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Discussion Starter #1
95 JX, 16v, EFI, Manual,

Recently, my engine started to vibrate at cold start up. Violent enough you could feel it sitting in the car, and the shifter was were you could feel the full intensity. The vibrations were still there at temp and idling, but didn't seem as bad as cold. No notable loss of power when driving.

I removed the plugs and wires. Plugs were clean and all gapped to .028. Cables looked new, no cracks or corrosion. I cleaned the MAF just because it was off the vehicle. I half assed checked timing as with #4 at TDC, crank pulley mark at 12, and rotor at #4 firing position. Next I did a pressure test at cold.

#1 = 175 psi
#2 = 165 psi
#3 = 75 psi
#4 = 170 psi

Well sumofaitch. Dropped about a tablespoon of oil in #3, and retested. 85psi.

Put plugs and cables and airflow back together, and went to the local part's store and rented a block tester. Test was negative (did a little dance of joy in my garage).

So that brings me here:

A 10 psi gain on cold wet test? I'm pretty sure that the slight improvement isn't indicative of worn rings being my problem, correct?

Assuming that rings aren't my problem, that means that a valve is leaking/or stuck open. Bent valve stem, broken valve spring? Even if I did get the valve cover off, is there anything I can do without pulling the head?
 

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95 JX, 16v, EFI, Manual,

Recently, my engine started to vibrate at cold start up. Violent enough you could feel it sitting in the car, and the shifter was were you could feel the full intensity. The vibrations were still there at temp and idling, but didn't seem as bad as cold. No notable loss of power when driving.

I removed the plugs and wires. Plugs were clean and all gapped to .028. Cables looked new, no cracks or corrosion. I cleaned the MAF just because it was off the vehicle. I half assed checked timing as with #4 at TDC, crank pulley mark at 12, and rotor at #4 firing position. Next I did a pressure test at cold.

#1 = 175 psi
#2 = 165 psi
#3 = 75 psi
#4 = 170 psi

Well sumofaitch. Dropped about a tablespoon of oil in #3, and retested. 85psi.

Put plugs and cables and airflow back together, and went to the local part's store and rented a block tester. Test was negative (did a little dance of joy in my garage).

So that brings me here:

A 10 psi gain on cold wet test? I'm pretty sure that the slight improvement isn't indicative of worn rings being my problem, correct?

Assuming that rings aren't my problem, that means that a valve is leaking/or stuck open. Bent valve stem, broken valve spring? Even if I did get the valve cover off, is there anything I can do without pulling the head?
check valve lash, and do a leakdown. You have a leaking valve or a blown head gasket, 10 psi gain wet is about normal, but since it didn't come right up, rings are not the issue, its something head related, could be a sticky valve, bent, or burnt. Sounds like the heads coming off.....

A tight lash will cause it, but it would be at zero clearance and holding a valve open. Not common for this to happen. Valve spring broken won't usually show on a compression test but will when running.
 

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Cross your fingers and check the valve lash for #3.
Has your car ever overheated??
 

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Discussion Starter #4
I keep a good eye on the temp gauge, being i live in the desert. It hasn't overheated since I've owned it.

As for valve lash, going to zero lash sounds like a long shot, but I've got nothing else to do until my mechanic opens next week.
 

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Discussion Starter #5 (Edited)
Here are my valve lash measurements. Keep in mind, it was about 100F when I took these measurements. Each number is .00x Each measurement was on the cam heel.


Looks like I'm borderline on a few, but none are .000. Each value moved as expected when the crankshaft was rotated clockwise. No obvious broken springs or anything else out of the ordinary.

Time to find a good mechanic.
 

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Not too bad, but you may want to set the lash up right anyway, as it’s best to do this. Have the V on the crankshaft aligned with the 0 on the timing belt cover, and check that the rotor is pointing to #1. On a cold engine, all valves set to 0.006, and you start with valves 1,2,5,7, then rotate the crank 360º and do 3,4,6,8.
Sounds like leakdown next.
 

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Discussion Starter #7
So I took it to a mechanic today. While the car was running, he took the oil cap off and checked for blow by. He said I should start looking for a new engine. Didn't charge me for anything, though.

Thinking about it, the only place I could be getting that much blow by from would be if the cylinder had a hole in it or if the rings were shot. Anyone know of a good place to get a new engine?
 

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So I took it to a mechanic today. While the car was running, he took the oil cap off and checked for blow by. He said I should start looking for a new engine. Didn't charge me for anything, though.

Thinking about it, the only place I could be getting that much blow by from would be if the cylinder had a hole in it or if the rings were shot. Anyone know of a good place to get a new engine?
Like i said, it could be as simple as a head gasket, given the wet test improved by 10 psi says to me that while your rings are leaking a bit, they aren't the major issue. This test should bring figures up 40 or more psi if the rings are shot.

