MGExp

MGA Forum

Help Find My Dad's MGA

Moss Motors
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor

jgravitt Avatar
jgravitt Jay Gravitt
Beloit, WI, USA   USA
1959 MG MGA 1500 "Mildred “Millie”"
While the car is laid up for the winter. I’d like to have the speedo and tach reworked, rebuilt, etc. Who should I have do this?

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
copernicus Avatar
copernicus Nick Kopernik
Springtime in, CT, USA   USA
In reply to # 3633230 by jgravitt While the car is laid up for the winter. I’d like to have the speedo and tach reworked, rebuilt, etc. Who should I have do this?


Over the years I've used both of these with great results:

http://westvalleyinstruments.com/

http://www.nisonger.com/

bikermga Avatar
bikermga Peter Tilbury
Surrey, BC, Canada   CAN
Oliver Bienz in White Rock BC provides a great service. Quick (like 1 week) and very competitively priced. He is a retired aeronautic instrument mechanic, and drives a TVR.

Peter.

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
barneymg Avatar
barneymg Barney Gaylord
(Somewhere in USA), Pick one (or more), USA   USA
1958 MG MGA "MGA With An Attitude"
The answer is, 0.020 overbore is about 1.27 cubic inches (for 4-cylinders total).
That may add about 1 horsepower to a stock engine.
In reply to # 3633052 by Redhawk1689 .... how much extra capacity does boring out the cylinders by .020 make? Specifically, I have a 1622 block that has an 1800 head and cylinders over-bored to .030 over. The pistons are high-compression, flat-headed ones. What capacity is that and what kind of bhp will this engine set-up produce? .... I'm just curious how you guys figure this stuff out!
Capacity or dispacement is a function of cylinder bore and piston stroke (displaced volume). The piston shape and cyinder head have nothing to do wih displacement, but they do affect compression ratio (which can affect power output). The "18" head is nearly identical to the "16" head originaly used on the 1622 engine, so your engine should produce same power as the original 1622 engine (with 0.030 overbore), around 90 BHP.



Barney Gaylord - 1958 MGA with an attitude - http://MGAguru.com - barneymg@mgaguru.com



Edited 3 time(s). Last edit at 2017-11-24 08:23 PM by barneymg.

Blueosprey90 Avatar
Blueosprey90 Jeff Sienkiewicz
New Milford, CT, USA   USA
Jay, I don’t pretend to be any sort of expert, but I offer some friendly suggestions for your further study and consideration and for discussion with your engine builder.

My understanding is that you plan to rebuild a 1500 block and 1H967 head.

Ask yourself what sort of driving do you really plan to do with this car. I know you’ve indicated that you want to install an MGB 3.9 differential for highway driving. But do you really plan to do all that much highway driving? Or are you going to be zipping this car around back mountain roads? I have a modern sports car, but if I have any choice, I never take the Interstate. It takes me about 2 hours max to swap out the differential in the MGA and I’ve been doing that about twice a year. Hang onto your 4.3 stock differential. You may find that it provides far more desirable gearing for your style of driving.

Your engine builder has recommended a .040” overbore. That is a reasonable and conservative modification. I think Barney is recommending a .020” overbore on the basis that it will provide options for a much longer engine life. That is also reasonable and conservative. 1500 blocks are pretty easy to come by. These engines get pulled and 1800 engines substituted. Keep your eyes peeled and you should be able to find more than one 1500 block for future rebuilds at reasonable prices.

I have sitting in my basement a 1500 block that is bored out to 1630 cc. The bore size is 3.008” versus the stock 1500 bore of 2.875”. The engine has .030” overbore 1600 pistons. I’m not recommending that you go to such an extreme (indeed, I’ve never run the engine as it has other technical difficulties that I haven't resolved), but it is a possible overbore to a 1500 block. See http://www.mgbmga.com/tech/mga3.htm

Power depends only partly on the ultimate engine size in cc. Two other very significant factors impacting power are your compression ratio and the head’s ability to breath. As you consider your rebuild, you need to consider these additional components.

