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1500 engine rebuild, suggestions for improvements?

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Hap,
When you say 1300 do you mean the 1275 MG Midget engine?

As opposed to the oil passage mods (which you don't recommend), what about using a oil feed hose that goes to the head to fead head and rockes (this is the external hose that Moss sells so that full oil pressure gets to the rockers). With this mod wouldn't this starve the engine of oil pressure elsewhere? Remember my car is not used for racing, but for a fun car to drive.

Another piece of info is that I do a decent amount of highway driving (65 mph) which is keeping the engine runnig at high revs for a length of time. My car does have a OD installed though which helps keep the RPMs down in the 3200 cruise range.
 
recordsj said:
Hap,
When you say 1300 do you mean the 1275 MG Midget engine?
Click to expand...
He means the 1296 Triumph motor (Spitfire late 1960s early 1970s), the predecessor to the 1500.
 
Re: 1500 engine rebuild, suggestions for improveme

Hap Waldrop said:
Here's a funny tractor/LBC story, years ago racing MGBs long before the introduction of gear reduction starters, with the MGB SCCA race engine getting pretty high in compression ratio, 14-15 to 1, it was not uncommon for to blow the starter drive to pieces, a wise older man came up to me after seeing one of my starter drive blow up and ask me if I had a Ford tractor place near me, which I did, he gave me a part number for a super HD starter drive to get at the Ford tractor palce, turns out some older Ford tractors used the same Lucas starter as the MGB and had the same issues and they had came out with his HD starter drive, I still have one of those things lying around in the shop. :smile:
Click to expand...

Hap I have heard this before. It is not uncommon for a person who splits a Ford tractor to find the remains of several bendixes rattling around in the bottom of the tranny case. It is said that Henry designed them with plenty of storage space knowing they would blow to pieces from time to time.

Sorry to hijack the thread.
 
drooartz said:
recordsj said:
Hap,
When you say 1300 do you mean the 1275 MG Midget engine?
Click to expand...
He means the 1296 Triumph motor (Spitfire late 1960s early 1970s), the predecessor to the 1500.
Click to expand...

Yep, thats exactly what I mean, the later large crank journal Triumph 1300 engine is the same bore as the Triumph (ah~la MG) 1500, the crank stroke is the only thing that changed displacement. Alot fo the part interchange between the two motors.

I know most of you know this, or I assume this, but we do have some new folks to MGs here, but the 1500 is a Triumph motor. They made several evolutions to this engine over the years, I've rebuilt 1147s, 1296s and the 1500s Triumph engine over the years.
 
recordsj said:
...I do a decent amount of highway driving (65 mph) which is keeping the engine runnig at high revs for a length of time. My car does have a OD installed though which helps keep the RPMs down in the 3200 cruise range.
Click to expand...
That OD will keep your 1500 happy and healthy for a long time, I'd think. I'm not comfortable at all thrashing Nigel at highway speeds in 4th gear. Just bottom-end trouble waiting to happen if you ask me. He's happy around three grand, and that's where I keep him.
 
recordsj said:
What kind of specification and where do you find it to give to a shop to balance components?

I understand and wanting balanced components, but how much is this giving you in longivitiy of the engine as opposed to the components as stock?
Click to expand...

IME, you don't give the machine shop balancing specs; so much as you take them your engine innards and ask them to do it. Increased longevety depends on how far apart the components are to begin with. If the shop doesn't ask for your flywheel, find a new shop. A 1500 has a long stroke and will benefit from balancing.

I'd also suggest having your crank indexed, which ensures the throws are exactly the same.
 
If you don't give a machine shop any specifications, how would they know how far to take it in balancing it?

In an example, if you go to the hardware store and ask for some nails they could just give you anything, but if you are needing those nails to hang a picture a 18 penny nail is most likely overkill for the application.
 
I agree with your statement that it's odd not to give the machine shop a specification... but I never have told them a value to aim for.

Sometimes when you read listings for balanced engines for sale, the seller will tell you how closely balanced in weight the piston/rod assemblies are, but I've never seen anyone list what "ounce-inch" balance the rotating assembly was taken to.
 
dklawson said:
I agree with your statement that it's odd not to give the machine shop a specification... but I never have told them a value to aim for.
Click to expand...


Well, when you think about it, it's either in balance or it's not.


kinda like a little pregnant or half a hole
 
Not really- it can be in balance within an ounce/foot or 3 ounce/feet or 5 ounce/foot. As that "within" gets smaller and smaller the price goes up and up.
Depends on how balanced you want to pay for.
Bill
 
"Well, when you think about it, it's either in balance or it's not."

