1973 Rebuild

[Zed Head]

The increase in displacement will far outweigh any effect from increased piston mass.  The increased mass would only be a factor for very high RPM engines.  But there are already big engines available.  280Z or 280ZX L28's.

I wrote the thing below up a while ago but didn't post it, but might as well.  I ballparked an L24 at 150 HP.  No offense but you might do some reading on general methods for increasing engine power.  David Vizard is known for writing good material.  I'm no expert myself but I can see that you  might be getting distracted with some of the racing engine factors, like piston weight at 10,000 RPM.  You are pretty far away from that concern.

 

An overbore to 86mm gives 7.4% more displacement.  If you can get the same power per unit of displacement that's 7.4% more power.  So a 150 HP 2.4 liter engine gets bumped up to a 160.5 HP 2.6 liter engine.  10 HP for the cost of the new pistons, rings, etc.  Notice that's about the same as the stroke change to 2.6 liter.  Mass of the pistons doesn't really affect power output.  87mm gives 9.9% more.  2.629 liter, 165 HP.

You could just buy an L28 and get 17% more displacement.  More stroke and an 86mm bore.

Seems like designing pistons might not be cost-effective considering all of the other limitations in the stock engine design.  It's been said, but the power gains are in the head.  Most people leave the bottom end alone until they get the top end working right, as I understand things.  The short block is very basic and very durable.  The head is poorly designed and full of potential problems.

[Matthew Abate]

The increase in displacement will far outweigh any effect from increased piston mass.  The increased mass would only be a factor for very high RPM engines.  But there are already big engines available.  280Z or 280ZX L28's.

I wrote the thing below up a while ago but didn't post it, but might as well.  I ballparked an L24 at 150 HP.  No offense but you might do some reading on general methods for increasing engine power.  David Vizard is known for writing good material.  I'm no expert myself but I can see that you  might be getting distracted with some of the racing engine factors, like piston weight at 10,000 RPM.  You are pretty far away from that concern.

 

An overbore to 86mm gives 7.4% more displacement.  If you can get the same power per unit of displacement that's 7.4% more power.  So a 150 HP 2.4 liter engine gets bumped up to a 160.5 HP 2.6 liter engine.  10 HP for the cost of the new pistons, rings, etc.  Notice that's about the same as the stroke change to 2.6 liter.  Mass of the pistons doesn't really affect power output.  87mm gives 9.9% more.  2.629 liter, 165 HP.

You could just buy an L28 and get 17% more displacement.  More stroke and an 86mm bore.

Seems like designing pistons might not be cost-effective considering all of the other limitations in the stock engine design.  It's been said, but the power gains are in the head.  Most people leave the bottom end alone until they get the top end working right, as I understand things.  The short block is very basic and very durable.  The head is poorly designed and full of potential problems.

No offense taken. You might be right that I'm getting distracted.

But I think you missed that this is an F54 block, so it's already at 86mm. The question is going to 87mm for a tiny increase in power or saving the $150.

As far as the head is concerned, we are fully taking care of the head. This is a situation where every component of the engine is getting examined and upgraded where it will have an effect. I was going to just run my E88 engine, but when my dad picked up this turbo for $80 we thought we would go nuts. So far we have about $650 in the thing. The Pistons will be about a grand, but he would have done it whether I put it into my car or not because that's what he does.

[Zed Head]

You mentioned looking for data about going from 83 to 86 so I thought you were working with an L24.  Going from 86 to 87 if there's no problems wouldn't make sense even if it were free, I'd say.  Unintended consequences, plus you take 1mm of life off of the block.  Might as well go to 89.  And stroke it.  Deja vu....

Good luck.  You know about these engine calculators right?  They're fun to play with.  http://www.ozdat.com/ozdatonline/enginedesign/

[Matthew Abate]

Can anyone confirm that the part number for tappets is 13234-21000 or provide me with the correct one?


