Questions about a Built OHV on Nitrous?

[87xjmike]

Hey all, I know a few on here have done it. few questions for those that have....

I'd rather not spend the money on arp studs if its not needed. What head bolts are people running that are working well?

What brand 90-94 pistons do you recommend?

Will factory piston rods hold up?

What dyno numbers are people seeing?
I've been rebuilding motors with DNJ (a quality Chineese product imo) gaskets, pistons and bearings and havent had any issues .But those were all stock rebuilds not performamce minded

Plans are to do a full build on the motor then throw a dry NOS kit at it

This is all I'm currently running and my motor pulls pretty hard now But I run in the desert and sand a lot so I'd like to have some extra pulling power through Sandy washes when i feel the need..

I currently have the SOHC underdrive crank pulley
UD alt pulley with a 165 amp alt
Morana racing Phenolic intake spacer
Throttle body half shaft mod
5.0 expo maf
Mahle head gaskets with rebuilt 90tm heads
Dynomax muffler
Hurst short shifter
Luk clutch that I hate
3 core radiator
FS 9" rear end with 4.56 gears, detroit tru trac, matching front d35 TTB built to the 9's on 33" tires..


Future plans for nitrous motor:
422 cam
988. Valve springs
Ported and polished 95 tm heads with 93 lower end and pistions
Ebay or jba headers

Im mainly worried about my 5 speed .My tranny guy seems to think my m5odr1 can handle anything the a 4.0 can put to it so I'd like to give him some real world numbers and see if he can build me something to handle it properly. I'd rather not switch over to a c4 if i dont have to . and no I'm not switchimg to a 5.0. I like the 4.0 and its mpg's and ive already built my engine cage and 14" coilovers around it. So i can't do a super charger or turbo as there's no room.

My rig is the white one

 

[974X4BLACKSPORT]

The most important thing when running nitrous oxide is maintaining proper air fuel ratio as we all know, and in my view, the second most important thing is setting the top piston ring gap. More air and fuel makes more power, with more power comes more heat, and with more heat in the combustion chamber comes the need for a wider top piston ring gap, this gap is generally set to the desired power level the engine is expected to make. The piston manufacturer should be consulted for guidelines on the required top piston ring gap given the type of construction and material the piston is made out of, all in the expectation of extracting the extra heat generated by the nitrous oxide. If the top piston ring gap is not set wide enough to allow for heat expansion, the ring ends will "butt" together and then the top piston ring land will break off and cause catastrophic damage.

 

[boominXplorer]

Throw a 75 shot on it and let it rip. You don't need a purge or a bottle heater since you'll be using it in warm conditions. You just need a dry zex kit and make sure to add a blow down tube for safety (definitely need in hot conditions).

I'm pretty sure @jd4242 will comment.

 

[87xjmike]

Ok thanks 974x4blacksport ill make sure to consider top gap when setting up.

I was planning on stock rebuilt injectors as they can supposedly handle up to 300hp and stock tuning/timing. Unless I can find someone local to Sacramento who can tune these old turds.

I like the idea of the dry zex kit as it seems my best option to easily change it back to pass smog

 

[87xjmike]

Hoping JD242 chimes in. Most of my research has been his experience.

 

[boominXplorer]

A 75 shot doesn't require a tune. I'd consider a wide band air/fuel gauge to monitor potential issues. Hell I think it will hold a 150 shot down the track but beating on it through the desert is a different story.

 

[Micah J]

Posting for updates. Would love to know if you find a tuner. Been tempted to go minisquirt and have a buddy write the tune.

 

[87xjmike]

Hey @boominXplorer did you go with forged pistons?

 

[boominXplorer]

I've never built a 4.0 but I know JD4242 personally. I know he's ran plenty on nitrous with no I'll effects.

I've personally put a 100 shot on my old V8 mountaineer and put 20 10lb bottles through it with no issues.