That is absolutely incorrect. Lets turn it around on you... Go cut a piece of steel bar 1" long. What is acceptable when you cut it? Is 1.3" close enough? Is 1.1" close enough? Is 1.0005" close enough? Obviously the answer is based on what the steel part is being used. If it needs to fit in a space of 1.05", a piece cut at 1.1" will not work!


So does anyone know what kind of specification is used when you have your engine parts balanced? Obviously balancing is done, but what kind of specification and tolerance is given?
 
I'm learning so much here. :smile: I'd always thought that balancing was like blueprinting ('cuz you always hear 'em both together); the goal was to get it perfect, plus or minus nothing.
 
Can you cut a steel bar @ exactly 1" long +/- nothing???
Good luck in trying, there is a tolerance in everything that is measured.

So does anyone know what can of specification that is practical and a range to balance engine components? At least in my application the car is a street car not for racing....
 
I wish I could tell you a balancing "spec" to ask for. I tried a little Googling and I never found a specific value mentioned anywhere with the exception of a couple of sites dedicated to flywheel balancing.

Surely the information is out there somewhere. However, it "may" be like so many other things and there are standard practices. Perhaps if you don't request something special... the "normal spec" is used. Unless Hap offers some information here, your best option might be to talk with your machine shop about balancing and balancing specs.
 
recordsj said:
"Well, when you think about it, it's either in balance or it's not."

That is absolutely incorrect.

So does anyone know what kind of specification is used when you have your engine parts balanced? Obviously balancing is done, but what kind of specification and tolerance is given?
Click to expand...


It's always been my understanding that the "tolerance" you speak of is the machine's scale limitations .
 
Balancing an engine is an involved process, but as an example, I undersand that the pistons and rods are adjusted in weight to within +/- .5 gram of each other.
Scott in CA
 
Guys, I'll talk a little bit about balancing since it something I do.

Your engien form the factory is balanced to within their specs, which is perfectly fine for almost all normal street drivng , even spritied dtreet driving. Some claim a blanced engine runs smotther, andI will not argue that but here the deal, a engine is like a tire, if not blanced close enough there will a rpm spot that it may run a bit rougher at, but mostly not even noticeable to the average paerson and that sopt would probably high enough in the rpm range that most people would never get to it.

OK, When you balnce a engine, you are balancing the rotating parts in that engine, crank, rods pistons are the m ost popular items to get balanced, some even go as far as doing the harmonic balancer and fylwheel as well, balancing cluthces is a waste of tiem they are already balanced to really tight spec as well as aluminum flywheels.

OK, piston are simple static balance, put them on a gram scal weigh them, make them all weigh the same, off the shelf pistons are better made now they they were years ago, and we find them noramlly pretty darn close. If you needed to balnce your piston, you would noramlly remove material form the under side of the piston in a non structual area by using drill, or milling amterial away.

Connecting rods, they are static blanced as well, but with a bit more to account for, you use a connecting rod trapese in conjunction with your gram scale to weight the bottom, top and toal gram weight of the rods, all three area must be balanced, so material is normally removed form the rod cap bottom, or the top of the small end.

Crannksaft, ok , this takes a very special machine for this purpose, the crank is spun by the machine and it tell you the balnce fornt and rear, and where exactly the weight needs to be reomved and howe much weight, material is removed with drills or by using a grinder.

When you balance parts in a engine, you are simply go to tighter tolerences than the fatory did, for example MG might be ok with the rods beaing within 2-3 grams of each other, but on balance job everthing would with the same gram.

The factory cranks are noramly +/- 2-3 grams as well, we would match both ends to within a gram.

Our engine are waht they call 90 degree motors, meaning a inline engine, with inline engine the crnakshaft balancing does not require bob weights on the rod journal (bob weight replicate the rod and piston wieght) only 180 degree motors, flat engines (VW, Porsche, Subaru) or V (any V6/V8/V12) engine needs bob weights in crankshaft balance.

So just to clear up something debated here, you would not need to give any balancing specs to a machinist, he would know what to do with the job, get it as close as he can, whitch is normally a gram or within a gram, if you actually try to get closer than that you will get back out of balance and have to balance some more to get back to where you where, ask me how I know this :smile:
 
From your statement of balancing it appears to be more of a good thing for a car that you race. Since my car is not for racing (just used as a street car and a fun car to drive), what other improvements can I make that when I do the rebuild can I do which will not add a lot of $$$ but will help improve reliability/durability and if it adds performance then it is just an added bonus.
 
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