It's been suggested it's possible with the heads on, has anyone done it?

 

My zed smokes a fair bit in the morning, but not once warm, hardly losing any oil, so pretty convinced they are to blame.

 

Ive got some jwt cams new HD springs and seals in my z1 order, as well as other bits, I was going to do the timing belt too,

 

Is it enough to have the piston at tdc or do I need to pressurise the cylinder too?

 

I'm trying to do it without asking our mechanics to help, so any tips advice would be appreciated,

 

Worst case it's heads off/ engine out, or I've another engine, but I want to try.

I thought I needed to do it and researched it, not done it though. It is possible but not very easy. There properly down in the head. I wouldn't be surprised if it was quicker to pull the block and do it the heads off.

http://www.twinturbo.net/nissan/300zx/forums/technical/view/1117366/A-Z-friend-of-did-it-using-a-self-made-tool-.html

> Is it enough to have the piston at tdc or do I need to pressurise the cylinder too?

 

you can use compressed air or with a piece of rope that fits through the sparkplug hole...fill the cylinder with as much rope as possible and slowly turn the engine to (com)press the rope against the valves

 

Once done, simply pull out the rope and on to the next cylinder

 

Apart from the tool that AndrewG posted, I also recommend a set of valve seat pliers to pull out the old seal (and put in the new one)

 

The hardest part will be compressing the valves,youll need to make a tool up to do it,i used to do many cars years ago like this but they were much easier to work on than a 300zx.

I did buy a jwt spring compresor, says it's designed for the 300zx, so will see, I do want a full rebuild, so hopefully this will buy me enough time to get the parts and funds together.

I did buy a jwt spring compresor, says it's designed for the 300zx, so will see, I do want a full rebuild, so hopefully this will buy me enough time to get the parts and funds together.

 

Your spring compreser will be no good with the heads left on...What Jim means above is finding a way to compress the spring downwards while still being able to retrieve the small collets. As Jim says again it was dead easy years ago on stuff like the Ford Kent engines ect,the valves were not buried in the heads castings and iff you had your Weetabix that morning then your thumb and 1st finger could compress the springs:w00t:. Iff i still had an old zx head i would of fabricated a tool for you but completly no spares anymore here..

That's annoying it said it was designed for doing it in the car...

 

It's this one, even the instructions ad with the heads still on...

Edited March 27, 20169 yr by (adl) phoenix

I've seen those before, can't see why it wouldn't work, IF you can keep the valve closed to compress against it.

I'll give it a go anyway, like the rope idea, not sure I trust compressed air, worst case I lose a valve and the heads have to come off...

Your gonna have to pull the plenum, cam covers, timing covers, cam belt, cam sprockets, timing cover back plate, cams and lifters as it is.

That's annoying it said it was designed for doing it in the car...

 

It's this one, even the instructions ad with the heads still on...

 

ahh i thought you had bought the normal C shaped type...carry on and goodluck

Your gonna have to pull the plenum, cam covers, timing covers, cam belt, cam sprockets, timing cover back plate, cams and lifters as it is.

 

egg sackly...another hour could have the heads off.

If the budgets there I'd pull the block, service it and pop it back in. Seriously, it would be worth it. Although the HG and lower plenum gaskets ain't cheap if you choose to pull the heads.

If the budgets there I'd pull the block, service it and pop it back in. Seriously, it would be worth it. Although the HG and lower plenum gaskets ain't cheap if you choose to pull the heads.

 

Yea but the OP has the chance to lap the valves in too Steve...ide do it as well as you would too given the depth of the strip down already.

True true, But where do you draw the line? I wouldn't really want to rebuild a top end and leave the bottom personally. I guess it's down to the £'s aspect really.

I've blown my entire budget for the summer already, on supporting mods, and bodywork, wad hoping to have enough to have jimmer rebuild my engine for me, but I want new turbos and injectors too before going that far. So this is me trying to stop the smoke and get it running right for the short term.

Then I think your plan is sound and wish you luck. Sure you can't live with it temporarily?

Just let it idle overnight and it wont smoke in the morning :1eye: