ROBZ442

The answer to this may be out there but I tried searching it and could not find it. If I missed something please let me know.

Will stock rods work with a 350-400 horse motor with 100HP of nitrous?

My 1966 400 was rebuilt by a reputable builder using the original reconditioned rods. I have had issues with spun bearings due to what has been diagnosed as timing issues. I am looking to redo the lower end again and have purchased Bill Trovato's Max Performance Olds book and he mentioned that stock Olds rods are junk.

Is this true? My application will be mainly street with the occasional run down the track a few times a year. My max rpm will be 5500 and I am using a controller for the nitrous to keep from shocking the system too bad. I know I am leaving some things out but I hoping this is an easy yes no answer. If more information is needed I can supply that.


Thanks
Rob

BIGJERR

Mine did,Stone stock rods with ARP bolts lasted 8-9 years with the last 5 with some NOS hits.....But you will NOT be able to take a full pass under 5500RPMs in my opinion.....I have 28.5 inch tall tires,3.73 gear....I shifted at 5500 on motor and 6000 on the NOS and thru the traps at 6200+...........Best passes in the 10s....usually low 11s with open headers but street legal otherwise....if your motor and tune in incorrect the weak link will be found very soon.......Right now I need bearings.....

cutlassefi

Here's the question you have to ask yourself is is it worth skimping on about $250 to risk throwing rods out the side and/or spinning bearings? Use the aftermarket rods, might want to consider using a lighter piston as well. That takes stress off both the rods and crank.
Jmo

ROBZ442

If I could find a set of rods for $250 I would not be asking this question. Everything I have found has been $450 and up.
I don't want to skimp but I also don't have a lot of money to put into it at this time. It may mean the difference between getting the motor back in the car this spring or putting new rods in it and finishing it later. That's part of the reason I'm asking plus curious why it wasn't recommended the two previous times before.

cutlassefi

You mentioned you need to tear it down again. So you'll at least have to have the rods checked and probably reconned if you spun a bearing. So the cost of a new set of h beams vs reconning the old ones is about $250.00 more.
Save your money once and do it right, get the aftermarket stuff.
Jmo.

coppercutlass

I think the stock rods are fine . People think if you throw money at the situation it will make it stronger yet it could still fail. It all comes down to what shape the rods are in. I have seen lots of guys at the track run 100 hp shot on stock bottom end engines . A 100 hp shot is still fine for stock stuff even on cast pistons so the nitrous literature i have says., many guys run 100 plus shots on sock bottom end 5.0's. Tunning plays a big role . The thing to keep in mind is that it's not gonna be up at the strip every weekend for the usual nitrous blast they should live.

captjim

This is the kind of post that I keep talking about when referring to guys promoting doing things as cheaply as possible instead of spending a little extra to do it correctly. Have you ever run a 400 HP 455 with a 100 HP shot? I doubt it. Adding 100 HP to a 250 HP engine is different than adding 100 on top of 400.
"The shape the rods are in"??? Stock rods are stock rods, bolts and reconditioning with extra clearance will help, but you are still talking about a big heavy piston on a long arm. The cost of new rods is a VERY small percentage in the overall scheme of things.
Are you talking about Ford 5.0s? Completely different animal. Big bore, short stroke, strong block, nothing like a 455.
Aftermarket rods are available for a BBO, not a SBO. Take advantage of this.

coppercutlass

Many guys run 450 hp plus on stock rods on bbo engines I wonder what bigjerr is running hp wise because i know that thing moves and he is running stock rods. Im sure there is a bunch of guys running nitrous on similar combos that are living just fine., again im not saying spend less if you have the money do it but if not there is guys running nitrous on big blocks that live more than a few seasons.

MDchanic

My question would be, Do you NEED to run Nitrous RIGHT NOW? or, can you wait a while, and add more appropriate internals at that time?

I mean, c'mon, if you're concerned about expenses, do you NEED to push 100HP of NO2 in the next 6 to 12 months?

