wideglide2011

so I'm in the middle of installing long tubes and I start investigating oil leaks..the top of passenger side v.c is oily???? the back of the block above the starter is oily.is there an easy way to tell where the oil is coming from at the rear of the engine?? I really don't want to pull the intake just for practice. any practical advice out there?

Chimera96

from the location of the leak you describe it is either the VC gasket or intake

cleaning those areas and then checking after a drive should tell you which is leaking.

Engine oil dye and a blacklight is also a way to check leak source

DrewHMS97SS

The LT1 is notorious for leaking from the rear seal on the intake manifold. That being the worst case, you can also check the valve cover seals, oil pressure sender and PCV.

I would clean the mess then inspect for leaks after driving for 10-20 minutes after the car warms up. If you are having trouble identifying the source, look for a dye kit. It will add a UV die to the oil, that you can inspect with a UV light.

wideglide2011

o.k. I will give the dye a shot after i'm back on the road.

Injuneer

On the top of the passenger side valve cover, is the oil around the rubber grommet where the vent hose from the throttle body connects? If so, that is pointing to a faulty PCV valve, or excessive ring blowby, beyond what the PCV system can handle. Check the hose from the throttle body to the valve cover for oil buildup. Pull the top cover plate on the throttle body and look for oil buildup.

wideglide2011

it appears as if there is oil leaking from around the engine oil fill spout where it meets the v.c on the passenger side v.c. is this a common area for leaks? the complete v.c is oil soaked/grimed up from one end to the other????but still dry where cover meets the cylinder head.

wideglide2011

also iniuneer. you seem pretty well versed on the lt1 can you tell me if i can or should remove all of the egr/a.i.r./ evap related items? no sniff tests done here.usually no visual either. thanks.

Injuneer

If there is substantial oil on the top of the valve cover, it’s most likely excessive crankcase pressure blowing the oil out of the vent grommet and fill pipe base.

If you want to remove those emissions systems to improve performance, there is nothing to gain. You also need to provide the year of your car. How many codes you get, and how to eliminate them depends on the year. We suggest every sets up a "Signature".

https://www.camaroz28.com/forums/lt1...nature-879835/

Keeping AIR is only of value if you have cats. The electric pump only runs for two or three minutes at startup to help the cats heat up and start to work. You can unplug the pump and remove it, and remove the metal lines to the exhaust manifolds. As long as there is a good fuse in the AIR pump relay circuit you will not get a code for the missing pump. However, if you have a 96 or 97 there are checks/codes in OBD-2 that determine whether air is flowing into the manifolds. You have to plug the connections on the exhaust manifolds, and plug the fresh air supply to the AIR pump on the air duct between the air filter and the MAF sensor (94-97) or the throttle body (93). Note that 93 has slightly different plumbing, that combines AIR and EGR.

EGR only operates under certain part load conditions, under 3,500 RPM, never at idle or at wide open throttle. No affect on performance, unless the EGR valve is leaking. If it’s leaking it will cause rough idle, and possibly stalling. When operating correctly, it actually helps performance be preventing detonation (knock) when lugging the engine at low RPM. All years have a diagnostic/code that checks for EGR flow into the intake manifold. Some years are more sensitive than others. There are sets of blockoff plates available for the three connections in the system - #8 exhaust primary, corrugated tube connection on the back of the intake manifold, and EGR valve mount on back of intake manifold. There are timing adjustment in the computer based on EGR operation, so that could be reprogrammed, although not a major issue.

EVAP serves a useful purpose. It collects the gasoline vapor from the gas tank, and burns the vapor in the engine. Delete the system and you waste the collected fuel, and can get a lot of fuel smell at the rear of the car. Strongly recommend keeping the system intact. Only causes problems if there are vacuum leaks in the system (detected by diagnostic/codes 96/97), or you tend to overfill the fuel tank, causing fuel to saturate the carbon canister in the driver side rear fender.

My vote: no cats - delete AIR; EGR - your call; EVAP - keep it.

wideglide2011

excessive blow by is concerning. is there a proper way to check for correct compression on the lt1? also thanks for the air/egr/evap info.just trying to research my way through all of the emission equipment. thanks again.

Injuneer

Pressure in the crankcase can be excessive blowby, or a plugged PCV valve.

Blowby can be diagnosed in part with a compression test on all cylinders, and if you find a cylinder or two that are low, adding a bit of oil to a low cylinder and rechecking to see if that bumps the compression up. That would indicate a ring problem, rather than a head gasket or valve problem..

More complete would be a leakdown test. Pressure the cylinder with compressed air, and see how fast it leaks down. And listening for air escaping can tell you what the problem is.

This article has a lot of good info:

https://www.pegasusautoracing.com/do...ocID=TECH00137

wideglide2011

i found the hose from the passenger side v.c to the throttle body was split open on the bottom from dry rot. i have a compression tester and a leak down tester. would there be any value to doing the compression test? good compression numbers should be 150-200 psi????? all of the spark plug insulators are tan in color. also how often do the steam pipe fittings on the rear of the heads leak?? just not looking forward to removing the intake. thanks in advance for any help.

Chimera96

Clean up the valve cover and replace the rotten hose (might want to look closer at other hoses also). Doing compression test and leak down test will show if a piston/cylinder or valve seat/guide is suspect

Pullngz

The intake really isn't too bad to remove, the most common area for these to leak is the back passenger side. But it sounds like you might have found your culprit, with the split hose.

wideglide2011

whats the easiest/simplest way to determine top dead center for each cylinder???? thanks again.

wideglide2011

I have replaced the oil pan gasket ,timing cover gasket and seals.now on to the intake
any good tips to seal the intake??