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Discussion Starter · #1 · (Edited)
well I just did a compression check. according to my harbor freight gauge nothing on any cylinders. (just bought it). For laughs, I used my thumb to plug the hole. #1 pumps some air, but no psi on my finger. #2 and 3 have more psi, but still no real force against my thumb. I did look at the timing thinking maybe it jumped and threw the valves off-nope, dead on perfect. So now I need to scope the cylinders to see what happened. I cant believe in an instant my rings would go bad. Im thinking maybe burnt valves or (unlikely) burned pistons with holes in them now. Correct me if im wrong, but the cylinder psi should be high enough to try to pop my finger off the hole-I know that's not scientific, but at least tells you if a cyl is pressurizing or not
..Oh, and starting fluid does nothing, not even a small kick :(

also, the reason im doubting the rings is I burn no noticeable amount of oil, plugs burn clean. engine till now ran basicly perfect-idled fine, had decent power (considering the mileage)

The valves I suspect more and more being that each time I crank it over, I get a lot of vapor coming out the throttle body
 

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Looking through the oil filler cap while cranking the motor can you see the valve train moving?

Sent from my DROID RAZR using AutoGuide.Com Free App
 

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Well if the pistons are going up and down, haven't got holes in them and your finger isn't blown off the plug hole/no compression then I would say camshaft/chain/broken.

May have bent all the valves and caused other damage if camshaft has failed.

Take off the cam cover and turn the engine over by hand.
 

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Discussion Starter · #4 ·
cover is off. chain good. all valves moving(minus vtech) as they should (and timed correctly).
 

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Try your compression checker on another car just to make sure it works.
Harbor freight stuff is real cheap. I wouldn't expect all three cylinders to lose compression at once and the valve timing to still be ok...
 

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Discussion Starter · #6 ·
lol! yeah, I noticed that! haha. I may have found the issue. I think my camshaft is twisted. At TDC I noticed #1 intake is being pushed down about 3/8". I have to back off the crank some to get slack in the rocker. I think ill try shooting a vid to explain/show what im talking about. Also, that same valve is stuck open about 3/8" at all times. Im going to recheck just to make sure and see how the other cylinders are doing-the whole thing is prob way out of wack (if im right)
 

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Discussion Starter · #7 ·
the normal valve. Im half tempted to bust out the shop lights, and pull the head tonight. Its gotta come off regardless so I can fix that valve and guide
 

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Discussion Starter · #8 ·
yep. just checked for the 9th time. My cam is twisted. You can see when the TDC marks are lined up on the crank and cam (at the same time) the valves are not at rest (compression stroke) but rather open till almost 70* or so past TDC. I had thought maybe the chain jumped a few teeth, but the fact that the cam mark lines up with the head and the crank lines up with the pointer disproved that. This is what threw me off when I first checked the timing. I hadn't noticed the valves not being at rest. I just saw the lines match up indicating it was good. Im still bothered though as to why it happened. My only idea is that the years of use, hot/cold cycles weakened the cam and it finally twisted. I may find a better answer when the head is off when I fix the stuck valve.

On the plus side. I believe I get to claim first to twist the cam in this car! (an achievement id have gladly passed up) :p
 

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Discussion Starter · #9 · (Edited)
heres a few pics. Ill post more as I really inspect everything. Things I know are bad are, cam, cam gear, #1 valve, slight hd gasket leak, main cat.
(on edit, I see the pics didn't work. Ill get them fixed)
 

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Are you positive you are on number 1 cylinder (Compression stroke) when the marks line up?

I have never heard of a "cam twisting".
A little to far for a "Road Call" for me. Anyone closer to assist?

HTH
Willie
 

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Discussion Starter · #11 ·
the marks is what gave it away. when I first looked, both tdc and the cam mark was spot on. How I noticed was when I started rotate to the #3 cylinder the valve on #1 started to raise about 70* past tdc. The gear pin that "locks" it to the cam was busted and the gear moved forward about 20*. It then seized, and the cam was next to give out. I had thought maybe I looked at it wrong-I checked the book, and rechecked about 9 times to make sure I was doing it correct-I was.
After getting the cam gear back in its original location/keyway. I rechecked the marks, put a scope in the plug hole to verify TDC (it matched the tdc mark) and looked at each cylinder/valve position as I rotated. #1 is off about 70*, #2 is of about 20*, and #3 is off about 20* ( #3 is BTDC, the rest are @tdc). The degrees based from when I hit tdc on the crank and cam vs when the valves are at rest (compression).
I too have never seen a cam twist. Snap yes. never twist. That's why I had to recheck so many times :p
 

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The cam gear is positioned on the cam by the pin behind the gear.
So what you are saying is that the pin sheared?
How did you determine the *........if that means degrees?
 

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Discussion Starter · #13 · (Edited)
yes. the cam pin sheared and broke a small bit out of the keyway on the cam.
The way I determined the degrees (*) is by the TDC mark on the crank. I put it at tdc, (number 1 cyl I was able to use the mark, 2 and 3 I opti-scoped the piston watching for tdc) and then would rotate clockwise till the valves were at rest . Wherever the cam gear line landed I took that degree and divided by 2


On edit..i got the cam removed. It just keeps getting better. The #3 cam journal is a mess. melted part of the cap and the head (enough that the head is shot). I think Ive located what made the 2 second noise I had heard before the car died. Im not sure what bent #1 intake valve but id bet the cam seized on this bearing and it all went south from there. So now I have to ponder. New head ($800) or risk a used one hoping its true and all the specs are fine. Id sure hate to go through all the work removing one from a donor car only to have it be bad spec wise
 

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Thanks for the info.
You....my friend have a first.
The cam probably seized first, then broke the alignment pin which threw off the valve timing enough to bend the #1 valve, caused by hitting the piston.
The question now is why the cam seized after so many miles?

I would just get a used head and after cleaning and pressurizing all oil channels, install.
 

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Discussion Starter · #16 · (Edited)
lol! Im gonna put that in my sig "first insight to twist cam" hahah

I am puzzled why the cam lost oil on that race. the #4 is in great shape so I know the main oil passage through the rocker shaft is clear. The port on the cap for #3 was clear as well, but I still need to inspect the feed from the rail to the cap. I suspect that's where its clogged. I will say I was shocked just how well the motor overall has worn (or the lack of wear) considering the mileage. Aside from this being the first major issue, visually the motor looks real good, and ran well
 

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Discussion Starter · #18 · (Edited)
heres a few pics
notice the location pin sheared off
yes, years of traffic leads to this much carbon
. this is the bent intake valve
 

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Discussion Starter · #19 ·

that's whats left of the cat!

the #3 cam race melted down on the head. you can see #4 is still good

the #3 race on the camshaft. no buffing that out! lol
 

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Very good pics. It looks like the cat is really starting to plug up.
The dark left side is unburnt particals.
The CAT was probably not getting hot enough to burn those off. City driving, short runs, putting etc.
The color on the 02 sensor looks good though.
(My opinion)

Thanks and good luck.
Willie
 
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