Questions tagged [valve]

Refers to engine intake or exhaust valves.

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Maximum valve clearances. How big is too big?

I have a 1700 Leyland "O series" engine which has what I believe to be a direct overhead cam (OHC). The lobes on the overhead cam push directly down on buckets with shims. I have just ...
Michael Sherpa's user avatar
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63 views

Will alien component found in new engine tear down effect valve behaviour?

OMG, I might have found the cause of a misfire in cylinder 1 that has been the bain of my life on and off for 3 years. I have a 1979 sherpa van with an austin/leyland "o" series engine. The ...
Michael Sherpa's user avatar
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21 views

Is it possible to test an exhaust system for a restriction without dismantling it?

I've had an overheating problem with a new/other engine (1991) for 3 years now. Some time back I discovered that there was a misfire on cylinder 1 and maybe an intermittent misfire on cylinder 4. I've ...
Michael Sherpa's user avatar
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Searching for poor burn problem. How to know if valve guides are worn?

I have a Chevrolet 2008 suburban 1500 v8 5.3L, and am looking for a problem that dirties the spark plugs and causes stumbling idle especially when cold. I am suspecting the valve guides are worn, ...
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Misfire! Does good compression mean there are no valve issues?

I have a new old stock sherpa "O" series petrol engine 1991 that I installed 3 years ago. I have a misfire on cylinder 1 (detaching spark plug lead makes virtually no difference to the ...
Michael Sherpa's user avatar
2 votes
1 answer
83 views

Flathead 8RT stuck valves — how to free 'em up?

I bought a '42 SnoGo last fall (with a newer flathead in it, an 8RT) that had sat unused for some time, at least fifteen years. Well, you just can't do that here in Alaska and hope to get away with it....
InteXX's user avatar
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1 answer
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Why is one bank of valves much more dirty than the other?

I'm replacing my valve cover gaskets because they are leaking. I noticed a significant difference between the valves in the front and rear banks. The front ones look quite dirty while the rear ones ...
Phil Anderson's user avatar
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Possible Top end or VVT replacement required? 75dB+ knocking from engine top end - 2018 - Nissan Pathfinder

First the link Hello, I have a 2018 pathfinder with a reasonably loud (i'm estimating it at over 75dB standing about a meter back from the front of the vehicle). The sound seems to be coming from the ...
McMozart's user avatar
2 votes
1 answer
84 views

Valves in pizza box fell out does order matter if lapping

I had my valves numbered in a pizza box for lapping and i lifted the pizza box up the wrong way and every valve fell to the floor. i can tell intake apart from exhaust easily because they look ...
User Name's user avatar
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806 views

How to resolve P0456 OBDII code?

What 3 things and in order can I DIY for p0456. Hard start after fueling every time and irregular idle when stopping at lights. P0456 and no other indicator lamps coming on. Didn't replace gas cap.
Jessica Tierno's user avatar
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310 views

Briggs & Stratton 33R877 Engine Problem

May I please receive help in solving an engine problem? I have a Briggs & Stratton 33R877 engine (ride mower), and it is blowing air out of the carburetor. Here is what I've done so far: Piston ...
gman2020's user avatar
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Burnt valves, '08 Mercury Mariner 3.0 V6, similar to Ford Escape

Seeing if anyone else has ran into this problem on a Ford 3.0 V6? It's an '08 Mercury Mariner, 150K miles. Well maintained. High quality synthetic oil used in engine. Almost if not the same as a Ford ...
Midnight Wrench's 's user avatar
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1 answer
96 views

Adjacent exhaust valves in a cylinder head

There are some engines in which you can see two adjacent exhaust valves in cylinder head. The following head (Chevrolet Small Block) is an example: Is it true that this particular head design causes ...
LFY MP7.3's user avatar
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Initial reassembly valve leak to be overcome by breaking in

I lapped my valves and got good results testing both off the engine (pouring alcohol in intake/exhaust chambers and waiting to see level unchanged) and on (cylinder leakdown test). However, as soon as ...
amphibient's user avatar
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1 vote
2 answers
250 views

How do splash lubricated horizontal crankshaft engines lubricate the valve mechanism?

In many small engines, splash lubrication is used unlike in cars which always have an oil pump. I understand that when the small engine is a vertical crankshaft one like in lawnmowers, where the ...
juhist's user avatar
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Do carburetors protect intake valves from carbon deposits?

For a long time, most car engines were using multi-point port injection that sprays fuel directly at the intake valves. Today, engines are increasingly commonly direct injected. A problem of direct ...
juhist's user avatar
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How much should you clean dirty pistons and valves when you aren't removing them?