Take a good look at the top of your engine block. Do you see any stamped numbers in the top of the block, perhaps <2> or <3>. If so, this means that you have a virgin block that has not been decked. Just to straighten you block’s deck, your builder may want to shave the deck .010”. It can be shaved more, but definitely keep track of what modifications he makes as it will help you to determine some other modifications and your compression ratio. I believe the thickness of the stock head is 3.187” and the stroke is 3.5”. If 0.10” is removed from the block’s deck, the thickness of the head will be reduced to 3.177”, the stroke will remain the same and compression will increase, thereby increasing horsepower to some degree. You will need to check how close the tops of the pistons come to the top of the deck.

The stock 1500 and 1600 compression ratios were 8.3 to 1. This is based partially on a 39cc combustion chamber (head) and upon dished pistons. The horsepower gain between the two stock engines was largely based on the larger bore size in the 1600 engine. But there was also a high compression 1600 engine that used flat topped pistons. Use of the flat topped pistons bumped up the compression ration up - to 8.9 to 1, if I recall correctly.

The problem is that you cannot easily get flat topped pistons for the 1500 or the 1600 unless they are specially made. So you need pistons in your chosen overbore size with the absolutely shallowest dish that you can find. The shallower the dish, the less cutting that you will need to do on the deck or the head to bump up the compression ratio. Check out what British Parts Northwest has in the way of pistons.

So what compression ration do you want. My humble opinion is that you should shoot for a 9.5 to 1 compression ratio and run high test gas.

Regarding the head, I think you already have a Stage 1 head. I may be wrong, but I’ve done some amateur head porting and was convinced that the 1H967 head under my grinder had already been ported at the factory to Stage 1 requirements.

The stock MGA head is supposed to have a 39cc combustion chamber. My own experience based on 3 heads is that the combustion chambers in the head might be closer to 43 or 44cc. This may be because of valve regression or maybe from the depth of sparkplugs. But the larger the cc of the combustion chamber, the lower the compression ratio. You want to get back down to 39cc or even lower - and you do that by shaving the head. (The reason I preferred to run a 15 head on an 1800 engine was to bump up the compression ratio. The 18 head had a stock combustion chamber of 44 cc.)

But don’t do any shaving until you have all of your measurements and have first calculated the theoretical compression ratio using the reconfigured block and/or head numbers.

Keep in mind also that if you polish the surface of the combustion chamber or remove the Westlake promontory (see Barney’s CH-100c) between the two valves or do anything else that increases the size of the combustion chamber for better breathing, you need to take that into consideration in making your compression ration based modifications.

Then the question is do you port your head? I think you should do some light porting (at least polishing to remove all the slag) – especially in the area just below the valves. Do this before you install your new valve seats and the new valve guides, because 1) you don’t want to damage the valve seats and 2) the valve guides should be shaved somewhat as well.

I think it would take about 50 hours of labor for a fully ported head, but even a lightly ported head – say 10 hours – will be a marked improvement over stock.

Check out the MGA Special Tuning Manual and the Supplement to the Special Tuning Manual. Barney has both documents in pdf format on his site. Turn to page 16 of the Special Tuning Manual and to page S5-1 of the Supplement. Read and understand those documents and the drawings.

I would also increase the size of your inlet valves from the stock 1.500” to 1.563” (the next size up) for better breathing. With this change, you can leave the exhaust valves as stock. You can go larger, but then you are into MGB valve sizes and creating eyebrows in the block are necessary.

I would also go for a lightened Fidanza flywheel. You want part # 126991. Most sales literature, including Fidanza, shows the wrong part number for the MGA flywheel.

Make sure you crack test and balance the crankshaft, balance the pistons, shot peen and balance the connecting rods and balance the flywheel and pressure plate as a unit.

You'll want a new high performance camshaft.

In the Vendors Forum, read Speedracer’s (Acme Speed Shop) thread as it contains many engine rebuilding tips.

Good luck.



Edited 3 time(s). Last edit at 2017-11-24 10:02 PM by Blueosprey90.

jgravitt Avatar
jgravitt Jay Gravitt
Beloit, WI, USA   USA
1959 MG MGA 1500 "Mildred “Millie”"
Thank you Jeff! Awesome read! I am starting to get it now!

I never thought about switching between a 4.3 to a 3.9 based on driving modes. Great idea!

