DIY Head Resurfacing... or "Post-apocalyptic machine shop techniques!"

[Whitedog]

I have for that extra minty intake air taste It works well.

 

It works good just before an emissions test.

[Whitedog]

OK, so surfacing the head can be done on the bench, but what about the rest of the head work? I have never replaced valve seats, but I have done lots of bushing and bearings by freezing them, so that doesn't scare me, but is it something that would need special attention for some reason?

 

My biggest concern in the valves is final valve height. Since the followers are hydraulic, that isn't very critical is it? Or would a new valve and valve seat need to be machined?

 

I have only done valve work on one Dodge 318 but I'm confident, I could do something, but will it be right?

 

And what about the valve guides after 250,000 milerones? If they are worn out, are they easy to R&R?

[GeneralDisorder]

Things like guides and seats can be problematic.... but with the right tools they could be done in the home shop. They are typically pressed in - sometimes guides are staked in place or knurled. Knurling a guide is not something you can easily do without a lathe...

 

 

You can definitely do most head work - lap the existing valves, etc. Guide replacement is usually done with special shouldered punches. Seats are usually pressed in with an arbor press arrangement - none of that stuff is outside of the realm of a home shop - but some trail-error is probably going to ensue if you don't have some experience or training.

 

Depending on which head design you are talking about - Subaru heads can and do end up with worn out guides. Especially the DOHC heads I've noticed.

 

 

Getting the valve adjustment set correctly is time consuming when replacing valves and seats on the bucket/shim or shimless bucket heads. You have to carefully grind the valve stem till you hit the mark that you want for clearance - or go shopping for shim or buckets. Shims are about $6 each and shimless buckets are like $16 each. Those suckers add up real fast and thus grinding the valve stem is the prefered approach to adjusting the valves if you have the head off.

 

 

GD

[ShawnW]

I accumulated shims at the junkyard. I pulled cams and shims from every engine I saw with the valve cover already off for years and have more than most dealers do. In fact, I got a call from one the other day wanting to "borrow" a size.

Theres also a tool you can use to shave the actual shims in a valve grinder if you have one. I have both and love the tool.

 

Snap-on sells an air hammer attachment for pushing valve guides out. Expensive but works good. I replace guides on every valve job, just cheap insurance but most are within tolerance.

 

Thanks for the info GD. I got myself a piece of granite from a counter top place that dropped a counter. Was easy to cut with an angle grinder and a masonry wheel. About as flat as it gets and my next step is to mount the granite in a permanent workbench sitting flush to the rest of the bench, with a piece of plexiglass on top of it for regular valve lapping and seat work and pop the plexi out for surfacing. Im going to use this primarily on EA series heads but in a pinch I might try a quad cam 2.5 head. My arms were numb after the first ea82 ones I did. Ill post photos of the finished table in a few months.

[idosubaru]

I think i'm going to start doing this as well. The picture/description as I read it isn't clear:

I then backed the 5/16" thick glass with a 1/2" thick section of plywood - also checked for basic flatness.

 

what do you mean "backed" with plywood?

 

the head sits on the sandpaper - which is glued to plywood - which is attached to the glass?

 

seems like the plywood would warp? the plywood is just to provide a surface for the paper to attach to since doing it with the glass initiates extra work?

 

size recommendation for the glass?

5/16" thick - 24" x 24"?

 

got a friends vehicle/motor/heads to work on too.

[Whitedog]

Things like guides and seats can be problematic.... but with the right tools they could be done in the home shop. They are typically pressed in - sometimes guides are staked in place or knurled. Knurling a guide is not something you can easily do without a lathe...

 

 

You can definitely do most head work - lap the existing valves, etc. Guide replacement is usually done with special shouldered punches. Seats are usually pressed in with an arbor press arrangement - none of that stuff is outside of the realm of a home shop - but some trail-error is probably going to ensue if you don't have some experience or training.

 

Depending on which head design you are talking about - Subaru heads can and do end up with worn out guides. Especially the DOHC heads I've noticed.

