Input on those who have rebuilt an engine

[AA_Ezra]

OK, so i trust youre people opinion even tho its not a P car it still puts money in my pocket to fix up my pcar

I did a compression check and cyliders number 1&2 were very low. i forgot how low bc i lost the paper that i wrote down the compression numbers on but they were past the - or + 15 psi more like 120 or so and 3-6 were abouts 170-180. all taken while the engine was up to temp. Engine has 200k+ miles on it, all original.

I thought either it was the cam lobes were to worn or the Vavles were not sealing right causing the low compression and missfire

i totally forgot to add a little oil to each cylinder and recheck compression to see if ti would bump it up in case it was the cylinder rings.

In the pictures i see alot of carbon buildup. maybe it normal or is it from the oil passing threw the rings?... cylinder #1 does have a score that i can just bearly catch with my fingernail

I still have to take the other head off that containes cylinder #2 that was causing the missfire.

I know for a fact the exhaust valves are leeking bc i was able to get watter to drip past the intake and more so the exhaust vavles sealing surfaces.


its my brothers girlfreinds car and i just dont know if i shoudl just tell them to junk the car if the piston rings are gone, im totally not wanting to put that much work into the car

[rick13]

Chances are, it is not junk. Well, that is, to an engine builder.

To someone who has never done it, it will definately appear a bit daunting.

So, what's in it for you anyway?

[looneybin]

what's the value of the car?
It probably only needs a valve job to get a couple of more years out of it.
i would think that if the rings are shot, then the compression would be low on all the cylinders, as they all wear at the same rate

Oh, is the brothers GF hot? sorry, had to ask

[John_AZ]

AA_Ezra,

You are not telling us enough about the car. The "car" has 200K+ and is a 6 cyl belonging to your brothers girlfriend. Someone is willing to pay you to do the work.

When you took the head off the car after a couple of tests that may or may not be accurate, I would think you have commited to do the work.

Model? Year? How long has your brother known her? Current typical resale value of a good running model. Does she have a sister? How long will it take to finish? Can the girlfriend pay for parts and your labor?

Lots of questions to answer.

John

[AA_Ezra]

2006 chevy impala 3.5 v6.
Shes cute in a cuddly way
She only has a brother.
It's actually her parents car and they can pay, her dad is 6'7" and bought another impalla but a 2012 version as he only buys chevy

Looney that does make sence the rings might be ok as the compression did increase on the cylinders closest to the rear of the motor.

I kinda shade tree mechanic checked the valves but all the valves seem to be leaking , some more then others

Time. A day to take it apart. Another day to put it together. And however long the machine shop takes.

Seems like I'll just put the head back on. Crank it and check compression. Then add some engine oil to each cylinder and check compression again and if it goes up it's probly bad rings?

And yes looney if the score I can just feel with my fingernail will be ok and just needs valve work and get a few more years out of it I think they will br happy.

These people know nothing about maintenance.low on all fluids. They just don't take car of there cars. It's been runing rough( missfire) for months and they think nothing of it.


What's in it for me is $$ I need to get from Cali to WI as soon as possible

[AA_Ezra]

Found the paper when i did my test results when the engine hit runnign temp
Piston 1 175psi
piston 2 140psi ( gave missfire code)
piston 3 180psi
piston 4 175psi
piston 5 180psi
piston 6 170psi

Going to do a wet test and add some oil to the cylinders. unfortunately it will be a cold test bc the engine is completely apart

Thanks for the input so far guys. im thinking it might be ok.

[John_AZ]

Piston 2 could be a bad injector washing the cylinder and giving a low psi.
I searched and found this:



or it could be a boot:

I Cured A Random Misfire Problem-3800 V6

Good luck and hope you get to WI. I left WI. years ago. I still own a couple of acres of commercial zoning in the Eagle River area.

John

[porschetub]

Engine has been running rich after seeing the carbon deposits on the pistons,these engines are very strong ,I would look @ your heads and hopefully relate your bad compression to the valves not sealing properly @ those cylinders.
If the engine has been running rich due to an air leak or related fuel problem your rings may be gone due to fuel washing the lubricant away from the ring grooves.