I took the heads off so I could get some broken exhaust manifold studs out and retap (actually I was advised to use a Heli-Coil instead so doing that) one of the other stud holes. The piston heads and ...
user875234's user avatar
2 votes
1 answer
92 views

Choosing the best timing marks

This question is somehow related to my previous question here: Compression of valve springs and camshaft rotation In that question, I asked about the pattern of camshaft rotation and how valve springs ...
LFY MP7.3's user avatar
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3 votes
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Compression of valve springs and camshaft rotation

As you know, in most cars it is not easy to turn the intake or exhaust camshaft by hand. You probably need to use both hands, grab the cam sprocket and apply a lot of force to rotate them even with ...
LFY MP7.3's user avatar
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How to interpret "crankshaft adaptation inlet Grad KW" value?

I'm trying to understand the meaning of this value and the implications of it being over the 120 limit. Do you think you could help me out with some thoughts about it? I think it should say "...
learner's user avatar
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Testing valve grind job that previously leaked

I had a leaky intake valve so I took that cylinder head off to grind it. Before grinding, I tested that it was indeed leaking and that the other two cylinders in the head did not by setting it on ...
amphibient's user avatar
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54 views

What keeps valve stem seals from dislodging from valve guides?

A valve stem seal, which prevents oil from the camshaft case from penetrating into the combustion chamber, is mounted on its valve guide simply by fitting it on with tension. Yet it endures probably ...
amphibient's user avatar
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3 votes
2 answers
711 views

Reusing valve stem seals

I just lapped my valves on a cylinder because they were leaking and reused the stem seals. Should I put new stem seals or is it okay to reuse them?
amphibient's user avatar
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3 votes
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Effects of intake valves leaking

I just measured cylinder leakdown rates on my 2007 Tacoma V6. 5 out of the 6 cylinders had retention rates of 75-85% (leaking 15-25%) but my cylinder 4 (left engine bank in the middle) was leaking ...
amphibient's user avatar
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0 votes
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Lubricating inside valve tappets/shims

Toyota engines come with tappets to shim between the valve rods and the camshaft. They look like small cylinders and are about the size of 2 oz shot glasses. When installing them on top of the rod ...
amphibient's user avatar
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252 views

Camshaft valve clearance and fuel consumption

Does the clearance between the camshaft and the top of valve tappets (AKA lifters AKA shims) affect fuel consumption? I am asking because it seems to me like the lesser the spacing, the more the cam ...
amphibient's user avatar
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1 vote
1 answer
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Minor discrepancy in valve clearance reading

I started my engine work on a V6 Toyota Tacoma 3 mohths ago and continuing now from where I left off. Back then I did a valve clearance measurement on all the 24 valves with all the timing chains on (...
amphibient's user avatar
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0 votes
2 answers
2k views

Correct installation of hydraulic valve lifters

I was doing some research about removing and installing hydraulic valve lifters. I watched some videos on Youtube and found this one quite informative. However, there are a few questions I should ask. ...
LFY MP7.3's user avatar
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7 votes
1 answer
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Stuck valve in lawn tractor Briggs & Stratton OHV

My John Deere LA120 lawn tractor has a Briggs and Stratton 21HP OHV engine that quit suddenly. Bad gas was my first guess. Along the way, I discovered a leaky fuel pump. So far, I have now replaced:...
Peter's user avatar
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Valve lifter replacement based on clearance check

Since I have the valve covers off on my 2006 Tacoma V6, I decided to do a valve clearance check. The manufacturer recommended ranges are: TYPE MIN MAX IN 0.006 0.010 EX 0.011 0.015 meaning the ...
amphibient's user avatar
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1 vote
1 answer
58 views

Turning crankshaft specific angle

To check the valve clearances, the Haynes manual for my Tacoma (2006, V6) says to first set the first cylinder of the firing order in TDC, do a sequence of valves, then turn the crankshaft 2/3 turn (...
amphibient's user avatar
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0 votes
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Can too much space between valves and camshaft cause oil in cylinder?

My 2006 Toyota Tacoma v6 is losing profuse amounts of oil although it runs just fine after adding more. I did a comprehensive overhaul several years ago and tuned the valves (ground them and ...
amphibient's user avatar
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1 vote
0 answers
57 views

Less oil on certain valves than others

I've got a 1986 3.8l 6-cylinder mustang. I've been hearing a ticking underneath the driver's side valve cover, so I took it off. I didn't see anything wrong so I started the engine sans valve cover. ...
MD XF's user avatar
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0 votes
1 answer
129 views

What are the pros and cons of valves being placed in a line vs valves being placed side by side in 2V engines?

As you can see in the picture below the valves in this ferrari dino dohc 2 valves per cylinder v6 engine are placed side by side and not in a row. And as you can see here in the other picture below ...
Timothy Scherer's user avatar
2 votes
1 answer
79 views

Which part of the valve stem do i need to replace?

