putting p90head on a 75 280z Block

[280zbeeT]

So tomorrow, I am buying a 75 280z Short block for $250, and Im going to put my p90 head on it, into my turbo setup. the 75 280z short block I believe has dished pistons, it is bored .30 over, anyway My car is completely set up top to bottom, I was at 20lbs of boost with my f54 block but since I didnt have my msd installed I blew rings. What do you think I should do if the pistons are flat topped? if I get a Good tune, and boost about 15lbs would I be alright?

what about block overheating? am I at risk for this? I have inter cooler, oil cooler, flexalite dual fans. any advice or comments. I know a lot of people have put p90 heads on na blocks other then the f54, even With flat top pistons... please give me advice and if anyone knows of a f54 with dished pistons in Great condition please let me know..

[skib]

dished pistons will still give you a ~7.3CR flat tops should give you a ~8.4CR

[280zbeeT]

so even the flat top pistons bored .30 with a p90head and a turbo setup that compression doesnt look to high! the block is from a 75 280z. so I think its a n42 or n47

[280zbeeT]

so then that would be an okay combo?

[2eighTZ4me]

If it's a stock block - and has not been gone through, then you no doubt have dished pistons - IF it's out of a 75. That combo would work fine for a turbo. I have an F54 block that I retrofitted with dished, and a P79 head on top, and the car has seen (on a bone stock motor) 20+psi.

 

Now - I fail to see what your MSD not being installed has to do with "blowing rings"??? If it's ignition problems you have, the detonation monster usually goes after ring lands or piston skirts - not the rings themselves. Unless your MSD (which MSD makes a myriad of ignition and fuel products - so you need to be specific) is a boost controller / timing retard device, I don't know what you would gain by having it installed. 15psi is a lot safer number than 20psi with respect to fuel and timing curve.

 

You shouldn't have any problems with overheating with a good oil cooler, proper timing curve, and good water cooling.

[280zbeeT]

Already great, but if it does have flat top pistons?

 

Well, I had my entire car and everything built to 20lbs of boost, but I didnt have upgraded ignition, so I detonated early since I was boosting to much.. :\

[2eighTZ4me]

If it does have flattops - then I wouldn't go much past 15psi. Dished you can get away with a little more. Upgraded ignition is not going to help you unless you have a device to retard timing under boost. The MSD 6-BTM has such a feature, so if you're using that - great. If not, it doesn't matter whether you light a match by hand and throw it in the cylinder, if the mixture ignites, and ignites too early under boost, blammo....you've got detonation and subsequent problems. I don't care whether it comes from a stock dist. and coil, or an MSD box. I showed my flattops 20psi of boost and broke off a quarter sized chunk off the skirt on #3. I couldn't get the timing backed down far enough.

 

You can still use the P90 head though. Nothing stopping you from doing that, however, until you have a rock solid ignition system that is capable of retarding timing +/- 1 degree for every pound of boost you build - you're still going to have to deal with the detonation monster if you go cranking up the boost.

 

The more boost you add, the more dangerous it gets. There's a tradeoff (that I'm experiencing right now) between power and longevity if you don't have a programmable ignition setup.....which I will have soon....

[z-ya]

Already great, but if it does have flat top pistons?

 

Well, I had my entire car and everything built to 20lbs of boost, but I didnt have upgraded ignition, so I detonated early since I was boosting to much.. :\

 

No 280Z came with flat top pistons.

 

Having an MSD in there is not going to magically fix your detonation problems. And the 280Z pistons will break even faster than the F54 ones. So you need to get to the bottom of what is causing the detonation or plan on picking up some extra short blocks. If you can give us more information about your setup we can probably help you out.

[280zbeeT]

That was my setup, I blew the ring lands or the piston rings from early detonation cus I had a stock ignition and I wasn't getting to much Air and Fuel and not enough ignition, which is/was my believe an also my friends and mechanics...

 

I had a stock little coil, and couldn't boost more then 10lbs because of the ignition (what I was told) but before I learned that limit I was boosting 15, with stock ignition, that is all I know.. And now I have the msd 6a, soo where do I get an ignition like that?? (the ring-lands were from a l28ET built, f54 with standard dished pistons- blown from detonation) so I dunno all I thought I need a msd ignition and Ill be fine.

 

 

Engine Upgrades:

82 Nissan 280zx Motor Stock F54 Block

ARP Rod Bolts

ARP Head Studs

76 Intake with 60mm Throttle Body

Rx7 550 Injectors

Rx7 Oil Cooler

24x12x3 Intercooler

2.5" Intercooler Piping

HKS Blow-off Valve

Haltech E11-V2 With flying lead harness

Palnet Fuel Rail with Fuel Gauge

Tial Wastegate w/17 PSI Spring.

