Hello, in getting closer and closer getting my sbo 355 ready for the cam break in and have a question about the valve spring pressure during the break in procedure.

My cam is a Lunati 272/276, 217/221 @.050 and 0.485 lift in/exh.

My valve springs are Lunati 73126 single springs with damper, Coil Bind height is 1.100" ;Seat Load is 103@1.800", Open Load is 303@1.250" and the Rate (lbs/in) is 364.

I often heard that its recommendet to have a open load UNDER 300 lbs for the break in.

Would you guys break in the cam with these springs or should i use stock springs for breaking in the cam?

For sure, i pre lubed the cam lobes and lifter bottoms with assembly lube and the lifters were rotating when turning the engine.

I also will use zinc-engine break in additive and prime the oiling system.

 

If your seat height is 1.800" and you have .485" lift........ 1.800" -- .485" = 1.315" this would be less pressure than the 303 # which is at 1.250". Check one valve spring to see what you have at 1.315". I would think you would be well under 300 #.

 

Ok, right, that makes sense!

So do you think i can break the cam in with these springs?

I just dont want to flatten the lobes and have an engine full of metal chips better be safe than sorry.

Thanks for the help!

 

I understand your caution. I am assuming you have a hydraulic, flat tappet cam and lifters rotate when the cam is turned. 1. We don't know yet what the full open spring pressure is. 2. We don't know what material the cam and lifters is made from. 3. We don't know the hardness (Brinell or Rockwell "C"scale) of the cam lobes or lifters. 4. What does your cam manufacturer recommend ?
I know if it were me, I would have had the cam "tuftrided" and I would be picky about the lifters.

 

Yes, the lifters were rotating when i turned the camshaft after assembly.

My lifters are Lunati 71951 micro-trol.

i really have no idea about the hardness of the cam and lifters, so I think i will ask at lunati if i can break the cam in with these springs.

Thanks a lot!

 

I have a set of Lunati Micro-trol lifters and Erson TQ40 cam in my 455 powered 1964 Olds Starfire. I have no miles on the engine to report any problems. Cutlassefi supplied the cam and lifters. I wanted lifters with internal snap ring retainers and not the hairpins.
Lunati would be my first choice for that information and Cutlassefi. Let us know what you find out.

 

Yeah, coppercutlass recommended these lifters fot me because of the snap ring. I think theyre a good choice.

i will try to contact Lunati today to hear their recommendation!

 

Good luck with Lunati.

 

Good news, i asked a guy from lunati and he told me that the pressure of the Lunati 73126 is fine to break the cam in with, so i did the break in today and all went well. First, i had a strange noise when revving the engine after the 20 minutes at 2500 rpm. Then i was suspicious, because i damaged the drivers side remflex header gasket while dropping the new engine ln. So i was lucky and had a new gasket lying in the garage and chapeu! The noise was gone.

after break in, i changed the oil and filter. I inspected the oil and the filter, and there was just really fine metal debris in the oil, so i think everything went well. Now, the car is ready to do the first miles on the road, but i will have to wait till winters over.

Thanks for all help!

 

Good job, yup finally some nice weather, just need a few good rains to wash the salt away.

 

Thats good news from Lunati. Thank you for letting us know.