98gti's 97VZR

Cheers for the advice & comments lads. The N1 pistons & rings work out about $300 which is pretty cheap compared to the custom cp's. I was thinking about a set of them but wezz talked me into the N1's. Just need to drop the cr down a bit
I've been having a look about & mazzworks do the apexi head gasket whch is supposed to be the strongest, from what I could work out a 1.1mm gasket would bring the cr down to about 12.3-12.5. Does that sound about right? Then I wouldnt need to get the pistons machined either, but the cost of the gasket added to the pistons about the same as a set of cp's.
 
craig my love if the pistons are 11.0:1 then they will be 12.3:1 in your motor so yeh they will be sweet :cool:

yeh gaz get a thicker head gasket but from what i remember the standard gasket thickness for all SR20's is 1.2mm so 1.1 would raise it a touch
 
1.2mm is standard. Thing with the CP's is there also lighter than any Nissan piston, so it will rev better with them.

Ideally CP's are the way to go, but just depends how much you wan't to spend. Get a Cosworth or Mazworx HG too if you can.
 
Got the block stripped down last weekend so I can get the bearings etc ordered up at last.
I've been thinking about getting the crank, rings etc WPC treated, anyone know anywhere in the uk to get that done?
I think I'll go for the N1 pistons, I should get about 12.3 - 12.5:1 with them & the cossie h/g.
Also been looking at a crank scraper & windage tray, I've been told that can gain up to 5hp & it's a pretty cheap mod.
Block will be going off to the engine shop soon, is it worth having the oil grooves cut in the journals like the gtir block as well as tapping for oil squirters?

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Good thread mate made an interesting read. Sounds like it's going to be a beast. Wezz you might want to stay N/A to run head to head ;).
 
sweet your doing the same as me then :P but i have a VE block with 2.0 cods with SR16VE\pistons.. im just building it and seeing what happens.. n1 cams though carnt afford them aswell as everything else!
 
crank scraper and windage tray?! :confused: :O


gonna be awesome build man, can't wait to get my bits either now. what bearings you goin for? and did you say you thought about eagle rods but weren't gonna bother?

how much are n1 pistons with rings then? my custom CPs will be 12.5 in my de block with 16ve head and they're bout $600 shipped after a little lucky discount.

i want n1 cams too :( :lol: or the kelfords! :D
 
crank scrapper is made of nylon and should sit less than a few thousands of an inch away from the crank so that excess oil is removed as it goes past and stop it getting thrown around inside the crank case..
 
Raceworx said:
crank scrapper is made of nylon and should sit less than a few thousands of an inch away from the crank so that excess oil is removed as it goes past and stop it getting thrown around inside the crank case..
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and more importantly reduce crank load and resistance ;)
 
No bother ross thanks for the help mate.
Which head gasket you using ian? Are you going to modify the pistons for the oil squirters? Just wondering if the N1 pistons will need to be modified.
In this case the scraper is teflon coated steel.
My undersdtanding is when the crank is spinning in the block it sits in a dense cloud of gasses & oil vapour that spins with the crank making it harder to slow down or speed up rotation of the crank (they both want to rotate at the same speed). When the crank rotation speed is changed the gasses momentum fights against the crank until they are at the same speed again. The windage tray & scraper help break up the flow of gas & oil around the crank in the similar way as knife edging the counterweights.
 
Raceworx said:
sweet your doing the same as me then :P but i have a VE block with 2.0 cods with SR16VEpistons.. im just building it and seeing what happens.. n1 cams though carnt afford them aswell as everything else!
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2.0 'cods' Ian? sounds fishy, are you using ebay chips in your build too? Sounds appertising :lol:

Keep us posted 98GTi, looks like VVL is going to be taking over...
 
craiGTi said:
gonna be awesome build man, can't wait to get my bits either now. what bearings you goin for? and did you say you thought about eagle rods but weren't gonna bother?
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Cheers craig. I probably will go for the eagle rods, I was thinking about getting the DE rods shotpeined & arp bolts but I think that would be not far off the price of a set of rods & the eagles are 100g lighter per rod. I've read good things about the calico coated acl bearings so I'll probably go for them.

Raceworx said:
ill be using a metal VET gasket and getting the pistons notched by 10mm or so that should be plenty..
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Cheers Ian, 10mm sounds good.
 
98GTi said:
Cheers craig. I probably will go for the eagle rods, I was thinking about getting the DE rods shotpeined & arp bolts but I think that would be not far off the price of a set of rods & the eagles are 100g lighter per rod. I've read good things about the calico coated acl bearings so I'll probably go for them.
.
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yeh i think you just persuaded me to try n save for some, nice light eagle rods with nice light cp pistons shoud be sweet :cool:
 
Crank, Rods, Bearings, Machining, Balancing, Coatings, Manifolds, etc.

