1HZ Compression - Advice?? (1 Viewer)

[nickw]

I spent 1.5 hours mowing my lawn so I had some time to think.
Assuming the above numbers are right what could it be?

-Leaky head gasket? Maybe he reused the old one? But its even accros the board...
-Maybe he never ground the valves? (can you loose that much compression from valves?
-Maybe he messed up the cam timing. (Can you check the timing on your cam? Maybe its running a little out.)

Logic make me think its the cam (would be an honest mistake) or the rings.

I averaged your compression and its only 311psi.
You said the numbers should be 525 psi (or about there in).
Are you loosing any oil?
You said it runs good right. Have you had the oil tested for fuel blow by?

Assuming the valves are good, and rings are good, it means your compression area is about 70% to big.
Which is a lot of space!

The only way I figure you can loose than space is to be have the wrong part in there. Wrong pistons, wrong head, wrong con rods, or wrong crank, wrong cam. I can't see you loosing that much compression from a head gasket (assuming you have no blow by).

What do others think?
Could someone of put an older engine part in?
Is there 2 versions of the 1HZ (like there is two 3B's)?
Or could someone of used a 1HD-T part think they were the same?
70% is a lot of space (assuming its not valves or blow by)

The more I think about this, the more I think the cam timing is out.
It seems the most simple to mess up (over wrong part, or rings), and the most honest mistake.
But take my advise with a grain of salt.
I am no expert. Just trying to use my head here.

So what do others think?

Cheers,
Nick

 

[Entaran]

I've used three completely different compression gauges and gotten the same result give or take 40 kpa.

I don't have the part numbers on the receipt, all it says is "pistons, rings" etc. all on seperate lines and it mentions a HG.

The timing and valves have been reset at the last service. This was all checked.

Unfortunately I don't have another 1hz to drive next to, so I don't know if it's "gutless"... how do you define gutless if you've never driven another 1hz? It definately doesn't have the pull of one of the ones that I test drove before I purchased this one at 77,000kms. <--- uhhh edit: I test drove a 99 model 75 series ute with a 1hz that only had 77,000 kms on the clock and it had a fair bit more "pull" (measured via seat of the pants) than this one.

Crushers, that DEFINES my car. Perfectly. The only issue I have is with the "gutless" call, I don't think it's gutless, it definately has a fair bit of get up and go.

Time to order a new headgasket and get the head ripped off to check.

 

[crushers]

best of luck...
let us know what you find...
do a timing check before you rip the head off, if the pump is out 1 tooth that can make all the difference as well

 

[Tapage]

when I go in my 2H overhaull ( years ago ) I'm very surprised to know there are 2 diferent headgastket kits .. for 2H.

One with superior pinton ring ( I'm not sure if is the right name ) other witout piston righ. This was why you can do it with cilinder jacket ring or outout it.

 

[roscoFJ73]

I've used three completely different compression gauges and gotten the same result give or take 40 kpa.

I don't have the part numbers on the receipt, all it says is "pistons, rings" etc. all on seperate lines and it mentions a HG.

The timing and valves have been reset at the last service. This was all checked.

Unfortunately I don't have another 1hz to drive next to, so I don't know if it's "gutless"... how do you define gutless if you've never driven another 1hz? It definately doesn't have the pull of one of the ones that I test drove before I purchased this one at 77,000kms. <--- uhhh edit: I test drove a 99 model 75 series ute with a 1hz that only had 77,000 kms on the clock and it had a fair bit more "pull" (measured via seat of the pants) than this one.

Crushers, that DEFINES my car. Perfectly. The only issue I have is with the "gutless" call, I don't think it's gutless, it definately has a fair bit of get up and go.
Time to order a new headgasket and get the head ripped off to check.

The power of these is usually defined by its abilty to keep going up steep hills and overtake at open road limits.
Even a worn out 1HZ will still get around ok in the lower gears especially when its not fully warmed up.


I notice the receipt didnt mention machining . Its not uncommon for some people to stick some rings and pistons in and call it" fully reconditioned".

 

[Entaran]

Mine is lucky to hold 80 up a steep hill. Gets slower depending on the load in the back. Weighbridged at 2460kg with 105 litres of diesel onboard (out of a total tank capacity of 230 litres).

Blows arseloads of black smoke when I push it while going up hills.

Never tried to overtake on highways, but it DOES NOT like going faster than 100kmh-105kmh.

 

[crushers]

hummm, i really want to see what is going on inside that engine...
did you get the timing checked? i would do that first before going inside just to make sure a gear isn't out by a tooth or something..

 

[Entaran]

My mechanic says he reset the timing to factory specs just incase. I won't have a chance to do anything further as i'm leaving Aus for Europe on the 23rd (Tuesday) and get back on October the 3rd. So I'll resurrect this thread from the dead when i've got more to say.

 

[roscoFJ73]

Mine is lucky to hold 80 up a steep hill. Gets slower depending on the load in the back. Weighbridged at 2460kg with 105 litres of diesel onboard (out of a total tank capacity of 230 litres).

Blows arseloads of black smoke when I push it while going up hills.

Never tried to overtake on highways, but it DOES NOT like going faster than 100kmh-105kmh.

It sounds like your problems are compounded by a fuel problem.

Im not sure if an engine clogged up with carbon would have an effect on a compression test.
I know that a thick layer of carbon on a piston will cushion the reaction from the fuel combusting thus lowering the power output

I can push mine up most hills at 100 kph in 5th and still be accellerating although I dont make a habit of it.
It will wind out somewhere past 130 kph .

Ennjoy yourself and make sure you come back with lotsa cruiser pics

 

[crushers]

if it was carbon build it the result would be the opposite of what he is experiencing...no?

 

[Entaran]

Rosco... the FJ73RV models only weighbridge at a little over 1800 kg with a full LPG kit fitted and 90 litres of petrol and 70 litres of gas onboard.

My cruiser is ~2500kg. That's a whole lot more mass to move... or keep moving. Plus i'm turning 33x12.5 BFG Muds.

 

[roscoFJ73]

Rosco... the FJ73RV models only weighbridge at a little over 1800 kg with a full LPG kit fitted and 90 litres of petrol and 70 litres of gas onboard.

My cruiser is ~2500kg. That's a whole lot more mass to move... or keep moving. Plus i'm turning 33x12.5 BFG Muds.

Toyota australia list the current model 79 series as having a tare weight of 1900-1980 kg.I know they are a little lighter than the older model but not over 500 kg

I thought my 73 weighed about 1890kg before the diesel swap and its also pushing 33x 10.5 with 35 psi.
It also has a full recovery kit,2-3 jacks and a 100 pice sidchorme toolset and other goodies on board
Ive also driven about 20-25 x 75 series ,from old bangers with 500000klms and brand newies and know all about the power.

Believe me you have a serious power loss there!

 

[roscoFJ73]

if it was carbon build it the result would be the opposite of what he is experiencing...no?

Its my understanding that the carbon build up can cushion the kick from the combustion.
A bit like trying to jump off the ground standing on a pillow,its more effiicent on a hard surface.
In retrospect I dont think it would affect the comp test.

 

[crushers]

In retrospect I dont think it would affect the comp test.

curious as to why you say this? carbon takes up space hence higher compression... no?

 

[Entaran]

My ute weighbridged at 2460kg. the 1800-1900 kerb weight is for the cab chassis minus the tray. My tray is 100% steel and I have long range tanks, a massive bullbar/brushbars, dual batteries and a few other doodads. Hence the weight.