Re: 91 civic - tough question about cooling
 

I'm solidly with the "smooth surface" view on this, but the question as it
relates to this thread is whether the head gasket is leaking or not. I
suspect not, but the OP really needs to check it out.

Mike

Re: 91 civic - tough question about cooling
 

Michael Pardee wrote:
> I'm solidly with the "smooth surface" view on this, but the question as it
> relates to this thread is whether the head gasket is leaking or not. I
> suspect not, but the OP really needs to check it out.
>
> Mike
>
>
yeah, if the head was done right, it's not the gasket, or at least, not
this quickly. more likely it's a crack. that's pretty unusual for a
honda, especially this vintage when their q.c. was really at its peak.

Re: 91 civic - tough question about cooling
 

Michael Pardee wrote:
> I'm solidly with the "smooth surface" view on this, but the question as it
> relates to this thread is whether the head gasket is leaking or not. I
> suspect not, but the OP really needs to check it out.
>
> Mike
>
>
yeah, if the head was done right, it's not the gasket, or at least, not
this quickly. more likely it's a crack. that's pretty unusual for a
honda, especially this vintage when their q.c. was really at its peak.

Re: 91 civic - tough question about cooling
 

Michael Pardee wrote:
> I'm solidly with the "smooth surface" view on this, but the question as it
> relates to this thread is whether the head gasket is leaking or not. I
> suspect not, but the OP really needs to check it out.
>
> Mike
>
>
yeah, if the head was done right, it's not the gasket, or at least, not
this quickly. more likely it's a crack. that's pretty unusual for a
honda, especially this vintage when their q.c. was really at its peak.

Re: 91 civic - tough question about cooling
 

"Michael Pardee" <michaeltnull@cybertrails.com> wrote

> I'm solidly with the "smooth surface" view on this, but the question as it
> relates to this thread is whether the head gasket is leaking or not. I
> suspect not, but the OP really needs to check it out.

The extreme smooth surface may not provide enough bite to hold the
gasket securely. Too rough can also be hard on the gasket itself or even
won't seal properly and the head gasket will leak. One way to judge
surface finishes is with a comparator gauge and follow the manufacturer's
surface requirements.

Laminated steel or rubber coated type of head gasket would require
an almost polished surface finish. But most older milling and grinding
equipment have spindle and bearings in weren't designed to meet these
requirements.

Re: 91 civic - tough question about cooling
 

"Michael Pardee" <michaeltnull@cybertrails.com> wrote

> I'm solidly with the "smooth surface" view on this, but the question as it
> relates to this thread is whether the head gasket is leaking or not. I
> suspect not, but the OP really needs to check it out.

The extreme smooth surface may not provide enough bite to hold the
gasket securely. Too rough can also be hard on the gasket itself or even
won't seal properly and the head gasket will leak. One way to judge
surface finishes is with a comparator gauge and follow the manufacturer's
surface requirements.

Laminated steel or rubber coated type of head gasket would require
an almost polished surface finish. But most older milling and grinding
equipment have spindle and bearings in weren't designed to meet these
requirements.

Re: 91 civic - tough question about cooling
 

"jim beam" <nospam@example.net> wrote

>original surface on these things is near mirror. that way, there's no
>small grooves for gas to leak along. if the head was machined on a
>traditional milling machine, particularly this alloy head, it's /very/
>hard to do without leaving scoring marks in it. last time i had to lap
>a head was to cut out the grooves from a bad machining job where the
>cutting die was picking up excess material on each pass of an exterior
>edge, then dragging that chunk across the rest of the head leaving gouge
>marks.

Try using a single-blade cutter, instead of the two-bladed cutter. This
is slower but yields a cleaner cut.

If they're caused by deposits, try removing the hard calcium deposits around
the water jacket openings. The deposits can be picked up by the tooling
and drug across the surface leaving a groove.

