Engine died after 20 minutes

[Venom S]

Tore the engine completely apart Friday night. What I found was not good. The piston skirts are heavily scored from the gunk splashing onto them and then riding up into the cylinders. And you guess it; the cylinder walls are scored as well. Time for new pistons and rings ($$$).

Pulled the rod caps off and the rod journals are OK. Pulled the main caps and all the bearings are damaged, as well as #1, #3, #4, and $5 journals on the crank. It will have to be turned.

The heads are fine. They just require disassembly and cleaning to get the contaminated oil out of everything.

Conclusion

I talked with several engine builders and the consensus is, that high lift mechanical cams require breaking in with just the outer valve spring (remove the inner). This produces less load on the lifters until they are broken in. Even the Comp Cams literature says to do this. I didn't, and now must fork out about $2200 to rebuild my engine. Had I known this going in, I would have selected a different type of cam.

I ordered new pistons and rings today (+.080). This will give me 514 cubic inches. I am going with a hydraulic roller cam AND whatever springs the cam manufacturer suggests.

I should be up and running in about 2-3 weeks.

This has been an expensive lesson for me. If you build a radical engine, and are unsure of anything, ask each part manufacturer what the proper build/break-in process is. I hope no one else has to ever go through this.

I will try and answer the many questions posted by all:

My cam "was" a custom grind mechanical flat tappet.

The pushrods are long (+.100). I didn't know that until this weekend. I should have used 8.550, but used 8.650. Not sure if this could have contributed to my engine failure.

I did not get any special machining instructions with the lifters.

Yes, I should have used springsd recommended by Comp Cams. This could have been a contributing factor, but when I asked Comp Cams if I could use the Edelbrock Springs, they said yes, but went on to say the stock springs were a little light.

Regards
Bill