Hey what’s up guys, i just finished a head rebuild on my 1.6. (Shaved, mild valve job, valve seals). I got the car running about a week ago and got some smoke at startup and decided to do the valve seals again because that was the most likely issue. So i did, and the smoking went away, for about a week. Two days ago, i noticed some smoking at stop lights, and at cold start. Both sets of valve seals were felpro and i gave the first set the benefit of the doubt thinking i screwed something up with the install. However, these ones should be all good. Anyone have experience with these? I’ve read they are ok, but just wondering what you guys think. I’ve already added a pop rivet restrictor to my oil feed, and made sure the drain line is a-ok, just to the rule the turbo out of the equation, which is a freshly rebuilt sr t25. Do i really have to do these damn seals again with OEM?

 

Did you happen to check the valve guides for ID specs?

 

No, i didn’t see much concerning with valve guide wear. And i didn’t plan on replacing them anyways as this motor will just be a temporary fix until i go with a built motor.

 

If the guides have worn oversize or have become out of round/oval it allows the valve stems to move and the seals lose their effectiveness. Not saying this is your problem but if going through the expense of a valve job checking the mechanical dimensions is a 1st thing as it kind of dictates what you do or if the head is worth doing.

 

I've run Fel-Pro's in my turd for years. Never had an issue with them.

 

Yes, i agree. Although it didn’t smoke before, and like i said was fine for about a week. Considering the seals see no actual movement (except if the valves were moving around that much), i don’t think the valve guides are causing this particular issue. Unless, valve play is causing the seals to prematurely sh*t the bed.

 

It is extremely common for these motors to need all 16 valve guides during a rebuild. That wasn't the case ten years ago, but it has been increasingly common as they have gotten older.

 

Unfortunately i am leaning towards that as well. Although i haven’t seen or read of many people even replacing them.

 

Any chance swapping em out with oem will give them a better chance at sealing? Would rather not pull the head but if that’s what it comes down to...

 

Could be worth a shot. The Felpros are supposed to be pretty good, and the OEMs are pretty spendy, although certainly less spendy than a full valve guide replacement.

 

@Savington Please comment on valve guide knurling vs replacement.

 

I've never heard of knurling the valve guides, presumably that decreases the clearance slightly to tighten them up. That sounds like a temporary fix at best, though.

 

You still have to re-ream the guide ID after knurling to get the ID back into spec.

 

Looked up replacement guides. Pretty economical: $50 for cast iron set, $80 for bronze. Seems like the way to go.

 

Much of the cost is in the install, since you typically have to recut the seats once the new guides are installed and reamed to size. IOW, it effectively requires a full head R&R. We use SI's manganese bronze guide and have had no issues with them.

 

Yeah, i think i’ll try the oem ones. If they work they work, id do the guides myself, but still just a little labor intensive for what my goal is with this motor at least. As far as knurling, i’d still have the pull the head and then send it off to get them knurled. So at that point i think anyone would be better off just replacing the guides.

 

Have you thought of trying Supermiata valve stem seals? OEM was a bit too expensive for my taste so i'm going to try Super Miata's valve stem seals.

 

They seem to be very similar to oem quality, according to the test done by Mudflap in the “which stem seals leak” thread. Although the fact that USED oem seals holds quite a bit of weight when compared to the other ones. A question for Savington, in this case, would i want a seal with the tightest fit (ie smallest ID) or one that holds the most weight?

 

Just an update for anyone who’s curious, i ended up doing my stem seals again, this time with OEM. They’ve been good for 2 weeks now, fingers crossed!

 

a little late but... I had mine knurled when I built it. can confirm, it is a temporary fix. My local shop made very clear that it was just buying time. dropping another 400 on guides was just not an option at the time.