Emma needs a new Carburetor

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Viewing 7 posts - 51 through 57 (of 57 total)
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  • #301667
    edward ericson
    Participant

    @edsnova

    Great tutorial, Jack. Extremely helpful for those who would follow in your footsteps.

    #301686
    KentT
    Participant

    @kentt

    Congrats! Most excellent results and detailed write-up! Third gear should be fun now, pushing through corners…

    Can you report back on the temps you’re now seeing, with the jetting set and the venture ring installed? Thanks!

    Early FF TDr on 69 VW pan
    Slowly coming back from the ashes...

    #301707
    HappyJack
    Participant

    @happyjack

    Hey Folks,

    Kentt was asking about running temperatures and performance with the new Weber center mount and the Venturi ring on the fan housing….so I plugged the Bluetooth 4.0 low power dongle into the under dash OBD II diagnostic port and used my iPhone 6 to read out the car parameters including:  speed; acceleration; boost/vacuum; engine rpm; instantaneous HP  demanded/produced; average hp; % engine load; torque; fuel level; average MPG; instantaneous MPG; oil temperature, and outside ambient temperature…….OOPS — no — that was on my Audi S4, not the TDr —

    Emma is not as precocious as the Audi — she only gives up oil temp, #3 cyl head temp, RPM and speed…..plenty for  my fine pre-OBD car!!

    So here’s what I found on Emma:

    –it depends…lots of variables like ambient temperature and humidity and…….But according to some supposed subject matter experts, the ambient conditions really don’t affect the running temperature of the engine…???

    Running around town with traffic lights, some stop-and-go stuff and “waiting in the queue at the bank drive-up window” the car stayed right around 180-190 degrees F. according to the oil temperature  sensor screwed in place of the rear oil bypass plug.   The cylinder #3 head temperature sensor was reading 240 degreed F (I have a thermocouple mounted to a lug that sits under the #3 spark plug).

    On a 20 minute high speed run (65-75 but mostly 68 mph) outside temp at 87 degrees,  the oil temperature got up to around 220 degrees F and the #3 cylinder head temp ran up to 340 degrees F.  Both temperatures dropped pretty rapidly when I came back down to 55-60 MPH on my 10 minute cool-down run heading back home (55 to 50 to 35 to 25 mph ) dropping to around 190 degrees F. for the oil and 250 degrees F. for the #3 cylinder head temperature as I pulled into my driveway .

    After talking with Royal about how the car was running (really well with lots of pep) and the engine temps I was experiencing, I think that, again, there are variables that people will encounter, depending on where the oil temperature sender is located, if the car even has a sender and gauge, and how it is being driven.   I have to remember that the factory VW only had an oil pressure low warning light and only the “fingers on the dip stick” temperature sensor — sometimes it is a case of too many gauges and too much unnecessary information to worry about, I think (ala, the Audi S4 readout).

    Case in point — Royal’s car has the sender in a T-connection along with the oil pressure sender screwed into the left side of the block where the oil pressure idiot light sender was on the stock VW engine.  His temps run cooler than mine rarely over 190 degrees — but he is measuring at a different point in the oil flow path.  My “other”  TDr Abby – (yellow and tan Fiberfab sold last year)  had the sender screwed in place of the oil sump drain plug — and the oil temperature gauge on that car rarely went over 200 degrees no matter when where and how I drove the car….????  It makes Apple-To-Apple comparisons difficult and maybe useless.

    Bottom line, with modern oil (either dino [standard non-synthetic] or “higher break down temperature” synthetic) our engines can run at higher temperatures without the oil breaking down causing failure of miscellaneous-yet-very-important parts.  So I guess I’ll  keep monitoring the temps, switch to synthetic which has a higher temp breakdown point, and drive the heck out of the car.

    Happy Motoring

    Happy Jack

     

    • This reply was modified 5 years ago by HappyJack. Reason: my spec check mis-spelled Kentt's name 1st it was Kenny, then it was Kennt...and now hopefully it is Kentt again

    Happy Jack
    "EMMA" Red BCW TDr on 1971 VW w/ rebuilt 1641cc
    Dual Kadron, mild street SCAT cam and lifters Hide away exhaust and headers
    "MANYPENNY" White CMC TDr '78 Ford Pinto components w/ 1988 Mustang II 4 cyl w/ Weber

    #301711
    edward ericson
    Participant

    @edsnova

    You got it, Jack. The sender location, and the accuracy of the gauge matter. As does out tendency to worry.

