DragSource

I am in NO WAY knocking the LS engine AT ALL.

I am currently running one myself. I created this post to hopefully help people find this useful information in one post so that they can use it to make wise decisions on their cars without having to search the HT archives for hours, sifting through postst that only say, SEARCH, to get all their questions answered.

I started out wanting only a mild build - (250 whp @ the very most). My goals quickly changed and now I have my sights set on a fully built race engine.

Needless to say - I wanted the BEST parts I could get.

Now. . . I am still running the Full LS engine - but in the process of getting things built I have learned several things that will benefit me on my SECOND time around.

Hopefully it can benefit you on the FIRST time around (Please keep in mind that these are things that come into play PRIMARILY when doing a FULL BUILT motor with high HP goals)

Here are the things I wish to cover:

1 ) The LS Head's flow abilities.
2 ) The LS Head's Rocker Arm Assembly
3 ) The LS Block's Poor Rod/Stroke Ratio
4 ) The LS Block's Lack of a Girdle for stability

:::::: ( 1 ) :::::::::::::::::
The LS head just doesn't flow well - sure, you can port it. . . but there are other downsides to the head that might make you think twice about porting it. (read on)


::::: ( 2 ) ::::::::::::::::::
Reluctant to ditch the LS head. . . I sent it off to get it ported, valve job, the works - I did this to raise my useable power-band up a bit. However, I found that no matter how ported my head is. . . I still can't rev as high as I want. Even if I can make power to the sky. . . the LS Rocker Assembly is just not solid enough.

The VTEC heads have a shaft (for oil) that runs through the center of the Rocker arms - the LS has just a ball that sits in a little pit. . . the only thing keeping the LS rockers secure is the Camshaft This makes it frightening to rev as high as you might like.

::::: ( 3 ) :::::::::::::::::
The LS engines Rod/Stroke ratio is less than perfect. . . this means more engine wear than an engine with a more perfet R/S.

The poor R/S puts a side load on the rods that increases exponentially as you climb higher into the RPM's. You can get aftermarket rods and rod bolts to withstand this pressure. . . and a lot of people will tell you that having a less than perfect R/S is no big deal (stroker kit). It's a matter of personal preference -- but you should be aware of it.

:::::: ( 4 ) ::::::::::::::::
The LS block is not as firmly supported as the VTEC blocks. . . The VTEC B-Series blocks have a Block Girdle that helps hold things together. The LS does not. You can install one - but often times doing so (if not done properly) can cause more harm than good.

Just a little info to try and save someone else going down the same path some $$$ in the long run.

- The main benefit of the LS engine is that its CHEAP and plentiful.

There are a few other minor disadvantages (less lubrication) - however I don't feel that they are as big of a deal as the four I listed.

Please let add to this if you have valuable info to add - chances are it's all on HT already - just not all in 1 post.

Please also keep in mind that there are positives to the LS engine as well. I just chose to make a post about the negatives.

FATBOYeg6

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DragSource &raquo;</TD></TR><TR><TD CLASS="quote">
1 ) The LS Head's flow abilities.
2 ) The LS Head's Rocker Arm Assembly
3 ) The LS Block's Poor Rod/Stroke Ratio
4 ) The LS Block's Lack of a Girdle for stability
</TD></TR></TABLE>

1) absolutely...porting will help as you said

2) i have also heard about this. i did not know that the only thing holding the rockers in was the cam. that is pretty scary.

3) with everything i have read about r/s ratio, i agree and disagree with this. side loads do increase, but a well built engine should be ok. like you said, personal preference. something to think about though, the ls r/s ratio is only .04 lower than the gsr or type r (1.54 vs 1.58) if im not mistaken.

4) block girdles also have mixed opinions. but if properly installed, should help greatly.

i think that the ls is a great engine. it has some shortcomings in the head, but nothing a VTEC head couldn't fix!

that was my long version of telling you good info. this will help some people on h-t when trying to build an ls motor.