Re: 91 civic - tough question about cooling
 

"jim beam" <nospam@example.net> wrote

>original surface on these things is near mirror. that way, there's no
>small grooves for gas to leak along. if the head was machined on a
>traditional milling machine, particularly this alloy head, it's /very/
>hard to do without leaving scoring marks in it. last time i had to lap
>a head was to cut out the grooves from a bad machining job where the
>cutting die was picking up excess material on each pass of an exterior
>edge, then dragging that chunk across the rest of the head leaving gouge
>marks.

Try using a single-blade cutter, instead of the two-bladed cutter. This
is slower but yields a cleaner cut.

If they're caused by deposits, try removing the hard calcium deposits around
the water jacket openings. The deposits can be picked up by the tooling
and drug across the surface leaving a groove.

Re: 91 civic - tough question about cooling
 

"Michael Pardee" <michaeltnull@cybertrails.com> wrote

> I'm solidly with the "smooth surface" view on this, but the question as it
> relates to this thread is whether the head gasket is leaking or not. I
> suspect not, but the OP really needs to check it out.

The extreme smooth surface may not provide enough bite to hold the
gasket securely. Too rough can also be hard on the gasket itself or even
won't seal properly and the head gasket will leak. One way to judge
surface finishes is with a comparator gauge and follow the manufacturer's
surface requirements.

Laminated steel or rubber coated type of head gasket would require
an almost polished surface finish. But most older milling and grinding
equipment have spindle and bearings in weren't designed to meet these
requirements.

Re: 91 civic - tough question about cooling
 

"jim beam" <nospam@example.net> wrote

>original surface on these things is near mirror. that way, there's no
>small grooves for gas to leak along. if the head was machined on a
>traditional milling machine, particularly this alloy head, it's /very/
>hard to do without leaving scoring marks in it. last time i had to lap
>a head was to cut out the grooves from a bad machining job where the
>cutting die was picking up excess material on each pass of an exterior
>edge, then dragging that chunk across the rest of the head leaving gouge
>marks.

Try using a single-blade cutter, instead of the two-bladed cutter. This
is slower but yields a cleaner cut.

If they're caused by deposits, try removing the hard calcium deposits around
the water jacket openings. The deposits can be picked up by the tooling
and drug across the surface leaving a groove.

Re: 91 civic - tough question about cooling
 

Burt wrote:
> "Michael Pardee" <michaeltnull@cybertrails.com> wrote
>
>
>>I'm solidly with the "smooth surface" view on this, but the question as it
>>relates to this thread is whether the head gasket is leaking or not. I
>>suspect not, but the OP really needs to check it out.
>
>
> The extreme smooth surface may not provide enough bite to hold the
> gasket securely.

ok, question: where do you get this information? both you and jim
clearly heard it from somewhere. what's the source?

there is no lateral load. no "bite" is required.

> Too rough can also be hard on the gasket itself or even
> won't seal properly and the head gasket will leak.

precisely. think about it logically: big grooves leak a lot. small
ones leak less. a smooth surface leaks not at all. make sense???

> One way to judge
> surface finishes is with a comparator gauge and follow the manufacturer's
> surface requirements.

and with a honda, that's a near-mirror finish!

>
> Laminated steel or rubber coated type of head gasket would require
> an almost polished surface finish. But most older milling and grinding
> equipment have spindle and bearings in weren't designed to meet these
> requirements.

no joking. that's one of the reasons why machining honda heads is such
a hit and miss operation.

Re: 91 civic - tough question about cooling
 

Burt wrote:
> "Michael Pardee" <michaeltnull@cybertrails.com> wrote
>
>
>>I'm solidly with the "smooth surface" view on this, but the question as it
>>relates to this thread is whether the head gasket is leaking or not. I
>>suspect not, but the OP really needs to check it out.
>
>
> The extreme smooth surface may not provide enough bite to hold the
> gasket securely.

ok, question: where do you get this information? both you and jim
clearly heard it from somewhere. what's the source?

there is no lateral load. no "bite" is required.

