Valve guides

Hi All, just had new guides fitted & noticed that they sit proud by approx 1.5mm(I didn't take any notice of them before it was done). Is this normal? It doesn't look right to me, as the outside of the bottom cup will not be supported.

Thanks in advance for all your replies, Paul.

I presume you mean the flange around the inlet guide.
Yes they do sit about 1.5mm above the bottom spring retainer seating.
The spring retainer should fit over these & onto the seating.
The exhaust should have tufnal washers below them.

Flo, so what you are saying is that the cup should sit on the head & not on the guide, if that is so then the inner spring will sit on the guide. I was going to ask about the tufnol washers as there wasn't any fitted, I didn't know if they were deleted on the 850s.

Cheers, Paul.

hayabusaman0 said:

Flo, so what you are saying is that the cup should sit on the head & not on the guide, if that is so then the inner spring will sit on the guide. I was going to ask about the tufnol washers as there wasn't any fitted, I didn't know if they were deleted on the 850s.

Cheers, Paul.

Click to expand...

Indeed the cup should rest on the head not on the guide, both springs should rest on the cup, all 850 Commando's had tufnol washers on exhaust guides some even on inlet guides but you should compare the lenght of all four mounted spring setups to find out if you need tufnol washers for the inlet guides as well.

Thanks Nortonspeed, am in the process of measuring fitted lengths now, I will post later.

Thanks, Paul.

Fitted spring lengths are; D.S. IN 1.270", T.S. IN 1.187, D.S. EX 1.285, T.S.EX 1.250. The guides are proud of the head by 0.071(ds inlet) .056(ts inlet) 0.090(ds ex) & 0.053 (ts ex). I am running a 4s cam & the figures from my book say 1.284" EX fitted spring length & 1.259" IN spring length. It looks as if I may have to get the bottom cups bored out to fit over the guides but then I have the prob of the inner spring rubbing on the guide(unless I put a washer on there) I will speak to the guy who fitted the valve guides to see what he has to say. I might just have to make the most of it because the in & ex valves are o/size & the in & ex ports had been re-aligned. I had to have std ex seats fitted as there are no 41mm ex valves available until July/August.

hayabusaman0 said:

Flo, so what you are saying is that the cup should sit on the head & not on the guide, if that is so then the inner spring will sit on the guide. I was going to ask about the tufnol washers as there wasn't any fitted, I didn't know if they were deleted on the 850s.

Cheers, Paul.

Click to expand...

I'm a little confused here. If you have an 850 head, your guides shouldn't have a flange on them, just the round circlip that locates them, and the spring cups/seats should fit over the guide and sit on the head, or on the tufnol washers if fitted. Are we talking about an 850 or a 750 head, and are these stock Norton springs and cups, or aftermarket? The stock inner spring is larger than either the 850 guide or the flange on the 750 guide, and would never have to sit on any part of the guide. It fits easily over the guide and seats on the steel spring cup. I've seen some 850 size guides with larger flanges on them, like the 750 design, but they were custom made for big valve heads, and had spring cups to match. Is it possible you've got a mix of aftermarket and stock parts that aren't compatible?

Ken

Yes, they have circlips, the inlets are turned down for the seals, which makes them look like they have a flange.
This is what I presume is sticking out 1.5mm.