Builing my engine, had some ?'s

[virus77]

okay i got it up to 12psi lately, running good till i see smoke the other day, pop the hood and i see oil all over the intake manifold, looks like the valve cover seal blew. Go home swap it out (felt like hard plastic) run the car and it looks good, later in the day smoke again. This time its from the tailpipe, so im thinking ring lands (164,000 miles, boosted for about 7K beating it hard), turbo seals, valve seals. Do a compression check and cyl 4 is at 90, i guess its the rings . I figure the recent advance in timing plus 12 psi was to much for her even though total timing is around 15. Anyways im gonna be driving around smoking for a week or two until i get a block built on the side, Ill be getting a new water pump, bearings, and timing kit while in there but here are my questions:

1) If im puttin in ross pistons do i need to have to rotating assembly balanced, do normal machine shops do this or just bore and hone, check clearances, etc.

2) Im not going for arp hardware, but should i change the main and rod bolts to new factory ones or do the old ones work

3) God damit should i just fork over the extra 7 bills and get rods ( this question is opinion based, I know)

4) anyone have a recomendation of good pistons, or is Ross a good choice, i was also looking at the other ones ka24de.com offers

im planning on runnin like 10 psi on low boost and 15 psi on high boost with our ****ty 91 octane, I dont really have big plans on running race gas to get to like 20+ psi so i dont know if i should get the rods (but i want them) I dunno guys, in a bit of a dilema, help a brother out.

[nizmo240sx_22]

1) If im puttin in ross pistons do i need to have to rotating assembly balanced, do normal machine shops do this or just bore and hone, check clearances, etc.

It's not needed but I would highly recommend it. The place I had do it balanced everything individually in 3 hours for $150. For longevity I would get it balanced.

Quote »2) Im not going for arp hardware, but should i change the main and rod bolts to new factory ones or do the old ones work[/quote]The only way to know is to measure them to see if they have stretched or not. I purchased all new oem bolts from a nissan dealer so that's also an option.[/quote]

Quote »3) God damit should i just fork over the extra 7 bills and get rods ( this question is opinion based, I know)[/quote]If I was you, with your hp goals, I would just have the stock ones shot peened (ie, boostdesigns). your motor should be plenty solid to a little over 400hp.

Quote »4) anyone have a recomendation of good pistons, or is Ross a good choice, i was also looking at the other ones ka24de.com offers[/quote]I bought the supertech phosphorus coated pistons and I couldn't be happier. If they're not just as good, they're better than the other options. With the prices all comparable, it's really up to you.

[JayPat83]

[QUOTE=nizmo240sx_22]

If I was you, with your hp goals, I would just have the stock ones shot peened (ie, boostdesigns). your motor should be plenty solid to a little over 400hp.

I agree. just get the factory rods shotpeened and hardened and they will be great to 400hp. that is what i did and it only cost me an extra $75 instead of $400-$600 for forged rods.

[virus77]

machine shops shot peen rods or do i need to go someplace for that. What about for the balancing of the assembly, should I go to a performance shop or can my machine shop do that to? I was gonna go with my normal machine guy i use for regular jobs but now im thinking maybe for my high performance app. i should get it done somewhere better. What are some good shops people have actually used in S. Cali that can do the work, first hand experiance would be best.

[virus77]

I was thinking of 8.8 compression Arias pistons, any bad things about these i should know.

[Frozen240]

If your machine shop does enough volume they should have the equipment on site to do a full balance of your rotating assembly.

I agree woth shotpeening your factory rods for your power application level, I'm currently getting my engine rebuilt and I'm staying with the factory rods. The guys at the shop aren't even going to charge me for the shotpeening, guess I'm paying enough for other stuff to cover that.

I was also going to go with the Ross piston or supertech, but ka24de.com didn't have anything in stock and never replied to my emails asking them when they would get some in stock. i went with the Arias instead (just got'em today). They have the pistons in stock, so it's only a phone call away. Maybe Ivan from soundperformance can offer a little more insight into the quality of the arias piston.

[virus77]

ya i guess if its good enough for ivan its good enough for me, they are local to me too so i think im going to be getting the arias pistons, probably order them by the end of the week. how long did it take for you to get them?

[IvanAtSPRacing]

We have been using Arais pistons as our primary piston for about 4 years now. We had lots of issues with JE pistons and made the switch and didnt look back. Their customer support is exelent also (which is a big deal when it comes to running a shop) Every built motor Supra motor that comes out of our shop including our 1147WHP Shop Supra and Marko's 1248WHP Supra uses them. These arent custom pistons with upgraded wrist pins either... Just plain old off the shelf Arais forged pistons for the 2JZ. On Marko's car, each piston is holding up under 275ish HP... let that digest for a second.....

The design and the material of the piston keep piston slap down (the JEs were SO NOISY) and we dont have any of the warping in the butterfly cuts like the JEs.

For the KA, I like the compression ratio being 8.8. I think this is still low enough to boost the motor a signifigant amount but high enough to not kill torque or spool up. I will be ordering pistons from Arais for Phil's KA motor this coming week so I will know if they are in stock.
Modified by IvanAtSPRacing at 11:36 AM 11/25/2004

[virus77]

Thanks for the reply, ill be getting them for sure.

