Comp Cams 268H and 1.6 rockers

[Supercharged111]

And that's great, if you didn't check you wouldn't know. I kind of doubt they're running those numbers on stock 80# springs. It's a clearance I always check when deviating from stock instead of taking somebody else's word for it.

If you get it wrong, crash, bang, boom, is a bad day.

Alright you dragged it out of me, I have stock springs still. Nearing 300,000 miles. They're on my short list to change out for something a little more robust.

 

[L31MaxExpress]

Alright you dragged it out of me, I have stock springs still. Nearing 300,000 miles. They're on my short list to change out for something a little more robust.

Good idea. Mine were 55# at the seat when I checked them. I had valve float so bad that I lost 40 hp at the tires between 5,100 and 5,300 rpm. I went from 229 whp to 257 whp and 304 to 310 wtq from only a spring change.

 

[Hipster]

Alright you dragged it out of me, I have stock springs still. Nearing 300,000 miles. They're on my short list to change out for something a little more robust.

Good idea. Mine were 55# at the seat when I checked them. I had valve float so bad that I lost 40 hp at the tires between 5,100 and 5,300 rpm. I went from 229 whp to 257 whp and 304 to 310 wtq from only a spring change.

Kinda what I'm talking about. A lot depends on how you drive your stuff, but even a roller cam can beat itself to death from insufficient spring pressure.

Not you guys, but people are funny, it's always the damn cam when it goes bad , and never what they did around it.

 

[L31MaxExpress]

Kinda what I'm talking about. A lot depends on how you drive your stuff, but even a roller cam can beat itself to death from insufficient spring pressure.

Which I have said in another post prior that I feel the Comp cast core XE cam I ran failed. I think the lifters were getting tossed off the lobes.

 

[Hipster]

Which I have said in another post prior that I feel the Comp cast core XE cam I ran failed. I think the lifters were getting tossed off the lobes.

lol, I was adding to my post, but yeah, and you don't always pick up on valve float audibly.

 

[Hipster]

Which I have said in another post prior that I feel the Comp cast core XE cam I ran failed. I think the lifters were getting tossed off the lobes.

I won't run Comp's stuff anymore after an XE hft failed on me. Never had a problem with Crane's stuff.

 

[PlayingWithTBI]

I won't run Comp's stuff anymore after an XE hft failed on me. Never had a problem with Crane's stuff.

FWIU pretty much all cam companies get their cores from just a couple places. Plus availability is scarce. The Comp Cam and lifter set I bought 3 weeks ago, said somewhere around 8 left, is now "not in stock" with delivery 01/13/23, at Summit (Comp Cam's website says "available soon"). It's still better than a flat tappet cam, ha ha.

 

[Erik the Awful]

Not you guys, but people are funny, it's always the damn cam when it goes bad , and never what they did around it.

I posted a link to a video just the other day where a pro engine builder refuses to build flat tappets any more because he can't guarantee the cams or lifters are good enough. He discusses break-in procedures and how they've become more stringent over the years. I can remember back in the day when you'd just throw a bottle of MMO in the crankcase and keep the revs up for twenty minutes and that was all you needed. It's definitely worse now.

Here's that video:

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[Hipster]

I posted a link to a video just the other day where a pro engine builder refuses to build flat tappets any more because he can't guarantee the cams or lifters are good enough. He discusses break-in procedures and how they've become more stringent over the years. I can remember back in the day when you'd just throw a bottle of MMO in the crankcase and keep the revs up for twenty minutes and that was all you needed. It's definitely worse now.

Here's that video:

xc_hide_links_from_guests_guests_error_hide_media

I don't disagree with him. He briefly touched on it. All these cam makers are pushing fast rate hft's as the best thing since sliced bread. Guys in the 60's were experimenting with ramp intensity. They've already been through how far they could go. Guys like Harvey Crane, Racer Brown, Cam Motion, Can Dynamics, etc. The list is long. Now we are bombarded with computer designed cams that a computer says should live, for what, a few ponies and ft. lbs. more. You can find a few ft lb, a few hp, or a few tenths in a quarter mile elsewhere.

He pretty much nailed on the 300 lb. springs. Off the top of my head without looking at part numbers would be a low lift number and maybe 110-115 lb seat pressure z28 type springs. .500 might need 340lb. over the nose(??). Cranes catalog is about the only one I know that shows what a given spring's open pressure is at different given heights making it easy to figure out where you're at. It's actually graphed and a great reference. He alluded to how difficult it can be to get the right pressure springs, how critical it is, and I 100% agree. I say it over and over on this site like a broken record.

Elgin was at one time an oem supplier and I have used their old school grinds, lifters, and springs on quite a few stockish type builds, for higher end I go with Crane. I pretty much stay away from fast rate hft's. No XE's for me.

 

[L31MaxExpress]

I don't disagree with him. He briefly touched on it. All these cam makers are pushing fast rate hft's as the best thing since sliced bread. Guys in the 60's were experimenting with ramp intensity. They've already been through how far they could go. Guys like Harvey Crane, Racer Brown, Cam Motion, Can Dynamics, etc. The list is long. Now we are bombarded with computer designed cams that a computer says should live, for what, a few ponies and ft. lbs. more. You can find a few ft lb, a few hp, or a few tenths in a quarter mile elsewhere.

He pretty much nailed on the 300 lb. springs. Off the top of my head without looking at part numbers would be a low lift number and maybe 110-115 lb seat pressure z28 type springs. .500 might need 340lb. over the nose(??). Cranes catalog is about the only one I know that shows what a given spring's open pressure is at different given heights making it easy to figure out where you're at. It's actually graphed and a great reference. He alluded to how difficult it can be to get the right pressure springs, how critical it is, and I 100% agree. I say it over and over on this site like a broken record.

Elgin was at one time an oem supplier and I have used their old school grinds, lifters, and springs on quite a few stockish type builds, for higher end I go with Crane. I pretty much stay away from fast rate hft's. No XE's for me.

My cam is on Magnum high lift lobes.