Radiantautos

iTrader: (1)

Hello forum:
I been doing alot of searching and think I finally made my decision on Pistons and rods but wanted to ask for some verification and thoughts before I purchase them. I was going to to reuse the Rods But since the motor is a 99 with almost 270,000 Miles Thought I would need new ones and not mess with the pressed fit. Or do you think the stock rods will be fine? .

The Parts List :

99 lq4 bored 0.30
243 or 799 heads
trunion upgrade
Mahle Pistons LS1340030F04
Eagle H beam Rods 6100M3D
cam .... Still doing massive amounts of research
I haven't decided On bearings yet any suggestions

namely worried about rod and piston fitment at the moment as those will be my 1st purchase's

Thanks all in advanced

smws6ta

iTrader: (5)

Are you doing a 370 or 408 build? With the 0.030 bore it matters in what pistons and rods are recommended. It will also determine if you need a new crank.

Cam -talk with Martin from Tick Performance. He help in my cam selection.

smws6ta

iTrader: (5)

Also with a 99 LQ4 you need to make sure the crank is the same length as the LS1. That year is on the border as to if it had a longer crank.

RezinTexas

I would replace the rods with aftermarket Scat I-beams and ARP 8740 bolts. You'll probably have to get different pistons with the aftermarket rods, as I believe the wrist pin is slightly smaller diameter (OEM pin is .945").

For bearings, I would do Clevite P-series.

As long as he's putting the engine back in his '99 2500 it won't be a problem.

Radiantautos

iTrader: (1)

Think a 370 Haven't ran the numbers. But I'm Just doing the Bore and trying to to keep stock stroke and rod length. Mainly doing the bore because It has Piston slap until it warms up, and Want a lil more engine .

Is the Stroke and or journals larger or are you referring to the extra flange at the flywheel ? in either case I don't know as i'm still driving it at the moment.

The Mahle Pistons LS1340030F04 Have a .945 pin bore and the Egale H-beam Rods (6100M3D) . I looked at the Scat I beams (926100944P) there a Lil cheaper and the will fit the Wesco piston (K398X3) also a lil cheaper. my Concerns are Most likely in a year or 2 depending on budget I will be adding a mild Turbo setup 650-700 hp. would the smaller 1.2mm ring and Lighter I beams be a issue then apposed to the 1.5mm rings a H Beams? I'd rather spend the almost $200 extra now then have internal issues later on.

Thanks everyone

Radiantautos

iTrader: (1)

Feel Free to Look at the part numbers n make sure I'm looking at the right stuff .
oh and i'll probably switch out the heads to a larger combustion chamber to lower the CR if I have to when I do the turbo. Just thought Id get that outta the way

batboy

iTrader: (6)

If you plan to boost it later, than definitely go with a balanced matched forged rotating assembly. Don't skimp.

Radiantautos

iTrader: (1)

I'm planning on getting it all balanced on the stock crank. I noticed the lower/mid range kits seem to come with a balanced cast crank with a option to upgrade to forged. From what I've read the stock bottom end can take a lot when balanced n tuned properly.

smws6ta

iTrader: (5)

The crank is longer on pre 99 LQ blocks (some early, not all 99's may have the extended crank), not much not quite a 1/2" but enough to make you either use a LT1 bell housing, mill the material to LS crank length or find another crank.

My point is to measure the LS crank vs the LQ. If they are equal you're good. Hate for you to get it all assemble and find out it is too long.

Radiantautos

iTrader: (1)

you guys are right I might as well go all the way. especially since this motor is going in a 1995 bmw 325is with a t56. the extra crank flange will be a pain in the butt. So talked the wife into letting me go all out and do a 408 stroker. Which leads me to my Quench Question:

the Lq4 has a deck height of 9.235-9.245 head gasket I found are 0.051 total 9.286 Will be using a 6.125 Rod and a 4" inch Stroke the pistons have a compression height of 1.110 that leaves me with a quench of 0.051-0.061

Are there thinner head gaskets or should I get the deck milled 0.014 or is 0.051 fine Ive just always heard it should bee 37-44

Thanks

Radiantautos

iTrader: (1)

So I been looking at head gaskets I cant seem to find one to match the 4.30 bore Cometic offers a 4.60 is that what i need ?

RezinTexas

The head gaskets should be one of the last things you pick for the following reasons:

1. Quench. As you have already calculated, the resulting quench from a OEM thickness gasket will not net you ideal quench without extra deck machining. I recommend paying the shop to deck your block, then wait until your short block is assembled and measure the deck height of the pistons. Then add your desired quench and you will have your necessary gasket thickness.

2. Gasket Bore. The head gasket bore just needs to be bigger than the cylinder bore AND the head combustion chamber width - which ever is bigger. Measure the bore on your heads before picking the gaskets.

Ideal minimum quench for a NA street motor is around 0.035"

Radiantautos

iTrader: (1)

I Plan on running my P/P 243 heads until I get a set ls3 l92 P/P . I was just curious because I found cometic has a .036 head gasket which would put me right where I wanted to be. with out Decking the block. My other thoughts are is running a thinner Gasket or decking going to cause intake Fitment and Push rod issues ? I need to look up and refresh my Memory on making those calculations.

Radiantautos

iTrader: (1)

Noticed there a used eagle 4" crank for sale on here https://ls1tech.com/forums/parts-cla...crank-24x.html

What's your guys thoughts think its ok to get this used crank of or would you just shell out the extra n get a new one

batboy

iTrader: (6)

A 408 bore is 4.030 not 4.30. You want gaskets a little larger than the bore. Gaskets that are 4.060" would be about ideal. I would not go any thinner than .040" thick Cometic. The thinner the gasket, the harder it is to seal.

Radiantautos

iTrader: (1)

Hey Guys/Gals

Just a update : Looks like i'm going 370ci some issues came up causing a tighter budget and quicker turn around. So I got a great deal On diamond flat top pistons, and Lunati H-beams. will be porting heads hopefully in the next week or so But until then I've been cleaning my stock parts here's some pics. I was wondering though how have you cleaned your PCV area in the valve covers ? should I remove the riveted cover or just try and brush what I can?