Head gasket now!!?

FiatFunk said:
But I don't think this would explain how the head gasket is more crushed in the back edge.
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A couple more ideas:

Did you clean out the head bolt holes prior to installing the bolts? If there is crud in the bottom on the holes, you can lose a bit of depth.

or

Did you measure the old vs new bolts for length?
 
A quality 24" machinist's straightedge is over $200 with tax and shipping. In my neck of the woods, that's not too much different from the price for a good local machine shop to professionally resurface the cylinder head.
 
JimD said:
A couple more ideas:

Did you clean out the head bolt holes prior to installing the bolts? If there is crud in the bottom on the holes, you can lose a bit of depth.

or

Did you measure the old vs new bolts for length?
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Yes I cleaned them out very well, tapped them, brushes them, brake cleaner, compressed air. The bolts have only 21mm below the head and there is 33mm if depth into the block.
I looked it up, it's this set of M12x1.25 bolts from Midwest. They call them straight torque bolts, 10.9 grade.
 
bruinbro said:
Unfortunately I believe there is no way to discern which type of bolt you have by visual inspection.
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It was this from Midwest, M12, they call them straight torque bolts. Not as long as the originals but they say they are good
 

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Dan Sarandrea (Phila) said:
A quality 24" machinist's straightedge is over $200 with tax and shipping. In my neck of the woods, that's not too much different from the price for a good local machine shop to professionally resurface the cylinder head.
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Yes, but the shops here are so frikkin slow. I'll check it out with what I have, I mean it was just redone and should be fine
 
Stuff to check..

~Head gasket hollow dowel alignment tube length. Measure the shoulder depth on the cylinder head and block, then verify the dowel tubes are shorter/less than the total length/depth of the pockets in the block and cylinder head. If the dowel tubes are too long they will prevent proper seating of the cylinder head/gasket to the block.

~Clean/chase the M12x1.25 internally threaded holes in the block using machine tool quality sprial/straight flute bottoming tap

KBC,12.0X1.25 METRIC BOTTOM TAP,1-373-070B,KBC Tools & Machinery

KBC,12.0X1.25 METRIC BOTTOM TAP,1-373-070B,KBC Tools & Machinery
www.kbctools.com www.kbctools.com

to assure the threaded holes are clean and in good condition.

~Measure the length of the M12x1.25 cylinder head "bolt" (technically a screw) including the M12 washer under the bolt heads from the end of the bolt to the surface of the cylinder head gasket.
Measure the depth of the internally threaded M12 hole on the block. There is a possibility the bolt threads are bottoming out on the internally threaded holes in the block.

~Flatness of the block & cylinder head should be checked..

~~ Based on the pattern left over after from the head gasket was the cylinder head was removed, it appears there is un-even clamping of the cylinder head/gasket to the block..


Bernice
 
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The bolts you pictured are not TTY, but regular "torque" type. I do not think you did anything wrong with regards to torquing. Over the years I have seen countless head gasket problems reported on this forum. Most of them have no logical explanation for why they failed - everything was done correctly. So it is just difficult to get a good seal with regular gaskets on these engines. That's why I use MLS ones.

I hear you about machine shops taking forever to do anything. And worse yet, all of the ones in my area do poor work and are untrustworthy. I've resorted to doing all of my own machine work, and I don't have a full machine shop! Plus here they charge more than that to resurface a head. Furthermore, if you buy a straight edge then you can check other things beyond the head. The block deck is very unlikely to be out of spec but with a edge you can verify it. Same with both manifold surfaces, crankshaft seal mount plates, cam box, etc, etc. So I'd be inclined to buy a straight edge. Maybe there's a more affordable option that is accurate enough?? I get that this one (link below) isn't a state of the art "machinists" straight edge, but within .003" will tell you if something is wrong. At least enough to decide if it warrants a trip to the machine shop:
I literally spent a couple of seconds on Google to find that, so shop around - maybe there's an even better option. I have been to machine shops and saw them use much worse that this for all of their measurements! Shocking what a lot of machinists consider "good enough". Typically a lack of education or proper training behind them.

