Head & Timing Chain Help

[fluegel]

My 260z has been fitted with a replacement E88 head. The total head thickness is now 105mm I am told by the people who last overhauled it that they don't go below 107mm. I have run the car without pinging problems so the compression is probably not too high. What worries me though is that the chain tensioner shoe is out of its bore a long way ,15mm. I would think this would not allow much for chain stretch, the chain is relatively new. Do I have to scrap the head or what are the options.

[benny]

wouldnt you be better off leaning the chain guide out as far as possible to get the extra tension??

[fluegel]

wouldnt you be better off leaning the chain guide out as far as possible to get the extra tension??

 

Thought of that, the chain guide is over as far as it will go.

[Riceburner]

In the pic the slack side tensioner can be moved over, it has slotted holes so you can move it in further. Seem very slack though

[benny]

In the pic the slack side tensioner can be moved over, it has slotted holes so you can move it in further. Seem very slack though

 

 

as Gareth said you still have that full slot of movement and really you could elongate the slot even further!!

[peter mc]

that gets moved in and the top hole need to be filed . but first pull the tensin er in all the way , with a cable tie and then move the guide out all the way top and bottom and then release the cable tie this will move it a long way 

[dat2kman]

Even with a brand new chain, ie no stretch, you are at the limit.

You can slot the oil plunger tensioner block, but will need to machine on backside the oil feed groove to allow. As well, the dowel will need a new corresponding hole.

Your frictional losses will be greater.

Other option, highly recommended, it is used in some race and rally L4 and L6 engines is the adjustable tensioner assy, with top and bottom sprockets, and the curve guide is not used, these are ex Japan, i can supply for $750.

These allow up to 4 mm off L6, and 3 mm off L4 heads

[d3c0y]

I dont know if a twin idler is worth it to be honnest you could spend that money on a better head and have change unless yours has work done to it.

[C.A.R.]

Topic split.

Fluegel, DO NOT make a post asking for personal help in an information resource thread such as the Head ID thread started by Steve. You have been warned.

[fluegel]

I dont know if a twin idler is worth it to be honnest you could spend that money on a better head and have change unless yours has work done to it.

 

The head has been overhauled with new hardened valve seats, cost me about $800 but it has had about 3mm machined off its thickness which would acount for the loose chain. The twin tensioners may be the way to go looks a lot better than the standard set up. Besides, removing the existing  head is a lot of work and fitting a copper shim could be dodgy. I would like the engine/car  to last me out so I am willing to spend a bit on it. I hope this message complies with the rules.

 

Richard

[RLY240]

Hi Richard, as the others have already pointed out in your photo the lower mount of the left side guide has two mounting holes.  If you move the mount to the left most hole you will take up most of the slack in the chain and the tensioner will sit further back in the block.

If you do a google search you will find plenty of threads and advice on shimming the cam towers to compensate for facing the head as well as selecting the correct lash pads to set the correct wipe pattern of the cam lobes on the rockers.

3mm is a reasonable amount to remove from the head and you will likely need an adjustable cam gear to get the cam timing back again.

Where abouts in Adelaide are you?

Roger.

[MaygZ]

Has anyone thought of putting a 2-3 mm plate between head and block?  Or even running with 2 head gaskets?

[RLY240]

Has anyone thought of putting a 2-3 mm plate between head and block?  Or even running with 2 head gaskets?

 

Yes, but then you lose all that compression which is why you faced the head in the first place.

 

[dat2kman]

Cometic make MLS head gaskets in varying thicknesses, expext to pay around $450

 

Yes you could shim up cam towers, and then fit massive thick lashcaps, and stuff up rocker geometry.

 

As per the pic above, if you run that like that, it will crap itself very quickly, in a horrible way. If the plunger comes out a tiny bit more, it will cock in the bore.

 

You could start over and get a head close to stock height, and work that one up.

Dunno why some on here are anti the adjustable twin sprocket chain tensioner, they solve this issue, and you dont need to go to extra cost of shimming, lashcaps  and incorrect geometry, slotting curved guide, slotting tensioner plunger block, maching oil groove and relocating dowel. All do able, or, straight bolt on the twin setup!!

No brainer.

[Scoota G]

I set 1mm shims under my cam towers and found it set up the pad wipe better than stock with the cylinder head i bought off you dat2kman

[fluegel]

Dunno why some on here are anti the adjustable twin sprocket chain tensioner, they solve this issue, and you dont need to go to extra cost of shimming, lashcaps  and incorrect geometry, slotting curved guide, slotting tensioner plunger block, maching oil groove and relocating dowel. All do able, or, straight bolt on the twin setup!!