Just let it ride a while, and build it up when you can.

- Eric

380 Racer

x2

Run to Rund

Lose the nitrous if you want to run stock rods. Your block will also thank you, especially around #4 main. I don't do drugs, neither does my car. 400-450 HP will work with well conditioned stock rods and 6000 rpm without nitrous. You can get 500+ HP without nitrous if you do your homework.

ROBZ442

I know the difference between a low budget project and trying to get by as cheapest as possible. That's why I am asking the questions now. For those who haven't read or have forgotten my story I have rebuilt this engine two of the last three years and need to do it again. I have tried to do my home work and have spent a lot of unbugeted money doing things in what I thought was the right way with the right shop but for some reason I have gotten the same results. My biggest problem with spending more money on parts is the fear that I end up in the same place again next year. My wife is very understanding but putting $2,500- $3,000 a year into the same motor every winter is pushing it. I am no different than anyone else and money is tighter this year than in years past.

I know its probably not the most popular or practical thing to run nitrous but that's what I want to do. For me it is something that I've always wanted and if I only use it to play on the street I'm fine with that. My goal is not to have the fastest car or to even push my car to within an inch of its life for another .10 in the quarter mile. I just want a reliable Oldsmobile that I can drive everyday and still have fun at the track and drive it home when I'm done.
I have put a lot of money into the nitrous system to give me the best chance at survival. So far the problems I've seen with my engine have been detonation related. My last motor never saw 400 miles or over 3,500 rpms, and none of that was with nitrous.
I know I can build a motor that makes more power than I have but again I am trying to keep a decent budget and also keep daily driver reliability.
Because of that I have kept my engine on the mild side which is why the rods were never considered in the beginning, even with the knowledge of the nitrous system.


Here is my set up.

66 400 block bored .030 w/ B heads
VooDoo 60802 cam
Crane roller tip rockers
Torker intake w/ 750 DP
130 gph fuel pump w/ 3/8" line
Hooker headers w/ full 3" dual exhaust
NOS 50-100HP nitrous system w/ controller and stand alone fuel system

I know that I still have timing issues to resolve and without that even aftermarket rods wont help. But am I truly at the limit of the stock rods at the power level I'm looking to make? I currently have a worn out 455 in my car now and have been driving it this past summer. It has very low oil pressure and makes some odd noises from time to time but has never failed me. So I agree that if it is recommended that I upgrade the rods I could run this motor one more year and rebuild my 400 over the next year and install it next winter.

Thanks again for your help and suggestions.
Rob

cutlassefi

I feel your pain.
The last 2 455's I did both had stock rods, my machinist hates them. This next customer build is going to have eagles in it. It'll be good to see how the bearings look after the dyno run as compared to the others, if any difference at all. Maybe that would be a good idea for you, save your money this year. It might pay for you to dyno your next combo with the nitrous, then take a peak at a few bearings when you remove it.
The only other thing is maybe change machinists. Not saying yours is bad but that takes one constant out of the equation.
As mentioned careful attention to the tune is critical too, again the dyno would be good place to get that right.
Jmo

captjim

What pistons are you running and what is your compression ratio? That is a fairly mild cam with steep ramps (builds a lot of cylinder pressure) for a BBO, that might be part of the problem.

cutlassefi

X2, I was going to mention that too but didn't want to go down that cam road.

Jaybird

Ha! I used to do drugs in my car!

I love this forum! Great info to be found here!

I'm just sorry that I could not add any great info at this time!

J-(Chicago)

If you want to run dependable junk in the 3-400 hp range, just come buy my delta's motor.
Stock(ish) build 9:1 compression. 13.1 with a 3.08 gear and 4800 shifts.
I wouldn't trust stock BBO rods and nitrous at 5500rpm. Everything is just so heavy. At least your crank is forged, no?

