compression check

[Wambat]

hey guys,

the 2h in my 75 seams to be a bit off, i have a couple of theorys to why but am unsure,

one is that the compression is not what it should be and i dont know how to check it or what i need with a diesel ( i obviously cant just pop the spark plugs out and put in the compression tester) so its through the glow plug holes that i go?? i have heard it is a bit of messing around??? also i remnber just a few days ago reading some one elses post on this( i was reserching stuff so i think its an old post) and they were quoting where it was losing pressure too, like the sump (and some where else but my memory is failing me. how do you know if its into the sump or one of the manifolds(dodgey valve seal or??)


the second is that maybe the injector pump is in need of a rebuild, what are the signs of this? ie, would you use more fuel,

as my 75 dosent blow much if any black smoke i think that the previous owner has wound down the injecter pump, the only time i get a bit of smoke is on start up and its isnt really black more white, and once its kicked over i get no more smoke, it dosent use oil, and i cant see any where that the sump has blown a gasket,

also im not suer about this, but (i could be altogether wrong any way) but with some engines, is fuel also not used to supply a very small fractin of cooling, ie if you run it to lean it will heat up ( i was reading that if you dont burn enough fuel that that does heat it up as it burns in the exhaust, and thats how the diesels get hot egts???)

so as an example, some may know of the calder hwy(most in vic should) after it goes to 110km/h after calder park, there are a few pretty long and decent hills, i get nocked back to 3rd on these, and down to about 45- 50km/h, the other day on the way up to wood end, my temp gauge was nearly up to over the top line(which puts it in the red) it wasnt quite there, and after i got to woodend i let it idle for a while and it came back to half so i wasnt to worryed,

but now i am looking into turboing the 2h, and i want to make sure that the engine isnt to far past it( its got 341k on the clock) but i have heard of people putting a turbo on and running small boost withot to much hassel, if the compression is good,

the motor seams to not have any thing i can tell wrong with it, apart from that serious lack of power. most of the time its pretty good, up most hills i dont have to much trouble, but on some decent accents it is pretty slow.

any help would be much appreciated guys,

cheers al

ps sorry about the novel

[skootin]

Try a few simple things first mate like the valve clearance and check for excessive wear on the rocker arm where it contacts the valve. If it has a significant wear mark you will need to get them built up and reprofiled.
Very common problem for the old 2H. If the valves are not opening as far as possible then you will be loosing power.

[Wambat]

ok so thats an easy thing to do on a sunday or monday arvo yeah??? just pull the rocker cover off, and slip in some thicness gauges( for the life of me i cant remember what them shim gauges are called and im a damn fitter i used to use them all the time)

[Wambat]

also any one know what thickness its ment to be? or should this be something my gregorys will tell me?

[oldmate]

also any one know what thickness its ment to be? or should this be something my gregorys will tell me?

it will be in the gregories, but the intake is .20mm, exhaust is .36

oh and it's called a feeler guage. now that's a fun word. feeler!

compression check can be done with the glowplug holes. minimum is 284psi, max is 398. cylinder difference is 2.8psi.

all figures are from the toyota workshop manual.

[Wambat]

thats right feeler gauge, man i feel like a dolt for not remnbering that, it would be like me not rembering a whats it called, oh yeah vernier lol.....


thanks for the figures, i will try and give that a check soon, also do i need a different type of compression checker for a diesel??? i am assuming that the threads on the glow plug holes are not the same as a spark plug thread, there fore not being able to use the same type as a petty one??

also round about what time frame am i looking at to do the job??? ie if i start at 3 in the arvo will i be done be fore dark, or is this a whole day kind of job??

[skootin]

Mate i would have a look to see if you got everything to do the job you are goin to need somthing to turn the engine over. Check the tips of the rockers for wear. If they are worn you are goin to need a feller gauge only as wide as the tip of the valve and the rockers are goin to need to be repaired.
A local engine reconditioner should be able to repair them. Spray weld the tips and reprofile them.
Remember this is only a starting point there could be other issues with the engine. Or exhaust system.

[Wambat]

you cant just do what you do witha petty?? take out the glow plugs, and give it a kick with the ignition???

i have feeler gauges, i have everything i need, except a compression tester.

oh right i think i figured out what you mean, i need something to turn the motor slowly so that i can get the valves in the right possition so i can accuratly use the feeler gauges, well i dont have anything to do that with, and i would assume, without taking out the glow plugs any way it would be almost impossible.


could you not take out the glow plugs, jack the read up and sit it on axel stands put it in gear and spin the tyres to turn the motor??( it may sound dumb, and you dont need to jump to calling me stupid, just remember i have never done any of this on a petrol let alone a diesel.) that being said i am mechanicaly inclined, i just havent yet done these things.

i would probably do the job with one of my mates who is a diesel mech any way, and i would hope he knows what i can and cant do

[oldmate]

you will need to disconnect the wiring to the edic motor, so that the pump stays in the stop position, and doesn't try and kick over when you're cranking it. other than that it's much the same as a petty motor.

Shouldn't be hard finding an adapter for the glow plug hole, it is a common thread size for toyota glowplugs and probably many others

with the valves you can do the jack up the tyre trick i've done it. the measuring is only done in two positions of the crank anyway. If i recall there was nothing on the front pulley to get a socket on?

You might beable to turn the motor via the alternator pulley, if you have all the glow plugs out doing a comp. check. no compression it will turn easier.