I recently bought a 89' Iroc/305 TPI with low mileage,and have successfully fixed a number of things thanks to the thirdgen members. When recently installing a set of Felpro gaskets,I noticed not only a good bit of stuck-on grime and sludge inside the cover and on the push rods and rockers, but also hear a bit of rocker noise on the passenger side bank. No visual problems inside,just needs lash adjustment and a flush to get rid of the sludge in there from sitting for 7 years.

Any recomendations on a good safe way of flushing the engine without plugging my oil pump,and more importantly what is the correct preload to go with? I've heard 1/4 turn all the way up to 1 full turn,I definately don't want to have the nut back off,or worst stick a valve by tightening too much.

Thanks,Niko.

 

You can use an engine flush product added to your oil just before changing it. You can also use automatic transmission oil to flush your engine. Add a quart or two after draining the filter and reinstalling it. Run the engine to temperature but don't load it heavily. While the oil is still warm, drain the sump and change the filter. You can continue to clean up your engine by using syntheic oil, since it cleans very well and doesn't produce sludge like mineral oils.

The transmission oil can clean your engine for several reasons:

1. It is very low in viscosity;

2. It has more caustic additives to help neutralize acidic engine sludge and deposits;

3. It has a detergent package that is a bit more robust than a typical crankcase oil;

4. It has more dispersants to cut through water (and water-based sludge);

5. It has fewer viscosity modifiers, which allows the unsaturated oil blend to dissolve more contaminants in your engine.

It is a lot like the use of synthetic crankcase oils, but just a little faster. In the long run, the synthetics will clean up and keep your engine cleaner. You simply have to decide if the additional cost is justified by the benfits.

Whatever you do, start changing oil at regular intervals, and your engine will clean up and stay that way. And don't use cheap filters.

 

AMSOIL makes an excellent crankcase flush that is a combination of solvent, detergent, & dispersants. You put a pint in the crankcase, run it at idle for 30 minutes, drain and fill with fresh oil & filter.

They developed it because synthetic oil does loosen up those deposits left by petroleum-based oils - if not removed, they will quickly contaminate the synthetic.

An alternative is to put one quart of synthetic in with 4 quarts of petroleum oil when changing, increasing the synthetic and reducing the petroleum by one quart each change, until the entire fill is synthetic. Takes longer, but is effective in removing the deposits while keeping a real engine lubricant in the crankcase while you're driving it.