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L28 rods


Riceburner

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I'm building up a newl28 bottom end for the riceburner, 88mm flat tops, everything balanced, p90 head with works 74 cam from Peter mc. I have decided to go for a less expensive option of standard pistons/rods but over bored pistons, so will standard L28 rods be reliable enough or should I spend some extra on spool forged L28 rods??

 

Also I have turbo head bolts new, will these be ok or should I go for ARP studs?

 

Is it worth getting the Kameari twin idler for the timing chain?

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What sort or revs are you planing on going to? My healthy L28 was only revved to around 6500 and that survived pretty well with standard rods. Just made sure the flywheel / clutch was well balanced..

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Have some sort of rev limiter just in case you miss a gear etc... cheap insurance. When I had my flywheel / clutch balanced I was told lucky i didn't run it the way it was; it was so unbalanced I could've destroyed it all!

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Rev limit on MSD set at 7150 and it does work  ;D scared the crap out of me when I hit it! LOUD. Everything will be balanced, BMW harmonic balancer, lightened balanced flywheel, crank journals polished, ARP studs and bolts, Kameari adj cam gear, Kameari H/D oil pump and possibly the twin idler gear......

 

Sound ok, anything missed?

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standard rods are ok when prep work has been done .I change them because i like the long rod . and short piston which is 200g lighter per cylinder .a 88mm piston on a standard rod will be heavy

 

Hoping this will get me by for a some years until I can do the dream bottom end we chatted about, but the finance department keeps reminding me of the word 'budget'  ::)

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I bought the "How to modify your Nissan/Datsun OHC" book and it has been a wealth of knowledge for this sort of thing. I recommend you buy it and read through it before doing your build because it will answer a lot of the questions you have, give you new ones to ask and give you a lot of ideas for bullet-proofing your engine.

 

All i can do is recite what i have read from it but, shot peening and cleaning up the castings is probably a good idea if you are going to that much trouble. It can eliminate weak points in the rods particularly around the bolt areas.

 

You should probably go ARP rod bolts too.

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I would get some aftermarket rods for the following reasons

 

1. Cost to prep stock rods = more than 1/2 the cost of new lighter rods already with ARP bolts

2. As the new rods are lighter the engine will spin faster and now have a more lively/rev'y feel.

3. They will be new and not a 30year old rod with some work.

4. Did I state the will be new and not a worked 30year old part.

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Yep - and then you can do what MC Pete said and put FJ20 rods in it 140mm long and get custom pistons say 89mm and end up with a 3.0L!  8) Thats what im doing.

 

I'd be interested about the Kameari idler too - Datman2k actually has one so he is probably best man to ask but i gather its mostly important when you want to take a lot off the bottom of a head (particularly P90) like over 2mm and the timing chain guides will be too long.

 

They are like $700 right? I think if i was in your situation I would rather spend that on rods and forged pistons to make the bigger capacity which will also give more compression.

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If the block is up to a 4mm overbore (I have build an engine like this in the past) with a L28 crank then that is 3015cc. 90mm bore with 79mm stroke.

 

If you sleeve the block you could go as far as 91mm but then if you are doing that you might as well start with a LD28 block and sleeve that out from 84mm to 90/91mm and run the LD28 crank. Then you a taller block so long rods are not an issue and a good rod/stroke ratio can be had to get the piston dwel you want for a large cam etc. We are now starting to talk about a big investment in an engine if you are going to build a long stroke/long rod LD28 blocked NA engine. Never seen it done but it has been done in USA that I know of. You will need to use a L20B front cover to match the NA L28 (highly modified for big power/flow for the 3200cc monster you will be building ;)) for the LD28 block and you will need custom head bolts as the diesel head is held on with larger bolts (so the L28 head will need the head bolt holes enlarged)

 

But as stated if $$ are limited for the build I would recommend new rods and skip the fancy tensioner just add that later ;)

 

Depending on the rod required spool do L28 spec H-beam rods with ARP bolts. Or Maxspeeding Rods so L24 H-Beams with ARP bolts. If you are using a L28 block and L24 H-beam rods you will need to relieve the block a little for correct clearances.

 

My 2cents if that counts :) 

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Getting a price on the spool L28 rods right now, SWM oversized pistons and other bits on their way.

 

Are you saying the Kameari twin idler isn't required?? I have a new rollmaster timing chain and kit with guides and adjustable tensioner, will this do? Thanks for all the help guys, It's nice to have educated people to bounce ideas off  :D

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Hi Gareth

 

FWIW, James Flett made me get one of the Twin Idler's for my L24 hotty. Rationale was that with a mildly shaved head, its insurance for the rest of the motor, particulalry given the ease of external adjustability. They are not cheap (i think mine was about A$600) but with the A$ where it is now, you can get via USA for less these days (maybe $450 or so). It is an extremely well engineered part that boasts of being able to handle 13000rpm!! (presuming its even possible). If you are in doubt, call James at MIA in Sydney and ask him.

 

On the rods, I note that James typically uses OEM rods for most of the L race engines, but he does do some work on them. Its also worth pointing out he uses new OEM rods, which gets to NZeders point about reliability. I actually asked the question at the time about light or titanium rods, and he said they are available, but at $2000+ a set and well up on that for titanium, its a huge investment for something that ultimately is not massively better than a well sorted OEM rod. My engine has OEM L24 rods, with some TLC lavished on them, that he suggests would handle ~8000rpm.  Suspect i'll chicken out well before that.

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4mm overbore would be well suited to boost (10psi)  then would it?

only if you want split bores :( I am talking NA only here. Boosted is best limited to 2mm over bore only :( aka 88mm - never never go more than 88 on a boosted application unless you want to keep rebuilding bottom ends

Its also worth pointing out he uses new OEM rods, which gets to NZeders point about reliability. 

See  the key there - NEW - if using NEW OEM Rod then that is perfect too but you still have to prep etc - but then you still want to check/balance any rod you install.
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