> Too rough can also be hard on the gasket itself or even
> won't seal properly and the head gasket will leak.

precisely. think about it logically: big grooves leak a lot. small
ones leak less. a smooth surface leaks not at all. make sense???

> One way to judge
> surface finishes is with a comparator gauge and follow the manufacturer's
> surface requirements.

and with a honda, that's a near-mirror finish!

>
> Laminated steel or rubber coated type of head gasket would require
> an almost polished surface finish. But most older milling and grinding
> equipment have spindle and bearings in weren't designed to meet these
> requirements.

no joking. that's one of the reasons why machining honda heads is such
a hit and miss operation.

Re: 91 civic - tough question about cooling
 

Burt wrote:
> "Michael Pardee" <michaeltnull@cybertrails.com> wrote
>
>
>>I'm solidly with the "smooth surface" view on this, but the question as it
>>relates to this thread is whether the head gasket is leaking or not. I
>>suspect not, but the OP really needs to check it out.
>
>
> The extreme smooth surface may not provide enough bite to hold the
> gasket securely.

ok, question: where do you get this information? both you and jim
clearly heard it from somewhere. what's the source?

there is no lateral load. no "bite" is required.

> Too rough can also be hard on the gasket itself or even
> won't seal properly and the head gasket will leak.

precisely. think about it logically: big grooves leak a lot. small
ones leak less. a smooth surface leaks not at all. make sense???

> One way to judge
> surface finishes is with a comparator gauge and follow the manufacturer's
> surface requirements.

and with a honda, that's a near-mirror finish!

>
> Laminated steel or rubber coated type of head gasket would require
> an almost polished surface finish. But most older milling and grinding
> equipment have spindle and bearings in weren't designed to meet these
> requirements.

no joking. that's one of the reasons why machining honda heads is such
a hit and miss operation.

Re: 91 civic - tough question about cooling
 

Burt wrote:
> "jim beam" <nospam@example.net> wrote
>
>
>>original surface on these things is near mirror. that way, there's no
>>small grooves for gas to leak along. if the head was machined on a
>>traditional milling machine, particularly this alloy head, it's /very/
>>hard to do without leaving scoring marks in it. last time i had to lap
>>a head was to cut out the grooves from a bad machining job where the
>>cutting die was picking up excess material on each pass of an exterior
>>edge, then dragging that chunk across the rest of the head leaving gouge
>>marks.
>
>
> Try using a single-blade cutter, instead of the two-bladed cutter. This
> is slower but yields a cleaner cut.
>
> If they're caused by deposits, try removing the hard calcium deposits around
> the water jacket openings. The deposits can be picked up by the tooling
> and drug across the surface leaving a groove.

it shouldn't be machined at all [or at least, not with "traditional"
gear] for the reasons stated. it just needs to be lapped on a properly
flat rigid bed.

Re: 91 civic - tough question about cooling
 

Burt wrote:
> "jim beam" <nospam@example.net> wrote
>
>
>>original surface on these things is near mirror. that way, there's no
>>small grooves for gas to leak along. if the head was machined on a
>>traditional milling machine, particularly this alloy head, it's /very/
>>hard to do without leaving scoring marks in it. last time i had to lap
>>a head was to cut out the grooves from a bad machining job where the
>>cutting die was picking up excess material on each pass of an exterior
>>edge, then dragging that chunk across the rest of the head leaving gouge
>>marks.
>
>
> Try using a single-blade cutter, instead of the two-bladed cutter. This
> is slower but yields a cleaner cut.
>
> If they're caused by deposits, try removing the hard calcium deposits around
> the water jacket openings. The deposits can be picked up by the tooling
> and drug across the surface leaving a groove.

it shouldn't be machined at all [or at least, not with "traditional"
gear] for the reasons stated. it just needs to be lapped on a properly
flat rigid bed.