BBC Flat Tappet Cam Break In

[Siegel1719]

I know this should go in the Tech board but I was hoping to get more eyes here.

I will be breaking in my cam this week hopefully and want some opinions on valve springs. I purchased matching spec Edelbrock springs for the cam with is a mild Comp Cam XE274H. However the current springs in the stock Iron heads are unknown specs triple spring valve springs. Should I break in the cam with the unknown triple spring valve springs or the matching valve springs. Im not sure which is the higher pressure spring.

The reason for this question is over the years this motor has wiped out 2 or 3 cams. This time I replaced the cam with matching lifters, springs, push rods and rocker arms. I also plan to break in and run the motor on Comp cams break in oil. I degreed the cam and came within .5-1.5 degrees of the intake center line.


Thanks
Jeremy

 

[AutoRoc]

I would pay for a roller conversion. I've had a new engine ruined because the first cam wiped out 5 lobes, then the next cam wiped out one lobe. These were all new Comp Cam parts, their springs, their lube, oil, break in procedure, etc..

Fingers crossed!!

 

[grr456]

I would guess your triple springs are really 2 springs with a damper? Typically real triple springs are used with a solid roller cam and if those heads were once used with a solid roller, then that is the reason cams are wiping out. You would have upwards of 650 to 750 pounds spring pressure on the cam when the valve is opened, depending on lift.

A couple things......First you shouldn't use the existing springs. Second, you should really use just the outer springs from the new set to break the cam in and then put the inner springs on.

Just my .02.....grr

 

[Beigg]

During all your past builds that used a flat cam use, did you use conventional oil and included additional zinc dialkyldithiophosphate?

 

[derbydad276]

I am building a 400m for my Mercury nd I'm petrified over this exact same thing
Lucas came out with High Zinc oils for flat tappet cams
http://lucasoil.com/products/engine-builder-lubricants/high-zinc-engine-break-in-oil

 

[Siegel1719]

grr456- Yes I'm thinking I will swap out the current valve springs and run just the outers of the new springs for break-in.

Beigg- In the past I was using Kendall Oil with Comp Cams additive.

 

[DRAG-ULA]

Hydraulic flat cams are fine, as long as you run good oil with zinc in it and make sure everything is correct (lifters spinning in bores, spring pressure , coil bind clearance, retainer to seal clearance, etc). My Imperial has 5-7000 on the rebuild and it's fine. I run Brad Penn oil and a zinc additive, have no problems. We dyno engines at my shop and follow the same guidelines and never have problems

 

[Anthony]

I always used the cheapest shit possible for first 2 changes on flat tappets .

Murrays brand!

Shit, shows how long it's been since I had a flat tappet!

 

[grr456]

Brad Penn makes a high zinc break in oil and their semi-synthetic has ZDDP in it. That is all we ran in our race car engines with solid lifter cams and never had a problem. We changed the oil a few times a season and I run the used oil in all of the other small engines I have......

grr

 

[Beigg]

Wiped a few lobes in the past before using BradPenn G1 with a small amount of zddp for the break in, then BradPenn G1 as a regular use oil.

 

[JACKO]

Sounds weird, but get a bucket, put your lifters in their, fill the bucket with oil, the the lifters sit in their for a few days, oil will get into the lifters,like priming a hydrolic motor, i have done this 3 different times, and have never wiped out a cam. Still follow all other directions, other thing i did, was once everything was installed, i had a oil pump priming tool, i used that also.

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