[T3] vapor lock and spacers cont'd
sjbartnik at mac.com
Mon Apr 8 10:06:40 PDT 2019
I wish you had found this out before spending so much time installing an electric fuel pump!
> On Apr 8, 2019, at 12:56 PM, David Yaghoubian <goob at roadrunner.com> wrote:
> Wow, this goes back to 2005! (below). I am guessing my engine rebuilder, who
> will remain nameless, didn't reinstall the phenolic spacers, and this is why
> I have been chasing my tail ever since.
> Should I go ahead and order two of these? I measured the gap between the air
> cleaner and the top decklid and there is 1/2in, so accommodating these 3/8
> spacers will work.
> -----Original Message-----
> From: David Y <goob at adelphia.net>
> Sent: Thursday, November 17, 2005 10:57 PM
> To: type3 at vwtype3.org
> Subject: [T3] End of 1776 overheat saga and vapor lock Q. (long!)
> Hi All,
> Now for the vapor lock question (I've got dual dual Solex H32/34 PDS13 with
> stock brazilian air cleaner setup, recently rebuilt and rebushed, balanced
> and running perfectly): twice now when I've had the engine at full
> operating temp, parked it for 15-20 min, then returned to drive it, I have
> only been able to drive about a block before the engine dies (clearly a
> fuel starvation sputter as it chokes). The first time this happened last
> week, I could see that no fuel was present in the in-line filter, and in
> pulling off the line to one of the carbs confirmed that nothing was getting
> through. I could turn the engine over and over, pump the gas a gazillion
> times, and get nothing. I tried removing and replacing the hose from each
> connector at the carbs and pump, and then making sure that all of the hose
> clamps were tight.. Still the engine wouldn't start. Then, after about 20
> min, I could see some fuel returning to the in-line filter, and the engine
> finally started up, and ran perfectly. Assuming that this was not a problem
> with the fuel pump--which to my knowledge either works or doesn't-- I
> surmised that the fuel lines were getting too hot somewhere, and adjusted
> the length of all the hoses so they weren't directly touching a heat source
> (such as the block, or shrouds/sheet metal) and in the one spot where there
> is still contact (the back edge of the sheet metal covering the stock oil
> cooler) I put a larger diameter hose piece around the fuel line to serve as
> a buffer. All was well until today, when the exact same thing/condition
> occurred! Aside from that single spot of contact with the sheet metal
> covering the stock oil cooler, there is no other contact between the fuel
> lines and heat source(s). I turned the engine over again and again, messed
> with all the hoses (removed/reattached/tightened clamps) to no avail...
> after about 20-25 min, at which point the fuel started flowing again, and
> the engine ran like nothing had happened all the way home.
> SO, my questions are
> 1) Am I correct to diagnose this as classic vapor lock? I ruled out the
> fuel pump because it otherwise works perfectly. Correct assumptions?
> 2) How could this happen again after readjusting all of the hoses in
> relation to heat sources?
> 3) Why would this happen even if the lines did touch the block/sheet metal
> directly? On my old motor, the hoses from the pump to the T-splitter and
> then to the carbs virtually laid right on the block, and I'm quite sure the
> in-line filter and/or hose between the pump and filter touched the sheet
> metal above the oil cooler directly, without the extra hose to buffer.
> Plus, in the last year of that motor's life, I got the engine up to
> 280-300F every DAY on my short commute before shutting it off, and still
> never had a vapor lock issue... again, with the hoses touching heat sources
> all over the place.
> 4) Does cloth braided hose stay cooler in the engine compartment than
> non-covered fuel line? The hoses from the pump to the T and then to the
> carbs are cloth braided, but the hose bringing the fuel to the pump (on
> both sides of the in-line filter) is the larger-diameter
> non-braided/covered hose. This is the one that comes closest to the heat
> source at the back of the cooler, and that I have buffered with the
> larger-diameter hose piece. Could this be a/the culprit?
> 5) If this is vapor lock, does anybody know any quick tricks to release the
> pressure/vapor and get moving again without the requisite 20-30 min wait?
> Needless to say, this has temporarily suspended my T3 Nirvana... TIA for
> any advise!!
> David Y.
> 68 Sqbk
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