CRAPP!! weird vibration, PLEASE PLEASE Help!!!!!!

[87-325ic]

i think ill pm him now,

UPDATE,
i popped the valve cover, and nothing looks out of whack, i was expected a slipped rocker, or even a broken one, but nothing looked bad,

Im still leaning towards the flywheel weight broken or something, it really feels like its down there,

But, since the stethoscope didnt give anything away in that area, im not positive,

although it could be just barely broken and moved enough to give me this horrible fucking problem!

[SchnellerVert]

I suggested he have Rigmaster take a look at it, He's local somewhat to him.

[MA325is88]

If you were closer I would!!

Just pick up another set of ignition wires and try them before you do all that surgery.

[87-325ic]

all plugs are sparking, none look bad, all were pulled and checked.

The distributor and rotor are fairly brand new, and i never touched that area, so ill assume they are fine.

Im putting on a new/ rebuilt head real soon, along with new plug wires while im there. ill see what that does.

Also, what should i check for while the head is off and i have access to the bottom end?


ps, if you are now REALLY interested, feel free to take a vacation and come look at it and try and figure it out yourself.



ALSO, is there any way teh increase exhaust pressure from the fixed flange had caused something in the head to go?

(i think im gonna pull the valve cover soon and see what things look like, hopefully ill find an obvious solution like a broken rocker arm or something..)

[porsche gt1]

:firehop:


2 times on that

[MA325is88]

#5 has compression, but isnt running right. Then there is a problem with ignition to cyl 5. Bad spark plug wire, craacked spark plug, cracked dist cap?

You did say one of the initial repairs was exhaust repairs so you must have been working in this area.

Now I'm REALLY interested.

[87-325ic]

yes, it does seem like 5 isnt running 100% right, but #6 was reading low compressions,

what all could cause #5 to be getting good compression, but still be running poor?

[porsche gt1]

ps, i may try the wet-compression test, but i feel the low scores were from, 1) engine age, and 2) Worn Head.

You are probably right,

hell, it seemed like nothing happened at all, i mean, of course a change occured, since it Was getting spark, but the running of the engine didnt change.

sounds like the misfire is in number 5

[87-325ic]

hell, it seemed like nothing happened at all, i mean, of course a change occured, since it Was getting spark, but the running of the engine didnt change.
All the others the idle dropped just a small bit.

Also, the bottom end is not getting rbuilt at all, Just a rebuilt head swap.

What can i do to the bottom end while the head is off though? i know i saw loads of build-up in the spark plug hole when i looked.. anything not-Major i can do to make things better while im there?

Thanks for the help.


ps, i may try the wet-compression test, but i feel the low scores were from, 1) engine age, and 2) Worn Head.

[porsche gt1]

piston rings are usually checked with a compression test, one way I have heard of is to put a little bit of oil in the piston chamber and do a compression test. if the results are different than your original then I would say the piston rings are bad. Other than that the best way it to take the engine apart and rebuild. Since you are having that done anyway, they should replace the rings anyway so no worries.

question when you pulled the plug on #5 while running did your idel go up or down?

[87-325ic]

thanks very much.

The entire head is being replaced very soon with a rebuilt, cleaned, and new seals head. i can't wait,

All gaskets will be replaced along with it. as well a valve adjustment of course..


NOW, while the head is off completely, what can i do to clean up, check out the pistons/ bottom end,
how are the piston rings checked?

btw, lots of oil is getting in #6 as its plug was pretty wet when pulled out..
also, #5 seemed to not change as much as the rest of them when the plug boot was pulled while running, granted a change did occur, just not as much of one.


Thanks very much, anyone else have some suggestions?


(ps, do you think the head itself could be causing all this? and if so how did i get such Decent compression test results)

[porsche gt1]

WOW, First off good work.

yes, if it sounds like it is coming from the tranny area and a bump, it could be a misfire in number six. This is the most common cylinder to have a problem. It is usually the first cylinder to have a HG problem.

What I would do is first is replace the head gasket(sounds like you need to anyway), and while you are in there I would check for bad piston rings on number 6(and 1-5). If you have a lot of oil going into a cylinder it might not fire. Replacing you HG also requires that you do a valve adjustment and replace the Valve cover gasket. This should solve a lot of the front end problems and could solve your bumping problem.

wish you best of luck.

[87-325ic]

Latest findings... the problem is still here though...
(I took it to my friends dad who used to worked as a mechanic for some 15 or more years..)

Compression test results.. Cranked and stopped after 4th bump.
1. 135 psi
2. 140 then drops to 135 where its steady
3. same, 140 --> 135 steady
4. steady at 137
5. 135
6. 131 (yes a little low)

I know the results are overall a little low, but they stayed relatively close to each other. It could also be from the 4 cranks the cylinder got, and maybe doing to 4-5 times like the bentley lists would have helped.. nonetheless.. they seem fine to me.. besides #6 being a little low.

I do believe the head has alot to do with the results, as i have plenty of valve tick and a little leakage from the head gasket, not to mention a lot from the valve cover gasket.


We also probed around a bit with a stethoscope.. and couldnt find much besides normal engine noises...
Especially on the bellhousing like we thought, i absolutely did not here anything even similar to the thump i hear in the passenger cabin.



All the plugs are getting spark, and none seem to be completely dead cylinders.

Now, he did say that is really seemed like a sort of misfire, almost as if as the rpms increase it gets worse.
Im a bit unsure about it completely.. but he was leaning towards ignition related.. and it causing an unbalance from the misfired cylinders...
as well as when load increases it would be misfiring too..

how could this have happened?

he reccommended i take it somewhere for lots of diagnostic work, particularly hooking it up the the oscilloscope to check the ignition..



What do you all think of all this? what could it be now?

i still plan on taking it somewhere, but im trying to narrow it down as much as possible myself.. since well, diagnostic work can get $$$$$$$
(especially when they say "well, we couldnt figure it out, but you owe us 300 dollars for the time and labor, and heres your printout.")



come on guys help me out as much as you can please...

Thanks!

[ecorrea21]

Yes. if its bad this would be a good time to convert to a lighter M-20 flywheel.

[87-325ic]

so you didnt want to tell me? id rather know the worse, than to not be told..

im not driving around, dont worry, its too bad..

i think i will listen to it when an "socket-extension stethoscope" and be sure its in that area...

then take it to a local mechanic to pull it apart and check,

depending on their price and the actual price, ill either let them take car of it, or learn to fix it myself....

Now, if something with the flywheel came loose, or has almost broken off, is there a high chance it can be reattached or fixed?

Or, will i need to buy a new flywheel...