Double check the dowel depth into the block and head to confirm that isn't an issue. Otherwise the T-stat gasket was your main issue this time. But those pics of the head gasket surfaces after head removal do not look great. So it is worth verifying everything.
 
Rupunzell said:
Stuff to check..

~Head gasket hollow dowel alignment tube length. Measure the shoulder depth on the cylinder head and block, then verify the dowel tubes are shorter/less than the total length/depth of the pockets in the block and cylinder head. If the dowel tubes are too long they will prevent proper seating of the cylinder head/gasket to the block.

~Clean/chase the M12x1.25 internally threaded holes in the block using machine tool quality sprial/straight flute bottoming tap

KBC,12.0X1.25 METRIC BOTTOM TAP,1-373-070B,KBC Tools & Machinery

KBC,12.0X1.25 METRIC BOTTOM TAP,1-373-070B,KBC Tools & Machinery
www.kbctools.com www.kbctools.com

to assure the threaded holes are clean and in good condition.

~Measure the length of the M12x1.25 cylinder head "bolt" (technically a screw) including the M12 washer under the bolt heads from the end of the bolt to the surface of the cylinder head gasket.
Measure the depth of the internally threaded M12 hole on the block. There is a possibility the bolt threads are bottoming out on the internally threaded holes in the block.

~Flatness of the block & cylinder head should be checked..

~~ Based on the pattern left over after from the head gasket was the cylinder head was removed, it appears there is un-even clamping of the cylinder head/gasket to the block..


Bernice
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Yes I did all that, only thing left is to check block and head for flat.
Thanks
 
FiatFunk said:
Also a photo of the t housing and gasket, clearly the wrong one. I really do have to be more thorough when building an engine.
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For extra assurance, I'd recommend running a tap in that small hole in the thermostat housing mounting area of the cylinder head & installing a threaded plug, in addition to using the proper (other style) gasket. Like this:

https://xwebforums.com/forum/index....igs-list-in-oregon-for-625.34131/#post-290556

strada1500head08.jpg


This is similar to the mod of plugging the 2 small coolant ports on the side of the cylinder head that would normally supply coolant to the intake manifold.
 
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From what I understand, to get the proper finish for an MLS gasket you need specialized tooling. I've heard shops using CBN instead of carbide. I would guess that if a shop isn't doing lots of engines that require that finish they may not have the tooling or appreciate the requirements. And if they're not doing a lot of that kind of work they also likely don't have a profilometer to actually verify the surface finish is right. In the last year or so I've seen several of the YouTube engine machinists talk about getting profilometers to verify their work, so I would argue having one isn't pervasive in shops at this point. I hope it doesn't feel like I'm trying to rag on you. Sorry to see the trouble with your engine. But I don't think a MLS job is one where "it should be fine" is correct.
 
jimmyx said:
Machine shops tend to overestimate their abilities at times. I've found that very few can replicate the almost mirror finish an MLS gasket requires. It's hard to illustrate, but if you can see the results of the cutting operation, it's too rough for an MLS gasket.

View attachment 84345

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Thanks for the photos and description. I'll take another close look at the head and block and call the shop.
Just yesterday I got a block back for my 124 spider, from a slightly questionable shop, they say it's fine enough for an MLS but I can see the texture and I'm not sure if they have a profilometer. I know you can get thin non MLS gaskets and this might be a safer way to go.
 
Kendall said:
From what I understand, to get the proper finish for an MLS gasket you need specialized tooling. I've heard shops using CBN instead of carbide. I would guess that if a shop isn't doing lots of engines that require that finish they may not have the tooling or appreciate the requirements. And if they're not doing a lot of that kind of work they also likely don't have a profilometer to actually verify the surface finish is right. In the last year or so I've seen several of the YouTube engine machinists talk about getting profilometers to verify their work, so I would argue having one isn't pervasive in shops at this point. I hope it doesn't feel like I'm trying to rag on you. Sorry to see the trouble with your engine. But I don't think a MLS job is one where "it should be fine" is correct.
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I don't take it like you're trying to rag on me at all, thanks for the input, it makes sense. I'm learning from everyone here and from my own failures, tho I want to keep those to a minimum! If it fails I will be the one rebuilding it, not the machine shop, and I do not want to do that again for awhile.
 
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