GT30R Ball Bearing Turbo

DynoMax 2.5 Welded Exhaust

Dual Electronic Fan from Summit

82 Maxima Alternator

Zeitronics Wideband with EGT sensor

Walbro Fuel Pump

K&N Air Filter

Stainless Steel Lines

CenterForce Clutch

MSD 6a

 

 

Drive Train:

240SX 5 Speed Transmission

B&M Shift Kit

3.9 Rear End

Spicer U Joints in Driveshaft and Half Shafts

 

Brakes:

Toyota S13 Calipers in Front

Drilled Rotors

Stainless Steel Brake Lines

ZX Brake Booster

 

Suspension:

Tokico 5 Way Adjustable Shocks

Poly-Bushings all the way around

 

MSA-Sway Bars

[280zbeeT]

Okay man thank you so much for your help!

 

So, dished or flat top pistons, regardless I can still put the p90head on the 75 280z block. and if I dont boost more then lets say 12 or 13lbs, with my msd6a, it will work and run without early detonation for a couple months or so till I can rebuild my f54 block on the side? cus Im getting this NA block today for $100, and Im deciding if I should get it or not? what do you recommend for boost? no more then 10? or no more then 15? or is 13 okay?

 

Also, for the msd setup.. all I have is the Box, I can go buy the MSD coil, but right now I have a stock coil, and a igniter coil, can I use those with my msd box? or should I not? also, what do you recommend for me to do to prevent detonation Less boost is best? I think Im going to get that msd that your talking about, its like 350$ on google.

 

please give me any other advice to help me out with this situation. as I said its a 75 280z block with bored .30 belowis what I was told...

 

"the 75 l28 should have dish pistons the the early blocks are not as strog as the later blocks and the turbo pistons are stroger then the na pistons. the boreing of the block 030 over is because of wear on the cylinder walls and is not an improvement over stock for strangth or endurance. the stock l28t motor will handle 20psi of boost, and with a larger turbo, injectors, fuel pump, an intercooler and a new program with q16 or c16 the wright set up will work great at 20psi. I don't see any way that it can run 20psi on 91 with any kind of air temp or for any amount of time. Its just to much heat."

[280zbeeT]

Hey guys... I got a questions shoulda added this earlier.. okay, since Im puttinga p90head on a 75 280z block, couple questions about what I will need...

 

Gaskets:

 

The engine was rebuilt 5k miles ago (75 280z engine).. can I use the head gasket or any of the other gaskets from this engine on my setup??

 

And, since the setup I have is for a 82 280z turbo engine, what Other gaskets do I need to put this together? Should I buy a 75 280z COMPLETE GASKET SET, or do I need to mix and match? If so, which ones do I buy for a 82 280zx engine, and which ones do I buy for a 75 280z engine??

 

Also, I have a Centerforce clutch, that I have been using on my 82 280zx engine (f54 block with a 240sx transmission) can I continue to use this centerforce clutch?? or should I use the Brand new clutch that comes with this 75 280z engine??? please let me know what I need to buy.. first time doing this..

[woldson]

For some reason something seems so strange. You have mods that have been done, yet, you seem to know so little. This is not a slam, but, rather curiosity.

[2eighTZ4me]

Woldson - you're on to something......my guess is the car was purchased this way. There also seems to be about 5 different subjects going on in this thread. Too much to keep up with. I'll defer to the others....or better yet - a search might be in order. These topics have been covered before.

[280zbeeT]

I bought the car with a lot done to it, and Im still learning more about engine internals and workings etc. Regardless, I dont see why I cannot get some help? These are serious questions, and this is the first Ive heard of ignition not being a factor with detonation, when Ive always heard it really is a big factor if your ignition isnt upgraded and the air to fuel is..

 

But as I said in the above posts, Im not good with engine rebuilds. I dont know why someone needs to be experienced with engine rebuilds or not to get advice on what gaskets to get when doing a rebuild haha. That doesnt seem right. Ive rebuilt my 83 l28et, no problem. But this time Im rebuilding a n42block to a p90head so yes Im concerned which gaskets to use! Why cant I get an answer. And since Ive never used a n42 block. Im not sure if the clutches are the same size from the 82 f54 block. Ive Only dealt with the p90head and the f54 block together.

 

 

Is it wrong for you guys to help and assist someone who just wants to make sure he gets all the right answers to His Specific questions? If I had already found these answers after 2 or 3 weeks of intensive searching, I then I would not be asking you now but I need to do this right since this is my daily driver and only car and with finishing my rebuild by next week I cannot work. So please clarify, I need to get a n42 block head gasket, and every other gasket to match up to a 82 p90 head That is correct? And I do have a brand new clutch for the n42 block, but I would really like to use my stage 2 center force clutch so please tell me allignment is the same from the f54 block to the n42 block for clutches.

 

And to tell you the truth I think this is the perfect place for these questions, since the thread title is Putting a p90 head on a n42block meaning in my ides any help involving that subject (including compression, drive train, assembly) as I have never dont This sort of rebuild before and I am still new to these cars and there engines. Ive only had a Z for 3 months or so.