I cant tell which part is messed up (I hit it with a hammer accidentally while trying to get my tire off). Do I need to replace the whole system, or just the body?
ale19's user avatar
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4 votes
1 answer
262 views

Are valve shims re-usable?

I'm in the process of re-shimming the valves on my 1994 Suzuki Katana 600. For the valves where I need to replace the shim, should I save the old shim I removed, or is it considered a disposable item ...
Brian Knoblauch's user avatar
0 votes
2 answers
2k views

Air intake cleaning/ yes or no?

2007 Impreza wagon 2.5. Previous owner didn’t take car of it and I was thinking of using the CRC intake valve cleaner. I would love your opinions on whether to do it or not. Please explain why it’s ...
Jenn's user avatar
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1 vote
1 answer
52 views

Tool requirements for moving rocker arms?

1994 Suzuki Katana 600. Manual says to pry the rocker arm aside "using a suitable tool" to get at the valve shims (unlike some other bikes where the procedure is to remove the camshafts). ...
Brian Knoblauch's user avatar
2 votes
1 answer
230 views

What to do in case of shim under bucket with no clearance?

Went to do the valve clearance check on my 1994 Suzuki Katana 600 and was dismayed to find that I have zero clearance on any of the valves... Even my thinnest feeler gauge won't slip between and it ...
Brian Knoblauch's user avatar
2 votes
0 answers
96 views

EJ205 - Valves Seats Recut and Reseated by machinist then failed leakdown test on engine stand

After getting the community's help on my previous question, I sent my cylinder heads to a local machine shop to get a valve job done (valve seats cut, valves reseated, and valve clearances redone). ...
Joe's user avatar
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0 answers
71 views

Is there a special procedure for preparing a new but very old stock engine?

I have a 1979 Austin morris (leyland,freight rover) Sherpa campervan 1979 model 230 with a "17v" "o" series engine 1.7 litre. I am soon to replace the engine with a new old stock (...
Michael Sherpa's user avatar
2 votes
1 answer
247 views

Leakdown Test | EJ205 on Engine Stand and replaced all Valves

I have my EJ205 out of my 2003 WRX. I pulled the engine in the first place to troubleshoot a 90% pressure loss in Cylinder 4 (measured via a leakdown test with the Engine still in the car). The ...
Joe's user avatar
  • 227
0 votes
2 answers
267 views

Does lapping valves ensure the seal of the valves?

I am building a 450-500 hp honda civic with a d16y8 head, i purchased brand new valves , and i was wondering how do I get these valves to seat and seal the chamber for combustion? Is lapping the ...
RonRon Scores's user avatar
1 vote
1 answer
111 views

Do you have to remove the heads to replace the lash adjuster on a 2002 Ford Escape?

Hello I guess I'm replacing a lash adjuster today. Before I start I'd like to get a better idea of what I'm getting myself into. I know that you're supposed to replace all of them at once and that you ...
user875234's user avatar
0 votes
0 answers
37 views

02 Ford Escape valve ticks on first start in the morning

It's only on the first start. If I leave it running after the first start it will take for a while. Possibly forever I'm not sure. What I've been doing is turning it off after a second or two and then ...
user875234's user avatar
1 vote
1 answer
379 views

Should valve pair open and close at same time?

My Audi A5 had some bent valves after the chain tensioner broke. I have replaced the bent intake valves and a single broken rocker arm. When I reassembled the top, I noticed the first pair of valves ...
user avatar
1 vote
0 answers
251 views

Is it worth replacing valve seals on a car with 200K kms?

I have a honda jazz 2003 gd1 1.3 with 200K kms on the clock. The car started burning oil around an year ago and occasionally (when the oil is topped up) puffing blue smoke puffs through the exhaust on ...
Zedzdead's user avatar
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1 answer
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Whats the valve clearance measurements for a 2006 Honda fit 1.3L I-DSI (L31A) engine?

I'm planning on adjusting the valve clearances myself for the first time but i don't know the measurements for the intake and exhaust valves clearances since its a second hand car and the manual is ...
john natalis's user avatar
1 vote
2 answers
4k views

Low compression in one cylinder with a misfire code, but no smoke in the exhaust

Chevy V6 4.3 with 281k miles. It recently threw a misfire code isolated to cylinder #3. The misfire seems systematic and not random, though, as it idles rough. I've got an open question on it already, ...
elrobis's user avatar
  • 391
1 vote
0 answers
35 views

Odd noise from top of engine

I'm helping a friend with their car. Its a 2014 Mazda 2, 1.5L engine, approx 105K miles. The car has been well maintained with regular oil changes. There is an odd noise coming from the top of the ...
zipzit's user avatar
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