 

 

Getting the valve adjustment set correctly is time consuming when replacing valves and seats on the bucket/shim or shimless bucket heads. You have to carefully grind the valve stem till you hit the mark that you want for clearance - or go shopping for shim or buckets. Shims are about $6 each and shimless buckets are like $16 each. Those suckers add up real fast and thus grinding the valve stem is the prefered approach to adjusting the valves if you have the head off.

 

 

GD

 

Thanks, GD. I would rather pay someone than have to go through all of that. Since it's a 2003, it has adjustable valves, I misspoke earlier. (The good news is that the proctologist called and he found my head.)

[GeneralDisorder]

I think i'm going to start doing this as well. The picture/description as I read it isn't clear:

 

 

what do you mean "backed" with plywood?

 

I mean the glass is sitting on top of a peice of plywood - just to reinforce the table top. And also I put nails at the corners of the glass so it wouldn't move around and the plywood add weight so the whole thing won't move around while I'm working.

 

size recommendation for the glass?

5/16" thick - 24" x 24"?

 

got a friends vehicle/motor/heads to work on too.

 

As thick as you can reasonably get and 24x24 is a good size. Should fit on most benches/countertops.

 

GD

[idosubaru]

great, sorry i'm still trying to picture this:

 

table - plywood - glass....

 

then the sandpaper is glued to the glass?

[Ricearu]

yes glue the paper to the glass with a THIN coat of contact cement. I have lapped heatsinks this way before back in the overclocking days. Back when every bit of heat dissipation counted when eeeking another 133mhz out of my pentium 2

[idosubaru]

wouldn't the glue add a level of un-evenness? seams minimal, but if perfectly flat glass is needed for the job?

 

how hard (and often) to replace the sandpaper...scrap, clean, reglue some more?

Edited November 16, 2011 by grossgary

[GeneralDisorder]

The contact cement doesn't add enough uneveness to talk about - and it stays pretty flexible. When you are moving the head in circles you are distributing the uneveness of the paper and contract cement (which is a "fine" sort of uneveness) across the head. The glass makes the whole sheet flat - the roughness of the contact cement is on the same order as the roughness of the paper itself and is inconsequential to the process. Some roughness is required on the part of the grit of the paper in order to remove material - the contact cement application roughness is in the same "frequency" as the paper grit..... if you understand my meaning.

 

I clean the paper when it gets clogged and I change it about halfway through each head. So that I end up using about two sheets of each grit per head. So two sheets of 220 and two sheets of 320/400, etc. I clean them by spraying liberally with WD-40 and blotting with a paper towel. Don't scrub or you will leave paper towel leavings on the paper. Blotting is the key and LOTS of WD-40.

 

Mineral spirits will remove the contact cement on the glass easily. No scraping is required. It will melt it and wipe away.

 

GD

[idosubaru]

1/4" is $25, thicker stuff has to be ordered and is $100 for 2' x 2'.

 

use 1/4" glass?

 

glue two pieces of 1/4" together?

 

18" x 18" be large enough? don't want awkwardly small but don't need the space used up either. i'll measure some EJ heads but experience is worth more.

[GeneralDisorder]

Wow - expensive glass shops..... I don't know the value on my glass since it's a peice of 5/16" that was just hanging around. Probably from a small table, etc. My father refinished furniture for decades and I pulled it from his collection of glass remnants.

 

You could look for a glass table top at goodwill.... :-p

 

I suppose you could stack it, yeah. use some contact cement in the corners. I don't see why that wouldn't work.

 

Any peice larger than the paper should be fine. 18x18 should work.

 

GD

[idosubaru]

it's a peice of 5/16" that was just hanging around. Probably from a small table, etc.

okay, i didn't know if that was a quantitative measurement, seems a little more arbitrary than that. two shops i called couldn't even get 5/16 and the next size up was 3/8".

 

i might google glass flatness when i have a better internet connection.

[GeneralDisorder]

My glass peice may be quite old - I really don't know. They may not make 5/16 anymore for all I know.

 

GD

[MilesFox]

A granite slab would work the same, and might be easier to find for the price. Look for a cut-out from a sink for a countertop. Sometimes you can get a fairly sized slab that is just shaped wrong to use for anything, but big enough for the job.

