The Cal-look Lounge

It's time to replace the exhaust valve guides in my MS230 heads.  Are they stock Type 4 guides?

As I'm in Canada, I'd like to have this work done locally, rather than sending the heads back to JPM.

Thanks.

They must have std Type1 or do you have 9 mm stem on the valves ?
Best is if you messure in the head to get the right press fit

Udo

I'd imagine JPM could sell you some spares if needed also. :)

Why do you think "it's time" ? What's the symptoms? , most heads I see for " new guides" are nowhere near that point, owners are frightened by the rock at the valve head, but they have a considerable tolerance limit, especially the exhausts, and there are rarely any Symptoms, I'd rather have slack guides than tight ones that's for sure, sucking oil is sometimes seen on VW circuit engine when a long time off the gas on the overrun, I've suffered from that, but I had hardly any guide anyway, they were ported right back with no guide bosses, high quality bronze liner systems are available for  "suckers" , these iliminate any risk of split guide bosses during re guiding,  they're good enough for Porsche and other pro race teams.

Thanks for the replies:

Udo: my information when purchasing the heads was that they came with Type 4 style valves. Yes, I will check the size once I remove the engine for freshening up.

kb: yes, JPM can probably send guides from Sweden to Canada, but doing the wire transfer is complicated (for a small purchase).

Spanners:  a few years ago, I made the mistake of trying the Web 226 camshaft (for racing) which caused the ends of the exhaust guides to break off in pieces. At that time, my head porter trimmed the guides back to the port wall, which allowed me to continue racing that year plus two more years since. However, recently I noticed a drop of oil seeping from the guide into the port (when I removed the header). I'll have to send the heads long distance to get them checked and am trying to find out what guides to send with them, if need be.

Neil, I too have had exhaust guides fall apart in the port, I put it down to very high EGT,s it was a dry sump high compression 1641 with ram air cooling, it ran at 130c oil even with very large oil coolers,  it also had no port side guide bosses so it is to be expected, port guide bosses are seldom seen these days. In your case, unless it was showing symptoms, I think on balance I would live with it, assuming the heads are performing well, too much risk in freighting heads, even re guiding has its risks, a missed 1/2 thou oversize guide will split the boss, and sometimes they just don't seem to go back in at the same axis to the seat, then you can end up with a large seat cut and have to balance up the other chambers, then re do the v.spring shims,,,,, la Dee da de da.   ;)

Thank you for the info.

I will pull the engine this week, inspect the heads and post my findings. A drop of oil in the port may not be indicative of major guide wear, so I'll make a decision based on how the valves fit.

Neil most times when they say stainless type 4 valves they are talking about the length which are longer than the type 1 but the ones I have used were the same stem size. 

Thanks.  The MS230 brochure states:  48 mm x 38 mm Manley Type 4 Valves, so that's what I assumed.

Here's a photo of what happened to the exhaust guides when I ran the Web 226 cam.  Darren was able to trim them back to the port wall and all has been well for 2.5 years since then:

(http://i65.tinypic.com/5vdm42.jpg)

Standard 8mm guides.  ;)

Hi Neil, I Can't see how the cam directly influenced that guide damage, differing lift and more travel may or may not have been seen at the valve, and geometry can affect side loads on the guides, but that is some skinny port side guide wall, I've run into some cases of rare sticking inlets lately, so I now counter bore ALL guides in and ex to about 5 mm deep port side to allow any carbon build up space to live in harmlessly, OE factory guides had this, but like port side guide bosses, don't appear on aftermarket heads, there's no meat on your guides to counterbore, it may stem from persived short life drag parts were maintenance periods are high , my port side turbo guides are massive for obvious reasons, I think the cause in your case is not enough port side guide wall thickness.

    Definitely, thankfully, quality guides should be easy to source, the 9mm exhaust guides are bigger o.d and require a conversion guide, but that can be a good thing tho' in view of Neil's picture, giving a good meaty port side guide for turbo use.

I changed once . It was standard vw guide.

 On my turbo heads I was told to remove all valve guide from the exhaust port so this would not happen , plus to prevent damage to the turbo turbine. Mike McCarthy

Yes, this would work for a maintenance intensive motor, one reason why I think Niel should be carefull, don't fix what ain't broke.

Neil, those guides appear to be tappered? making them thin and hot. Type one guide with a nice bull nose and a small counterbore for a carbon trap should work good. I just would'nt have them hanging to far out into the port.

Finally got the engine pulled today.  Here's an iPhone picture of the worst exhaust guide leak.  I'll remove the valves and check them all for tightness:

(http://i68.tinypic.com/xfe2oy.jpg)