NA Engine Question

[Frankie7799]

Being a newbie to the LSR world but having a 20+ year drag racing background I am a bit confused when it it comes to engines run in LSR. In some posts ive read and in talking to Sparky, drag racing motors arent used much in LSR. Lets just say for kicks and giggles I want to build a NA 555 cid BBC to run in an AA class. The basics being Dart Big M block, Callies Crank, Oliver rods, JE Pistons, Comp Cam roller, 904 lifters, Jesel rockers and belt drive, Dart Big Chief heads, manifld, 1050 domintor etc. Pretty much your run of the mill super class engine. What would be different about an LSR engine parts wise over the stuff that I have listed? Now granted I havent gathered anything up yet, nor do I have ring thicknesses, valve or valve spring types listed. I understand that an LSR engine has to last much longer than a drag motor but the confusion I have is parts are pretty much parts. How do the two engines differ when yet they pretty much use the same internals.

[Stainless1]

Not been drag racing a lot lately, but when we ran a hi strung small block it was hard on valve springs... so my guess is the part you didn't mention in your list... the bump stick.  You are looking at it correctly, takes all the good stuff to last 5 miles of WFOT... not just once but several times.  So you may give back a couple of HP for the sake of longevity

[Dan Stokes]

Durability is the big deal.  Much of that is in the tune-up, too.  Dial out a bit of timing, add a little more fuel.  If you think of an LSR motor as more like an off-shore boat racing engine, NASCAR, or a Baja race motor you're more or less on the right track.  I personally don't like high-winding engines but notice that I'm not a national record holder!

Dan

[Roadster943]

I ran a Reher and Morrison Super Series 412" SB a few years ago. I took 4 degrees out of it and put 4 sizes bigger jets on all four corners. I put 40 to 50 miles on it with 3 to 5 mile runs. In that time I replaced the valve springs, rockers, and lifters.The only problem I had was keeping enough oil pressure to get past the 3. The only way I could get to the five was to put 9 quarts in the 7 qt pan and I had a 3 qt accumulator on it for a total of 12 qts  and even then I would have only 50 to 55 lbs of pressure at the 5 at 7400 RPM. The last 2 passes I made on it I put 2 degrees of back in and it was fine. I pulled the engine and it has been sitting unused for 3 years. I believe it is fine and plan on freshening this winter and switching it over to run on alcohol. I ran a drag race motor without killing it but I only ran 215 on a 234 record. My experience. Good luck.  Vince

[jimmy six]

I'll pop in for two things....
#1 Think off-shore boat engine since you are looking at AA.

#2 on what Vince about oil pressure. 99% run dry sumps. If you choose not to you need a pan designed to retain oil and do it fast. At one time we had oil pressure problems trying to get to the 3 mile at >5000 rpm. A correctly designed pan, external drains, and a vacuum pump made everything work to the 5 mile with 80 psi so it can be done. ....Good Luck..PM sent

[gas pumper]

We run a similar BBC in AA/GL. Right now it's being freshened up after two seasons of good running. The dry sump and vac system are the keys to lubrication and reliability, says our engine guy. Our guy relates our engine to a pro-stock drag engine.

You might think about more carb volume. And all the compression you can get.

Frank

[POPS]

We ran a super gas motor with a dry sump.   Valve springs gave us grief until we bought PAC springs and a good stud girdle.  Good drag racing parts work perfect.

[Frankie7799]

Thanks for the input so far guys. In speaking with Sparky a couple of months ago, he mentioned the offshore boat mentality when it comes to big inch motors. Plus in what ive read on other threads dry sump seems to be the way to go oiling wise. Sure its more expensive parts wise intially but if it saves money on parts in the long run, its money well spent. As I had mentioned in my original post, I dont have anything gathered yet, just trying to get my ducks in a row and advice from youse guys  on the right way to go so im not wasting money when I do start gaterhing parts.

[JustaRacer]

IMO:

A drag motor never gets up to max piston temps.

If you stayed in it, the pistons would fail if you were at bleeding edge already.

You need to address piston cooling, oil temps, and water temps.

This was my big failing year 1.  The pistons got hurt.

Then I made it so the pistons got more cooling, then the ring lands collapsed.

Piston cooling jets, thermal coatings, more block cooling, more intake air cooling.

If you can control temps, there is no reason a drag engine can't survive.  But it's pretty hard to do.