MOTOWN BLOCK - VS- DART BLOCK

[CNC BLOCKS]

Check out this link as its very interesting.

http://drr.infopop.cc/eve/ubb.x/a/tpc/f ... 077031/p/1

[SchmidtMotorWorks]

Interesting failure, the description of the material sounds like it should be looked into, I wonder though if perhaps the screw-holes for the mains may not have been tapped deep enough or with a dull tap causing stress when the screws were thightened.

In the current condition the screw holes should be easy to inspect.

[SStrokerAce]

After reading the R&D that goes into GM Race blocks I wonder how a aftermarket company can compete with them? I really like Bowties and have never seen a need to go from them to a Dart or Mowtown.

Any good insight on this Carl?

Bret

[CNC BLOCKS]

Bret

This is from an earlier post I did on a Bow-tie block and since then they were suppose to send another on right out but since then they are now 8 weeks back ordered as we had waited 10 plus weeks for the block that is damaged. I would say that they found that all the other blocks were damaged the same way and thats why we are still waiting. Over the last few years we have found a lot quality control issues with the Bow-tie blocks and the oiling on the Dart I feel is better the Bow-tie block and the Dart is about 900 Dollars cheaper then the CNC Bow-tie block.

These blocks have a radius cut in the register which is good but they never beveled the 3 center caps to fit the radius and damaged that area pretty good and they had a burr on the cap and still installed it damaging the side of the register as well. Hope this is clear enough?

[ChrisU]

The main bulkheads are undercut what looks to be about 1/8" per side under the caps, on the Mowtown block. That's around 1/4" less cross section in the material. This is right where the threads are for the main caps. Highly compromising design in my opinion. I don't recall ever seeing another SBC block like that in the past ever developed. That's a poor decision of theirs.

Stick with the Dart block. They have the experience of working with the OEM's and that experience alone is a valuable tool for them to produce quality parts. Not saying that everything Dart is quality, but again, they have a much larger resource of engineering knowledge than BM.

My .02.

[joe]

This brings up an issue I've been watching for some time . One of my friends that owns a junkyard has an old 400 laying out in the field that is cracked beside the main bolt hole , the inner 1/2 inch bolt .
After that I started taking calipers to every block I ran across and the webbing is very close to 1" wide on all of em la,b,rb ,sbc,bbc,sbf,bbf ,bop .
Now you know if the bolt is 1/2 inch that only leaves~1/2 material ,or .25 on either side . It was enough for ever so long but I can't help but believe that it will be an more of an issue now that people spray and squeeze amounts unheard of in times past.
I like nodular iron caps ! they have vibration damping properties like cast ,but are stronger , they'll give more than rigid cast iron ,or billet steel.
Sure billet steel is stronger but what good is it if your webbing is only 1/4 wide beside the main bolt holes ? I think it's best to put a "shock absorber" on the bottom , why are people looking at the caps when the webbing broke ?

[Trev]

For you Carl

This is my two cents worth.
On that block that blew up like a hand grenade, how on earth would you be able to diagnose that. I understand the owner being angry but wouldnt there be so many things that he possibly failed to do in the assmebly inspection. God ive seen so many stuff ups in stock engine builds let alone big race style engines.
That block of yours was pretty slack hey, but then again, thats what sets the better guys apart from the slack guys, being able to inspect and find that stuff.

Trev

[CNC BLOCKS]

For you Carl

This is my two cents worth.
On that block that blew up like a hand grenade, how on earth would you be able to diagnose that. I understand the owner being angry but wouldnt there be so many things that he possibly failed to do in the assmebly inspection. God ive seen so many stuff ups in stock engine builds let alone big race style engines.
That block of yours was pretty slack hey, but then again, thats what sets the better guys apart from the slack guys, being able to inspect and find that stuff.

Trev

What do you mean by this statement, (That block of yours was pretty slack hey) I don't understand your statement.

The block with the webbing blown out of it I had nothing to do with, But all I can say is that I feel the Dart block is a better peice over the Motown block

[Trev]

Whooooooooooooo Carl
Settle

I was trying to say that the way you recieved the block was pretty slack and it was your good skills that picked up the faults with it.

Was trying to say that no matter what block you get, Good builders like you Carl check and fix faults if you find them.

I hope thats a bit clearer.

Trev

[ChrisU]

Well, we as the consumers also need to be alert, and at least somewhat knowledgable enough to see the potential for things like this to happen. One single look at the Mowtown block makes a strong statement to the main webbing. There's an issue there. There's no reason for this area to be undercut.... absolutely none, other than the possibility of a casting issue, weight issue, or material savings issue. NONE of which hold water.

[Trev]

So Chris

You dont think it could have been anything in the assembly process that could have contributed to that webb problem.


Trev

[dirtnap]

I have a very hard time laying all the blame for this failure on the block and before I go MFing Motown blocks all over the internet I would make sure I knew the all the facts and all I see from this is a blown up engine granted its worse than most I am sure most of us here have seen similar disasters This engine ran 50 races .What kind of races ? He has good parts but I have had customers run them till they stop and a lot of those ended up kicking the rods out breaking the cam breaking the crank and tearing the main webbing out with it .I would like to see the rest of the parts from that engine before I jump on this bandwagon.I use Motown blocks usually the race block and have had no problems with them I use them for 360 sprint car engines that routinely see 8600 and above I also use Dart blocks havent had any troubles with them either actually the only blocks that I have had more than one failure with are bowtie blocks and I would not hesitate to use them again because I dont think it was the blocks fault.I can understand someone being upset when they have had a failure like this but I dont see a huge trend of failures related to that particular brand .I had a Sonny Bryant crank break in a very expensive motor could not find a reason for it but I didnt run out and bitch up and down the internet about it because I know building racing engines sometimes produces very expensive scrap.