# Checked compression



## nismosleeper (Jan 16, 2005)

Ok, so I checked my compression cyl 1 172 cyl 2 195
3 160 4 183
 5 165 6 190
I've heard that if it's a reasonable number, from lowest to highest if there is only a difference of 20 then your car is in good shape, and if it's within 10 then it's awesome....so is my engine healthy, or should I get a better one? Thanks


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## Matt93SE (Sep 17, 2003)

you've either got some serious gunk buildup in #2,4,6, or you've got leaky valves/rings/something in #1,3,5.

try a good dose of seafoam and see what happens.

also make sure you're holding the throttle wide open when you're checking these and that you run the starter the same amount of time for each one. (I usually just run the sucker for about 6-8 seconds each to make sure the thing peaks out.)


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## nismosleeper (Jan 16, 2005)

Matt93SE said:


> you've either got some serious gunk buildup in #2,4,6, or you've got leaky valves/rings/something in #1,3,5.
> 
> try a good dose of seafoam and see what happens.
> 
> also make sure you're holding the throttle wide open when you're checking these and that you run the starter the same amount of time for each one. (I usually just run the sucker for about 6-8 seconds each to make sure the thing peaks out.)


Will do...thanks. Oh, I did run it hot once, could that have messed up one of the head gaskets? I'll run seafoam and do the throttle and get back with ya.


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## Matt93SE (Sep 17, 2003)

unless you got the cyl #s wrong, they're alternating position and side...
123 is down one side and 456 is down the other...


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## nismosleeper (Jan 16, 2005)

Matt93SE said:


> unless you got the cyl #s wrong, they're alternating position and side...
> 123 is down one side and 456 is down the other...


oops, they are on the same side, I guess that i was wrong. I was just going off of the cap, and the numbers on it. Sorry 'bout that; think that it might be a head gasket then? Thanks


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## Matt93SE (Sep 17, 2003)

yup. prolly a HG. buy a new engine. it's easier than the HG replacement.


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## nismosleeper (Jan 16, 2005)

Matt93SE said:


> yup. prolly a HG. buy a new engine. it's easier than the HG replacement.


I think that i might just save up and get some headwork on it then. The local yards either want too much, or have compressions like 140 across the board. Thank you for the help and advice.


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## Matt93SE (Sep 17, 2003)

bah.. Apex used to sell me VGs for $300 a pop and had dozens sitting on the shelves in good condition.


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## nismosleeper (Jan 16, 2005)

Matt93SE said:


> bah.. Apex used to sell me VGs for $300 a pop and had dozens sitting on the shelves in good condition.


Those fools sold me one for 375. Three hundred is still kinda steep. All Parts did have a perfect one for 105, but not anymore. A HG is hard to do, but only like 150 to do, plus my time. I don't know....guess I'll just look around and decide. Thanks


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## Matt93SE (Sep 17, 2003)

dude, 300 is still cheap. try finding a VE.
the only places that sell $100 engines are shady u-pull-it yards and other places that aren't exactly reputable.

check car-part.com for a reasonable price. usually the bottom 30% of them are what I consider fair pricing. the top ones are often higher than new OEM.


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## nismosleeper (Jan 16, 2005)

Matt93SE said:


> dude, 300 is still cheap. try finding a VE.
> the only places that sell $100 engines are shady u-pull-it yards and other places that aren't exactly reputable.
> 
> check car-part.com for a reasonable price. usually the bottom 30% of them are what I consider fair pricing. the top ones are often higher than new OEM.


I found a good guy (the same guy that did turbogxe's stuff) that will do headwork for 225, and can get reground cams for another 190 or so, I know that there are other costs to be had like new HGs and springs..., but I will probably go that route.


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## Matt93SE (Sep 17, 2003)

new valve guides, seals, cam seals, head bolts, intake and exhaust and head gaskets....

you're looking at about $300 just in parts to pull the head and rebuild it.. not just a head gasket.

look at courtesy's site.. they used to have a "head rebuild kit" that included everything you need- all seals, gaskets, etc to rebuild the heads. it was around $250-300 IIRC.


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## alexnds (Oct 1, 2005)

*new engine?*



Matt93SE said:


> bah.. Apex used to sell me VGs for $300 a pop and had dozens sitting on the shelves in good condition.


Hi Matt,
I read many of your posts and found them excellent. Would love your advice. I have a 1993 Motor and the car changed hands many times before me. It has 146k miles on it. Doesn't smoke, but runs really rough. Dealer tells me one of the injectors is bad and recommends changing all of them to the tune of $1300 for parts and labor. I checked it out and found that one injector alone is $125 each and you can't get NISSAN OEM for less than $85 each. So all together, o-rings and injectors, I'll pay $800 in parts alone. I just spent money on new water pump, timing belt and timing belt. (I can obviously transfer the new water pump to the new motor). Where is a good source of used VG engines you'd recommend? I heard very, very mixed reviews of the JD motors imported from Japan. Will the Nissan Pathfinder motor, at 3.3 Liters, and it's a VG motor, be a good choice? I'm thinking that at this point, getting a used motor with accessories on it and fuel injectors is a good option to have on a cost comparison basis.

Any ideas? Where is APEX? I have heard of Jeg's but they seem to specialize in American cars only.


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## nismosleeper (Jan 16, 2005)

Apex is on north Peoria in Tulsa, Oklahoma. They don't do much if any online business. You would have to change a LOT of things on the 3.3L vg to make that happen, but it would be quick. I would just get a used one in the states, JDM is overrated unless you are getting something not produced domestically, like an sr20det or rb series engine. Can't you just change the bad injector?


