Trued an engine head

[Batmanacw]

I had an emergency job fall into my lap last night at 6 pm. My buddy was going to true up the head on a 1.4 liter engine for a relative. His mill was already set up for an urgent job so he brought the kid over to me.

It took an hour and a half with set up and a couple of cautious passes before I got into the meat of the matter.

It took 0.012" to clean up except one small mark with no depth. I used a fly cutter that covered the main surface in one pass but I had to move the Y to cut the tabs that stick out on both sides. The cut overlap is so good you cannot feel it with a fingernail or pick. I know it's not idea but the head is dead flat.

I am sure to get an earfull on how it won't work and is ruined forever.



The finish is extremely smooth. No idea of the RA but it's near a ground finish. Is there such a thing as too smooth? Should I feed a bit faster to create some "tooth" to the finish? I used a dcct insert for aluminum. I've never seen such a nice finish off my big fly cutter. 660 rpm and around 2 ipm feed.

 

[Jake M]

Surface finish gets determined by the gasket type.

0.012 is a lot to take off of an overhead cam engine. As the head moves when it's released from the deck, so does the cam bore.

Probably would have been a lot safer to not let the extra pass for the one ear cross partly into the liquid circuit. Water OR oil. That, or it looks like maybe not in this case, but finish running the extra pass across the port, so that it's working seal is on one finish is a good option too. Leave the transition out in the "body" of the gasket, away from the edges.

That said.... I've seen a lot worse compromises from professional shops. I bet it works out just fine.

 

[markba633csi]

Depending on what the "tabs" connect to/with you might need some extra gasket sealer there- otherwise it should be ok
Strange looking head- what is it from?

 

[Batmanacw]

C

Depending on what the "tabs" connect to/with you might need some extra gasket sealer there- otherwise it should be ok
Strange looking head- what is it from?

Chevy sonic

 

[OTmachine]

My main concern would be the cam bores. IMHO, 100% clean-up is not really necessary, as a couple of low spots in the middle of large areas, do not hurt anything. I have seen a Lot worse, watching the mechanics in the shop, where I used to work, when they would take an abrasive wheel on a die grinder to clean off old gasket surfaces. Lots of divots. Made me cringe, just watching them.

 

[pontiac428]

Nice work.

I've decked heads by 1/8" and only "lost" a fraction of a degree of cam timing. A little valve retard never hurt a small engine. Just do the math as a sanity check if it bothers ya. The Daewoo 1.4 ecotec has a lot of grunt, the tiny bit of retard won't be noticeable. Just re-set your base ignition timing before starting.

Looks good to me. It sure is nice to be able to do your own work, isn't it?

 

[Batmanacw]

Surface finish gets determined by the gasket type.

0.012 is a lot to take off of an overhead cam engine. As the head moves when it's released from the deck, so does the cam bore.

Probably would have been a lot safer to not let the extra pass for the one ear cross partly into the liquid circuit. Water OR oil. That, or it looks like maybe not in this case, but finish running the extra pass across the port, so that it's working seal is on one finish is a good option too. Leave the transition out in the "body" of the gasket, away from the edges.

That said.... I've seen a lot worse compromises from professional shops. I bet it works out just fine.

Next time i will pay special attention on any surfaces outside the width of a single pass is not coming so close to or splitting a passage. I understand what you are saying.

I think I'll get away with it this time because the match is so perfect that even a hardened steel pick can't bump the transition. Doesn't mean I won't seek to do better next time. Good call.

 

[deakin]

if it's overhead cam and the head is warped so is the cam journals the method is heat straightening instead of surfacing

 

[Batmanacw]

if it's overhead cam and the head is warped so is the cam journals the method is heat straightening instead of surfacing

Maybe true. I'm no engine guy. Just a machinist truing a head for a kid trying to get his car running. I'll report back if it doesn't work out.

 

[3strucking]

We used to stick them on a big belt sander if they just needed touching up. Put lead shot bags on them for weight. Yours looks as good as one that has been decked on the decking machine