Head removal / timing chain procedure

[RodimusPrime]

Hi Guys!

Over the weekend I'm planning on removing the E88 head on my L24 for it to go away and get it's valve seats changed and cleaned up ready for a new camshaft / webers / exhaust etc. I've procrastinated a while over it with the panic of screwing it up.

Do you have any hints or tips regarding the timing chain (and specifically how to ensure that it's set to TDC). Whilst I would love to minimise the need to replace the chain/tensioners etc I feel like it's probably wise to replace everything whilst I'm at this stage.

If I set it to TDC, is it simply a case of then replacing the timing chain plus the sprockets/tensioners and ensuring the marks align with the head set at TDC. I'm assuming TDC is piston 1 at the top position and the first 2 valves at their top positions

Do you have any recommended guides to ensure that it all goes back correctly? (Or indeed any specifics you can advise please?)

Also, the engine will stay in the car - do you see this as a major problem or just make it a bit more awkward to access?

Many Thanks,

Matthew

 

[Rob Gaskin]

Do you have a workshop manual?

 

[RodimusPrime]

Yes, I have the Haynes and the Monroe but I was just wondering if anybody had any real world experience. I know the sprocket for the timing chain has 3 points (1,2 and 3) to take into account the potential stretching of the chain over time. If, for example, I find the old chain set at '2', and fit a new chain, would I simply install the sprocket/new chain so that point '1' is on the mark (i.e., the camshaft will remain in the same position?)

Thanks,

 

[Rob Gaskin]

I've had the head of a 240 a few times and never had a problem following the Haynes manual.

The most important thing is not to let the chain tensioner piston come out. I got sloppy once and it very nearly dropped into the bottom of the engine. I managed to get it back after about an hour of fiddling with long screwdrivers - I almost gave up! That was a win.

To hold the chain I used wire (think it was one of those cheap coathangers) and pushed it through the chain.

 

[RodimusPrime]

Thanks for the tip, Rob - I'll keep an eye out for that

 

[RodimusPrime]

Sorry Rob, just a quick question. Is that if you want to keep the chain in place for the head removal? I'll inspect it once the rocker cover is off in the hopes that it is immaculate however if not, then I suppose it doesn't matter too much if I let the chain drop as I'll have to take the cover off anyway to replace the sprockets and fit the tensioners/chain (I have a tool that should hopefully keep the chain tension on if I choose not to replace).

 

[Huw]

If you have a standard cam and the head is not crazy skimmed and all you intend doing is changing the timing chain, guides and tensioner, just follow the Haynes manual. If you’ve never done the job before, its very straight forward job to do and for once the Haynes manual is easy to follow.

If you have the head off and timing gear removed, TDC is very easy to determine using a dial test indicator if you have one or a straight edge and mark one eye ball if you don’t.

 

[nospark]

You need to buy the book "How to rebuild your Nissan Datsun OHC engine" by Tom Munroe

From your questions on how to do the job my guess is that you need to take your time, read the above book, have a clear understanding of what needs to be done and how to go about doing it

I wonder why you are going to replace the chain and tensioner . It will be a simpler job if you leave the existing chain in place. You wedge it with home made piece of wood (you'll find the shape/dimensions of this tool if you search the web). Again, read the book first

I am not that experienced in working on cars but have learned a lot from working on my Datsun. I took the head off and changed the valve seats on mine a couple of years ago. The key is to read and understand before you start. I advise that when you eventually send it off to the machine job you photocopy all the relevant pages from the FACTORY Manual (it will be available online if you search) to guide them on specs of the valves; valve/seat cut; springs strength etc

Good luck

 

[nospark]

oops. Just seen that you've got the Munroe book so disregard most of what I just said

 

[RodimusPrime]

If you have a standard cam and the head is not crazy skimmed and all you intend doing is changing the timing chain, guides and tensioner, just follow the Haynes manual. If you’ve never done the job before, its very straight forward job to do and for once the Haynes manual is easy to follow.

If you have the head off and timing gear removed, TDC is very easy to determine using a dial test indicator if you have one or a straight edge and mark one eye ball if you don’t.

Thanks - the new camshaft is slightly more aggressive than standard but not crazy, and I believe there hasn't been any skimming done on the head. I'll make sure I have the book to hand. Much appreciated.

 

[RodimusPrime]

You need to buy the book "How to rebuild your Nissan Datsun OHC engine" by Tom Munroe

From your questions on how to do the job my guess is that you need to take your time, read the above book, have a clear understanding of what needs to be done and how to go about doing it

I wonder why you are going to replace the chain and tensioner . It will be a simpler job if you leave the existing chain in place. You wedge it with home made piece of wood (you'll find the shape/dimensions of this tool if you search the web). Again, read the book first

I am not that experienced in working on cars but have learned a lot from working on my Datsun. I took the head off and changed the valve seats on mine a couple of years ago. The key is to read and understand before you start. I advise that when you eventually send it off to the machine job you photocopy all the relevant pages from the FACTORY Manual (it will be available online if you search) to guide them on specs of the valves; valve/seat cut; springs strength etc

Good luck

Thanks for the reply - it is quite daunting as this is the first head removal for me but thanks for the tips. I guess the only reason to replace the chain is if there is any sign of wear plus I'll be removing the head anyway so it would be an opportune moment. If I can avoid it, I will! haha. I went and got one of those PVC chain tensioner tools from ZStore which I hope will work as I see most people use the piece of wood method of keeping the chain under tension.

Thanks for the tip about the factory manual, I'll make sure I do that.

 

[jonbills]

IMO it's quite fiddly with the engine in the car. I'd suggest doing the job with the engine out.

 

[status]

If you have the plastic tool then that is spot on for wot you are doing,plenty of room as you know under the bonnet so should be straight forward