Can I rebuild heads myself?

YTNUKLR · YTNUKLR's Garage

Can I have the valves reground, the valve seats/guides replaces, get new springs, retainers, etc., and rebuild heads myself? Thanks

aigel · aigel's Garage

You are basically asking if you can assemble your heads yourself. Yes you can. It may not save you any money though. I would want mine assembled, that way things don't get mixed up.

George

jgparker · jgparker's Garage

The tricky part is setting the spring height. You need the right tools to measure it accurately. Remember, the spring height changes depending on what cam you are using and for some aftermarket springs. On my last engine, I had the machine shop replace the valve guides and grind the seats, and I did the head assembly, but I was replacing all the valves and springs anyway, and had not picked my cam yet. I doubt it saved any money.

Good luck,

JP

69911e · 08-13-2004, 07:18 AM

You can set the spring height without the special tool, it just takes longer. Put head together without stem seal and outer spring, use a dial caliper to measure spring height.

David · David's Garage

The cost savings would be minimal. I'm a hard core DIY'r but I leave head assembly to the guys that do it every day.

If you're planning to this for a living down the road then now is as good a time as any to start gaining new skills.

afterburn 549 · 08-13-2004, 03:37 PM

M.O. look for a seat faceing set (ebay?) you probly do not need a valve grinding machine (replace the valves with new).....now you can do the seats the way you want (after you replace the guides)... I am a firm beliver that I am the only one that will do a valve job the way I want it ,,and it is not that hard!!
It is nice to have the valve grinding machine thoe cause you can take your time and blend it all in....like the seats

camgrinder · 08-13-2004, 04:01 PM

Do any community colleges in your area have automotive classes?
The school I went to for Automotive technology is De Anza College in
Cupertino CA. They have a really good valve service and shortblock course offered in the evening. You even get some hands on.
The ebay idea for seat grinding equipment is ok, but... the stone arbors wear out, the pilots wear out and unless you have a valve seat runout gauge you might never know.
I have also seen brand new valves with as much as .0015" indicated runout on the face.
I am not a cylinder head machinist, but I have some equipment and the knowledge to do the work and I still send the heads out to someone who
does it everyday.

RoninLB · 08-14-2004, 10:06 PM

I though the valve guides or heads had to be heated for install ?

ChrisBennet · ChrisBennet's Garage

It costs me about $400 to have a set of heads done (labor and parts) if the valves don't need to be replaced and I get them back in a few days. Years ago I got a quote (just for labor) from the machinist who does the head work for a friend of mine and it was almost that - and that local machinist only does a set every year of two.
The back of Peter Zimmerman's book "The Used 911" has a good explanation of how 911 heads are rebuilt.
-Chris

afterburn 549 · 08-15-2004, 09:39 AM

you are about to aproach a religion here....but this is how I did mine and it works for me.
knock your heads apart and clean them to the bone
size you guides to the heads.....you may have to turn a little off the guides (if they have been done b4 maybe not. ) make sure you get std. od. guides (from mom).
now if the size to bore is remotly close this is what works- wait till wife goes shopping, preheat heads to about 300 deg. in her oven.
have your guides on DRY ICE (safeway sells it)
1 head at a time from oven and slam them in . if I remember I had a little baby powder there to eze the friction
re heat the heads a couple of times to get everthing relaxed so you valve job dose not change later.
ez part is done

john walker's workshop · 03:57 PM

do you really want to do your first valve grind on your own 911 heads? the technique takes a while to figure out. you don't just grind until it cleans. after the 45 is cut, it also has to be narrowed from the top with a 30° stone to both true the top edge, and size it so the valve just overlaps it, and then cut from the bottom with a 60° stone or hand cutter, to both true it to the top edge and narrow it to the correct width. (i use a hand cutter because i can take off metal where i want, as the stone tends to follow the hole). there is only so much metal to work with, and only the minimal amount should be worked. too much grinding drops the valve too far in and ruins the seat. some seats are pretty wallowed out from the valve beating around from a loose guide problem and you often have only one chance to save the seat if you're good. then it's seat replacement time or another head. not that you can't do it, but beware.
as for replacing guides, the best way is to drill 1/2 way through with a step drill, leaving just a thin shell of the guide, then using a stepped drift to drive them out. can't say i've ever heated a head to remove or install guides. mic the diameter of the old ones and compare it to the new ones. the guides i get from worldpac are usually just a couple hundredths of a mm oversize and using WD40 as a lubricant on the guide and in the bore, drive in quite nicely. i use a guide driver tool in a air hammer with a thick washer slipped over it so the top of the guide isn't damaged. easy on the trigger.

CliffBrown · 08-15-2004, 11:03 AM

John

Can you recommend a source for guide reamers you're using and part numbers ? I have the K-Line catalog. Where do you buy your stones for seat grinding? What part numbers for the stones, I have a Sunnen catalog. Are you doing a three step cut on the seats.

Thanks
Cliff Brown

afterburn 549 · 08-15-2004, 01:28 PM

soux machine, snap on , ect. ect.,......all you have to know is which size valve stem,,I usually do it in 2 step process ,,dono why just do.
like Jn W. drill out the guides.........
I have for got the size weather it's a 9 or 10 Mabe Jn W. will tell you ,, but you have to go a couple thou. bigger then your stem