Project Crush

[siteunseen]

Is it a P90 or a P90A? The P90A will or should have hydraulic lifters which won't not need adjustment like all the other heads do.Be sure and get the turbos ECU, THEY'RE different. I can't remember which head you have now, MN47? The P90S have square exhaust ports. You're doing what I did, learning by disassmbly of junk yard motors. You will learn these motors whether you like it or not. It's great!

Don't you live in an apartment? I do and had to build a 10x12 storage building.

[HuD 91gt]

I do indeed.  The motor is advertised as an '81 so it should be a p90 (Which is what i'd like).  Honestly I haven't even seen the motor yet but money has not been exchanged.  I will be travelling over on friday to make the final deal.  He says the motor turned over and offers a guarantee if it's not good.  

I am not planning on using the ECU at all, as I will continue to use my carbs for the time being, and 280zx distributor until stage II (Megasquirt) comes along for EFI and custom ignition.  I do live in an apartment which is why I am doing this in steps.  I have room for one more motor in my storage.  
 

My girlfriend is going to love it.

[HuD 91gt]

As for which head I have. I was originally planning to run my N47 head (I also have an E88 on my L24).  After a lot of thought, price comparison and end goals it just made sense to go the turbo route.  Replacing the cam to take advantage of the N47, and buying a header add's up quick especially in Canadian funds these days and I can't guarantee my DIY porting work will equate to much success.   The turbo route seems to the be the more expensive, but hopefully way more fun route.  Not to mention i've always wanted to try fuel injecting a vehicle via megasquirt as i've been reading about them for 10 years.  Buying the JY motor includes basically everything required to do so, so it just makes sense.

 

It will be a little different from the route most go, being it will be a turbo charged flattop motor, but I hope to have fun experimenting, and hopefully not pull my hair out in frustration.  

I may have to borrow some workshop room this winter at a family members at the rate this is going.

[HuD 91gt]

Well good news is I just got off the phone with the machine shop.  He says the bores look good, pistons are good.

 

The bad is the price he quoted.  I basically asked to get the engine checked out, polish the crank, magna fluxing etc.   Total price was around $7-800.   Having never rebuilt an engine this seems a little out there.  I also asked about balancing the bottom end.  He quoted $275.  Now I asked if this is balancing the rods weight individually, and I believe he said that is balancing it all as one piece (rods, crank, flywheel etc).  That is not what I want correct?  I want the rods to be of similar weight, with a balanced crank it should all be balanced correct?

I was out on a walk, and will be getting another call back so I can write down all the prices indivually.

 

 

Edit:  I feel much better about the price breakdown after hearing from him again.  Looking forward seeing the end progress.

Edited August 27, 2015 by HuD 91gt

[rossiz]

perhaps i'm missing something, but i was under the impression that the flattops provide the higher cr for na application and the turbos used the dished pistons to lower the cr and avoid detonation. i don't claim to know the intricacies of a turbo setup, so take this w/a large grain of salt - just what i've read.

 

for comparison, i had the following work done at a local seattle shop:

 

block tanked, surfaced, decked, honed

crank balanced

rod/piston assys tanked, balanaced

flywheel lightened & balanced

clutch pressure plate balanced

head tanked, shaved, surfaced

 

i believe this was around $750 

 

the balancing is really nice - makes for a very smooth motor at high revs.

they did it in stages: rod/piston assys individually, then crank, then flywheel, then crank + flywheel, then crank + flywheel + clutch pp.

the clutch pp has a "V" mark stamped into it which indexes to a similar mark on the flywheel for proper assembly.

[HuD 91gt]

Ok my prices seem reasonable then.  Especially in Canadian funds.   A little more then you quote but within the ballpark.

You are completely right on the higher compression topic.  It is generally not done, but with proper intake cooling and proper tuning the car "should" be a great all around runner.  I will never get 400hp out of it, but that isn't the plan.  The higher compression will give it a little more low end oomph, and still be safe with the right tuning.  It has been done in the past many times, it's just not the norm.

Cheers

[siteunseen]

He's getting the P90 head off the turbo motor and putting it on top of the F54 with flat tops he already has, I believe.  Should be about the same as a N42 head but with a drilled cam and the peanut shaped combustion chamber. 

[HuD 91gt]

Siteunseen, you are correct.

