I don't have the head apart from the block too often. I'll be replacing my valve springs in my head. Should I also replace the seats & retainers while I'm at it?

It's an R head, and will be replaced with OEM parts. What do I look for, or rather, how do I know if a retainer or seat should be replaced? Is there a service thickness or something?

 

Just from my own experience on the 2 B18c1's I had apart. Both looked pretty good on all of the head stuff EXCEPT the valve guides and seals, and the seals might have been OK, but the guides had a fair amount of play in them, and the seals get f'ed when you take out the guides.

The FSM test is stick them out 10mm fromt he seat, and measure the lateral (side-to-side) movement. It should be less then .006", with a service limit of .009" (??).

Mine were like .030", which couldn't have been a good thing. Motors had a lot of high rpm miles on them (one with 100k and the other with 170k), so yours might still be pristine.

I wouldn't worry about the seats, unless they look worn (which I seriously doubt), since they really don't have any load, or stress, other than the very slight rocking from the compressing spring.

As far as the retainers go, I wouldn't mess with them, unless you plan on upping the redline. Foctory ones are plenty reliable. Went 200k with the same ones (from the 170k motor).

My 2 cents...

Adrian

 

how do you remove the valve guides anyhow?

 

thx for the information. Mine is marked as a 98, so I'll most likely reuse most of it and just check the guides. thanks. You saved me money on stuff I probably don't need to buy.

 

Sorry for the delay, been tied up with an engine build. Yeah!!!

To change the valve guides, I think it would be best taken to a machine shop, but the FSM says you can do it with an air chisel, with a custom attachement, or if you have all day, you can use a regular hammer...

Look here:http://www.redpepperracing.com...b/abl. You can scroll to the previous and next pages to get more info...

To install them they say you need to heat the head to something like 300°, and freeze the guides to get them in. I think it only cost around $60 to get the guides replaced... but I'll be getting it done here next week so if I'm way off, I might be telling you how hard it was with a hammer...

 

Changing guides is no walk in the park, trust me. Heat the head to 300 degrees F. (not as easy as it sounds), then use the special valve guide driver and smack the guide down (towards the combustion chamber) to break off any carbon. Once the guide is loose, drive it out the top (towards the spring side of the head). You have to be very careful when installing the new guides, or you can get them cocked. Just ask Tom at Portflow, he checked a head for me after I changed the guides

 

I'll take that as word of wisdom...