Boost_Crazy
Boost_Crazy HalfDork
7/3/17 5:11 p.m.

I'm finally getting around to assembling the EJ25 for my Subaru Legacy GT. I had the heads sent off to a machine shop a while back, and I noticed that the new exhaust valve guides are not all positioned as they should be. Two of them protrude down about a 1/4 farther than they should.

I've seen a couple methods of moving the valve guides, and each has people claiming "this way is best" while other say "never do this."

Factory manual shows using a press and a jig to hold the head at the proper angle. I have a press, don't have the jig.

I've seen a method of using an air hammer to move the guides. They have a tool for the air hammer that goes into the guide. I have an air hammer, and can pick up the tool for about $15. Any advise, or reasons not to do this?

I could go back to the machine shop that did it incorrectly, but it was over a year ago. I'd also like to get it done over the holiday. I've also lost confidence in machine shops, as this is the third mistake made by the third shop on just this engine.

APEowner
APEowner GRM+ Memberand Reader
7/3/17 5:18 p.m.

Are they pushed in too far or there just a few that are too long? If they're just too long, cut 'em off.

Boost_Crazy
Boost_Crazy HalfDork
7/3/17 5:57 p.m.

In reply to APEowner:

They are pushed too far into the ports. New guides, all the same length, two hang down an extra 1/4".

Here is a pic. Note how much father the one on the right protrudes. It should start right where the valve guide tapers down...

[URL=http://smg.photobucket.com/user/AWDpower/media/image_2.jpg.html][/URL]

Streetwiseguy
Streetwiseguy UltimaDork
7/3/17 6:14 p.m.

Were they replaced and pushed down too far, or was the engine overheated, they moved by themselves, and the machine shop wasn't smart enough to notice? Unless they were replaced, there is no reason for the shop to have touched them.

oldeskewltoy
oldeskewltoy UltraDork
7/3/17 6:44 p.m.

in addition... the guide up inside the head will be located 1/4" further down too... possibly making seal fitment difficult. Recommend you have the whole thing checked by another machine shop

einy
einy Reader
7/3/17 8:17 p.m.

While working on a cylinder head machining job for Cummins, we used an air hammer to install valve guides, but they were finish machined after. The tool used between the guide and the hammer did only contact the guide on its OD, so it did not affect the pre machined ID much if at all. Thinking this thru, if you can get a tool that only pilots on the OD, the air hammer gently applied is what I would elect to do.

stuart in mn
stuart in mn UltimaDork
7/3/17 8:27 p.m.

If they're installed wrong, can't you go back to the machine shop and make them fix it?

Zomby Woof
Zomby Woof PowerDork
7/3/17 8:42 p.m.

I have installed thousands of valve guides using an air hammer, and it works fine. Drop the pressure down then adjust it up to get the force you need to move them.

ChasH
ChasH New Reader
7/3/17 9:43 p.m.

Don't move the guides, you may change the center of the valve seating which will cause poor sealing. As others have mentioned, a guide installed too deep can affect the proper install of stem seals. Either go back to shop what installed the guides for an explanation or move on.

Boost_Crazy
Boost_Crazy HalfDork
7/4/17 1:33 p.m.
Were they replaced and pushed down too far, or was the engine overheated, they moved by themselves, and the machine shop wasn't smart enough to notice? Unless they were replaced, there is no reason for the shop to have touched them.

They were replaced when the machine shop did the valve job. No problems with them prior, they were replaced because the shop thought the clearance was a bit excessive and at PM since Subarus tend to have valve guide issues.

Don't move the guides, you may change the center of the valve seating which will cause poor sealing. As others have mentioned, a guide installed too deep can affect the proper install of stem seals. Either go back to shop what installed the guides for an explanation or move on.

Thanks, I hadn't thought of that. I'll just take it back to the machine shop. I was hesitant because it had been a while, they already messed it up once, and the shop is not in town to it takes a bit of planning to get there during business hours. But it's not like I'm in a hurry, the car has been down for a long time.

Dr. Hess
Dr. Hess MegaDork
7/4/17 2:42 p.m.

So, they have messed it up TWICE now and you are going for Three Times? Personally, unless you have a real strong reason otherwise such as the kid they had working there screwing up people's stuff got fired, I'd pick another shop.

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