Is this cylinder head borked?

[Dave_G]

I've got two cylinder heads sitting in my garage. I know Head A is a mess, owing to a broken timing belt -- bent valves, broken rocker arm, the usual chaos.

This is not as total a disaster as it could be, because I've got a spare engine already sitting on a stand, ready to donate its recently rebuilt head. This donor head (Head B) is in perfect shape.

Or so I thought until I pulled it off. Upon removal, I discovered that the head bolts had been installed without washers, causing the bolt heads to dig into the top of the head, like this:



For comparison, here's Head A, the one with smashed pieces but a good surface on top:



I'm just going to sit for a while and consider my options, though I suspect that I don't want to just use Head B as it is, without addressing the gouges in the top. Or can I? My other option would be to transfer all the valves, rockers, etc. from Head B to Head A, but that's a job I would probably ending up spending a lot of money to have someone else do. And I was thinking I was going to get out of this cheap. :( Other options?

Is there a consensus on this?

[e30davie]

Im not proud, but i too installed the headbolts without washes on my current m20. 10pm at night rushing to get the job done and forgot to put washes on...Once I realised i backed off each bolt one by one, put a washer on each one and re-torqued. 12,000km later, no issues.

However mine were not as badly scored as yours. especally that first photo, thats gotta be 1-2mm deep?

One option might be to get a machine shop to flatten the bolt head area with their mill, the only issue is that there will now be a bit less room for the bolt in the thread of the block, so you risk the bolt bottoming out. You can probably calculate this by bottoming out the bolt in your block and taking a measurement to the base of the head bolt.

Or use head studs, then there is no issue with bolt length bottoming out.

[redlightpete]

I wouldn't worry about the damage to the clamping surface as long as you use the stock type washers. You'll want to verify the condition of the head in general, since the factory certainly didn't assemble it like that.

[TobyB]

seconded- make sure the rocker tubes slide freely, put washers under there, and run it

t

[digger]

i would want it to be spot faced to a diameter bigger than the washer diameter otherwise the washer isnt supported properly

[Kershaw]

Or find a small washer to fit in there?

[redlightpete]

i would want it to be spot faced to a diameter bigger than the washer diameter otherwise the washer isnt supported properly

This is certainly the safer bet. Without machining that surface flat, there's a possibility that the washer will settle into the head during use and reduce the clamping force.

[hasa]

Put thick washers and it'll be fine. I once did this mistake too.

[Dave_G]

OP here. Thanks for all the suggestions. They were about 50:50 between "fix the divots" and "it'll be fine as is". I don't want to have to do this twice, and I'm not that interested in taking chances, so I took it to a machine shop to get their input. They pointed out that if they do any machining to the head, little bits of aluminum will inevitably get into places I don't want them, so if I went the "fix the divots" route, I'd be looking at disassembling the head first.

Since I'm not 100% comfortable with using the head as is despite the reassurances, I'm going with Plan C: I'm going to completely disassemble both heads, bring the bare heads and valves to the machine shop, and have them build a new one with the good valves and the good head. It'll be more expensive than just putting on the head as is, but at least I know it'll be done right.