Is it tough to reseal a cylinder head?

tallqball · Post by **tallqball** » Fri Jul 14, 2006 7:18 am

I have a buddy that runs a flow lab. He is flowing a set of 46x36 2.0l 914 heads that I will likely sell. They flowed 211 cfm at .55 lift at 28" depression with the intake manifold!

Now that the fixtures are all figured out, thought I'd have him flow the heads on the engine I bought from Ephry.

I know E said it is ready to run, and I believe that, but I'm a tinkerer at heart.

Is it a big deal to reseal the heads after 2,000 miles of run time?

It has HD Type 1 single springs and stock retainers, should these be changed out? It also has stock adjusters with hydraulic spacers, and I do have a set of new 911 swivel feet.

They are 2.0l Porsche heads, 12mm plugs, 48x38 valves. Thanks!

Ephry73 · Post by **Ephry73** » Fri Jul 14, 2006 7:42 am

If you must, then you can always clean the mating surfaces between the cylinder top and the head. Then lap them in place. If you do this, and floow the torque sequences when bolting the heads again, you will be ok.

I have used copper gasket sealer, as per Jake's recommendation, with good results. I didn't take the heads off the engine, and it's not needed, but it will be sweet to know how much those heads flow.

E

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Fri Jul 14, 2006 7:58 am

Be more concerned with where the flow is made and also the exhaust port flow and it's margin to the intake.

Flow alone does not make power, it can make for a useless power band, but "its all in the combo".

tallqball · Post by **tallqball** » Fri Jul 14, 2006 8:06 am

Jake, if you're interested, I'll send you the flow data when complete. The intake flow curve on the first heads is similar to your LE200.

The exhaust needs to be rerun. I tried using a cobbled header, and it was too small at the port, and had some nasties. So it needs to be rerun with some A-1 stub pipes.

Q

Riff131 · Post by **Riff131** » Sat Jul 15, 2006 9:14 pm

I'd like to see some data here. There are too many statements made about info that have no backing. Maybe an excell spreadsheet with some #'s on different engine combos.
What do you think?

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Sat Jul 15, 2006 9:22 pm

Riff131 wrote:I'd like to see some data here. There are too many statements made about info that have no backing. Maybe an excell spreadsheet with some #'s on different engine combos.
What do you think?

I have about 1600 pages of them already. I take this very seriously and not only try out everything I can think of, but also document all of it- thats the difference.

Post by **Piledriver** » Mon Jul 17, 2006 9:12 pm

tallqball wrote: .....Is it a big deal to reseal the heads after 2,000 miles of run time?

It has HD Type 1 single springs and stock retainers, should these be changed out? It also has stock adjusters with hydraulic spacers, and I do have a set of new 911 swivel feet.

They are 2.0l Porsche heads, 12mm plugs, 48x38 valves. Thanks!

No Big deal, as long as the heads weren't loose and dork up the sealing surface.

Jake recommends CrMo retainers and ground keepers, and the solid spacer set he sells for $24 is a bargain. Also the 8mm rocker studs/nuts etc.. All cheap insurance, replaces a lot of bits that sucked from the factory.

Who did the heads, Ephry?

Ephry73 · Post by **Ephry73** » Tue Jul 18, 2006 6:27 am

The heads were done by Adrian at HFM. Good points here on head resealing.

E

Post by **Piledriver** » Tue Jul 18, 2006 9:05 am

Ephry73 wrote:The heads were done by Adrian at HFM. Good points here on head resealing.

E

No worries then, but if the keepers/retainers are really the stock bits, replace them.

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Tue Jul 18, 2006 9:25 am

but if the keepers/retainers are really the stock bits, replace them.

ABSOLUTELY!

with that cam I acn't believe that the retainers haven't failed yet!

tallqball · Post by **tallqball** » Wed Jul 19, 2006 9:23 am

Ok, so it makes sense to upgrade the valvetrain hardware. Is the HD Type 1 springs adequate, or should these but upgraded too?

My concern is the auto-x, where the rpms will be up and I'll be looking at the cones....

tallqball · Post by **tallqball** » Wed Jul 19, 2006 9:25 am

I should have mentioned the stock german lifters. If the spring pressure goes up, am I asking for trouble?

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Wed Jul 19, 2006 9:26 am

That cam requires duals IMHO, I very seldom ever run a single with that cam, the ramps are pretty fast, especially on the exhaust.

tallqball · Post by **tallqball** » Wed Jul 19, 2006 10:42 am

Jake, thanks for answering on the springs.

So the lifters will be ok with the dual springs?

Q

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Wed Jul 19, 2006 11:21 am

If the lifters were not OK, it would have already failed. In my tests dual springs didn't cause any more wear than singles...

Note that dual springs require the spring bosses to be cut for installation.

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Is it tough to reseal a cylinder head?

Is it tough to reseal a cylinder head?

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