If you repeat the compression test but use a bit of 90 weight gear oil instead of engine oil in #3, what does the test do? Try it and see, I bet it won't come up much more which points to a head or gasket issue.
 

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If you repeat the compression test but use a bit of 90 weight gear oil instead of engine oil in #3, what does the test do? Try it and see, I bet it won't come up much more which points to a head or gasket issue.
Nope. The poster is correct.
With the massive blow-by it has to be rings, pistons or block / cylinder bores that are the degraded issue, not head or head gaskets. ;)
 

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Nope. The poster is correct.
With the massive blow-by it has to be rings, pistons or block / cylinder bores that are the degraded issue, not head or head gaskets. ;)
I disagree, I have seen several engines in my shop that have blown head gaskets from the cylinder into the oil return galleries that give exactly the same symptoms as this. If the rings and bore were that bad, oil would bring the tests up, and heavier oil will prove this.

Only way to prove it is a gasket however is to take the head off.
 

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Why bother at this point...

A leak-down test will be no more conclusive than what the just completed compression test already reveals...

#1 = 175 psi
#2 = 165 psi
#3 = 75 psi
#4 = 170 psi

Couple with...
While the car was running, he (the Mechanic) took the oil cap off and checked for blow by. He said I should start looking for a new engine
Pretty much seals the deal! :(
 

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A leak-down test will be no more conclusive than what the just completed compression test already reveals...

#1 = 175 psi
#2 = 165 psi
#3 = 75 psi
#4 = 170 psi

Pretty much seals the deal! :(
Except the LD would confirm the leak source....rings, valves, HG...

Wet test did not raise the PSI...

.... Philip
 

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:huh:

But it did!


That AND leaking valves (if the case) don't attribute to blow-by. ;)
yes, the wet test raised pressure by 10 psi, now, use heavier oil and redo test, if it comes up further then rings are suspect, if it doesn't, then head gasket blown between cylinder and oil return gallery is a distinct possibility. Its more common than you think.

I have a Subaru Justy here that the owner had 3 other mechanics tell him it had bad pistons / rings/ bore due to excessive blowby and needed a new engine. I've just replaced the head gasket and its fine, not burning oil, no blowby. It does happen. Diagnose it properly.

Do another wet test with thick oil (like 90 weight diff oil), if pressure doesn't come up significantly then rings and bore are more than likely not the issue.
 

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yes, the wet test raised pressure by 10 psi, now, use heavier oil and redo test, if it comes up further then rings are suspect
Again, wasting more time. The oil test done once and the on-site Mechanic's analysis statement make it conclusive.
There is nothing to gain in a second test attempt. It won't fix the compression lost / blow-by issue, nor provide any additional credible info. :rolleyes:

It's time to dive in and investigate / repair or replace said engine.
 

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Discussion Starter #18
I scoped #3 today. Other than carbon the top of the piston, it looks okay, but there is some scuffing on the bore wall. Only in one location from what I can tell. Broken or worn rings I would think.





Doesn't look too bad to me. Rebuild candidate?
 

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Scoped #3...some scuffing on the bore wall....only in one location....broken or worn rings?
Probably. Certainly no surprises there! The symptoms didn't lie. ;)


Rebuild candidate?
A more in-depth tear-down inspection is needed.

And 'the call' is dependent on the size of the overbore required to facilitate new pistons. Is it even able to be brought back in (oversize) specs, damage and piston availability / size wise? :huh:

That and the cost of same to include all parts and labor, even to other potential internal repair needs yet unidentified. :(
It may be too cost prohibitive for you.

How much of the effort are you willing to take on? Is the repair turn-around time critical? Do you have the personal time, talent and tools to take on much of this challenge? All things that you have to ask yourself, and too many unknowns for us to make the call for you.

Consider a good / used engine swap as well.

Wish you the best of luck. Keep us posted on your decisions going forward.
 

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Discussion Starter #20
I've never tried to get an engine rebuilt before. What are the steps needed. I know the ultimate goal is to yank the engine out, then send to a machine shop, rebuild, then stuff the engine back in. So who would make the call to determine if I go down the rebuild path?

Supposedly, the car has the original engine with 130K on it, but the previous owner also said it had a new clutch put in within the last 10k miles when I bought it. That was until I ended up buying a new clutch for it a few months later, so no clue if the engine is already rebuilt or not.

While I feel I could select bearing size, ring size, and tear down/assembly or the engine given enough time, I have no measuring or honing tools, not all that much space, work 5 days a week, and must keep the wife happy enough not to divorce me. I'll need to hire some professionals to help me out. I'm not sure where to start though.
 
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