The SR20 is blessed with a near bulletproof bottom end. The crank and rods are forged steel unlike the typical cast iron that most American motors run. The rod bolts are a beefy 9mm. The crank features rolled fillets, an uncommon strengthening operation used usually only for racing or heavy duty parts. The rod bolt registers are spot faced, leaving a generous amount of metal around the bolt holes, a traditional weak area in connecting rods.

Both the crank and rods are subjected to a severe shotpeening from the factory. Shotpeening microforges the surface of the part making it stronger and harder while leaving the interior soft and ductile. This step can improve the fatigue strength of a part by over 100% and is usually reserved for high end racing parts. The main caps are tied together with a stiff aluminum girdle which improves bottom end rigidity significantly. This feature is usually found in all out race motors. These design elements produce an engine that is nearly bulletproof. I have seen motors with over 100,000 miles on them with the factory honing marks still visible in the cylinder bores! The number of list members in the 100,000 Mile Club is a testament to the durability of the SR20.

The only catastrophic engine failures that I know of (Tom Paule and Zak Nilsson) were the result of low oil levels with spun bearings. Chuck Nibbana’s super trick engine also mysteriously disassembled itself but that might have been because of improper clearancing. I have screwed up 3 SR20’s myself but that was the result of not watching the temperature gauge while racing IMSA and SCCA. Gross overheating was an understatement. Clark Steppler of JWT has never seen a catastrophic failure that could be traced to the engines fault, either.

The same bottom end of our US model SR20DE also is used for the turbo SR20DET so we have a lot of headspace before we start to challenge the strength of the bottom end. The stock parts can be used until the hp climbs well into the 200’s. So bring on the NOS, turbo boost and compression! We have run Ryan Besterwich's turbo car (formerly Searl's) as high as 20 psi of boost which pushed the car into the low 12's with a completely stock bottom end with no harm. His car has over 80k miles on it and is still going strong. I estimate that his car is putting out over 400 hp with the stock bottom end! If detonation can be controlled the stock bottom end is pretty strong!

If you are building a hot street SR20, I recommend leaving the rods alone. By doing the traditional beam polishing you will be removing the factory tough shotpeened surface. If you reshotpeen the rods after polishing they will have to be resized and straitened as proper shotpeening distorts the parts. It is not likely that a local shotpeener can do as good of a job as the factory either. The same goes for the crank. It won’t hurt to do these traditional race prep steps but it is probably not worth the effort on the SR20.

If you do prep and re-shotpeen your rods make sure that the piston wall oil squirter hole does not get blocked or peened over. This hole sprays oil on the thrust side of the cylinder helping with lubrication and keeping the engine quiet.

In fact, I might say that no matter what you do to build a naturally aspirated motor, if you keep an 8000 rpm or less redline, you don’t need special rods.

I do not have any personal experience with the well-publicized-by-Turbo-magazine, Metalax treatment process but have heard good things about them. I do have plenty of good personnel experience with shotpeening solving many parts breakage problems. Recently I have had very good luck with cryogenic treatment preventing breakage of drivetrain parts with high powered SE-Rs and I am currently building a VG30DE motor using cryogenic treating extensively.

For extreme use in killer turbo motors running near 20 psi of boost or for those of you running 100+hp NOS units, racing rods may be in order. JWT can get Crower rods. I believe these rods are machined from 4140 billet. I am using Cunninham rods in another engine. These rods are a little lighter than Crower and seem just as high quality. Carrillo makes excellent rods also but they would be a custom application and take 6-12 weeks for delivery. These racing rods do not have the oil squirter hole in them which could result in slightly shorter life of rings and pistons.

The rods and pistons should be balance to within ½ gram and the crank dynamically balanced. I have found that Nissans are generally within 1 gram from the factory! A typical American car is usually off by as much as 5-12 grams! I like to polish the journal surface of the crank. You can have a local machine shop do it using the lightest grit of polishing paper belt. You don’t want to remove so much material that the crank dimensions change, just reduce the RMS of the surface by knocking off the peaks of the machining marks.

The factory Nissan bearings are strong and durable. I recommend running bearing clearances in the middle of factory spec on a typical street motor. Clearances on an all out racing motor can be set on the looser side of factory. When buying bearings, Clark Steppler of JWT has told me (and I have also observed) that if an engine has any kind of mileage on it, the next tighter bearing size can be used other than the number that is stamped on each journal of the block and crank. Remember to mike and bore gauge all the journals to confirm proper dimensions before assembling. If you don’t have access to these , at least use plastigauge to make sure that you are in the ball park.
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taken from the SR20 forum
 
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