A couple of Engine Building Questions
Thread Starter
TECH Regular
iTrader: (13)
Joined: Aug 2002
Posts: 472
Likes: 0
From: Ancaster, ON - Where F-bodies are rare!
A couple of Engine Building Questions Hi Guy's
First of all sorry for the rookie questions.
How do you determine the length of connecting rods
when building an engine. ( possibly a 409 with a 6.0 iron block??)
Is a certain length of connecting rod better/worse?
Does it make sense to build an all bore iron block (use a stock crank to
keep cost down) and save for a stroker crank in the mean time
and reuse the rods and pistons down the road after some $$ has
been saved.
Also, one more question, how eager would the various sponsors/tuners be
to tune a car that they have not worked on or built?
Thanks in advance guy's, this site has been very, very helpful!
Dave
It sucks having this sickness and being on a budget! <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
First of all sorry for the rookie questions.
How do you determine the length of connecting rods
when building an engine. ( possibly a 409 with a 6.0 iron block??)
Is a certain length of connecting rod better/worse?
Does it make sense to build an all bore iron block (use a stock crank to
keep cost down) and save for a stroker crank in the mean time
and reuse the rods and pistons down the road after some $$ has
been saved.
Also, one more question, how eager would the various sponsors/tuners be
to tune a car that they have not worked on or built?
Thanks in advance guy's, this site has been very, very helpful!
Dave
It sucks having this sickness and being on a budget! <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Re: A couple of Engine Building Questions </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by CanuckSS:
<strong>
Also, one more question, how eager would the various sponsors/tuners be
to tune a car that they have not worked on or built?
<img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Most sponsors are very willing to help in anyway they can. MTI did (mail order) tuning for my cars heads and cam package and did an excellent job! I think most of the >>>>>>>>>>>>>>> one that do tuning would be willing to help.
They can also offer good advice on parts selection or even do a turn key package for you.
<strong>
Also, one more question, how eager would the various sponsors/tuners be
to tune a car that they have not worked on or built?
<img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Most sponsors are very willing to help in anyway they can. MTI did (mail order) tuning for my cars heads and cam package and did an excellent job! I think most of the >>>>>>>>>>>>>>> one that do tuning would be willing to help.
They can also offer good advice on parts selection or even do a turn key package for you.
Re: A couple of Engine Building Questions The rods would be 6.125". The compression height on the piston won't work if you switch to a stroker crank down the road. If you bore the block to 4.060, and offset grind the crank to 2.0" rod journals you would have a sweet little setup. Get a 232 237 lunati grind and you will make about 460 rwhp. My friend did the same thing except without offset grinding the crank. It put down 452rwhp 429 lbft.
TECH Apprentice
Joined: Aug 2002
Posts: 331
Likes: 0
From: Gambrills, MD
Re: A couple of Engine Building Questions A bit more about rod length. In general, the longer the rods, the better. The LS1 already has OEM rod length of 6.125", compared to an SBC rod length of 5.7". Longer rods decrease side loading, and increase dwell time at TDC. This translates to less cylinder wear and parasitic losses, and better toleration of high combustion pressures w/o detonation.
You can get longer aftermarket rods, but you will also need to get matching pistons, with the wristpins located higher on the piston --- otherwise the piston would stick up right out of the bore. With the pin mounted higher, there is less room for the rings, so there is a physical limit to how long a rod you can use.
Hope this helps....
You can get longer aftermarket rods, but you will also need to get matching pistons, with the wristpins located higher on the piston --- otherwise the piston would stick up right out of the bore. With the pin mounted higher, there is less room for the rings, so there is a physical limit to how long a rod you can use.
Hope this helps....
Re: A couple of Engine Building Questions </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by HITMANSS:
<strong>The LS1 already has OEM rod length of 6.125", compared to an SBC rod length of 5.7".</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">WRONG!!!! the stock rod is 6.098" Don't want anyone thinking they can go directly to an aftermarket rod on stock pistons.
When i was doing my motor research, the general consensus was the rod/stroke ratio should be around 1.7.
Pick a stroke, and rod length that's close to what you want, and have the piston CH set to match those and the deck clearance you choose.
<strong>The LS1 already has OEM rod length of 6.125", compared to an SBC rod length of 5.7".</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">WRONG!!!! the stock rod is 6.098" Don't want anyone thinking they can go directly to an aftermarket rod on stock pistons.
When i was doing my motor research, the general consensus was the rod/stroke ratio should be around 1.7.
Pick a stroke, and rod length that's close to what you want, and have the piston CH set to match those and the deck clearance you choose.
TECH Addict
Joined: Dec 2001
Posts: 2,298
Likes: 2
From: new england
Re: A couple of Engine Building Questions Although debatable i also disagree with longer dwell time at TDC helping with detonation suppression, i believe it to be the oppsite. Less time at tdc would make detonation with hi cylinder pressure less likely or prone to it. Longer rods also require more port velocity to fill cylinder properly because of slower piston accelleration away from tdc creating less of a pressure difference between cylinder and intake port. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
