91Toyota

O.K,

Noticed my truck would not rev very high (above 4K) and didn't get that "great" of gas mileage.

So, here is the compression test

#1 - 189
#2 - 179
#3 - 60!!!
#4-183

So, I took my head off and took it to a machine shop...they told me it needs a valve job and they are currently doing it. Now, I am going to buy some rings and a hone and replace that ONE cylinder with new rings. So, does anybody have any suggestions on how to hone?

I am afraid that if I take it apart anymore I am going to forgot how to put it back together...lol

DeathCougar

iTrader: (23)

Why would you replace just the one cylinders rings? Thats silly. If you already have it apart, just do the whole engine.

Just take your time taking it apart, and label EVERYTHING, including the direction they come off/go on.

91Toyota

The rest have good compression...they don't honestly NEED it like this one does.

DeathCougar

iTrader: (23)

well if one cylinder went out, how far behind are the others? Willing to take that risk instead of the minor extra time to just do it all?

dcg9381

Does the machine shop thing the low compression was due to your head? If so, don't touch the bottom end.

I generally don't like the idea of "hone job" rebuilds - not even on all 4 cylinders. I like the idea of doing 1 cylinder only even less.

Ask at a machine shop about which tool to use for honing your cylinder. Remember to gap your rings and check the bore for being round, if you're going to give it a try.

91Toyota

Yes...I will probably end up rebuilding it anyways. I want to put a turbo on it too.

No, they said the head was holding fine...and it could not have been the rings. I should have known about the leak down test before I tore down.

Sorry, but how do you gap the rings? They are standard size...don't I just put them in?

Thanks...I know it seems like I am an ignorant kid...but I have NO money. I have about $200 and that pretty much covers the head alone.

toytech76

You should have done both heads at the same time. I hope they are REPLACING your exhaust valves when they grind the intakes. If they grind your exhaust valves you will have the same problem in no time. 3.0's burn valves all the time. I know you said you don't have money, but you need to spend money and do it right or it will end up costing you more money down the road. As far as putting a turbo on your 3.0.... don't. The top end wont be able to handle it. Save your money and dont touch the bottom end of your engine. Put it all into your cyl heads

toytech76

oops..I just read it was a 4cyl. my bad. It still stands tho, do it right, don't touch the bottom end. A turbo should be ok if its mild

91Toyota

It will be right.

I have a 25% chance of screwing up this one cylinder...and honestly how could it get worse.

If I do all I have a 100% chance or screwing up. Then what do I have? I will do one cylinder and one cylinder only...unless someone convinces me other wise.

It is still a thought though...I "might" do all 4 but it is unlikely.

Roger Fairclough

Just a few technical points:-
a) you can only loose pressure from your valves piston rings or head gasket. If the machine shop says its the valves - problem solved. As you have got the head off , ask them to check that the head is flat. Check the old head gasket for black soot marks leading from the cylinder to open air. If in dought, take to the shop and ask their advice. When you clean the crap of the top of the block, put a bead of grease between the edge of the pistons and the cylinder wall. This will stop the carbon getting down by the pistons. Just wipe the grease off when you are ready to put the head back. Dont strip out the pistons just for the sake of it.

dcg9381

The rings are usually too large for the bore and need to be filed to fit. Ask your machinist. Rings expand when hot, so if they are too tight, its Very Bad...
There is a designed piston to bore clearance and a ring gap clearance.