About that 3400 Bottom end in the 3.4 DOHC...

[ThirtyTwo]

well how do you think the bottom end would hold up to 600hp??? I know guys with 600hp 4 cylinders and I know enough to make that power out of a 3.4TDC but I just need to figure out how to keep it from blowing apart

but thats what im shooting for

[SappySE107]

I dunno nor would I even bother trying 600 on stock internals. Crank might still be fine but the pistons and rods need to be better quality.

[Weston19]

yes, the gen3 mains are pretty hefty... i dropped one on my foot when i tore down my 3400. Fun times, lol


For priming the whole system, i've never done it but was told it's pretty important. I usually use a ton of assembly lube.


I almost thought about making some sort of adapter to run the oil pump drive shaft with my drill, that should prime most things... atleast get some oil in the crank and up to the cam.

That first 30 sec scares the hell out of me...

I primed my 160k 3.1 before i fired it up, simply because it sat for 3 months. Im 99% sure the oil pump shaft is 3/8, but it could be 7/16. I used a 3/8 bolt driver with a screw driver extension, on a electirc drill, and blew my oil filter adapter gasket out. lol. (however i think the gasket i bought from gm was creased causing failure) It gives you peice of mind that theres oil in the galleries at least. Like you said, the first 30 seconds is scary.....

[Fierobsessed]

That usually just makes a mess, there is distributor/oil pump drive assembly has the beginning of the main oil galley going right through the hole. That's why the dreaded Z34 (LQ1) O-ring is so bad when it goes. That O-ring keeps the oil pressure inside the engine. Let alone having that hole open while you spin the oil pump drive shaft... Iv'e learned my lesson the hard way once. I've since then used an old distributor, with the gear turned down on a lathe, I just put the drill on it and run it for a while. That's a little more difficult when you are dealing with a LQ1, since the Distro/drive cannot be removed without removing one of the heads... Yeesh!

[patgizz]

i just caught up on this. little mis-info on the 383 small block clearancing. sometimes you need to grind on the rod bolt heads - NOT the cam.

[prophiseer]

at the shop we usually turn the motors by hand about 8-10 times to prime the system; as long as you don't fire the motor you're not going to exert the amount of stress necessary to REALLY damage anything

[gpse3400]

I just go heavy on the assy lube, oil pressure usually kicks up pretty quick for me. Once I primed it, I barely had to kick the drill over for like 3 seconds and it loaded up and oil came flying out of the drive hole....It's probably more important ro prime the system if you just got the engine hot tanked..Eitherway I usually have max pressure by 5 seconds of cranking. After that it's just waiting for the lifters to inflate..FYI I do belive the GEN3 mains are Powderd Metal. It's a toss up if they are stronger depending on how they were made.....But not for nothing, the bottom end of these engines as far as journal sizes are concerned is a metric copy of an SB chevy. Whatever that engine can take, I beleive ours can as long as we have the same metalury....Oiling is a different story....GEN 1 and 2 prioritize the Lifters while the TDC and GEN3 go for the mains and cam bearings first....The later is what an SBC uses.

[Husky]

I was curious about the oiling thing... Check out the 3 pics I tossed up in the DOHC gallery about oiling. Ilustrates nicely the 3.4's oiling setup, I think.

[Fierobsessed]

I actually found a really nice way to prime the oil pump on the LQ1. But it only works with the engine out of the car. Pull the plastic timing belt cover cover, take the bolt off of the dummy cam and put some large nuts on the bolt so that when you put the bolt back in, it does not contact the belt drive sprocket. Loosen the timing belt as to not add stress to the dummy cam bearings. Tighten the bolt till the dummy cam starts to rotate. Make up an adaptor for your drill to turn the 15 MM bolt on the dummy cam. Run the drill slowly till the pressure builds, remember that the dummy cam bearings are waiting for pressure to build as well, so go easy on them for the time being, once pressure builds, go ahead and run the pump at a higher speed for several minutes. As far as I can tell, this is the cleanest most thorough way to prime a new 3.4 DOHC, from the Outside of this, an external pump is pretty much the only other alternative.