No brainer.

 

I still favour the twin sprocket setup ,as you said just bolt it on. As long as it takes up the slack I will be happy. Besides if I were being paid to fix my engine the $750  would be cost effective because it would take more hours work in money  value pulling things apart and driving all over town to pick things up. The compression increase seems to be an advantage, after I had the engine redone we passed a V8 commodore easily going up the Willunga hill.

 

Richard

[peter mc]

I'm with dat2kman  the twin idler is the go if the head and block have been shaved to far , lifting the towers is old thinking and not good for geometry  ,, i don't like making comp by shaving, its just the cheep way to make it work  not the right way , there are better ways for power production  ... 

if you have shaved the block or head to far the slack side guide will wear very fast at the top then it all goes wrong fast

and hp will drop in no time , the top of the Chane guide ends up in the sump and that's not cool

 

so the twin idler is cheep in a engine like this

[d3c0y]

I'm not anti-twin idler, it's just weird to be using such an expensive part on what sounds like a very stock motor. It's odd you decked it past what your head guy recommended without knowing what it would do. it's not like e88s are hard to get or expensive. Then you could of spent the $750 on something else, you get my drift?

[fluegel]

I'm not anti-twin idler, it's just weird to be using such an expensive part on what sounds like a very stock motor. It's odd you decked it past what your head guy recommended without knowing what it would do. it's not like e88s are hard to get or expensive. Then you could of spent the $750 on something else, you get my drift?

 

Now I am getting a bit stressed. The head was replaced originally by a mechanic who didn't know much about Datsuns,and Southcotts didn't mention the head thickness when they replaced the valve seats with hardened ones. I rang them to get the specs on head thickness I certainly didn't get the head planed to increase comp I would rather have things original. 

So here is the situation I have a reasonable but thin head bolted onto the block no leakes I have a reground camshaft in the head turning freely and I have new hardened valve seats. The head  has 3mm planed off and the timing chain tensioner is at its limits (I was able to move the slack side guide in at the bottom so things look better but the tensioner is still out 15mm so I don't think there is much adjustment left when the chain eventually stretches). The twin sprocket thing will fix the tension problem and besidesI would prefer device over the standard system. Also I want to replace the rocker arms with new and I will need new lash pads as well. If I use the existing head I will need about $1500 or more for the extra bits to get things working nicely. If I get a good head with the hard valve seats and use the original chain tension system I could still be up for more or the same depending on the price of a head.

 

Richard

[dat2kman]

Whoa! Dont stress! It is all fixable.

With that amount off the head face, for one reason or another, can't cry over spilt milk, the twin idler tensioner unit will solve that issue, at least you know the history on your head.

The next couple of shaves you, or next owner give it, i'd suggest keep it to less than 15 thou.

 

To go the route of another head will involve unknowns plus their costs.

 

With your current rockers, close inspection, if they are not ok, Stew Wilkins can supply exchange regrounds, using the CORRECT rocker gringer jig, around $15 ea?? It will for sure reqire new lash caps, but for now, measure thickness of current lashcaps, assemble, check cold clearances, to see what new thickness caps you will need, allowing for 10/12 thou clearances.

I have one of the twin idlers avail ex Brisb, for immediate delivery if needed.

 

On final assy, use a high Zinc content oil, ie Joe Gibbs Break In, LAT, or, Brad Penn. our rocker to cam is not able to cope with current "new" oils technology of today!

[MaygZ]

Has anyone thought of putting a 2-3 mm plate between head and block?  Or even running with 2 head gaskets?

 

Yes, but then you lose all that compression which is why you faced the head in the first place.

 

Now I am getting a bit stressed. ......... I certainly didn't get the head planed to increase comp I would rather have things original.

 

So $200 (ish) to have a de-compression plate made and then never wrry about it again.

 

it's not like e88s are hard to get or expensive. Then you could of spent the $750 on something else, you get my drift?

 

If I use the existing head I will need about $1500 or more for the extra bits to get things working nicely.

 

So who has an E88 head laying around for sale? 

 

$250-300 for a clean head

$200 - 300 for trueing, inserting hardened seats and matching the valves from your current head

$100 for head gasket

reduction in stress - priceless.

[salty]

 

 

 

 

So who has an E88 head laying around for sale? 

me...................................LOL