    #301712
    KentT
    Participant

    @kentt

    Sounds like you have Emma sorted out really well! Props to you and your pit crew for diligently working through all the issues! Congrats! 😂😂

    Couple of side notes,:

    1. Your oil temps sound really good! You are correct in that sensor location is very important. I tend to like reading temps at the sump drain plug – they don’t fluctuate as much, and give you an indication of the temp of the oil being picked up and fed to the engine. You want those temps to ideally be at least 180 degrees – most good thermostatically controlled remote coolers have a 180-185 thermostat, and will bypass the cooler until they come up to that temp. Similarly, you can run safely for long periods as long as you keep oil temps at/below 235F. Above that point, you start risking some oil breakdown, which will vary some based on the quality and properties of the specific oil.

    2. Your #3 head temps sound really good also. 325-350 on long, high speed runs is considered quite cool.  Note that with your doghouse oil cooler, #3 is no longer the key cylinder to monitor since the oil cooler is no longer blocking the airflow there (or anywhere else).  Head temps will fluctuate much, much more than oil temps – you can actually often see them drop when you’re off throttle, going down a long hill. Out of curiosity (and just for grins) you could move your thermocouple to other cylinders and see how your slightly different jetting is impacting temps there (leaner mixtures burn hotter) similar to yanking the plugs and checking them.

    Sounds like she’s jetted well, timed well, and ready to enjoy some extensive seat time on the Twisties! Again, a big “well done” to you and Roy! Grin and enjoy!

     

     

     

    Early FF TDr on 69 VW pan
    Slowly coming back from the ashes...

    #301713
    Royal
    Participant

    @royal

    Thanks Kent.  Yes, Jack’s TDr is running about as well as a TDr can run.  This has been a long drawn out affair where we took our time to get to the finish line.  Starting with purchase of a used spare engine, complete teardown of both Jack’s engine, and the spare.  Then junking the “new” spare, installing the best of parts that were not bought new.  New bearings throughout.  New oil pump, new camshaft, carefully balanced rotating machinery using my jewelry scale, new valve springs, new pistons, wrist pins, piston rings, 1641cc heads, installed new air vanes and thermostat, new distributor.  New full rebuild on IDF 40 Weber carb.  Ported intake and exhaust manifolds.  Etc, etc.  Basically, anything which was suspect was replaced with new.

    Special care was taken to make sure that everything was squeaky clean.  Everything was carefully checked for correct clearances with many measurements with micrometer, feeler gauges and plastigage.   Basically we checked and re-checked every move before taking it.  Made a few mistakes, but stopped and backtracked however many steps required before moving forward.  Plus we found times where (especially clearance values) our documentation’s advice conflicted.  Resolved, before proceeding.

    Darn near ideal working conditions, with great lighting, air conditioning and clean work environment.  But, the most important thing in this rebuild was patience.  (Jack’s, not mine. —  I ain’t got none. :-))  We went slowly and quit when tired or aggravated…sometimes letting a new ideas ferment for many days before proceeding.

    #301714
    HappyJack
    Participant

    @happyjack

    Hey Kentt

    I’d like to do a check on the other cylinder head location temperatures, but to do that I’d have to pull the spark plugs, move the thermocouple drive and repeat — and remove the back and side fiberglass to get easy access to the plugs.  But since I’d also like to get one last look at the plugs to see how rich/lean/just right they are at speed I will undress the back end and check  Emma’s temperatures at the other spots.

    But for now, I’m going to just drive it and enjoy it.

    I will be thinking about having to take a look at the front shocks and front beam torsion rods  — I never checked the front beam to see how it was created by the original builder, but was told that it is a narrowed beam????  The car is a bit skittish and kind of hops around turns more than Abby did — the car is more than drivable but I’d sure like it to be a little more surefooted.

    One final note on the Weber…I was having trouble with the engine being loaded with gas when I 1st started it in the morning…so much so that I was getting a black soot ring and raw gas out of the down-facing tail pipe — big black round soot spot on the garage floor.  When I went to remove the air cleaner in preparing to check the carburetor float level, I found that ALL of the mounting screws that secure the top of the carb to the bottom were finger tight……either I forgot to tighten them or the gasket between the 2 halves compressed causing the screws to be loose (can’t be the 1st reason, gotta be the 2nd one….).  Now that I tightened the screws, replaced the air cleaner and put the car through its paces, it drove like I just put a new engine in the car.  Amazing how such a simple thing as loose screws can cause such chaos.  I have an even bigger smile pasted on as I cruise down the road now that I’m no longer pouring raw gas through the engine and out the tailpipe. — and no more soot spot on the garage floor.

    I’ll check those cylinder  head temps and post the results….soon

    Happy Jack

    Happy Jack
    "EMMA" Red BCW TDr on 1971 VW w/ rebuilt 1641cc
    Dual Kadron, mild street SCAT cam and lifters Hide away exhaust and headers
    "MANYPENNY" White CMC TDr '78 Ford Pinto components w/ 1988 Mustang II 4 cyl w/ Weber

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