dragline

okay, here's my story as best i can recall over lunch:

1. bought ff roadster with a rebuilt '89 5.0 mill back in sept - 4k miles on rebuild.
2. do not know ANYTHING re: engine from previous owner other than it being rebuilt and that the block was bored .030" over.
3. sounded like an aggressive cam might have been used - had a pretty good lope to it at idle anyway. was running perfectly until...
4. for reasons i'll not bore you with i inadvertently ran the fuel tank dry.
5. got it filled back up again and she started having a distinct surge at idle so i replaced fuel filter, fuel pressure regulator (probably didn't need to do that), cleaned throttle body, cleaned IAC, new plugs (probably didn't NEED those either but cheap and the old ones were rather fouled with soot) put some sea foam in the tank.
6. seemed to do the trick - idle was good, between 900 and 1000 rpm.
7. drove it around (less than 30 miles since running out of gas) and once, when i was pulling hard there was a somewhat violent shudder and then seemed to be ok. within a mile or so, though, i had hell getting home. engine would die if i didn't keep applying throttle. chugs, sputters, no power, won't stay running.
8. checked fuel pressure - 37 psi - all good.
9. checked compression (here's where i start getting a sick feeling in the pit of my stomach) and get readings of 55 up to 80 psi. Ugh.
10. pulled dipstick and (more sickness in aforementioned tummy) i smell the distinct odor of gasoline in my oil. fudge.

i should mention, too, that before all of this recent debacle i had checked the ignition timing and it was 20deg (!!) advanced. when i saw that i pulled it back to around 14deg or so. i later got to thinking that maybe it was at 20 for a reason and put her back there.

i'm thinking about pulling off the timing cover and seeing if i've somehow jumped a tooth or got a worn out timing chain. wouldn't explain the gas in the oil though.

did the seafoam somehow bite me? if it's blowby how the heck do all 8 cyls go bad at once?

any thoughts out there?

PNYXPRESS

The only way gas would get into the oil is by the piston rings. If that is occuring then you arent getting spark or a weak spark to one or more cylinders and the fuel is running down into the oil pan. I would check your ignition coil and cap and rotor for adequate spark.

When doing the compression test, you should be able to hear if its leaking into the exhaust, intake or crankcase.

If its the intake or exhaust then you can use a brass hammer and tap on the top of the valves of the cylinder you are testing it will reseat the valve and you will gain back your compression.

If it sounds like its leaking into the crankcase then you will need new rings, either that or during the rebuild, they didnt offset the ring gaps during install

dragline

thanks for the reply, pnyx. i'm unable to tell where the leak might be - i just pulled each plug, hooked up my hose/gauge assy and cranked the motor. no way to hear what's going on over the whine of the starter motor and the sound of the moving parts in the engine. haven't tried actually applying pressure to a cylinder to see where it might be leaking.

i'm guessing that if i've got a bunch of raw fuel sitting in the cylinders it could work its way into the crank. i have a hard time believing my piston rings all went bad at once.

PNYXPRESS

The rings may not be bad, just not offset like they need to be and that would allow oil blow by and loss of compression. Also, is it fuel injection or carbed? FI should be around 50-80psi, I believe, and carbed should be around 5-7 psi.

88 orangepeel notch

If fuel injected yet, set pressure to 35-38 lbs. When you checked timing, did you remove spout? Was compression test done with a good (name brand) gauge, don't trust cheap gauges.

mjr46

fuel pressure should not be 50-80 on a efi 5.0 vac line on 32-37 acceptable, vac line off SHOULD be around 38-42 depending on if it has an adjustable regulator, 39 psi is the norm......as for gas in the oil, your rings are not bad!! this is a common occurance on ANY CAR that has been severly flooded, run way to rich, or had an injector or SUCH hang open, drain all the oil, change the filter AND IF SUCH WAS THE CASE, It should run better once all the gas saturated oil is removed

PNYXPRESS

I stand corrected and learned something today.

dragline

i did remove the spout connector when checking the ignition timing.

the vac line was on the FPR when i checked my pressure (37 psi). the 50 - 80 psi numbers i mentioned were the compression values, not fuel pressure.

point taken on the cheapo gauges out there. my first attempt to measure fuel pressure with the rental kit from O'reilly's was aborted when i realized the needle never moved off of 70 psi. tapped on it once to see what was what and the damn needle fell off!

to verify my compression gauge wasn't FUBAR'ed i hooked it up to my air compressor. both gauges agreed with each other at 30 lbs all the way up to 100 so i'm thinking it's working.

i'm starting to think strongly that i've jumped a tooth on cam/crank gears. maybe the engine builder went cheap and re-used the old timing chain. i really have no idea. i'll pull the timing cover off and see if they still line up. to do so i suppose i'll have to pull the water pump and harmonic balancer. what about oil pan?

Mike T

The oil pan does not have to come off.

dragline

so, before i rip off the front end of my engine, any other tests i should try beforehand? i have a code reader but can't find where the guy left the self test connector. it's nowhere in the engine compartment. if he left it buried behind the dash that would be kind of goofy. would a leak down test tell me anything more than the compression tests i just ran? i guess i'm hanging a lot on that test but sure seems like it's valve timing issues.