[andrave]

I dunno for your modest goals 8.8 seems a little low. You could step up at at least 9:1 and still be fine on pump gas, and have better off boost response. I hate to ask this, but did you look into a blown headgasket? I mean, with low compression on one cyl and oil in the engine bay that would be what I'd look at first. Compression test, 4 is low, add a cap of oil to that cyl, see if it comes up. If it does its rings. If you aren't sure do a leakdown test with the dipstick out.

[C-Kwik]

I dunno for your modest goals 8.8 seems a little low. You could step up at at least 9:1 and still be fine on pump gas, and have better off boost response. I hate to ask this, but did you look into a blown headgasket? I mean, with low compression on one cyl and oil in the engine bay that would be what I'd look at first. Compression test, 4 is low, add a cap of oil to that cyl, see if it comes up. If it does its rings. If you aren't sure do a leakdown test with the dipstick out.

I'd agree with andrave here and suggest looking for another source for an oil leak. Blown rings are not likely to spew out oil in the engine compartment. Perhaps drop a little oil in the #4 cylinder and run the Compression check again. If it is still the same, you may have issues elsewhere. If it goes up, then the lands are bad, but don't rule out other possible leaks as it is possible for there to be more than one source.

[IvanAtSPRacing]

Blown rings will most certainly blow oil all over your motor thru the top of the dipstick tube and the oil fill cap. Trust me, if anybody should know its ME. I popped a ring land on my S14 with a 250 HP NOS wet shot and two different motors in the S13 R&D car. Every time, there was oil blow everywhere.

[virus77]

The car spewed oil into the engine bay through the valve cover gasket on the intake side. I had originally thought this was my only problem but afterward i got to thinking that exessive blow by caused to much pressure in the valvecover and blew oil out, the seal was in really bad condition anyways when i checked it out (hard as plastic) so it didnt take much to make it leak. The back plug also was dowsed in oil, and I have a catch tank on the car that has always been dry as a whistle and now it is taking a healty serving of oil, also the car burns a clean blue cloud, absolutly no white. I was waiting for this to happen so i could build a block anyways, but I guess ill check compression again with some oil.

[andrave]

I'm aware of the dipstick problem- one of my friends cars just did that. But a blown headgasket can also cause the dipstick to shoot out too, you know, if the headgasket blows in a way that allows boost to vent down an oil passage.You may also want to look into a bad valve if you did indeed blow your valve cover gasket. This shouldn't have happened. Perhaps you are venting a little boost up inside the head and you are getting low compression....

[virus77]

I guess when i tear the motor apart it will be aparent what the problem was, but Ill give a good look into on sunday. Ever since it has happened and i gave it my first diagnosis I havent had time to look at the car.

[MarkEmark]

When I finally re-build my engine I am looking at either these super-tech phosphorous coated pistons or Arias...The supertechs, however, have a rather low CR (8.5:1), compared to the Arias' 8.8:1. What is the benefit of phosphorous coated pistons anyway, and how come almost all people just run regular forged pistons if the phosphorous coated pistons are the same price?

Ivan, do you know if Arias makes forged pistons for the KA24DE with a higher CR than 8.8:1 or is that the only CR they offer?

Also, I thought the factory rods were both shot-peened and forged...is it really necessary to get them shot-peened again? I'm not looking to make 400 whp either...I'd be extremely content with around 320 whp @ ~15 psi of boost.

[WDRacing]

They are shotpeened from the factory, but after use I guess they could use another dose of to get rid of any metal fatigue. I'd cryo mine also, its cheap and is PROVEN to work. Having a good motor that can run quite a bit of boost that only needs pistons and rings is awsome...and cheap.

[Red-KAT]

What needs to be done to get the engine to go to 7500 - 8000rpm's safe?

I know Cams are a must if I want any power and valve springs are a must... But what needs to happen to the bottom end?

Do I need to knife edge the crank and get pauter rods to hold the force?

[nizmo240sx_22]

What is the benefit of phosphorous coated pistons anyway, and how come almost all people just run regular forged pistons if the phosphorous coated pistons are the same price.

Those pistons just came out not to long ago. I'm going to be running them as a few others. The phosphorus coating is supposed to add to heat protection.

[WDRacing]

What needs to be done to get the engine to go to 7500 - 8000rpm's safe?

I know Cams are a must if I want any power and valve springs are a must... But what needs to happen to the bottom end?

Do I need to knife edge the crank and get pauter rods to hold the force?

With the long stroke of the KA, making 8000 rpm is going to be difficult. You'll need to seriously lighten the bottom end, have the entire rotating assembly to include the clutch and flywheel balanced, and replace the entire valve train with ultra light weight parts.

[andrave]

and yes rods are a definite. 8k is pretty high for the poor ka... Its not really a high RPM screamer...for that high of an RPM I'd be thinking custom ground cams, sheet metal intake, To4B turbine, port, polish, valve upgrade, new valvesprings and hardware. And I'd probably undercut the crank, have it chamfered and knife edged and then the full assembly balanced. You'd probably want an experience machine shop to look at building the engine on one end or the other of factory tolerances to be able to extract that kind of RPM from it. Even if you do all that, I'm still thinking it might not last as long as it might.