When there's a number stamped around the valve tip like that they're OEM in my experience. Yes you can set your heights with the replacement valves.
What do you mean by "set", can the new valves by machined to the correct height? Sent from my MAR-LX1M using Tapatalk
Update and good news, my valves are not sodium filled. They are stainless, non-magnetic, however the valve tip IS magnetic, the rest is clearly stainless steel. It is also obvious from the weight. The tip is marked with the same (or similar) code as the OEM one: EK107082 M86 My guides are all copper, the exhaust has no play at all, but the intake does, so I will be replacing those with bronze.
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Going over this thread again, I now have doubts. It seems the OE valves are NOT magnetic at the stem, and only magnetic at the tip and head - which is what I have. Hmm...
That looks like a sodium filled one to me especially given the magnetic properties you described. Just a word of warning about the valve guides - if you are using Superformance supplied ones check the specs on them. Only about 20% were the right size out of the 48 I purchased from them in two batches a couple of years apart. The rest had to be machined down to the correct size.
I think I will go ahead and sacrifice one - will have it cut at the stem, seems it is the only way to know for sure.
The numbering on thr stock valves are on the tip. It's normal that intake and exbaust valves do react differently tl the magnet: only the exhaust valves are sodium filled. As far as the shim size is concerned, you do have to adjust the valve seats, not make custom valves. I've posted a link to an ebay seller that does offer proper shims with extreme sizes. The stock shims made in Italy are easy to source and nlt overly expensive, but the thinner sizes are hard to come by, except on special order. I've bought a set of thin shims, as they are used to take the measures: put new thin shims, measure the gap, buy the proper size.
Mine were all within spec. No idea if I should have changed them for fear they may sudenly fail, but in any case, there are two springs, so the failiure would not be an absolute disaster (?)
So, the mystery is over, I have (had) sodium filled valves. They are all being replaced by stainless ones, either from superperformance or Maranello parts. Getting new guides and new valve stem seals as well. Image Unavailable, Please Login Sent from my MAR-LX1M using Tapatalk
It has been stated by many experts that the springs are of very high quality and do not need replacement. Read this thread from the beginning. Sent from my MAR-LX1M using Tapatalk
There's a few things I take into consideration. My 400 wouldn't be one I would replace all of the springs on because the cam is low lift and the engine isn't a screamer. The springs get tested and shimmed to get the correct seat pressure ever time. When Im putting a different cam in then the springs get matched to the cam rather than run the originals. Buying new springs can be a double edged sword now because of where they could be made and by who? Good intentions could lead to a spring of unknown quality failing.
Further to what has been mentioned here, I placed the valve in a vise by the stem, and gave it a slight tap with a hammer; result: see below. Image Unavailable, Please Login Sent from my MAR-LX1M using Tapatalk
Try dropping one on the floor, sometimes they break that way too. Scary stuff and I think about it every time Im out in mine.
Now that the heads are off, should I do some porting and polishing of the ports and combustion chambers? Sent from my MAR-LX1M using Tapatalk
No but it could use a better cam profile to wake it up. ....now I'll wait for the CIS nay-sayers to chime in
For sure the K-Jet system/air flow sensor plate is a major restriction. The entire intake setup on the 400/412 are a major restriction, the carbureted 400 made 340 HP, while the K-Jet 315 HP. The 412 should easily reach 380/400 HP with electronic injection. Sent from my MAR-LX1M using Tapatalk
The intake plenums on a 400i / 412 are upside down BBi plenums. I haven't flowed 400 heads but the central intake port design probably flows more than the boxer engines do, I know the restriction on boxers is the intake port. The CIS cars all suffered from lame cams. The cams on the 308's became lame before CIS which was an emissions thing, the CIS was a bolt on because the engine specs were mild. I haven't checked cam specs on a 400 vs an i or a 365 but I imagine they are all different. I've done cam upgrades on 8 and 12 cylinder CIS cars and the performance difference is substantial. CIS will support over 400HP as will the stock injectors. There are other tricks one can do if they put their mind to it. V8 sensor plate housings vs 6 cylinder units, cams and higher compression thats pump gas friendly.
The 412 already has a 9.6:1 compression ratio, so not much more can be done if you are running on "pump" fuel. Is there anything I should/can do while my heads are off?
Good day, I think you need to measure your engine's CR than assume the quoted spec is accurate/correct. I say this, as I remember Paul mentioned that the published spec for the 308/boxers? was actually higher than reality. Cheers, Sam
Lower than specified yes. The 9.2:1 boxers were closer to 8.75:1 and the 308's were more like 8:1. It was like Ferrari didn't take the valve reliefs into consideration or they just fudged the numbers. 10:1 is a nice number and 91 octane without methanol is sufficient.
