Date: Tue, 21 Aug 2007 11:45:58 -0400
Reply-To: Jim Akiba <syncrolist@BOSTIG.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Jim Akiba <syncrolist@BOSTIG.COM>
Subject: Re: Re-sealing a cylinder head? Sure, why not?
In-Reply-To: <001001c7e3b4$4bd64320$7eb2d8d1@dhanson>
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Plenty of people do it and will have no discernible difference over a
factory sealed long block. But for many this will not be the case. Ask any
old mechanic or tech, and you'll hear the same sentiment. Now as to why that
happens, plenty of reasons from simple things like dirt, grease, to things
like the head has warped in place, removed not squared, and reinstalled.
Poorly lubed head bolts, a bad torque wrench, crap head gasket, anything..
not to mention you can't tighten all of the head bolts simultaneously like a
robot(or maybe you can? sweet). Lower reliability of a longblock once
opened is a common understanding, this is not just my opinion but that of
most people in the repair mainstream and aftermarket. In my experience
you're looking at maybe 4 out of 10 will have a problem, of course I do this
entirely by "feel" in terms of problem rate, but it's quite high. And 2 of
those 4 will have multiple problems(that reflects more on the person doing
it). That's great if you're not one of them, but there is no guarantee that
you aren't one of those people already and just don't know it quite yet. The
best thing you can do is manage the risk, and not unsealing the longblock is
a far better way to do that than unsealing it. Yeah modifying the body
isn't great, but if you're just talking about the deck lid which is easy,
it's debatable which is more work, modding the deck-lid so it'll fit, or
swapping a head. Given the chances of success and chances of introduced
problems with each operation, I'd advise most people do the deck-lid mod
less chance of problems. If you do the head swap, then when you want to
freshen the engine you'll have to do it again, and open yourself up to the
same risk... again. Whereas the deck-lid mod is done, and won't cause a
showstopper of a problem even if you do a poor job. Am I making any sense to
you Don? I think this is a really important point that many people ignore
and eventually find out the hard way. It isn't say "don't do it", but if
you're not aware of what can happen in such a project, and don't understand
fully what risks you are undertaking and what cans of worms are being
opened, then the safest advice for anyone is going to be avoid it if at all
possible. Especially if there can be a scenario where down the road you'll
benefit again from the single choice you made back when.
We've all seen the pics of the mid-mounted twin turbo v8 haven't we? That's
a trip.. but I don't think benny is the type to get excited about an LT1..
I'm definitely not ha. You can get the same power and torque out of
something that weighs half or less of what the LT-1 does... although
smallblock v8s do sound really sweet. My 5.0L pushrod v8 can just barely
outperform a turbo direct injected 2 liter 4 cylinder.. but didn't even come
close in it's factory configuration, which the GDI turbo motor is. The GDI
turbo motor weighs under 300, my v8 is just about 600 dressed.
Jim Akiba
On 8/21/07, Don Hanson <dhanson@gorge.net> wrote:
>
> I dunno, Jim, about your statement that you will never get as good a seal
> as
> comes from the factory if you remove and replace a head..Maybe on the WBX
> motor, that might be so, but the inline four..why not? If they can do it
> once at the factory and it lasts for years and years, why can't it be
> properly done a second time?
> I thought, when I did mine, that it was dead-nuts simple! I used every
> assembly trick known to the auto industry(I hope) and it went right
> together
> in about an hour, motor in the van..Well, I half-torqued all the new head
> bolts in sequence and let them sit overnight and then re-torqued em half
> way
> again, then once more around to final specs..A very simple little motor
> and
> quite robust, with a good quality new gasket and clean surfaces..I guess I
> can get a good seal if I use due diligence..We shall see if it lasts
> another
> 25 years till the next fool overheats it...
> Putting a motor into a van and then modifying the body to fit the
> motor..that seems a bit odd..If you have to 're-create' the interior of
> the
> van, why not use something really cool to power it then, like maybe a 944
> Porsche Turbo motor, or a Valiant slant-six? Grin...How bout a LT1 Chevy
> V8?
> That would get Benny Boy excited...There is a company that sells kits to
> do
> that for the 914/911/944 Porsche cars, the V8 Chevy kit..
> Don Hanson
>
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