1098cc motor compression

[Vigil]

What is the stock compression on a 1098cc motor?
I looked at several books & coould not find it listed any where.

Thanks for your help,

vigil

[chrisryder]

not sure on the standard figure, but about 150psi is reasonably healthy!

[bmcecosse]

150 is decidedly marginal - a decent engine will be 160/170.

[Vigil]

Thank You

I am getting 130 / 135 / 132 / 136 on the motor i checked.
That is why i was wondering what it should be.

Vigil

[mike.perry]

150psi = HC
130psi = LC
Workshop manual General Data Page 11

[bmcecosse]

Figures will depend on the condition of the engine, whether taken hot or cold, condition of the battery and condition of the starter motor, and of course the throttle should be held open during the cranking. These figures ~ 130 psi are really pretty desperate and will not make for an efficient engine. To put matters in perspective - a really good competition engine will be in the 200/220 psi range and I would hope for 160/170 from a GOOD road engine.

[Vigil]

Is there is a way to tell if the motor in a high or low compression motor?
I believe only the high compression motor was exported to the USA.
The vehicle is left hand drive with a crayon mark USA on the firewall.
Assuming it is a high compression motor is 130's mean I am looking at a rebuild?
The motor does not smoke and seems to run very well.

Vigil

[Vigil]

i for got to post the battery is is good condition with a high torque starter from a Isuzu.
It works very well.

Vigil

[Fingolfin]

I've got a 1960 Traveller you can have, Vigil, and it's left hand drive...or once was...Stiltzkin's Rebirth

In my experience, all the engines over here are high compression. My experience is limited, though, to about seven Minors.
What sort of performance do you get out of the car? Acceleration and top speed and all that?
And what's the advantage of having a starter motor from an Isuzu...?

[Vigil]

The stock starter the bendex comes engages from the rear of the ring gear.
My old starter - the teeth on the starter were chiped all the way around.
I did not see any damage on the ring gear. But it is hard to tell with out pulling the motor.
The Isuzu starter engages from the front side of the ring gear.
So it uses the teeth from a different direction.
That way even if the teeth were chipped on the back it gives you time before replacing the it.
It looks like the high torque starter sold by Moss & others.
It cost less then rebuilding the stock starter.
I paid $70 from my local auto parts store.

Where are you located?
write me at uniquelittlecars@yahoo.com
I may be interested in the 60 traveler.
It was hard to tell what was left of it.

Vigil

[MarkyB]

As Roy says the throttle needs to be wide open when you take the reading and I should think the engine should be hot too.
If it goes well and doesn't burn oil a decoke and valve grind may be a good idea.

[minor65]

Both my 1098 engines are giving between 130 - 140 psi and both are excellent (i.e burn no oil, pulls well and does 40+ mpg). Your figures seem evenly enough between cylinders. If your engine is pulling well , idling evenly and not noisy then leave alone.

[Vigil]

Thank You for the suggestion


Vigil

[bmcecosse]

That Suzuki starter is a good idea - and good price too. It may however crank the engine more slowly - so that may drop the figures slightly. I assume too that you have ALL the plugs out while cranking. But basically - if it's running well - LEAVE IT ALONE! Maybe just check /set the valve gaps - 12 thou inlets and 15 thou exhausts.... And enjoy!

[mike.perry]

Low Comp. engines were used in LCVs and Military Travellers where there was a requirement to use low octane fuel.

[Fingolfin]

I'm pretty certain the US armed forces never used Morris Minors! Come to think of it, it seems odd to me that any military would. What did the British forces use them for? (Sorry for the departure from topic.)

[MarkyB]

Bomb disposal people drove them, with distinctive Red wings.
There was a picture here recently.

[mike.perry]

The British Forces used them for general running about, they never went to war so no machine gun mounts

[Fingolfin]

Dang! That'd be the Minor to have...a trav or pickup with a portable machine gun...

[MarkyB]

All you need is a ropey pick up and a Lewis gun and you could build your own technical!
It would certainly get peoples attention, particularly by the police