Bad day on the dyno...

[carbuff]

Scott,

Based on running into a part number on the site that has been discontinued, it's possible that the site has out of date information. I've read other sites that explicitly say the DragonSlayer is USA forged and cut/finished at their US facilities, while the CompStar is forged and rough cut overseas with a US finish. So it seems like there are different marketing materials in different places...

I appreciated you posting the information. I had an option I was looking at in which I would have had the crank turned locally. If not for your post, I wouldn't have pursued the knowledge further. So keep any relevant data coming!

[GregWeld]

The reason people don't like the smaller journals is that there is actually more rotational speed and load on the bearing with a smaller journal... speed and friction create heat. Heat is bad. While .10 difference seemingly is "small" == when you're revving at 6,000 rpms - all the math adds up quickly.

Sorry to hear of all your headaches Bryan! Been there - done that.

By the way -- I hate aluminum radiators. Old cars were never made to support big aluminum radiators... we "wrack"(?)(twist 'em) them and the tank to fin area doesn't like that!!

My Nomad was a master at it. #1 the standard radiator had a tank on the top and bottom and was narrow. We then modify our cars and put a WIDE radiator in with tanks on the sides... Then we add stiff suspension (over stock) - big fat ass tires... drive our cars like they're Porsches... beat on them... and then wonder why that poor radiator couldn't take it.

The fix?? Isolate the hell out of it... don't bolt it straight to the core support... Get some wubba (rubber) in there. Or have it supported in a way that the radiator "floats" on it's mounts.

[71RS/SS396]

If I had to buy a crank I wouldn't stick with the small journal sizes, the bearing options become far more limited with the smaller sizes.
FWIW the bearing damaged was NOT caused by debris from the valve spring incident. Something else caused this, the broken valve spring likely saved you from turning the whole thing into a boat anchor. I'm going to do some checking today at the shop, I may have a solution for you. Text me before you buy anything.

[carbuff]

Originally Posted by 71RS/SS396

If I had to buy a crank I wouldn't stick with the small journal sizes, the bearing options become far more limited with the smaller sizes.

Understood... I wouldn't have selected it myself if building the motor, but it was already there since this was complete when purchased.

Originally Posted by 71RS/SS396

FWIW the bearing damaged was NOT caused by debris from the valve spring incident. Something else caused this, the broken valve spring likely saved you from turning the whole thing into a boat anchor.

I agree with that also. The bearing damage was likely done during either a track day or an autocross during some long high-speed turns. I have had my oil pressure light blip on me before during those events, so it's likely that I lost pressure long enough to do damage.

To prevent this, I'm going to add the Accusump to help prevent these kinds of problems in the future. I'm also going to a normal volume pump instead of the high-volume pump. Finally, I may switch lifters to get rid of the plastic lifter trays that I think can hold oil. Mine have been drilled, but it still seems they could be a source of problems. Thoughts on that topic?

Originally Posted by 71RS/SS396

I'm going to do some checking today at the shop, I may have a solution for you. Text me before you buy anything.

Will do. I owe you a PM about Sunday also. Will reply shortly...

Thanx again everyone for the suggestions and knowledge you've all shared. I'm still learning about the LS internals since this is my first time digging into one...

[carbuff]

Originally Posted by GregWeld

The reason people don't like the smaller journals is that there is actually more rotational speed and load on the bearing with a smaller journal... speed and friction create heat. Heat is bad. While .10 difference seemingly is "small" == when you're revving at 6,000 rpms - all the math adds up quickly.

Greg, I don't quite follow this... I understand the potential for additional load (less circumference to absorb the same load), but shouldn't there be less rotational speed with the smaller journal? With the less circumference, spinning the same engine RPM, wouldn't the rotational speed be lower? Doesn't really matter I suppose, but was just trying to get that in my head.

Originally Posted by GregWeld

By the way -- I hate aluminum radiators. Old cars were never made to support big aluminum radiators... we "wrack"(?)(twist 'em) them and the tank to fin area doesn't like that!!

The fix?? Isolate the hell out of it... don't bolt it straight to the core support... Get some wubba (rubber) in there. Or have it supported in a way that the radiator "floats" on it's mounts.

The radiator in my car does 'float'. I think the 1st gens were mounted to the core support, but the second gens sit in 2 rubber bumpers at the bottom, and the cover panel holds it down from the top. So there should be plenty of ability to flex in my car. I really don't think that was the problem...

It's on it's way back to PRC now, should get there Tuesday, and I'll find out what the heck happened.

[Che70velle]

Originally Posted by GregWeld

The reason people don't like the smaller journals is that there is actually more rotational speed and load on the bearing with a smaller journal... speed and friction create heat. Heat is bad. While .10 difference seemingly is "small" == when you're revving at 6,000 rpms - all the math adds up quickly.

Sorry to hear of all your headaches Bryan! Been there - done that.

By the way -- I hate aluminum radiators. Old cars were never made to support big aluminum radiators... we "wrack"(?)(twist 'em) them and the tank to fin area doesn't like that!!

My Nomad was a master at it. #1 the standard radiator had a tank on the top and bottom and was narrow. We then modify our cars and put a WIDE radiator in with tanks on the sides... Then we add stiff suspension (over stock) - big fat ass tires... drive our cars like they're Porsches... beat on them... and then wonder why that poor radiator couldn't take it.

The fix?? Isolate the hell out of it... don't bolt it straight to the core support... Get some wubba (rubber) in there. Or have it supported in a way that the radiator "floats" on it's mounts.

Greg, your mostly correct concerning the smaller rod journal diameter. It does have the POTENTIAL to create more heat, because there is a greater load on the smaller bearing (all things being equal), but the rotational speeds, at the bearing surface, will be slower. You have to think radius here. Why people DO like the smaller rod journals, is because it gives you the opportunity to run a lighter rod/rod bearing combo, which allows an engine to accelerate quicker. You nailed it on the radiator twist info, however.
Ok, carry on people...

[Panteracer]

I always thought a smaller journal was easier
to keep lubricated... thus keeps from having dry spots
and spinning bearings.. I think my dart has smaller
journals like a cleveland in a windsor style block

Also same thing with Pontiacs ...400's have a smaller
journal than a 455.. bore etc are the same but it
has an advantage.

Accumulator or dry sump is the best bet in
motors with issues.. never seemed to be a problem
with my dart block.. always a problem with my
Pontiacs... spun many a bearing in my time even
a DZ 302 motor.. but as at kid 8000 rpm was cool

I have tried many pans with sumps three trap doors etc
never seemed to work on a Pontiac

Bob


Bob

[glassman]

[carbuff]

Not much new to report except that I got more quotes from TSP. I had a 4 hours drive yesterday during which I spent more time thinking about my combination. I realized that if I'm going to have to buy the rotating assembly, I could bump the cubes by adding stroke to the combination. I'm going to discuss this with TSP and BTW regarding my cam option, but for $50 or $100, that's a simple choice unless there is a disadvantage that I'm not aware of...

[gerno]

I decide to not stroke mine due to lateral load on the block and extra heat. The offset is that you don't need as much RPM to make power if you do stroke it. Overall I'm happy with my HP number and feel my combo is reliable overall which is what I wanted. Just something to think about. You have to decide for yourself