[idosubaru]

doubt i have any reasonable source for granite tops around here, but maybe i'll peruse the phone book right quick.

[GeneralDisorder]

If you plan on doing a lot of them - then something like this would be ideal:

 

http://www.ebay.com/itm/18-x-24-BLACK-GRANITE-GRADE-B-SURFACE-PLATE-STAND-/230290100102?pt=LH_DefaultDomain_0&hash=item359e5c0f86

 

GD

[maozebong]

i have a nice circle marble outdoor table, that if cleaned up, im sure would be flat... but id like to check it with a straight edge someday.

[Dirk]

This thread has been haunting me for some time.

 

Time to stick my neck out.

 

Proceed with Caution!

 

For those of you who have done this successfully I commend you! But I really would not recommened this to any one.

 

I have tried this before and it is very easy to muck it up fast. The motion of your hands moving the head tends to remove more stock on the outer edges of the head faster than the middle causing a convex shape.

 

Once things start to go wrong they can get worse very quickly and then you can throw away the heads.

 

I strongly recommend to anyone thinking about this to spend the money at the machine shop or at the very least try it on a spare head first before you destroy a good set of heads.

 

Rick. My appologies to you. I realize that this is a credible method and can produce good results but I don't think it should be published as a cheap DIY short cut.

 

Regards

 

Dirk.

Edited January 14, 2012 by Dirk

[GeneralDisorder]

Rick. My appologies to you. I realize that this is a credible method and can produce good results but I don't think it should be published as a cheap DIY short cut.

 

I appreciate your input. You can indeed foul things up if you apply uneven pressure, or don't check your progress often and insure you are creating a flat surface. I grip the head only by the sides and let the weight of the head do all the work. I apply my force to move the head as close to the paper surface as possible. It's key not to rock the head in any way while performing this task.

 

I have to say that I fundamentally dissagree with not publishing this type of methodology - the concept is sounds and it's up to each individual to decide if they want to risk doing this themselves or pay a machine shop. I think that our modern society is too far removed from old-world techniques - those of us that can and do practice these tried and true methods and have been given this knowledge by the "old timers" we have worked around should spread it as best we can.

 

If, due to the use of this information, someone should damage a set of heads then they will have at least learned how *not* to do it the next time.

 

People make mistakes when learning. It happens. I don't think they should be insulated from knowledge just because they might hurt themselves though. Sadly that's all too common in our increasingly socialist world - the removal, by the state, of the individuals right to fail. And in a world where you cannot fail - success is meaningless. Failure is the essense of what it means to be human and when you take that away you diminish the humanity of us all.

 

GD

[Dirk]

 

People make mistakes when learning. It happens. I don't think they should be insulated from knowledge just because they might hurt themselves though. Sadly that's all too common in our increasingly socialist world - the removal, by the state, of the individuals right to fail. And in a world where you cannot fail - success is meaningless. Failure is the essense of what it means to be human and when you take that away you diminish the humanity of us all.

 

GD

 

This I agree with whole hearted.

 

So perhaps I should amend my statement from 'don't do it' to 'proceed with caution'

[Dirk]

I believe that learning from your own mistakes is the best way just as long as no one gets hurt.

 

Sometimes however it is good to learn from other peoples mistakes.

 

(the nanny state.... this is something that winds me up very easily. That said, if someone does insist on slapping a warning lable on something, it would be foolish not to read it)

 

And yes I am a Libra sign.

 

Regards

 

Dirk.

[Stubies Subie]

I believe that learning from your own mistakes is the best way just as long as no one gets hurt.

 

Sometimes however it is good to learn from other peoples mistakes.

 

(the nanny state.... this is something that winds me up very easily. That said, if someone does insist on slapping a warning lable on something, it would be foolish not to read it)

 

And yes I am a Libra sign.

 

Regards

 

Dirk.

 

I can tell you from an outboard boat motor prospective that this is the accepted method of resurfacing heads, and given the thinness of an outboard head, there is a far greater probability that an uneven resurface could occur, I have a couple of running outboards I’ve done this to and both of them are still running fine, as well as my car that GD did.

[987687]

This thread is awesome. It should go in the USRM.