In the process of putting the finishing touches on the low-mileage 86 305 I'll be putting into my 91 Trans Am, and was thinking about replacing the valve stem seals while I've still got everything apart. Found these http://cgi.ebay.com/ebaymotors/Chevr...spagenameZWDVW on eBay, looks like a good deal and a good upgrade to the original, but I'd rather not do any machining or modifying to my engine to get them to work. Anyone know if machining is necessary on these? Or better yet, does anyone have a source for a good upgrade from stock that won't break the bank?

 

use these on both intake and exhaust.

http://www.partsamerica.com/ProductD...pe=108&PTSet=A

 

Hmm, I seem to remember that Fel Pro had different part numbers for the intake and exhaust set...these would definitely work for both though apparently?

 

Some would say yes, but as far as i know i use the umbrella style seals on the exhaust and the positive style on the intake, and thats where the two part numbers come from. Are you running any sort of a performance cam or 1.6 rockers? If so pay close attention to the clearance between the retainer and the seal is using OE style.

 

I would [ did ] just get a good brand name . you should be o.k. , make sure all the sludge is clear on the front and rear drain holes on the cylinder heads if its a used engine . this allows the oil to go back imto the pan . also put umbrella seals on all valves , intake and exhaust . [ CLEAN AND FLUSH EVERYTHING ] . just an old school tip on umbrella seals . they are cheap so why not .

 

Umbrella seals are a waste of perfectly good rubber. Somebody just ruined some otherwise useful material by deforming it into that shape.

Use the FelPro "positive" seals on both intake and exhaust. They actually DO SOMETHING, instead of riding up and down on the valve stem and just keeping the oil from running down it onto the guide, which is all that umbrellas do.

The reason FelPro shows the umbrellas for the exhaust, is because on some engines, the exhuast guides get too hot for the material, and it degrades rather quickly. Tends to be more of a problem on stock motors with excessively lean fuel mixtures and inadequate ignition timing advance, as compared to hot-rod motors.

 

Autozone, Murrays, Pepboys.

The positive seals on the intake, because of the low pressure created (vacuum) on the intake side. Umbrellas on the exhaust, just to keep residual oil off the stem so it does leak out. I've seen umbrellas on the intake with the positive seals too before (on a head I disassembled).