylinder heads?
From what I understand the answer to this very simple and logical.
When someone might be attempting to DIY a fix and have a particular socket that fits a nut, they may just turn it not realizing what ...
- 32.9k
5
votes
Accepted
Assembly lube or engine oil when reassembling cylinder heads
I would not use assembly lube with the valves (in the valve guides), but just oil there. The reason for this is because there is no way to flush the assembly lube out of this orifice like there is in ...
- 148k
5
votes
Can I run on 7 cylinders if I shut the injector to that cylinder off?
The engine is unlikely to be damaged. This is not true for the catalyst. With one cylinder pumping air into the exhaust the mixture sensors (oxygen sensors) will see this as a lean condition and try ...
- 11.6k
4
votes
Can I run on 7 cylinders if I shut the injector to that cylinder off?
One thing worth mentioning is that running with a missing cylinder will result in engine vibrations that will be felt across most of the rev range.
This will not cause damage in the short term, but ...
- 39k
4
votes
How much vehicle life is added by rebuilding cylinder heads?
Realistically, you haven't added any extra life to the vehicle itself. The vehicle is a combination of it's sub-parts (ie: engine, transmission, differential, etc.). Any part at any time can fail for ...
- 148k
4
votes
Why do manufacturers use different bolt types on cylinder heads?
Having had to work in tight spaces, I say it's very useful to have a bolt which you can turn in less than one-sixth turn. What I mean is, that bolt can be turned with a common hex tool, but sometimes ...
4
votes
Accepted
Can I use hard tools to remove hardened carbon buildup on valves?
It is OK to used a metal tool on the valves. They are very hard and difficult to scratch. It is also OK to use oven cleaner on the valves. The steel is a relative of stainless and will be little ...
- 11.6k
4
votes
Accepted
Using a thicker head gasket when the cylinder head resurface limit is reached
The pressure generated at Top Dead Center on the Power stroke is very high. A "taller" gasket will have a larger cross-sectional area exposed to this pressure, so high "pounds/sq inch" grows ...
- 12.4k
4
votes
Should I get 2nd Opinion on head gasket issue?
Wouldn't hurt to get a second opinion. However, be careful if you try diagnosing yourself. If coolant is leaking into one of the cylinders and you try starting the car you could hydro-lock the ...
- 143
4
votes
Accepted
This valve is pitted - what options do I have?
This valve can absolutely be salvaged. You just need a valve job. You can have a look at what's entailed in a valve job by watching this Jafromobile video.
To the uninitiated, I won't go through all ...
- 148k
4
votes
Bubbles in radiator despite several cylinder head overhauls
There are a limited number of places where combustion gasses can get into the coolant. A cracked head is the obvious one. It is also possible that it is a crack in the block going from the cylinder ...
- 23k
3
votes
Peugeot 406 1.8 engine, oil comes to radiator
is there any sealant to stop engine oil leak to radiator
No.
or do I need to replace cylinder-head-gasket?
Yes. But also you need to have the head and the block checked for warping. They head ...
- 3,363
3
votes
How can head port volume affect the power curve of an engine?
From doing some reading here: http://www.jegs.com/tech-articles/cylinder-heads.html
it looks like what you are referring to the size of the values and the amount of lift they get. Here's a couple of ...
- 9,316
3
votes
Last year my timing chain had broken
As Brian commented, your question and the information we have is a little vague.
Not repaired already:
It won't drive at all if the timing chain is broken. No amount of cranking the engine will start ...
- 658
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