Lateral-g Forums - Bad day on the dyno...

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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.

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.

Quote:

Originally Posted by GregWeld (Post 591206)

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.

Quote:

Originally Posted by GregWeld (Post 591206)

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.

Quote:

Originally Posted by 71RS/SS396 (Post 591240)

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.

Quote:

Originally Posted by 71RS/SS396 (Post 591240)

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?

Quote:

Originally Posted by 71RS/SS396 (Post 591240)

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...

Quote:

Originally Posted by GregWeld (Post 591206)

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...

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

Quote:

Originally Posted by carbuff (Post 591130)

Thanx guys... I agree with all of you, and even though I may sound like I am doing it, I won't scrimp on any selections just to meet the event timelines. I completely agree that I would regret that down the road. But I should be able to accomplish a simple engine rebuild in a 6-week timeframe, right???

Now, that said, nothing can be simple with this project, so I got 2 more doses of bad news today that are pretty much going to make my decision for me. I hadn't heard back from TSP about the crank, so I decided to call Callies directly myself to see what the story is. It turns out that every crank is serialized, so with the serial number they could tell me what was originally done to it. This crank was nitrided, and per my 2 discussions with Callies today, it should be rehardened after being turned.

Interestingly, it turns out they don't do the machine work and hardening in-house on a fix like this. They have a local place do the work for them. So they gave me their number to call. Shaftech in Ohio. I called them to see what we could do, and they also confirmed the need to reharden. BUT, they don't do it in house (even though their website implies that they do). They would do the machine work and ship it out for hardening, then back to me. They also quoted me 3.5 - 4 weeks to do the work, and a price of $525. Yikes!

At that price, and on that timeframe, I'm not sure if makes sense to repair this crank myself. So I made the second call to Callies to discuss my options. I wanted to understand the difference between their DragonSlayer cranks (which is mine) and their Compstar line (the step down). The Compstar is forged and rough-cut overseas and finish cut here, while the DragonSlayer is forged and cut in the US. But the real difference is the intended application. The Compstar is good for about 900HP while the DragonSlayer is good to about 1500. This engine will never see those levels, so the Compstar should be fine for me.

Ok, decision made, or so I thought... The other little trick here is that the original engine was built with 2.00" rod journals. The LS standard is 2.10" journals. It would seem the 2.00" journals are not popular. Callies lists a part number on their website for the Compstar with a 4.00" stroke and the 2.00" rod journals, but apparently they don't actually make that one anymore. So if I want to use those journals, I'm back to the Dragonslayer.

This means my options are:

- buy a Dragonslayer and use my 2.00" journals connecting rods
- buy a Compstar crank and a new set of 2.10" connecting rods

Given those options, I'm back to considering abandoning ship on salvaging parts from this engine shortblock and looking at TSP building me a completely new one. I've asked them to price me out using my block (which I can still use) and just do a completely new 402 (actually 405 I think) ci rotating assembly, and additionally pricing out a completely new 418ci shortblock. I'm about sure that I'll do one of these, and sell off the leftover pieces that I have. The crank and rods will make a nice setup for someone who is on a timeline that can have it fixed...

So I'm back to making another decision tomorrow. Hopefully my heads arrive at TEA so that they can determine the chamber volume and I can finalize my piston selection. That may not happen until Monday though.

While I'm at this project, I'm going to add an Accusump to the car. I don't want to take any chances on losing oil pressure with this setup after this investment! I'm sure that I probably caused the crank damage with some pressure loss at either an auto-x or a track day. I've had the oil pressure light blip on me before in extended-G turns. So I can't say that I'm completely surprised by the crank damage, I just didn't expect it to cause so many problems in the rebuild...

Maybe some other crank company makes a 4" stroke with 2" journal for LS?

Step it up and go for the 1.88 Honda journal. :)

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...

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