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camshaft is broken...

V

Viper

New member
hi!
my 1995 gp 3.1L camshaft is broken into half... :th_shakinghead2:
i got another one in tip-top order!
bought the bearings and an overhaul kit.
many mechanics told me not to touch the engine. just to replace him.
my machinist told me he can fix it. (replace the camshaft, bearings, etc.)
what is your opinion? should i get rid of the engine? he done ~170K miles.
all of the coolant passages are so clean! he looks brand new from the inside.
 


Being a 3.1, I consider it to be an evil motor to begin with. I'd wonder or ask the other machnists etc why they say to scrap it. Might be labor/work cost vs replacement cost.
 
BillBoost37 said:
Being a 3.1, I consider it to be an evil motor to begin with. I'd wonder or ask the other machnists etc why they say to scrap it. Might be labor/work cost vs replacement cost.
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they said that it will never be as a new one... and that probably it will broke again.
what happened is that there wasn`t enough oil pressure (maybe due to a metal chip in the oil), the camshaft caught and broke...
the bearings are incised and with lots of scratches.
the camshaft has "steps" and broke.
the machinist told me it`s only the bearings that damaged (except the camshaft).
any ideas?
 
Viper said:
they said that it will never be as a new one... and that probably it will broke again.
what happened is that there wasn`t enough oil pressure (maybe due to a metal chip in the oil), the camshaft caught and broke...
the bearings are incised and with lots of scratches.
the camshaft has "steps" and broke.
the machinist told me it`s only the bearings that damaged (except the camshaft).
any ideas?
Click to expand...

if it broke in half id suggest getting a new motor. if it did like mine and twisted from a bearing failure then id say replace the cam.... but since it broke... no id get a new one...its cheaper to have done plus you got a warranty if it goes bad...
 
so the camshaft has been replaced, the engine is on the vehicle.
when starting- a rough idle and working. (then dies).
replaced the camshaft sensor- which was broken...
checked the electric, fuel injectors, firing order wires and proper spark plugs. all o.k.
did a compression test- 180-185 psi per piston. (quite good!)
nothing...
still rough.
the only thing i haven`t checked- is whether some of the valves has been bent.
one of the push rods was bent and replaced.
is it common that when the cam twisting and breaking it will bend a valve?
to me it sounds like a valve problem.
what codes should i expect to see except misfiring?
thanks!
 


Do you have engine noise? why didn't they replace all the Pushrods? I broke the crank in my 2.8 years ago, and for good measure, I changed ALL the internals. With a broken cam you could have metal in the engine, man, you could have a large amount of issues, I would do a compression test.
 
Lvgrandprix2003 said:
Do you have engine noise? why didn't they replace all the Pushrods? I broke the crank in my 2.8 years ago, and for good measure, I changed ALL the internals. With a broken cam you could have metal in the engine, man, you could have a large amount of issues, I would do a compression test.
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compression test- i did = 185.
the entire engine block has been cleaned thoroughly.
 
haven`t touch the heads except cleaning them.
that`s why i`m thinking it`s maybe one or more bent valves...
 
Viper said:
haven`t touch the heads except cleaning them.
that`s why i`m thinking it`s maybe one or more bent valves...
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when my camshaft twisted it bent 2 pushrods and 3 valves... theres probably at least 1 or 2 bent valves..... did you check the compression in all of the cylinders? and did they hold pressure for up to 2 minutes without dissapating? because you will get pressure with a bent valve it just wont hold pressure for a period of time.
 


yep... that`s the next test i`m going to do!
this is the only thing i haven`t checked- so i`m pretty sure this is the source of the trouble.
 
Hmmmmm......
did the pressure test. looks fine.
what the hell could be the problem?!?
i`m gonna get a scanner to check it out.
any ideas?
 
Viper said:
Hmmmmm......
did the pressure test. looks fine.
what the hell could be the problem?!?
i`m gonna get a scanner to check it out.
any ideas?
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did you leave it for a few minutes and it held pressure and didnt drop more than 3-5 psi? and did this to every single cylinder?
 
o.k.
so i took the heads off, checked for vacuum (to see if the valves are o.k.). everything seems fine... except the soot (carbon) on the heads, probably because the fuel mixture isn't burning right.
weird...
someone told me that maybe the new camshaft doesn't fit.
are there several types of camshaft for those engines? (3100 sfi 1995)?
 
Viper said:
o.k.
so i took the heads off, checked for vacuum (to see if the valves are o.k.). everything seems fine... except the soot (carbon) on the heads, probably because the fuel mixture isn't burning right.
weird...
someone told me that maybe the new camshaft doesn't fit.
are there several types of camshaft for those engines? (3100 sfi 1995)?
Click to expand...

you know what i just thought of..... did you make sure your pushrods were in the right place? also is your timing 100% correct? even 1 tooth can throw off the engine.
 


91gpse said:
you know what i just thought of..... did you make sure your pushrods were in the right place? also is your timing 100% correct? even 1 tooth can throw off the engine.
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yep.
timing is 100% correct (checked the timing more than 5 times...)
all the pushrods are in correct order.
 
Viper said:
yep.
timing is 100% correct (checked the timing more than 5 times...)
all the pushrods are in correct order.
Click to expand...

did you get the cam from another 95? because i know older 3100s have hydraulic lifters instead of roller lifters like the 94 and newer.
 
91gpse said:
did you get the cam from another 95? because i know older 3100s have hydraulic lifters instead of roller lifters like the 94 and newer.
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don't know the year... but when they took the cam apart, there were roller lifters. is it good? (or they both look alike?) are all 94 and newer 3100 have the same cam?
thanks for the help!
 
Viper said:
don't know the year... but when they took the cam apart, there were roller lifters. is it good? (or they both look alike?) are all 94 and newer 3100 have the same cam?
thanks for the help!
Click to expand...

yeah as long as its from a roller lifter motor it should work fine. the hydraulic lifter motors have a different cam. they have bigger lobes i think, i could be wrong though. another thing.... is it backfiring and missing at all? oh and make sure your plug wiring is in the right place.... ran on 4 cylinders for a week and didnt know what it the problem was until i found a diagram of the coil packs.(bad idea i know but i was desperate had no other car....)
 
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