At 7:18 AM -0700 5/26/03, Kendel McCarley wrote:
>Thanks, Gerard.
>
>Okay, I can add some more information then.
>
>All the original smog equipment is in place. I did replace the gulp
>valve to stop the thing from going vrooooom, BANG as I accelerated
>and made a shift.
Is there a PCV valve on the intake manifold between the carbs? It
looks like a big round disk a couple inches in diameter. Don't take
it apart as I've heard they will never work right afterwards. I've
never opened one so I can't advise you on how to clean pr refurbish
them.
>
>I checked airflow at the oil filler cap on top of the valve cover
>and I am pulling a vacumn there, not blowing out air.
That's good. You should still check to see where and how much oil drips below.
>
>I probably have what I need to do a leakdown test but don't know how
>to do it. I have a compressor and this particular gauge set
>(http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=39224).
That's just a compression gauge. A leak down kit has two gauges. See this link.
http://www.geocities.com/dsmgrrrl/FAQs/leakdown.htm
The only thing I don't see in the explanation is that you should get
the engine to operating temperature before beginning the process. You
should also check the cooling system to see if any air is escaping
via the head gasket.
Gerard
>
>
>- Kendel
>
>ps - Kate, coyotes keep the cat population down here in the desert,
>so I have no need of firearms.
>
>
>gerard wrote:
>
>>Hi Kendel,
>>
>>Lots of possibilities here.
>>
>>First, since you mention the dipstick guide is broken, I would make
>>sure you don't have blow-by pumping oil oil that hole. I have seen
>>one engine that was in otherwise good shape do that. You don't say
>>of the original smog equipment is in place so there are some
>>variables there as well, particularly the PCV valve. You need one
>>in place that works. These engines develop a lot of internal
>>pressure especially if the rings are bad, and the oil will find
>>it's way out wherever it can, especially through the rear seal. The
>>best way to determine if you have a valve or ring problem is a
>>leak-down test. If you aren't familiar, that requires a special set
>>of gauges and some compressed air. My experience with rebuilding
>>these engines is that the rings seize up or break when they have
>>sat for a long time. Also, the ring lands widen further
>>complicating the problem. I would run the engine until warm and
>>then park it and observe where the oil drips.
>>
>>Balancing and adjustimg the carbs is a lengthy description, but
>>basically, you want to start 12 flats down (2 full turns) from full
>>up position and turn them up equally until a slight manual raise of
>>each piston does not cause the idle to go up or down. Make sure the
>>jets return freely to their rest positions and that the choke cable
>>is not holding them open. Other issues common on that old a pair of
>>SUs, is that the throttle shafts wear causing air to leak.
>>Incorrect float levels will also cause rich mixtures. There are
>>several other factors in balancing and adjusting. If you plan to do
>>much work on the car, get a Bentley Publsher's workshop or a Haynes
>>manual.
>>
>>Obviously, incorrect valve adjustment is a problem too. Get a
>>remote starter switch to bump the engine over... or... If you take
>>out the plugs, you should be able to easily turn the engine by hand
>>or by putting the car in gear and rocking the car back and forth.
>>If you don't have a position guide handy, the two numbers should
>>add up to nine, i.e. adjust 1 with 8 fully open, 3 with 6 fully
>>open, etc.
>>
>>This should keep you busy for a while.
>>
>>Gerard
>>
>>At 11:09 PM -0700 5/25/03, Kendel McCarley wrote:
>>
>>>Hi, all.
>>>
>>>I'm a new subscriber to the list with an immediate problem. I've had a
>>>couple of Midgets follow me home in the last few months and I'm trying
>>>to get one ready for a trip (a father/daughter thing where I'm going to
>>>deliver the car to my dad... er, her granddad). This little '72 is
>>>absolutely gorgeous, but isn't running so well. It was probably running
>>>better when it was donated to the museum from which I acquired it, but
>>>sat for most of the last five years in a metal building with no
>>>attention (along with a couple of P-40s, an Osprey, a Quickie, an IL-2,
>>>and... well, okay, it was a metal aircraft hangar stuffed with neat
>>>aircraft awaiting restoration or repair). While it was inside at least,
>>>the Tucson heat and dryness wasn't nice to some rubber bits.
>>>
>>>Anyway, I'm burning a lot of oil in this thing. I mean a lot. Like a
>>>quart every sixty miles or so. At least I think I'm burning it instead
>>>of just pouring it out on the road because I'm fouling number four plug
>>>and I'm smoking out the tailpipe, particularly on acceleration and
>>>particularly after the engine has run for a while. There's also
>>>droppings in my driveway from somewhere on the bottom part of the engine
>>>(dipstick cup pulls out of the block... not sure that's the problem).
>>>
>>>I've replaced the SU jets because the hose on one of them had split at
>>>the end on the float bowl and believe I'm now running rich (long time
>>>DGV user, first time SU tinkerer). The engine is down on power some
>>>since the rejetting.
>>>
>>>The engine is running a little smoother since I put a hotter plug in #4.
>>> Runs a lot smoother with a clean, non-fouled plug. Before, it would
>>>get to where it wouldn't even idle after I'd driven it ten miles or so.
>>> Just rough idle now. Compression is pretty even, but lower than the
>>>Datsuns I've been used to at around 110psi. This is on a cold engine.
>>>I started but didn't finish a valve adjustment because I couldn't figure
>>>out how to hand turn the engine to the right place. Found number five
>>>with too much gap and think number eight might not have any.
>>>
>>>So, here's the possible culprits I think I can name: 1) bad intake
>>>seals, 2) worn intake valve guides, and 3) stuck oil rings. Gosh, I
>>>sure hope it's not the rings because I don't have time to deal with that.
>>>
>>>What advice do any of ya'll have to help me track this down and fix
>>>it... expeditiously? Also, what's the recommended method for rotating
>>>the engine for valve adjustment?
>>>
>>> - Kendel
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