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[Zed Head]

Rockauto shows a cross-reference, for a different brand, for 1984 Maxima, which appears to where that part number comes from.  Probably superceded the early numbers.  Click on the part number and it will bring up all of the applications.

http://www.partsfornissans.com/nissan/maxima/1323421000/1984-year/gl-trim/2-4l-l6-gas-engine/engine-cat/engine-scat

http://www.rockauto.com/en/catalog/nissan,1984,maxima,2.4l+l6,1211241,engine,rocker+arm,5656

Edited August 28, 2016 by Zed Head

[Matthew Abate]

Yeah, that's where I pulled it from, but if you google "13234-21000 Nissan" you only get two sites that say "lifter" but a whole ton that call them other things, and the illustration looks like it's a 510 rocker pivot like this:

http://thumbs.ebaystatic.com/images/g/BfoAAOSw7XZXgNp1/s-l225.jpg

I saw there's also a part with the number "13234a" but I can't tell what it really is. Do these two parts together comprise the entire lifter?

[Zed Head]

Actually, this one shows it as a rocker pivot too - http://www.partsfornissans.com/nissan/maxima/1323421000/1984-year/gl-trim/2-4l-l6-gas-engine/engine-cat/engine-scat

I wrote a whole thing then realized I don't know what you mean by "tappet".  It's not a word generally used with the L engines.

You can pick a number from the diagram in that link.

 

[Matthew Abate]

The long and short of it is that we rounded the hex on three of our mechanical lifters when we stripped our p90 head, so I'm looking for replacements. I and trying to figure out WTF is going on with the parts on courtesy Nissan's site because they've been closed. I'll call them tomorrow to see if this is in fact the complete lifter or if it's just the skinny threaded part that pushes the rocker arm.

This is the only solution I can find for buying lifters of any kind (mechanical OR hydraulic) short of grabbing up heads to strip parts from, or crossing my fingers that I can get a good set on one of these forums.

The other option is use a p90a and one of the two sets of good hydraulic lifters I've got. This will be dependent of my dad's conversation with Ron Iskanderian whenever that happens.

[madkaw]

The easy remedy is to buy the inserts for the hydraulic head so the mechanical lifters just screw in.
But maybe pics will verify that we are all talking the same thing


Sent from my iPhone using Classic Zcar Club

[Zed Head]

Aaahhh...you fell in to the "lifter" trap.  People have been mis-identifying the hydraulic pivots as lifters because they come from pushrod valve train world, where the common US-designed engine has hydraulic lifters.  They're not lifters.  I wouldn't use the words lifter or tappet at all when talking about these engines.  Nissan calls it a pivot, and the adjustable ones they call "oil pivots":  They don't move, therefore not lifters,  Not lifting.

[Matthew Abate]

YES! I did fall into that trap, because everyone and their brother on these forums calls them hydraulic or mechanical lifters.

BUT! I have dug into this site I found in a thread when I was looking for the club CD so I could get the part numbers: http://www.carpartsmanual.com/datsun/Z-1969-1978/engine-280z/camshaft-valve-mechanism

You can see they have the full spread of numbers for the entire valve mechanism, so I think I'm good on that front. It's the Rocker Pivot Nut-lock (13235-U0100) that I need to replace.

Bonus: autocorrect keeps changing nut-lock to nut-lick. Not sure what that says about me.

Edit: looks like this fixed my immediate problem. Courtesy and Zcardepot both seem to have the screw, the nut, and the spring in stock. Let me know if you guys have any pro tips I should consider, but I'll probably buy a full set of all three plus lash pads once I talk to them.

[Matthew Abate]

Update: it's not the rocker pivot nut lock. That's just the jam nut that keeps the pivot in place. I need the cylindrical base that the pivot threads into and the jam nut pressed against, which is the pivot bushing (13215-A8600) and NLA.

The one on the left is the assembly in talking about:



Gonna call Courtessy in the AM anyway to see what they can pull off.