Re: Paper or Plastic? (valve guides) and Cooling flush before teardown

[C2slayman@domain.elided]

Hi Jon,
> Date: Tue, 24 Sep 2002 01:45:27 -0700
> From: Jon Pike <jhpike@domain.elided>
> Subject: Paper or plastic?  (valve guides)
> 
> I've been wondering the relative merits of different valve guide 
> materiels,  i.e. the silicon-aluminum bronze that Sperry uses in their 
> rebuilt heads,  vs the manganese bronze that IAP and others use.

I don't think it matters.  The quality of the valve stem seals are more 
important.  But I can't comment on the different valve stem seal 
manufacturers.  I've heard teflon is the best.
> 
> Of course this leads to other comparisons,  of differing places doing 
> your head work..  and I know that the Digest discourages such direct 
> comparison.  So if anyone had some "input" about it,  letting me know 
> off Digest would be appriciated.

I highly recommend Sperry Valve works.  They are honest and do good work.  
But if you have a local head shop that has done a ton of Alfa heads, take it 
to them.  Just remember a good head shop is not necessarily a good Alfa head 
shop.

> Hmmm..  as for some more on topic, in Digest fodder..  how about sodium 
> cooled exhaust valves as opposed to the newer (assumably better heat 
> transferring?) alloy ones?  And how do you know the ones in a catalog 
> are sodium cooled,  if they don't say so?  Price??  I've seen $13 and 
> $40 exh valves..  that might be a clue?

 Well, when I was a teenager, I thought the sodium-filled Alfa exhaust valves 
were trick.  Since I've burned two of them on my '89 Spider, I think it's a 
case of "Too soon old, too late smart."  Sperry replaced the stock sodium 
filled jobs with newer technology valves.  I vote for newer technology 
material now.

> Prepping myself (hopefully) for my head work,  and what to do if they 
> say "ya need a few valves"..
> 
> Jon
> 77 Spider,  engine to be rebuilt
> 
> ------------------------------
> 
> Date: Tue, 24 Sep 2002 01:57:17 -0700
> From: Jon Pike <jhpike@domain.elided>
> Subject: Coolant flushing before teardown..
> 
> Digestians..
> 
> Another dark thought has cropped up,  I was wondering how big a deal not 
> flushing, descaling, cleaning, etc,  the coolant circuit of an engine 
> is,  when you are going to tear it down?  
> 
Not a big deal, but certainly a good idea to clean the cooling system before 
the teardown.  If not, you can do it after reassembly.

> I didn't do that when I got the car..  and with the lack of maintenence 
> I've been seeing,  knowing the car was virtually in storage a few years 
> in the recent past..  I'm wondering just how much silt, or mineral 
> deposits might be in there to mess with my rebuild.
> 

I've found oil/water gunk from a blown head gasket to be more insideous than 
the normal corrosion.

> Or,  do I worry too much?

Yes.

> At least now,  the car's coolant looks a normal color..  so perhaps it's 
> not been running on straight tap water the last 14 years.
> 
> The "issue" is,  I have the oil out,  lower sump off,  alternator off, 
> etc..  and it would be a bit of work to put it back to running,  just 
> to do a hot flush..
> 

Do a hot flush when things are buttoned back up and you have retorqued the 
head for a second time.

> While I'm asking..  what is a good, safe descaler/cleaner for an 
> aluminum motor,  and the best way to use it?  My Autobook manual says 10 
> oz of baking soda in 1 3/4 gal of water,  and run the engine for 10-15 
> minutes..  

Yes, that's good.  Or you can try a little TSP (or Cascade Dishwasher 
Detergent or Sugar Soap for our Alfisti down under).  But be careful with the 
TSP and keep the time under 5min.  It tends to swell rubber parts.  I prefer 
the baking soda.  It's safer.

> Thanks again..
> 
> Jon
> 
Cheers,
Charlie

PS  Use viton o-rings and brass pin kit when reassembling the head.
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