Valve guides question

[Guest]

I think I have 1 or 2 valve guides that seem to be more worn than the rest.

1 whats involved in replacing them?

2 whats the cost per guide ?

3 How loose are the valves supposed to be when cold ?


I'm thinking its just a matter of heating the head up in an oven and beating the guides out and in but I've never done it or know if there is a special way or set of tools for it.


Something I've noticed while washing the head in hot water is that the guides seem tighter when the head is hot.

Are the exhaust valves loose or worn more because the exhaust valve gets hotter and expands more ?


thanks

 

[Nessism]

You might want to measure the valve to guide using the wobble test. Pretty easy to do if you have a dial indicator. Lift the valve near it's max normal lift point and test - the factory service manual details how.

The factory service limit is very generous in regards to the allowable clearance. My personal opinion is anything beyond .004" is too much, but Suzuki allows way more than this in the later service manuals. I've often wondered if Suzuki made a mistake since they allow something like .012" which seems crazy to me.

Replacing guides requires some special care. Heat the head then drive out the guide using a special drift. Suzuki recommends reaming the head oversize and using oversize OD guides, although aftermarket guides are available that are the normal size.

After installing the new guide they need to be reamed/honed to size. You also need to perform a valve job (cutting the valve seats) since the new guide won't index exactly perfect. Needless to say this is a major undertaking.

I did my own valve job using Neeway cutters but didn't have to do the guides. I'm going to have a go at some one day though. Fun project if you have the tools.

 

[Guest]

Ok thanks Nessism. Its more than I thought it would be. But If I had the tools I would do it if necessary.


Only one exhaust valve has 0.007-0.010 X/Y. The rest seem the same but the intakes are better. Maybe that 0.012 isn't so far off? Is there something special about the 4 valve head with smaller valves heating up more and expanding more than one large valve?


Would bad seals cause a guide to go bad prematurely?

What causes them to wear?

Would It have been a tight overheating valve ?


A while back I had the head rebuilt with new seals. The seals were garbage and leaked badly from what I saw in the combustion chamber. More buildup in 1000km since rebuild than in 26000km prior to rebuild !

I put 7 seals on one valve and held the bottom one. The valve fell clean out with hardly any resistance
Not a single mark on them either so I don't know what they are.
I kind of expected them to last longer than the original 31 year old seals

 

[gearhead13]

Be careful what new seals you buy. There are some on ebay that are junk. I got some from Z1 and havent had any problems. Of course stock suzuki ones are the best but pricey.

 

[Guest]

I know what you mean!

http://www.ebay.ca/itm/230451327426?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

This is what I got.

Seems like oem or better quality. Definitely better than then the ones in there.

 

[gearhead13]

I know what you mean!

http://www.ebay.ca/itm/230451327426?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

This is what I got.

Seems like oem or better quality. Definitely better than then the ones in there.

Good luck. I had problems with leakage with those, especially if your guides are worn.

 

[rapidray]

If you have more trouble, use stock seals. I have TRUE Viton seals & have no problems with them. I only have for 5.5 mm stem size valves. I sell them if someone needs. Ray.

 

[JEEPRUSTY]

What shocked me about my recent burnt valve episode is that the stems are alll still within specification for diameter. The guides must be sacrificial. What are they sintered bronze er sumthin?

I also wonder how much lift the valves should be set to before the wobble is measured. It makes sense that the very end of the guide at the ports would be the most worn and that the higher up less so.

 

[gearhead13]

What shocked me about my recent burnt valve episode is that the stems are alll still within specification for diameter. The guides must be sacrificial. What are they sintered bronze er sumthin?

I also wonder how much lift the valves should be set to before the wobble is measured. It makes sense that the very end of the guide at the ports would be the most worn and that the higher up less so.

I would think that the top of the guide would be more worn because of side loads of the cam/rocker pushing the valve. Maybe less side loads with the 2 valve setup than the rocker setup of the 4 valve

 

[tkent02]

Maybe less side loads with the 2 valve setup than the rocker setup of the 4 valve

This is a big reason the two valve engines last so much longer before needing engine work.