Here in Southcentral Wisconsin we do have hills. However, we do not have anything that is remotely considered to be a mountain. Most of my driving will take place in two forms. Either 10-20 mile ice cream/dinner runs or 150-300 mile overnight/weekend runs. Based on our geography these two runs are about as flat of a driving experience as one can get. I would have to do some longer drives to get myself into some serious hills.

This was my first summer with the “ole girl”. It was an interesting one sorting out everything that is wrong with her. The last and biggest problem under the bonnet is that she is running on a Nash-Metro cylinder head attached to a Magnette engine with fuel being supplied by a Weber carb. This has to be the trifecta of bad/dumb ideas!!!! Being new to the MGA world I quickly discovered I have a lot of learning to do.

That is all being taking care of this winter. I have freshly rebuilt su carbs waiting to be installed on the rebuilt engine and head. I guess I should see how she performs next summer before talking about a 3.9 rear end.

Oh, Btw.
The motor I recently purchased is untouched! The block still has the #2 stamped next to each cylinders and the original stampings on the top of all four pistons. I believe the head has been shaved down but the valves are untouched.


Attachments:
B47937F4-3100-481A-AC7B-FD174D42DEBF.jpeg    26.4 KB
B47937F4-3100-481A-AC7B-FD174D42DEBF.jpeg

70B13432-6259-42AA-87B9-50108F416594.jpeg    38.2 KB
Sign In or Register to view this photo
Blueosprey90 Avatar
Blueosprey90 Jeff Sienkiewicz
New Milford, CT, USA   USA
You can plunk the MGA head on the Magnette engine. eye rolling smiley


http://www.mgtoronto.com/pdf/Tech/Understanding_Compression_Ratio.pdf

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
jgravitt Avatar
jgravitt Jay Gravitt
Beloit, WI, USA   USA
1959 MG MGA 1500 "Mildred “Millie”"
Jeff
I know, but the Magnette engine has all sorts of unknown issues of its own. After the MGA 1500 Engine,15 head, and the su carbs are installed the car will be setup the way it should be. Sort of a “ground zero”. I’ll then tear down the magnette engine and either keep it a spare or bore it out for future fun.

Judge Jeffs Avatar
Judge Jeffs Gold Member Bill Jeffries
Chichester, West Sussex, UK   GBR
1959 MG MGA "Maggie"
Jay
Superb and comprehensive advice from Jeff and exactly what I did with my 1500 plus careful lightening and balancing of the reciprocating components, mated to a 5 speed T9 with standard diff, makes a great driver....I grin every time I’m out!
Bill

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
jgravitt Avatar
jgravitt Jay Gravitt
Beloit, WI, USA   USA
1959 MG MGA 1500 "Mildred “Millie”"
I can hardly wait for spring to come to Wisconsin and a BIG!! shout out to Nisonger Instruments!!!!

Last April I purchased what I believe to be my father's 1959 MGA 1500 "Mildred". She is chassis number 65845 and body number 78272. Mildred was assembled on March 24-25, 1959. In the winter/spring of 1962 my parents were expecting the birth of my older brother and decided to trade Mildred in for a family car. Sometime in the late sixties or early seventies, Mildred was in an accident involving the front end. She was subsequently put out to pasture with 43,616 miles on her, and remained there for the next 40-45 years. Since being resurrected a few years ago, Mildred went through a series of at least 2 or 3 owners along with several nonprofessional partial restorations including the body being repainted from it's original black to what I think is orient red, and a engine transplant. After purchasing Mildred last April, I soon discovered the engine block and cylinder head were not the originals. The engine block is from either a 1958 Nash Metropolitan or MG Magnette and the cylinder head is from a 1959 Nash Metropolitan. To make things worse the original SU Carbs were replaced with a Weber 2 barrel carburetor and in order to make her run the choke had to be pulled wide open. Using a gps app on my mobile phone I managed to limp her around town last summer/fall for a total of 567 miles! All the while having the gearbox rebuilt, electrical system updated, cooling system replaced, steering components replaced, brakes replaced, wheels and tires replaced, and a list of too many other things to remember.