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## Matt93SE (Sep 17, 2003)

for injectors, try just buying a set of used ones.. you can swap them in a few hours with basic hand tools. do some searching for some of the FAQ pages I 've mentioned in the past and there are writeups there telling you how to do them.

you can usually buy a set of 6 used injectors for roughly $50-100.. then you'll need the new o-rings from the dealer at about $2 each. if you swap the entire fuel rail, you'll only need to buy the 6 that go between the manifold and injector. 
then stick your old ones in a box and save them for later. if one of them fails, you have 5 working ones to swap later.


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## nismosleeper (Jan 16, 2005)

I have a set w/ rails that I can sell you, PM sent.


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## ddude2uc (Sep 7, 2005)

Just want to add on compression readings. 20% difference is cause for concern. Can be a few things, like worn valve guides, seats & or rings. A wet compression test will let you know if the rings are bad. (My personal write up on another board.)

The ignition & fuel system must be diasabled before proceeding with the compression tests. During the compression tests, the throttle is blocked open and the engine is cranked through four compression stokes for each cylinder. The compression readings are recorded for each stroke and compared to the manufacturer's specs. Slightly low readings in all cylinders are not cause for concern if the performance is acceptable. Compression readings that vary more than 20 percent (from the highest to the lowest) are cause for concern. Compression readings may be interpreted as follows:

When the compression readings on all the cylinders are about 
equal, but significantly lower than specs., the pistons rings or
cylinder walls are probably worn. If the compression in all the cylinders
is low & the engine spins freely during cranking, check the valve timing.
The timing belt or sprocket may have jumped.

Low compression readings on one or more cylinders indicates 
worn rings, leaking valves, a blown head gasket, or a cracked cylinder 
head. Performing a "wet" test will narrow down the cause of the 
problem. Remove the compression tester and squirt approximately
2-3 tablespoons of engine oil through the spark plug opening into 
the cylinder having the low compression reading. Crank the engine to
distribute the oil around the cylinder wall and then retest the 
compression. If the compression reading improves considerably, 
the rings (or cylinders) are worn. If the compression does not increase,
the valves are leaking, the head gasket is blown, or the 
cylinder head is cracked.

Low compression in two adjacent cylinders is probably 
due to a leaking head gasket or cracked cylinder head.

Zero compression in a cylinder is usually caused by a hole in a
piston or a severly burned valve. If the zero compression reading is 
caused by hole in a piston, the engine will have excessive blowby.

Higher than specified compression usually indicates carbon 
deposites in the combustion chamber.


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## alexnds (Oct 1, 2005)

*Bad injectors*



nismosleeper said:


> Apex is on north Peoria in Tulsa, Oklahoma. They don't do much if any online business. You would have to change a LOT of things on the 3.3L vg to make that happen, but it would be quick. I would just get a used one in the states, JDM is overrated unless you are getting something not produced domestically, like an sr20det or rb series engine. Can't you just change the bad injector?


Thank you very, very much for your input. I very much appreciate all this helpful advice. You see at $1300 bucks, for injectors and labor, the cost of a different engine sounded being attractive, and so, as long as I was thinking of a new engine in the VG series, I thought, why not go to the Pathfinder engine. I figured, I'd get increased displacement to boot. I don't have an engine hoist so I don't have the ability to take out the old motor and put in the new, but that's something I would leave to a professional shop. 

My only reasoning about the Pathfinder or Mercury Villager motor was because on a cost comparison basis, it sounded like a possibility. However, I'll replace the fuel injectors first. The engine doesn't smoke, so I figure, it still has plenty of life left in it and with the new water pump and auxilliary tranny cooler, I should have some life left in the power train of this puppy. Please see my PM regarding the injectors. Again much thanks!


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## alexnds (Oct 1, 2005)

*Bad injectors*



Matt93SE said:


> for injectors, try just buying a set of used ones.. you can swap them in a few hours with basic hand tools. do some searching for some of the FAQ pages I 've mentioned in the past and there are writeups there telling you how to do them.
> 
> you can usually buy a set of 6 used injectors for roughly $50-100.. then you'll need the new o-rings from the dealer at about $2 each. if you swap the entire fuel rail, you'll only need to buy the 6 that go between the manifold and injector.
> then stick your old ones in a box and save them for later. if one of them fails, you have 5 working ones to swap later.


Hi Matt,

Much thanks for the valuable input. I will definitely follow your advice. I know that the Nissan comes with "red" or "yellow" injectors, being the early motor (1989-1993) the later SOHC motor (1993-1994). 

How can I see what I have without actually taking one out? Is an ohmeter test across the wire of the injector a sufficient test of its health? (I'm an EE, so I'm very familiar with DVM). 

Can you point me in the right direction of the procedure? I can't seem to find it. Likewise, do you think a novice like myself, that is pretty mechanically handy, can do it? 

Any input highly appreciated, as always. Alex


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## alexnds (Oct 1, 2005)

*fuel injectors/Procedure for removal*



Matt93SE said:


> for injectors, try just buying a set of used ones.. you can swap them in a few hours with basic hand tools. do some searching for some of the FAQ pages I 've mentioned in the past and there are writeups there telling you how to do them.
> 
> you can usually buy a set of 6 used injectors for roughly $50-100.. then you'll need the new o-rings from the dealer at about $2 each. if you swap the entire fuel rail, you'll only need to buy the 6 that go between the manifold and injector.
> then stick your old ones in a box and save them for later. if one of them fails, you have 5 working ones to swap later.


I found the procedure for pulling them. Sounds intimidating a bit:

How to remove fuel injectors
http://www.autozone.com/servlet/UiB..._us/0900823d/80/1f/51/40/0900823d801f5140.jsp


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