General Tech TR3/4 Tuning

[Read T]

Okay Fellas, first post on the site

Over the past week I think I've finally gotten my TR3-powered '60 Morgan back on the road and I'm just working on fine-tuning the carbs. I had the carbs rebuilt by someone else which turned out to be a huge headache and then rebuilt them again myself. They are not leaking at all, and as far as I can tell the vacuum advance is working normally (I can see it move the distributor plate when suction is applied). The car has a TR3 engine with 87mm piston liners and the stock H6 SUs, now running the richer than stock "RH" needles. The engine was completely rebuilt by a reputable TR expert with a new waterpump and aluminum radiator and bellows type block off thermostat. It was also converted to a lead-free head with hardened valve seats.

Over the past month I have also converted to negative earth, switched over to an alternator, welded up a custom manifold-back exhaust with a slightly larger diameter, and installed a wideband oxygen sensor to track AFRs. I also picked up an el-cheapo infrared thermometer to check manifold and radiator surface temps. This seems a little bit more technologically advanced than when the car was built.

When warmed up, the original temp gauge reads about 1/3 way between the normal and hot marks. My handheld thermometer reads about 155F (68.5C) on the aluminum end tank next to the water inlet, and the top radiator hose reads about 165F (73.8C) I attribute this to the shiny aluminum reflecting the laser. The exhaust manifold reads in the 550F (285C) range when warmed up and idling.

At cold idle the AFR is around 12.0, warm Idle it rises to around 13. At throttle while driving and WOT I'm getting around 12.5 with a split second spike into the 15's on overrun from WOT. When using the piston lifting pins, the idle does drop slightly and the engine runs poorly which would normally be indicative of a slightly lean condition, even though my AFRs are on the richer side.

The car otherwise seems to run and idle well. I just didn't know if anyone with more experience with tuning carbs could look at this data and say "looks okay!" or "Oh gosh, it's bound to blow up" before I go out driving more. I'm probably being a bit OCD about this.

Happy Motoring! And thank you in advance for your replies.
Read

 

[TR3driver]

Sounds pretty good to me, although my wide band O2 sensor is still in the box.

 

[Geo Hahn]

Hah, not likely to blow up I think.

For another mixture test - I like to examine the plugs after an abrupt shut-down of a fast run and see what color they are. Light cocoa brown is good, sooty black probably rich.

I also enjoy using Colortune but cannot swear it has really told me anything I didn't otherwise know.

...My handheld thermometer reads about 155F (68.5C) on the aluminum end tank next to the water inlet, and the top radiator hose reads about 165F (73.8C) I attribute this to the shiny aluminum reflecting the laser...

I painted a flat black spot on the thermostat housing to give me a better target for my IR thermometer.

I expect to see about 185° when the engine is fully warmed up.

 

[Read T]

I painted a flat black spot on the thermostat housing to give me a better target for my IR thermometer.
...
I expect to see about 185° when the engine is fully warmed up.

I should have thought of that! I'll be doing this in the next few moments.

 

[TR-3rg]

Hi,

I have a wide band oxygen sensor on my 3a. I see similar readings with RH needles. The engine has 87mm pistons, H6 carbs and a 4 tube header. I can check the header temps.
What size exhaust did you go to?

I had a hard time getting the vacuum port on the carb to seal. You might want to put a gauge on it and drive around a bit to check.

Good luck, Roy

 

[GTP1960]

Hey Read,

can an you post some pics of your TR3 powered Morgan ?

its a Great feeling to finally get them back on the road, isn't it?

Best at of luck.

Guy

 

[trrdster2000]

Read T, I think you will find the being ANAL over these cars is just part of it. Good job on all the work and give us a few pictures, love the early Morgan's.
There was a guy in Lexington, just up the road, that had the 3 wheeler. His name was Morgan and lived on Morgan Lane. I am sure he's gone now and the car was donated to a museum somewhere.
Keep up the good work.

Wayne

 

[Read T]

Thanks for all the replies so far y'all!

Here are some pictures since you guys asked. The first one is both of my Triumph-powered doodads. The car has been in my family since new so I have a lot of cool old (non digital) pictures of it as well.

 

[PatGalvin]

Great photos, thanks for posting.

