16 replies to this topic

[Steve-O 2014]

How do you check these, do you just feel for movement? Got my head in getting work done and they said the guides seem OK, how are they checked?

Are they easy to diy replace if you have access to a press?

They said if I want them replaced its £5 per a guide (plus cost of the guide) to press out and new one in but said I don't need to replace them

[nicklouse]

if I was changing guides I would be changing valves as well.

 

guides will need reaming to size after fitting and seats recut.

[Spider]

An easy way is to fit an unworn valve and measure the wobble with a Dial Gauge.

 

Personally, I rarely bother checking them, i just replace them as a matter of course.

 

In addition to the Reaming that Nick mentioned, you'll also need to get the Seats re-cut following this as the new guides may not be on the same centres as the old ones. Again, all standard head reconditioning stuff.

[slidehammer]

Unless the guides are fairly new phosphor bronze ones I would get them changed and reamed to size as a matter of course. I ordered a set from mini spares, got them sent direct to the machine shop and they fitted them.

[Turbo Phil]

The iron type guides are fine for most applications running the road spec valves, & are only about £1.50 a piece.

Phil.

[Spider]

The iron type guides are fine for most applications running the road spec valves, & are only about £1.50 a piece.

Phil.

 

They also withstand 'abuse' way better.

[Turbo Phil]

Yep ! Folk just seem to think they must have the bronze ones, just like they must have double valve springs to.

Phil.

[Fast Ivan]

Get a mic on the valve stems as well if you plan to reuse them

[Steve-O 2014]

Is £5 per a guide an OK price for fitting them? Thanks

[Spider]

Is £5 per a guide an OK price for fitting them? Thanks

 

IMO, quite cheap!

[Fast Ivan]

Is £5 per a guide an OK price for fitting them? Thanks

That's a fair price, you can get it done cheaper but that's not extortionate
As mentioned above though they will need sizing and the valve seat will need recutting

[EOA]

There are tolerances in the workshop manual, the bore of the guide and the valve stem need to be measured to see if the clearance is within limits. If they are do not change them, there is a long way between new and Knackered. "If it aint broke don't fix it"

[DomCr250]

£5 a pop is not bad .. I've done it myself at home a good few times using an old guide and a cut down valve welded together as a removal tool.  I seem to remember it taking me an evening to hammer out the old ones and put the new ones back in ...so £40 seems good value

 

As to having the seats recut I've never found a problem with just lapping either new or existing valves into seats after guide replacement, same for reaming or sizing...maybe I've just been lucky.

 

If you are not that confident then get an engineering company to do it, keep in mind they may and try to 'up-sell you' to stuff not really needed ...if you think that's the case just ask on here...

Edited by DomCr250, 27 January 2017 - 10:05 AM.

[panky]

I did it myself too, a mate turned me a tool and the old ones came out quite easily with a few stout thumps. I put the new ones in the freezer for half an hour before fitting and again the went in nicely. The cast guides dont need reaming and I didn't need to re-cut the seats, may have been lucky but a short session grinding them in was all that was needed. Just remember to drive the old ones out from the top and the new ones go in the same way - and make sure the guide is left protruding the required amount.

£5 a guide does seem a good price though if you dont fancy DIY.

[Turbo Phil]

Always, always ream the guides. They're an interference fit and pressing them into the head means they do need to be reamed to ensure correct clearance. You may get away with it as mentioned above, but I personally wouldn't chance it.
You also must recut the seats, no if's not but's, to ensure proper seating of the valve.
You can knock the old guides out with a punch and hammer, but a press is better and they should be pressed back in to avoid distortion.
You're just asking for trouble if you don't do things properly.

Phil.

Edited by Turbo Phil, 27 January 2017 - 10:50 AM.