[otto_kretschmer]

Originally Posted by AA_Ezra

its my brothers girlfreinds car and i just dont know if i shoudl just tell them to junk the car if the piston rings are gone, im totally not wanting to put that much work into the car

why are YOU working on her car?

just put the head back on and do a tune up (at most, plugs wires cap rotor, filters ect)

don't worry about valves or rings, this isn't your car and its a soulless chevy

[924RACR]

I wouldn't bother putting the head back on until I'd first done a valve job. Easy to do, just rent a valve spring compressor, mainly it's just manual work - clean all deposits off the valves, and lap them back in by hand till they don't leak with the water test.

Engine doesn't actually look that bad inside; I've seen plenty worse that still ran fine.

3.5L? Not a 3.6? Hmmm, I guess that'd be the "high-value V6" vs. the "high-feature V6" (worked with the latter, most excellent engine, 3.6L putting out some impressive #'s). Still a very solid motor, built to last.

Tell her dad he should've waited for the 2014 - looks a TON better than the rental-spec cars through '13...

HTH...

[AA_Ezra]

Originally Posted by porschetub

Engine has been running rich after seeing the carbon deposits on the pistons,these engines are very strong ,I would look @ your heads and hopefully relate your bad compression to the valves not sealing properly @ those cylinders.
If the engine has been running rich due to an air leak or related fuel problem your rings may be gone due to fuel washing the lubricant away from the ring grooves.

Yeah, im thinking maybe one of the intake manifold gaskets was possibly leaking and making it run rich, but all the cylinders seems to have the same amout of deposit after taking the other head off.

Funny think is the valves on cylinder #2 werent to bad, there were others that were worse and had higher compression.. this is not good.

The shop they took ti to before thought it was a bad injector and repalced the injector.. the idiots replaced injector # 4 tho geez.

[AA_Ezra]

Originally Posted by 924RACR

I wouldn't bother putting the head back on until I'd first done a valve job. Easy to do, just rent a valve spring compressor, mainly it's just manual work - clean all deposits off the valves, and lap them back in by hand till they don't leak with the water test.

Engine doesn't actually look that bad inside; I've seen plenty worse that still ran fine.

3.5L? Not a 3.6? Hmmm, I guess that'd be the "high-value V6" vs. the "high-feature V6" (worked with the latter, most excellent engine, 3.6L putting out some impressive #'s). Still a very solid motor, built to last.

Tell her dad he should've waited for the 2014 - looks a TON better than the rental-spec cars through '13...

HTH...

Thanks man, i did just that, I hand lapped the head for cylinders 1,3,5 and checked them with the water test for a good 30min -1hr and went over again untill i saw no water period.


its been raining alot the past few days so i only now had the chance to check out the head for cylinders 2,4,6, valves on #2 or leaking watter but not as bad as some on the other head.
I also checked the cam for wear and it seems to be good, granted i didnt take out the cam but i wanted to be sure it still had enough lift.

Going to post my wet vs dry test results.. they dont look good and i would like your opinion

[AA_Ezra]

cylinder 1 165/195
cylinder 3 190/210
cylinder 5 100/120


cylinder 2 115/155
cylinder 4 180/215
cylinder 6 195/225


cylinder 5 valves were the worst and leaked water like a faucet so that makes sence

they all jumped 15-20psi when i addes some engine oil but cylinder #2 went up 40psi so is it just me or does that not look good and maybe the piston rings are shot on that cylinder?

if thats the case this engine is toast. Might as well lap the vavles on the second head for more expeirence and slap it all back together used gaskets and all?.. No point if the engine is toast i think right?

[924RACR]

Wow... pretty nasty numbers... of course, that's why leakdown is really so important, to tell you where the leakage is, not just how much... it would more clearly indicate if a valve job might get it decent or not.

Your choice if you want to spend the time/effort to re-lap the other set of valves, but I wouldn't bother reassembling with old gaskets at all.

Maybe the answer is do the other head, reassemble with fresh gaskets and unload the car...