While Mildred has been laid up over the winter I purchased a completely untouched MGA 1500 engine (casting date May 2, 1958) with it's original pistons, camshaft, and crankshaft. The engine was in beautiful shape and showed very little signs of wear. Attached to the engine strangely enough was a cylinder head for a MGA 1600 that was cast on May 28, 1963. Both the engine and cylinder head are currently being rebuilt. The engine is being over bored to .040 and will also receive a stronger cam with all the trimmings. The cylinder head is getting hardened valve seats, enlarged intake and exhaust valves, as well as having the chambers enlarged to 43cc's.

A few weeks ago I took the speedometer and tachometer out of "Mildred" and sent them to Nisonger Instruments to be rebuilt and refurbished. Neither of the gauges functioned "at all". Nisonger did an absolutely amazing job! The list of items that needed to be fixed or replaced is quite extensive so I won't bore you with it. Instead you can judge Nisonger's work for yourself by looking at some before and after pictures. Anyway, I can't wait for spring!!!!



Edited 1 time(s). Last edit at 2018-03-13 01:44 PM by jgravitt.


Attachments:
IMG_2451.JPG    35.7 KB
IMG_2451.JPG

IMG_E2690.JPG    33.3 KB
Sign In or Register to view this photo
IMG_2453.JPG    30.7 KB
Sign In or Register to view this photo
IMG_2685.JPG    25.4 KB
Sign In or Register to view this photo
jgravitt Avatar
jgravitt Jay Gravitt
Beloit, WI, USA   USA
1959 MG MGA 1500 "Mildred “Millie”"
More photo's of Nisonger's work!!!


Attachments:
IMG_E2454.JPG    35.9 KB
IMG_E2454.JPG

IMG_2672.JPG    29.8 KB
Sign In or Register to view this photo
IMG_E2456.JPG    35.2 KB
Sign In or Register to view this photo
IMG_2686.JPG    28.3 KB
Sign In or Register to view this photo
Redhawk1689 Avatar
Redhawk1689 Gold Member Steven Stockham
Salina, KS, USA   USA
1958 MG MGA 1500 "Belle"
Okay, now I'm jealous! How much to refurbish them?

Gary E Avatar
Gary E Silver Member Gary Edwards
Kernersville, ,N.C., USA   USA
They did a standard refurbish and recalibrate for my speedometer $230 delivered.



Gary

jgravitt Avatar
jgravitt Jay Gravitt
Beloit, WI, USA   USA
1959 MG MGA 1500 "Mildred “Millie”"
Steve,

For a basic refurbishing/reconditioning as well as checking the operation and calibration of a somewhat functioning gauge. Nisonger charges $175 per gauge. If something is wrong that needs a replacement part. They will call, tell you about it, and ask what you would like to do. Plus they warranty their work and parts for a year.

My gauges however were a different story. I knew that when I sent them in. They hadn't been in an operating car for over 40 years. Almost everything inside and out needed to be replaced. Including: bezels, gaskets, faces, all the gears and number wheels for both the odometer and trip meter, the trip meter arm, speedometer drum.... pretty much everything!



Edited 1 time(s). Last edit at 2018-03-13 05:29 PM by jgravitt.

barneymg Avatar
barneymg Barney Gaylord
(Somewhere in USA), Pick one (or more), USA   USA
1958 MG MGA "MGA With An Attitude"
Wait a minute. MGA 1500/1600 engines used the "15" head with 38cc chambers, and dished pistons. The MGA 1600-MK-II engine (1622cc) used the "16" head with 43cc chambers, and flat top pistons. So why are you enlarging the chambers of the earlier head? If you do that you need to use flat top pistons. The larger chambers with dished pistons would make for very low compression ratio (not good).

In reply to # 3696567 by jgravitt .... The cylinder head is getting hardened valve seats, enlarged intake and exhaust valves, as well as having the chambers enlarged to 43cc's. ....



Barney Gaylord - 1958 MGA with an attitude - http://MGAguru.com - barneymg@mgaguru.com

. Hide banner ads & support this website by becoming a > Gold Supporting Member <

To add your reply, or post your own questions




Registration is FREE and takes less than a minute!


Having trouble posting or changing forum settings?
Read the Forum Help (FAQ) or contact the webmaster