A "light" cylinder head refresh - does that exist?

[Healey3000]

Hi,

 

My head is plagued by two oil leaks, one at the step at the front timing cover and one at the distributor housing.  I'm not sure why the timing cover step exists because the head was "replaced" by one of the PO's.  I assume it was a new head but it might well have been a rebuilt one, hence the step.  The distributor leak is most likely due to a fair amount of pitting on the head rear face (I'm baffled how that could have come about).  Attempts at re-sealing both leaks have been frustrating and unsuccessful.

 

I am considering purchasing the head shown in the photograph (E12).  What is the bare minimum I must do to use it?

• Decarbonize?
• Check for warping and deck if necessary?
• Check for cracks?

 

I know that a full rebuild would require a lot more - new valve guides, valve-grinding, cam polishing (or upgrading to a 284/292), etc., etc.  Am I wasting my time doing a partial job?

 

Thanks!

[Son of Marty]

It's kinda hard to say with out knowing the history of the head but it you could try just have the deck skimmed (along with the front cover of course) and give it a try if that doesn't work out due to leaky valves or valve seals pulling the head is not that big a deal.

[Healey3000]

Just now, Son of Marty said:

It's kinda hard to say with out knowing the history of the head but it you could try just have the deck skimmed (along with the front cover of course) and give it a try if that doesn't work out due to leaky valves or valve seals pulling the head is not that big a deal.

Hi,

 

That's what I was thinking as well.  Is it okay to deck it with all the guts in place?  That would make life a lot easier.  The only history I know is that it was "never overheated".  From the photographs, it looks decent, as far as corrosion goes.

 

Is it a given that each time the head is pulled it will need to be decked?  Or, are M10 heads reasonably forgiving?

 

Thanks.

[Simeon]

Measure the depth of the new head to try and establish if it has been decked before. 

 

Personally, unless I was time poor and I needed to get that head back onto the car, I would disassemble and lap the valves as a minimum. You can also check them by pouring gas into each chamber and check for leakage into the inlet / exhaust runners. The disassembly does at least give you an opportunity to check for wear if components and then replace if required. 

[SteveJ]

Yes, but the full disassembly is a slippery slope.

 

So far,  2 years long for my tii.

[Arizona02]

 the timing cover needs to be on the head when milled avoid the step. To stop the leak  use RTV on the head where the valve cover gasket lays spreading it  back 2 inches or so before installing  valve cover & gasket. Just like filling in a dent  low spot when doing body work.

 Dist housing , you might need the one special seal that a bolt goes thru , same design as a crank seal seen in the parts diagram. On the pitted surface use a sealer before gasket install. I use the old style Permatex 80016 form a gasket, it is like a brown clay substance.

[Stevenc22]

My head rebuild was under $500 for skiming, lapping and new guides. Seems like alot of work to save $500.

[Healey3000]

1 minute ago, Arizona02 said:

 the timing cover needs to be on the head when milled avoid the step. To stop the leak  use RTV on the head where the valve cover gasket lays spreading it  back 2 inches or so before installing  valve cover & gasket. Just like filling in a dent  low spot when doing body work.

 Dist housing , you might need the one special seal that a bolt goes thru , same design as a crank seal seen in the parts diagram. On the pitted surface use a sealer before gasket install. I use the old style Permatex 80016 form a gasket, it is like a brown clay substance.

Hi,

 

I've tried these, no luck.  The PO had used what looked like the 80016 on the dizzy and it leaked too.  I haven't tried Hylomar as yet but it may not handle the pitting.

 

Thanks for the thoughts.

[Healey3000]

4 minutes ago, Stevenc22 said:

My head rebuild was under $500 for skiming, lapping and new guides. Seems like alot of work to save $500.

Hmm, that's pretty good.  Is that typical?

[irdave]

My machine shop bill was $1000- hot tank (clean) everything, block bore 2mm, deck block, deck head and timing cover, head valves all done at +1mm with valve job, install everything to do with the new valves (springs, seals, etc), bull nose the crank, polish everything, balance total reciprocating mass- all the work to rebuild a very sporty engine.  It's more affordable than you think.  Pulling and installing the cam is a little bit of a pain, but not really bad.  And then you can gasket match the intake and smooth out the casting marks.  :)  Plus top end gasket kit / head bolts for you.

[Healey3000]

4 minutes ago, irdave said:

My machine shop bill was $1000- hot tank (clean) everything, block bore 2mm, deck block, deck head and timing cover, head valves all done at +1mm with valve job, install everything to do with the new valves (springs, seals, etc), bull nose the crank, polish everything, balance total reciprocating mass- all the work to rebuild a very sporty engine.  It's more affordable than you think.  Pulling and installing the cam is a little bit of a pain, but not really bad.  And then you can gasket match the intake and smooth out the casting marks.  Plus top end gasket kit / head bolts for you.

Aaarghh!!  Slippery slope, slippery slope!  I feel the pull.

 

Must. Hold. On. Tight.

 

That is surprisingly well priced.

[TobyB]

That head looks like it is going to need more than just a refresh.

 

1 and 2 have been sharing a smoke, and 3 tried to join in at some point.

Maybe after it nibbled on some #1 compression ring...

 

It might be ok- but it shows signs of a head gasket failure between bores,

and possibly to the water jacket.  Which means it has a statistical chance of warpage.

The corrosion around the bolt holes looks historic- meaning, it's been off before.

And if the damage to #3's squish pad is deep, it'll be a detonation- starter...

 

As to your original question, sure, you can pop the head off a good motor, check the guides,

lap the valves for good luck, replace the stem seals, and clean the sealing surface.

I have even used abrasive paper on a surface plate to take off a high spot or two.

I've never polished a cam- I usually just keep the rockers with their lobes.

But cams and rockers are cheap, after a certain point...

 

t

 

Edited October 31, 2018 by TobyB

[irdave]

1 hour ago, Healey3000 said:

Aaarghh!!  Slippery slope, slippery slope!  I feel the pull.

 

Must. Hold. On. Tight.

 

That is surprisingly well priced.

 

Yeah, just trying to point out that the machine work can be more affordable than you think...  It's all the other crap (fancy valves, double valve springs, fancy this, fancy that) that gets you.  Just keep it simple- shouldn't be too terribly bad.

[Healey3000]

Toby,

 

You have quite the eye - thanks for the heads-up.  Seller did say it was removed for a head gasket replacement and never went back on.  It's not his, so it's difficult to get details.

 

A few questions:

• Why do you feel #3 was involved with #1 ring debris?
• Where did you spot the water jacket punch-through?
• What is a squish pad?
• If the total height of the head is greater then 128.5 mm, should I be concerned that it's been taken off once before?  Would the bolt hole corrosion matter?

Thanks!

[Stevenc22]

Yes $500 is a normal price for a head job. 

 

No need for new valves, just clean and lap.