when to cut down exhaust guides?

[brisbon]

hey guys, Ive had a oil burning issue from my engine rebuild from day one and i took out the egr valve and the lower port was full of oil and also shot it out while it was running, i then removed the valve covers to notice that the machine shop did not cut down and install umbrella seals on the exhaust guides.

my cam has a lot of overlap causing suction on the exhaust and intake alike, am i true to assume the guides should have been cut and sealed?

I've rulled out every other possible cause of the oil consumption issue.

 

[corsair231]

I don't really think it's necessary if your guides are in good shape but it doesn't hurt. I have heard that if you have a high volume oil pump it may pump too much oil up top and cause it to seep past the stock guides even if they are in good shape.

 

[turbofabricator]

If you are running anything over .510" lift, you NEED to cut the guides down for adaquate retainer to guide clearance. IF the guides are cut, you will also NEED to run aftermarket stainless valves. The factory valves (exh.), have an oil pump groove machined into the stem, just under the keeper groove. If you try and install a seal over a factory exh. valve, it just plain will NOT work. PERIOD!!!! The oil pump groove will ride in the seal area, and do absolutely nothing. I can't believe how many machinists do that! If you are sucking that much oil down the guides, you probably also have bad guides.