7 replies to this topic

[username2k2]

Hi,

I'm currenty rebuilding a metro a series engine to go in my mini . eventully . I have removed the valve guides tonight, simply heat around the valve guide, then found a drift the correct size and a lump hammer. An hour later and they were out. I have the tool to fit the new guides and the new guides, however I do not know how to insert the guides to the correct height, and how to measure this. Please could someone tell me of they know this information as I want these babies in tonight!!

Its a 1275 by the way

Many Thanks

Kev

Edited by username2k2, 06 March 2008 - 10:33 PM.

[dklawson]

I have always paid machine shops to insert the new guides. I'm sure Haynes has a figure for how much of the guide is to be left exposed but I don't have a copy at work.

Out of curiosity... does heating the head help in REMOVING the guides? With a cast iron head and a cast iron/alloy guide... heating the head shouldn't really change the fit of one to the other enough to help removal. However, on INSTALLATION, I can see the merit in heating the head as this will open the hole for the guide... which would be inserted at room temperature. Installation would therefore require less insertion force if the head were pre-heated.

[ginigwunkle]

they just tap out anyway heating wont have done anything.....

when you say you have the tool what do you mean?

i got mine from mra-minis its a cylinder that the guide sits into then with the aid of a press(g clamp at least) press the new guide into the head....

when the 'cylinder tool' touches the head it goes no further and is at the right height.....simple in theory

main prop is getting them in straight

ALSO MAKE SURE YOU HAVE THE CORRECT GUIDES!!!!!

[The Matt]

And ream 'em out when you've finished pressing them in!

[username2k2]

Hi

Heating around the guide, not directly on the guide, sightly expands the head. I did this both sides of the guide for about 5 mins on each one. I tried without heating, but you know when you get the feeling its going to break if you hit it any harder, I got that feeling. Sufficent to say that with heating the guides move much more freely. Trying to remove without heating tends to take more force and, runs the risk of cracking the ports. I have removed and fitted most of my guides this way, but I have not got the clearences. However I have ones from minispares.com for bronze guides, but again I dont know if the guides are the same measurements as the cast ones.

Many Thanks

Kev

[ginigwunkle]

id contact minispares about that as only they can tell you the sze of there bronze guides.....

[Guess-Works.com]

Get the tool to put them in....

[minimender]

I squeeze mine in with a lump of hardwood on the guides and in a big vice, you can do two at a time like this and they naturally go in straight. Stop and measure when they are close to where they should be. I take a rough measurement with a gauge before knocking the old ones out but, the measurements are not critical and near enough will do as long as they are far enough in.

The old ones knock out pretty easy again with a lump of hardwood as a drift to get them down to head level. After that use a suitable drift and if your lucky they will break and fall out.