 

Spent the better day of Friday pulling the motor from the junkyard myself.   Grabbed what i could off the motor and made my way to a safe place to disassemble what and I needed, and dispose of the rest (That was tough).  The motor was completely seized (Which worked out for the best), and was in rough shape.   No hood on the vehicle, cold side of the turbo was open to the air.  Cam was rusted, thermostat housing was taken off allowing who knows what to go inside (Including water).

 

When I first contacted the wrecker last year they wanted $1500 for the engine.  A month ago it was $700.  I negotiated $500.  When we found out it was seized (He swore it was good two months back) I got it for $250 if I did the labour.   

As I started disconnecting things, I was regretting it badly as I learned how bad of condition everything really was in. But I'm a man of my word.  When I finally disconnected everything, the JY got the car up on the loader and I took my first look underneath.  Oil pan was completely crushed.  Ah man,  That was one of the reasons I wanted it.

 

Pulled the engine out and took it to where my car is currently parked and started disassembly. Got to the point of removing the head, and 2 head bolts snapped in the block.  Good thing I don't plan on using the block.   With the broken studs, I ended up having to hang the engine upside down and gently tap the head off little by little to remove it. A second set of hands caught it as it finally broke loose.

 

What I ended up with....

A P90 head, unmolested but very very ugly to look at.  It looks as though my little niece was emptying her diapers in cylinder 5.  But I'm very positive the head itself is useable.  I'de say the valve train is good for scraps, but I have spares.  During disassembly, I realized someone had previously tried to remove the manifold.  2 studs are broken off in the head.  I don't know if I want to attempt to remove these or let the machine shop do it.  It'll cost me i'm sure. 

Turbo manifold is great.  

Turbo - Hot side feels great, cold side spins with no play but is rough.  Lots of corrosion from water.  I guess I'lll learn how to rebuild one of these.   

Intake Manifold - Needs some cleanup, but not a whole lot can go wrong with it.

TB - I'd say its pretty much junk

Oil Cooler Sandwich Plate - If I ever plan to use a oil cooler this should come in handy.

Oil Pan - Managed to salvage this I think.  Cut out the baffle, and hammered it out.  Learned how to weld again. I went with a Mig welder and welded the baffle back on.  Anyone see anything wrong with doing this?  I'll post some pictures in a few days to see what you guys thinks.

Edited August 30, 2015 by HuD 91gt

[HuD 91gt]

I'm a little upset I didn't take more photos.  The head gasket area looked like it had no leaks, which was great.  The oil pan was really crushed.  We by no means made it perfect, but I think it is completely useable.

[HuD 91gt]

I managed to get the P90 head back from the machine shop. They did a pressure test on it, and made sure it wasn't warped beyond repair. Good news, it's never been shaved, and needs about .006" off the top to straighten it out. They took off the cam towers during their testing process.

I took the head home as I'm going to attempt my own port and polish job. I ended up buying the spring compressor listed in this thread earlier. So putting the cam towers back on was required. I just tightened them finger tight. I think I may have done some damage. As I was removing the valve springs, I had to turn the cam, and I think I may have have scored the tower bearing surface by doing this. They obviously weren't lined up perfectly. I mean the damage could have always been there, I honestly didn't look. But they are scored no doubt. Some of marks can barely be felt with a fingernail. I'll let the pictures do the talking.

I've read about people having luck sanding these out. Is this a safe option? My other option is to steal the cam towers from my N47 head, this is a safe bet, but perhaps I won't be able to line them up properly?

 

I also tried following Blue's footsteps and tried to clean up the rusty cam that was in the P90.  I'm getting it reground, so I thought I may as well use a "junk" cam if he will accept it.  I tried scotchbrite but was getting nowhere.  I ended up using WD40 and 400 grit sandpaper.  After a few hours of rubbing I was able to clean most of it up.  I'll be discussing my cleaning process with Colt Cams to see if it is useable, or just a paper weight right now.  

Edited September 28, 2015 by HuD 91gt

[Patcon]

Do the Nissan heads not use a pressed in cam bearing? I have never looked that close...The one with the deep grooves are pretty deep. I wouldn't think sanding them out would be a good idea. If there is no bearing then replace the towers or have them line bored and add a bearing sleeve.

[siteunseen]

When I sent my cam to Schneider they used it as a core trade in and sent a nice clean cut cam back to me, I marked mine with a Dremel engraving bit to see.  If you have some spare towers I'd use them, peace of mind for the future.  I cleaned mine with 600 grit and WD-40, just enough to get a shiney finish inside the cam towers.