[280zbeeT]

Haha People and there High, Very High Horse once someone finds out someone is new there ego jumps in. I guess people forget were all the same and discrimination needs to be ended over minor things. Im a 21 year old who needs help with his 3rd rebuild ever.

Edited June 24, 2010 by 280zbeeT

[2eighTZ4me]

It's not ego dude - you're asking questions that have been answered many many times before on this forum. There is a search feature on this forum that will tell you "differences between clutches" - head gaskets etc. If you come in here with the attitude that you deserve to be spoon fed answers every time you ask, people are going to start ignoring you (and flaming you), and no amount of tantrums you throw will get you any answers. Wait until TonyD sees this - you think we're being tough on you?

 

1) Use the head gasket that matches the block - so order it for a 280Z

 

2) There are 2 sized clutches. One for a coupe, and the other for a Turbo and 2+2. The turbo/2+2 has a 240mm surface. The one for the coupe has 225mm surface. You'll probably have to measure them once you get it out of the car to see if they are the same. It has no bearing whatsoever what block you're using. It's irrelevant. But since you have a turbo car - and you don't seem to know much about it, or its' heritage, you "may" have the 240mm setup in there. No way to tell unless you pull it out and measure it.

 

I'd highly suggest using the search feature of this site. There are probably NO questions you could ask that haven't been covered before and documented on this site.

[280zbeeT]

No tantrum here, haha wow..

 

Anyways, Thank you but I had already figured out the answer to those questions. Im getting the head gasket for the n42 block and all the rest of the gaskets for the p90 head, I was confused about the clutch cus I have 2 f54 blocks and 1 n42 block, the n42 came with a clutch and the f54 block one has a center force clutch the other has a OEM clutch and I have a 240tranny so I wasnt sure if I should use the centerforce from the f54 or the just leave the stock New clutch from the n42 block (worried it wont work with the 240 tranny) Anyways, I did search I couldnt find thread, I searched google, zcar forum and here couldnt find an answer for the p90head and n42 block swap, not whatI needed to know for my setup, and since I got the block Last night I was in a hurry to know since I needed to get the gaskets and stuff this morning so I can do my swap friday and I couldnt find the difference in these clutches. I figured these all have to do with ap90head and n42 swap so why not.

[Tony D]

No 280Z came with flat top pistons.

 

A better statement might be 'No US SPECIFICATION L28'...

 

There are PLENTY of JDM engines floating out there as replacements which not only have flat tops, but in some cases SLIGHT DOMES.

 

'Never Say Never'

 

I have been running a 1977 FLAT TOPPED PISTON N42 Head and N42 Block combination in my turbo car for years. Decades, in fact. Horsepower was similar to yetterben's levels but I didn't get greedy nor did I have a 'boost fetish' that compelled me to keep upping the boost beyond the capacity of the chassis to turn a corner and apply all the power it could produce...

 

As for 'all the questions'----I think the OP needs to read the sticky "Why is HybridZ so..." and thank his lucky stars he got any help at all here asking questions which obviously were not researched very well at all. "Getting Help" doesn't mean spoonfeeding people information. You can tell all the most complex things in the world to a 13 year old, but if he doesn't do some pre-reading to figure out what you're telling him it's all a waste of time, space and effort.

 

Why am I always the designated attack dog? I'm a harmless fuzzball. Really. I enjoy wiping noses and that kind of motherly crap.

Edited June 24, 2010 by Tony D

[Tony D]

Haha People and there High, Very High Horse once someone finds out someone is new there ego jumps in. I guess people forget were all the same and discrimination needs to be ended over minor things. Im a 21 year old who needs help with his 3rd rebuild ever.

 

OMFG did he really just say that?

 

Dude, you are feeling entitled to information, and calling people names or insinuating they are on some 'high horse' because of your own ignorance is insulting to those of us who were at (apparently) your level when we were in our early teens. Just because you're 21 doesn't entitle you to special dispensation from the rules of the forum, or of the common courtesty of searching and reading. DISCRIMINATION IS NOT A BAD THING! You have been told it is, but that's a fools errand. You look at an apple with a worm in it, and DISCRIMINATE when you say "I'm not going to eat that worm, it may make me sick!" You are ASSUMING it is discrimination BECAUSE you are new to the forum. It is simply people INFORMING you of your transgressions against the site rules and ettiquette. Like I said, maybe you need to read the 'Why is Hybrid Z so...' before you start lashing out at people and calling them names for pointing out YOUR misconduct!

 

This issue is YOURS to deal with, not the boards. You want to ask questions here, follow the rules.

 

I have overstepped my commentary bounds already, and will stop now. But I can't believe that whining swarf was actually posted to this board. That alone makes this entire thread (to paraphrase Elaine Benis off "Seinfeld"):

"Shedworthy"

Edited June 24, 2010 by Tony D

[2eighTZ4me]

Refer to post #16 - " Wait until TonyD sees this - you think we're being tough on you? "

 

Called it..... - Gold star to me.......wait -- I gave him the answers he was looking for........minus Gold star to me......crap!!!