I picked up a 5.3l iron block for $200, and ls1 pistons and rods for free. My question is is it worth it. The block had a spun main and rod bearing, so it was trashed with slug and a few metal shaving. I plan on taking the block to the machine shop to have it looked at any way so while I'm there why not. I am doing this on a budget or sorts, so what are people on average paying to have them bored? Also this is most likely going into a 240sx, For drift purposes.
Thanks in advance.

 

Also forgot to mention I already have an Ls6 intake manifold and will keep the 5.3l heads on for the time being.

 

I've been wanting to build one of these for a while(iron 5.7). Assuming the block and crank can be salvaged, you end up with an iron LS1. The 5.3 heads(862s perhaps?) should have smaller chambers and get your compression ratio up nicely with the LS1 pistons. Cheap improvement to those is stock LS1 valves. the early 5.3s came with smaller intakes than the LS1 but there is enough seat material there that a machine shop can just cut the existing seats out to fit a stock 2" LS1 intake valve. At that point, you basically have a high compression stock LS1 head on the cheap. Stock LS1 intake valves can usually be found for $5/ea. or less.

If I had to guess, boring will cost you a couple hundred. But then since you have mismatched rotating assembly, you should have it balanced. That will add more cost.

Bottom line is that it is totally doable. Machine shop will have to tell you how much to get the parts ready. A stock LS6 or even LS2 cam($100-$125) would do nicely for budget or even a stock LS1 cam(~$50) for a smaller budget.

Good luck with your build.

 

It is completely doable. I run an iron 5.7 that started with a 5.3 block. I had mine built to handle a lot of nitrous.

 

Is swapping a stock cam worth it. Will my valve Springs handle the bigger cam from the ls6

 

And thanks for the replies.

 

What casting heads? Most likely not on the valve springs. But LS6/2/3 valve springs are cheap. Like I have picked them up in the classifieds for $30 shipped cheap. That opens up some nice, cheap factory options for cams.

I love this article as it is a great primer for folks unfamiliar with the factory LS cams:

http://www.hotrod.com/how-to/engine/1307-ls-cam-test-comparison/

It is a little confusing but know that all power numbers are with a stock 5.3 with headers and tune. Each cam will say displacement, etc. but it is just letting you know the details of the engine it came in originally.

IMO, if you cut your seats out for 2" valves and go 5.7 as planned, your numbers should be 5-10% higher at a slightly lower RPM than what you see for the 5.3 in the article.

Deals can be found on the LS6 cam if you watch the classifieds. LS2 cams can be had real cheap but you will have to go to a front cam sensor. Figure around a hundred bucks to do that.

At VERY LEAST if you do anything upgrade the truck cam. Even a stock LS1 cam which can be had for $30-$50 will slap right in and make a world of difference as you can see from the article.

A used 224-ish cam would be awesome as well..might get lucky and find one for $150-$200 but aftermarket LS cams hold value VERY well.

Bottom line, unless you are going to hang a turbo or similar on that thing, it's going to act like a truck engine until you get the truck cam out.

Chris

 

Hey thanks for the little lesson on cams ill start looking for a stock one from an Ls1 or if I find a deal on an Ls6.

 

You are welcome. Good luck with your hunt and project.

 

i too wanted to do this as I have a very similar pile of parts on hand and here's what I found.

hunt down a 5.7 crank. they'll have to add mallory to a 5.3 crank to get the bob weight up and damn is it expensive.

also most shops charge extra to cut iron LS blocks. it's hard on cutting tools.

and my experience with automotive machine shops has been that you definitely get what you pay for. and get any quoted work spelled out to the letter, in writing.

 

Interesting. I hadn't thought about that. The 5.7 pistons weigh that much more than the 5.3s?

 

Just an option on cams for a budget build Willhoite cams in OKC will take a stock cam and regrind it for you for ~$125. I've used several of his regrinds for SBC and LS motors. My 6.0 in a Foxbody ran 5.60's with a Willhoite cam and nitrous.
Tell him, what you want to do with the car/motor and he'll grind you cam. He has a number of master lobes.

 

yeah iirc the 5.3's were like 400 grams, the 5.7's were 425 or so. these were both from press fit era motors. i also had some 6.0 pistons and they were almost 500 grams! no rings of course

not saying it's a deal killer at all, but where I live quality machine shop work runs $120/hr. I hear some places it's half that for good reliable work.

 

Ok stupid question time..please don't whip me all at once. I've not done this but 25 grams doesn't seem like that much. If one had a scale they trusted, why not grind 25 grams worth of material away from non-critical areas underneath the piston to get to 400 grams? Or is that too much to remove?

 

When I had my rotating assembly balanced for my iron ls1. They didn't take any off the pistons or rods as long as the grams matched weight for weight to each other. Then they took the combined weight of both rod and piston. Compared it to stock using 5.3l crank, (I used aftermarket pistons and GenIV rods) and reduced mass from crank counter weights to compensate.

 

Aluminum is about 2.8g per cc, so yeah that would be a lot of material removal.

Some of the aftermarket pistons are actaully very light. Probe's P2600F is a 3.902" piston and weighs 376g for example.

 

Dang; when you put it like that it does seem a bit much. Guess I should have just done the simple math to know one would have to remove almost 6% of the overall material.

 

Maybe it's an option to use a 6.0 crank. They are easier to get they are 1.0 - 1.5lbs heavier then the 5.7 crank. I don't know how much it'll cost about to cut down the bob weights, just trying to give you some options.

 

Interested to hear some educated opinions on this. Seems quite logical; just a bit out of my wheelhouse.