Weak points? 3500 LX9 or LZ4

[ericjon262]

Mars is running low 11's with his 3500...

fixed that for you.

[nonhog]

I think the 60 degree engines are good for turboing. Of course I'm building an LZG... The LX and LZ series made more then 200 HP with pushrods out of the box. If memory serves they made 220 HP maybe even 230 HP in the LZ version.

How much HP are you looking for? 50% on 220 HP is 330 HP. I think they'd be good for that. I'm sure there are a number of people making that or more on this forum.

What kind of future upgrades are you looking for?

I'd like to start with the right combo, hence all the questions. I'm close to being sold on the 60* engine. Details tend to get in the way. I'd like a streetable 11 sec. machine. I'm thinking turbo should get me there.
Seems the easy way to go would be getting a Firebird/Camaro 3.4 and swap it in. But reading up it seems the newer 3.5
may be a better engine (after RWD mods) for my needs (wants)
If there are builds like what I am thinking I'd love to see links posted here.
Thanks in advance!

[NateD4]

I think the 60 degree engines are good for turboing. Of course I'm building an LZG... The LX and LZ series made more then 200 HP with pushrods out of the box. If memory serves they made 220 HP maybe even 230 HP in the LZ version.

How much HP are you looking for? 50% on 220 HP is 330 HP. I think they'd be good for that. I'm sure there are a number of people making that or more on this forum.

What kind of future upgrades are you looking for?

[nonhog]

Mars is running 11's with his 3500...

And that car is much bigger than mine. Hmmm! Build thread?

[Fireball]

So is the LX9 a decent platform for turboing? I liked the idea of the LS style ports on the LZ4. I want an engine that is priced well but capable of future upgrades. No expensive adaptors. Will the heads on a turbo'd LX9 allow a 50% or more HP increase? I don't want to play unless I can run 11's.

Mars is running 11's with his 3500...

[nonhog]

Although they both have the same displacement, the LZ4 has a shorter stroke, 76mm vs the LX9's 84mm, and may be better suited for higher RPM operation. However, it is expensive to swap due to the VVT and u-flow cooling setup. IMO, the LX9 is a much easier and economical swap.

So is the LX9 a decent platform for turboing? I liked the idea of the LS style ports on the LZ4. I want an engine that is priced well but capable of future upgrades. No expensive adaptors. Will the heads on a turbo'd LX9 allow a 50% or more HP increase? I don't want to play unless I can run 11's.

[1988GTU]

10w30 the green oil.

[NateD4]

What oil grade and type were you running?

The clearance on a stock engine might be a half thousandth tight for high rpm. Also the oil holes on the stock cranks I have done have any lead out on them. They need to be blended and polished to get better oil flow. GM recommends this in their old Chevy power book for gen II engines.

[1988GTU]

High rpm (7k) and oil temps above 210F seem to shake up these motors. I've pushed some boost thru the 3500 and every failure I've had the oil temp was 220ish and I was spinning 6800+ for just about a 1/4 mile. Afr was on the rich side of 10-10.5 running 110 octane.

[NateD4]

I think if the crank oil holes are properly blended they bottom end issues will go away with the right oil pump.

As for the cam... the design is a bit problematic as they start with a tube and hydraullicly swage the lobes onto them.

I'd think the bolts are the big problem in the rods above 7K RPM. Though I think they should be good for about 7500 or so with stock fasteners (I'd have to run the math).

[Mars]

Honestly though, I'm pretty much the only guy that really pushes these motors (3500) that I know of and they just RUN. even with stock stuff... (cept valve springs)

I had one fail and it's in my build thread, it may have been an assembly error or something though, the cam gear spun on the cam and blew the locating dowel pin right off and I lost the timing and wiped out a motor. I had another 3400 fail but it was high mile (200 000 miles) and just died from bearing issues. (it was more of a mock-up motor really)

Pistons, rods and botom end seem tough as hell.

[NateD4]

Maybe I'm inserting my foot in my mouth but why stick with stock head bolts? They are only rated for 150 KSI vs 180-190 KSI for ARP studs.

As for valve float... Anyone run 400 lb springs?

[nonhog]

Although they both have the same displacement, the LZ4 has a shorter stroke, 76mm vs the LX9's 84mm, and may be better suited for higher RPM operation. However, it is expensive to swap due to the VVT and u-flow cooling setup. IMO, the LX9 is a much easier and economical swap.

Noticed your links, when is the site going to be up and complete? looks like some of the MG stuff would come close to working in my Volvo.

[NateD4]

What oil pressure do you see when rod bearing failures happen.

[CNCguy]

Although they both have the same displacement, the LZ4 has a shorter stroke, 76mm vs the LX9's 84mm, and may be better suited for higher RPM operation. However, it is expensive to swap due to the VVT and u-flow cooling setup. IMO, the LX9 is a much easier and economical swap.