chawin

Hey guys, So stuck tons of money into the car last year and made great power. Half way through the season it started smoking on start up and idle and just figured id just fix it last winter/spring. Dug into it today and pulled the spark plugs and found the cylinder burning oil. Figured it was valve seals so pulled the rockers picked up some valve seals and went to pull the valve stem seal and the whole guide that the seal presses onto just pulled of the stem of the valve. Therefore the guide is broken right at the base of the valve spring.

Whats the fix?

I assume pull the head, Take the valve out, press the guide out and press a new one in?

This is the valve guide correct?

SEE PICTURE

chawin

Any body have some thoughts?

Darkman

iTrader: (2)

I would have machine shop replace the guide, check the clearance, and recut the valve seat if needed.
https://ls1tech.com/forums/generatio...placement.html
https://ls1tech.com/forums/generatio...-upgrades.html
https://ls1tech.com/forums/generatio...lve-guide.html

vettenuts

iTrader: (4)

Guide definitely needs to be replaced so the head has to come off. Careful how much work they do on the valve seat so that one valve doesn't sit deeper. If it were me, I would disassemble the head keeping the valves and springs so they go back in the same location. Then I would lap the valves once the head comes back from the shop. Since they are LPE heads (per your signature) there may be some angles on the valve that a local shop can't duplicate. Unless the seats are damaged lapping will ensure a good seal. Just make sure you clean the head real well prior to assembly.

chawin

Thank you very much to both of you for your insight. I've never had to do guides before. I will be bringing them in to a shop. These are the LPE heads and if I remember right I think they did a 2 angle grind on them.

chawin

The heads have maybe 2000 miles on them total. Would you think lapping would already be necessary or is that standard procedure when doing guides? Possibly because the valve may seat different with the new guide?

KCS

iTrader: (20)

When you do guides, the general rule of thumb is to cut the valvejob too. Many times, the new guide isn't aligned with the old valvejob, so it needs to be recut to correct it.

A.R. Shale Targa

iTrader: (2)

Also KCS does it help with aluminum heads to oven preheat them as well as drive the old guide out the top from inside the bowl. Bottoms up if you will ??

KCS

iTrader: (20)

Sure, heating the heat up in an oven helps. I usually just let the guides sit in the freezer over night before I run them in.

In the LS heads, you can pop them out either way, however, I prefer to drive them out from the top where they come out in the bowl. Reason being is that if there is any crud or carbon built up around the guide in the bowl, all that stuff gets drug through the guide boss and could imbed in or score the ID.

A.R. Shale Targa

iTrader: (2)

Makes sense!! The freezer trick also works great for pilot bushings and rod bolts in GEN I/II stuff.