The History Of M engines

[rob]

Clickety Click Here To See The History Of M Engines Article

One mistake in the article i made is that the 2000GT had mikuni carbs not SU carbs.

[river]

Hi,

Very good article. But what I don't understand is what exactly is the "M" series engine. Surely over those 27years the design of the block, head and pistons had changed so much that the original "M" was designed out of it.

I can understand a limited series of the early M engines being all basically similar (like the 18R series all being similar, including the 18RG which had a similar block/desing but with a DOHC head).

I guess I am trying to figure out Toyotas naming/design convention. For example, what is so different from the (say) 1G series engine, being DOHC 6-cyl, to the equivalent M series.

Similarly, other than capacity, there is little difference between the 2T and 18R series of engines.

Or, as I suspect, am I missing something here.

In any event, I did enjoy your article and I learnt something. It's always a good day when you learn something new, and for that I thank you.

seeyuzz
river

[gearb0x]

Do not try to "understand" the naming convention, thats impossible
Instead, only try to realise the truth

There is no naming convention

[clubagreenie]

What is fairly revolutionary, or at least a common sense revolution tha seemed to anticipate the future of modifying is that from M to 7M the engine mount holes are there. Even the last of the 7M's have holes in position for the different mount points for fitting to crowns, MK2's etc. Sumps cross over, even oil pickup's, the 5MG has 3 holes for each possible configuration, nothing was deleted just because it wasn't needed.

5M to 5MG isn't that much of a leap to change using the same block.

1G equivalent in M's would be a 5MGE, difference of 0.8 lt, much physically larger and heavier plus other things I don't know about 1G's

[river]

Hi,

Interesting point you made regarding the "bolt in" ability of the various M engines.

Engines take a lot of time, money and effort to design and, like aircraft engines, you hope to get a pretty long life out of the design and the same engine (sometimes with minor mods and add ons) can go into various chassis.

Take the 18R series engine for an example. In its normal form it is 2000c (near enough). It can be bored to 2.2 litre and stroked on top of this to get 2.4 litre. It begs the question why design the 22R and 24R engines when a fairly cheap bore/stroke can get the extra capacity. Especially so when, in the case of the 18R series, reliability isn't severely reduced in doing this upgrade.

Maybe I'd be a tight-arse designer. When someone says lets build a new 2.2litre engine for the X-model, I'd say "no just bore and stroke the old engine".

seeyuzz
river

[rob]

Maybe I'd be a tight-arse designer. When someone says lets build a new 2.2litre engine for the X-model, I'd say "no just bore and stroke the old engine".

i think there is a good chance toyotas design philosophy they do the opposite to just that. The engineers design an engine with its potential in mind, with clearly defined future design and implementation objectives.

they wouldnt be best in the business otherwise

[The Witzl]

It's true, Toyota is the world's no.1 manufacturer.

River,

the naming convention for Toyota engines is kinda like their model codes, in that the letter carries through, but the numbers indicate a new revision.

# The letter(s) in the engine code before the dash reflects a series of engine, eg. the "M" series, the "R" series, the "A" series, the "K" series etc etc.....
# The number in front of that letter represents the revision number of that engine series...
# and the letters after the dash represent the type of head, fuel delivery, induction, emission standards etc.

In response to the comment that the "original M was designed out of it", in essence that is true - but the basic design, the block, and type of engine remain the same. Example - A series are always small 4 cylinder economy donks, R series are mid sized 4 cylinders with torque in mind, M series are inline 6's for bigger cars...... yes many of the internals and 99.99% of the parts are different, but the basic fundamentals of the original series remain.

Similarities across two different engine series are typically nil to minimal, there is the odd similarity or compatibility, eg the bellhousing bolt pattern of a 1G and T series engine are the same, but usually there is very little...


As for the development of the R series engine..... River my old friend, you dont what to know what their intended purpose was...

[JustCallMeOrlando]

I guess I am trying to figure out Toyotas naming/design convention. For example, what is so different from the (say) 1G series engine, being DOHC 6-cyl, to the equivalent M series.

I think that can be easily summed up by checking out the 1G on a stand. The 1G was designed to be the "small" six for taking advantage of certain tax breaks in Japan. It was always designed to be 2l, and there is only one real variant. Because of that, the engine itself is quite tiny, especially so when comparing it to other 2l sixes like Nissans RB20.

[CrUZida]

What is fairly revolutionary, or at least a common sense revolution tha seemed to anticipate the future of modifying is that from M to 7M the engine mount holes are there. Even the last of the 7M's have holes in position for the different mount points for fitting to crowns, MK2's etc. Sumps cross over, even oil pickup's, the 5MG has 3 holes for each possible configuration, nothing was deleted just because it wasn't needed.

Not entirely true.
Halfway between the 4M motor, the block changed.
Early 4M blocks do not have the correct holes for 5M/7M mounts.
This is 2nd hand info from CLG, who knows it first hand.
Contact him for the correct info.

[RobST162]

Unfortunately there has been a head gasket problem with the 7M engines that has seemed to have tainted its reputation.

ehehehehee

Nice article thanks rob, had a good read

[oldcorollas]

to add to Witzls comments..
the K series went from 1966 to early 2000's (2003?) thats nearly 40 years!!!
the K, 3K and 4K all share same piston diameter, just different stroke/deckheight. 5K is a 4K with bigger bore (and hyd lifters). but all the K,2K,3K,4K,5K heads will swap across.
7K was the first major revision, with 5K bore, but taller block AND wider skirt, although i believe the 7K head also bolts across. the 7K could have been called a different family, but it was still a shitbox (and finished off the toyota car pushrod seris due to emissions.. finally)

the manifolds bolt across from EVERY model.. 7KE injection works on ALL model heads, as does exhaust manifolds.... in fact, the port size is nearly identical from the 1000cc model to the 1800cc model..


but "K" always meant "small shitbox motor that was hard to kill"

Cya, Stewart

[peeack]

What did the K series engines go into once they stopped using them in corollas? Those tiny work vans etc?

Good read about the M line of engines Rob!

[wilbo666]

M series engine comparison (Flywheels, Sumps, Engine mounts)

http://forums.toymods.org.au/index.p...96bd6eca8a1ec7

Cheers
Wilbo

[andrew_mx83]

wow how did i not find this thread earlier!! good read, credit to the author

awesome to see a factory triple DCOE'd M engine!! also interesting to note that going to EFI never really helped them power wise, gives weight to my 7m-ge carb conversion which will be running shortly.

i would say the "M series" part of it (largely speculation here) would share the same bore centers and journal spacing on the crank (there are different journal widths between some) as well as bellhousing/sump pattern. maybe front timing case bolt pattern too?
you certainly see evidence of the old days when you pull a 7m-ge block apart, the aux shaft has a spot for a fuel pump drive on it and a hole in the block for the mechanical pump. there's also the crankcase ventilation which quite clearly used to run a distributor.

i love the interchangeability of some M parts... ive really only played with 5m-e/ge and 7m-ge/gte but from the head down i play mix & match quite a bit. one day ill finish my destroked 5m/7m contraption..........