Your horsepower goals are not very high in my opinion, and you could get 400hp out of any olds motor pretty easily. Hell, I have a 350 with stock rods in that range, too.

Not trying to be a salesman here, just saying is all.

archeryshooter

Hey Rob
thinking about spring already? good for you me too!
i know mine has scat crank and eagle rods they say the crank oils better than stock i guess they are drilled diff i think i would go with the rods my ta's motor is hammering for the 3rd time and im not going to do it till i can make the bottom end stronger its too much fun to have it broke anymore i dont think you would be sorry you did it if you do

ROBZ442

My engine is the original 400 that came in my 66 442. It is basically a stock rebuild with cast 10.25 pistons and stock crank and rods. The block was completely machined and the rotating assembly was balanced. The cam was recommended by the builder, I was open about the nitrous from the beginning. I realise that cast pistons are not the best choice either but was told they would work for my application. So far I have only sprayed 50 hp. a few times.

I was told this would be a reliable motor in the power range I was looking for and so far I have had nothing but trouble.

I have read on this site that the cam is not be the best choice and would like to change that in the future as well. Right now I am just trying to make the best of the situation.

I am starting to think I may be better off using a stock 455 rather than a somewhat stock 400. I understand everyone has there own opinion and that I may have been led down the wrong path but how far off from my goal am I with the engine I have?

ROBZ442

Hey Tony good to hear from you. I am sold on the aftermarket rods, it will slow things down a little but it'll be worth it.
I took my car out for it's last run of the year and came across your buddies 442. Turns out he lives one block north and one block east of my house.

I saw your post on a scatter shield, does that mean you were ready to install the engine?

archeryshooter

i thought he was close to you his name is travis stop and say hi hes a good guy a fireman there. i did some checking and like you everyone recommended i go with a steel flywheel and scatter shield made good sense havnt got the motor yet but i will be ready when i do

BIGJERR

As I remember after market rods are just as heavy as stock rods? I know my Eagle Rods are some stout stuff....

Never dyno'd my motor and didnt try NOS on it till the combo was reliable and solid into the 11s but I wanted a 10 second pass out of a garage motor that I built........I figure my motor was a solid 450HP motor before NOS......Nitrous is like crack,Just a 50 shot turns into a 150 shot turns into scattered parts.....its cheap and easy HP till your one thing off ...And its BOOM time.......

ROBZ442

This is my plan as well, get things sorted out first with a proper break in period then start with the nitrous. The system I have will only support 100HP due to the solenoid size. Thats part of the plan to control the crack.

coppercutlass

That's just it doing it in moderation is the key. Making sure the timing is right again alot of factors. If i read it right you ran the last 5 years on the bottle. Im just pointing out that you ran nitrous on a bbo since some people seem to think it's impossible or non reliable . I mean how often is this thing going to be on the track . i think the occasional blast of nox shouldnt hurt much as long as its in moderation of course.

BIGJERR

Moderation was my M/O At say the Byron Races I would blast off a 10.90 pass get in the quick 16 and then I could dial the normal et for bracket racing.....The car ran a 10.98 to qualify me in at 16th fastest and my dial was 12.10 first round,those fast cars hate to wait on that pro tree which I always thought was to my advantage leaving first with a faster tree than normal.....Good times!

J-(Chicago)

I did love that about your car, Jerr. Good strategy, and it works well. That's how I took home a trophy in street with an 18 second car this year. Dial slow, make them wait all day, and hit the hooks.