Pat

 

[trrdster2000]

Thank you very much for the pictures. Look just like the new ones I saw in England in 1961, what a great job you have done.

Wayne

 

[tdskip]

Welcome to the forum!

Looks like you are having fun already.

 

[Read T]

Sure am having fun, just waiting for this week of rain to pass :cold:

I have been anal/worried about my temp gauge reading incorrectly (it's an old original Smiths). Took it out today and tested it in a pot of oil. When the needle is sitting right in the "normal" range the temp is about 155*, where it normally sits about 1/4-1/3 of the way between "normal" and "hot" is about 170-180* so I think sitting a little above "normal" is where I should be. Not sure if Morgan just skipped on a voltage stabilizer for the temp gauge or something. I was worried that I was overheating slightly. I believe that the gauge has a calibration slot on the back, but I don' think I'm going to mess with that too much.

 

[TR3driver]

Not sure if Morgan just skipped on a voltage stabilizer for the temp gauge or something.

Smiths made both kinds (with or without a VS). Could it be that your Morgan originally had the kind that doesn't need a VS, and some DPO switched the gauge?

I didn't have to tweak the temp gauge, but I did adjust the voltmeter for the Stag (which is essentially the same movement as the TR4-6 temp gauge). Pretty easy once I decided to make a tool for moving the adjustments. I made this on the lathe (out of a 1/4" bolt) but you could file down the tip of an old screwdriver to work the same.

 

[Read T]

It has the original sender/gauge still. I did just read on some websites that it's typical for Morgans to read above normal (This is getting off the "triumph" topic now haha).

 

[GTP1960]

Read,

i am am curious about your tranny.
in your engine bay pic, it looks like a standard triumph tr3 housing, but the engine positioning would seem to place the gear shifter to far forward, causing driver to stretch for it.
Also, is that a standard morgan thermostat housing? Or one you modified for the tr engine installation?

great looking car.

best regards,

Guy

 

[trrdster2000]

Guy, The shifting on a Morgan was on the center of the dash for many years. Kind of a push pull effort, not sure when it changed to the floor, or if it ever did.
Something you get use too very quickly, like driving a right hand drive car and shifting with your left hand. Wait a minute here, the TA is that way but the Roadster is a right hand column shift. Sometimes I get in one of the cars and have to think about where I need to be, as we still have a Jeep and Ford F150.

Wayne

 

[Read T]

Guy, The shifting on a Morgan was on the center of the dash for many years. Kind of a push pull effort, not sure when it changed to the floor, or if it ever did.

Wayne

Wayne is correct - in the 4/4 a remote push/pull transmission was used. Details on the plus 4 below :wink-new:

 

[Read T]

Read,

i am am curious about your tranny.
in your engine bay pic, it looks like a standard triumph tr3 housing, but the engine positioning would seem to place the gear shifter to far forward, causing driver to stretch for it.
Also, is that a standard morgan thermostat housing? Or one you modified for the tr engine installation?

great looking car.

best regards,

Guy

Guy,

Morgan +4s came equipped from the factory with a TR3 and later TR4 engine. The blocks themselves were stamped by triumph with a MA-xxxx serial number which denoted the blocks to be sent to the Morgan factory. Per the Morgan owner's manual the engine differed by the original triumph unit in three ways 1) A shorter water pump and pulley is used 2) The center springs on the clutch driven plate are different 3) A double water outlet elbow is fitted as opposed to a single on the original

The transmission that Morgan used on the TR powered cars was pretty slick. The clutch, pressure plate, and graphite-block throw out bearing are attached to the flywheel in an orthodox manner. From there, a ~2 foot long high speed input shaft runs to the remote mounted Moss gearbox located between the seats. The 'box is similar to the unit used in an XKE although the casting is slightly different. The input shaft and clutch/pp are enclosed in a magnesium bellhousing that stretches from the engine to the gearbox.

I'll try to find a real picture of the setup, but this is from the manual

 

[Read T]

And if you ever thought lining up and stabbing in a transmission was tough, try it with a 2 foot input shaft

 

[Read T]

Picture I grabbed online of the bellhousing showing how the remote gearbox would be situated, it would be just out of the picture.