Unfortunately, the last 2 years, the quick 16 race has only been the quick 8, or quick 12 since no one shows up anymore.

archeryshooter

Rob did you check the spec's on the rods? to see if they failed or is it a oiling problem maybe clearances? MSD has timing controls too that help on detonation

archeryshooter

If you take what Rob has spent already redoing things, time and frustration he already spent enough to already have the rods ,pistons and crank and a big smile the first time. I think he has figured it out the hard way I hope that takes care of his problem and he can drive that bad boy without worry hope to cruz with him sometime soon

BIGJERR

Or like me this year have your Pontiac daily driver take a crap on you half way there and miss the event for the first time in 15 years.........POS GM new cars......

coppercutlass

Yeah my last build is scary compared to some I spent half and it held up the whole season if it holds up one more I'll just about crap my self

Run to Rund

My 9:1 400 with Comp XE, stock rockers, stock Tri Carb intake ran 12.45 with the original Rund driver who hadn't raced for 35 years. It has re-done stock rods. My 10.6:1 400 with Comp solid cam has Scat rods, from Rocket Racing, stock rockers, and runs 11s; Tri Carbs. It has gone 116.2 mph at Vegas (2100 ft actual, and bad air makes it seem higher elevation than that), so would run low 11s if I had a better clutch and could drive.

ROBZ442

This is similar to the goals I am looking to achieve. I just assumed that I could do this with stock rods. I would like to run low 13's on motor alone and have the nitrous as a toy to play with on the street, top of first gear into second type of thing. I am not trying to build a powerhouse nitrous motor, that has never been part of the plan. What I would like is a strong motor that will take the occasional hit of nitrous. I know there is a fine line between the two and I will take all responsibility for my actions. LOL

To some people its nuts to spend the amount of money I have on my nitrous set up but it is something I have wanted for ever.
I have a stand alone fuel system (a small cell and electric pump) two fuel pressure switches and a programmable controller to limit the amount of nitrous and the speed at which it comes in. The whole system is run off of a full throttle switch. To me it is more of a toy than a way to make cheap power. If all I ever spray is 50hp I would be fine with that.

coppercutlass

Hey if you have it use but know your limits . I think a 50 shot will be fine but why on the street ?

ROBZ442

The usage at the track will be determined by the rpm. I have only had my car at the track three times and I loved it. That's what has started this whole process in the first place, looking for a motor combination that will hold up on the street and at the track. Once I get a better feel for the car on the track I will see where to go from there.

I met you at Byron this year and would love to be racing with you next year.

J-(Chicago)

Sorry I missed you.
I was in the Brown electra.
http://ricksactionphotos.com/photos/..._0028.JPG.html

coppercutlass

I remember saying hi to you rob . I love going to the track but with plans of buying a house soon I won't be able to go as much but will not miss the bop races . Its always a good time .

380 Racer

I doubt there will be another BOP race at Byron.

coppercutlass

Why so . Lack of funds or attendance

coppercutlass

Thia last year they put the bop guys with the mustang guys and the place was packed . I forgot whi they put us with sunday but I think as longas they stick the bop guys with another crowd like thay did last year we will be fine. I remember when great lakes cancled their bop. It was lack of attendance bop specific day with low turn out.

captjim

There are a ton of mispercetions about nitrous. It does chemically what other power adders do mechanically, get more air and fuel into the combustion chamber.
The stocker the engine is, the bigger the effect of nitrous. It "likes" mild cams with wide lobe seperation. There is much more margin for error when spraying an 8 to 1 engine vs a 10 to 1 engine. The detonation issues revolve around cylinder pressure.
The real benefit of nitrous is not the 50 HP at 5500 rpm, it is the 85 ft/lbs at 3800 rpm. Nitrous allows for lower shifts and less gear due to the increas in torque. My 9 to 1 355 wagon ran 12.7 with a less than 100 shot shifting at 4800 rpm. Yes, 4800. A lot of guys use it incorrectly. Hit it at the line, short shift the 1-2 and 2-3 shifts, get off the nitrous and let the car run out n/a. This will give a good ET and be safer. Only spray over 3,000 rpm and at WOT.
Personally, I see it as useless on the street. In racing, there are several advantages. Your mild, dependable, reasonably fuel efficient low 14 second car can run mid 12's (or faster) with the flip of a switch. The cooling effect also moderates weather conditions, making the car more reliable.