[steve25]

With the multitude of these type of failures being posted up I like to request that folks that start a new thread on such an upsetting thing also post up what there seat and open pressure was please.

If you can’t then what can I say other then your talking blind because your at the mercy of whoever set up the heads.

[Apache Warrior]

Interesting topic as I prepare to fire my engine sometime soon…

Edelbrock 87cc heads w/CNC chambers.
Comp 305H HFT camshaft - 253/[email protected] .350 lobe lift.
Comp 1.65 roller rockers = .577 total lift.
Heads are untouched.

My set-up for these heads is a Comp 950 spring for the above HFT. Free lift before CB (1.2) +.060 is .640, which allows for some additional room if I want to step things up a bit.

Published IH from Comp is 1.9”, but I want to target a spring seat pressure of 125-130 AFTER break-in.
With a locator and shims I have the springs set right at 1.865” - 1.875” IH and had them bench tested at a local machine shop on a Rimac tester at my desired IH (1.87) with a Comp tool steel retainer I’m planning to use. They all came in right at 140-145lbs. and 330lbs. at 1.3” (CB is 1.2”).
Pretty consistent and accurate per published specs from Comp Cams.
Bottom of retainer to top of valve seal clearance is .900 free length with the longer valves I’m using (Ferrea 6000 5.275 length). Used a Mitutoyo telescoping gauge that was locked and then measured with a Mitutoyo 2”-6” digital dial caliper.

Comp cam was purchased used from this board (Paul K) and looks good. No unusual wear that I would call out. I put the cam in my Goodson V blocks and rolled it through to check lift on each lobe with a dial indicator mounted on a magnetic stand and they all show .350 as published.

I will use Rhoads lifters on the intakes only.

Sound good or do I need to do a heel pivot to avoid any surprises?

[PAUL K]

What does seat pressure have to do with flattening a cam lobe?

[steve25]

Seat pressure just to get a feel for what people might think is acceptable, actually more so to see if purchaser of a Cam even knows or has left it up to there engine builder.

[P@blo]

Originally Posted by PAUL K

What does seat pressure have to do with flattening a cam lobe?

Yes! Open pressure. Not sure the focus on the closed?

[Apache Warrior]

Well, I’m certainly not an engine builder but I spend time learning and/or trying to learn.

All things considered, I believe I’m on the right track to get this engine fired and ready to go.

125-130 seat and 330 open for my HFT is my target.

Using good lifters (mix of Rhoads and Johnson’s). Cam already has some runtime. Removed inner springs for first fire-up. Washed the liters thoroughly in hot, soapy water, then a mineral spirits bath, then back to a hot, soapy cleaning and compressed air blow-out, to now soaking in 10/30 oil with a little GM EOS added.

[Steve C.]

Stated above- "...but I want to target a spring seat pressure of 125-130 AFTER break-in."

Good point and brings up an important topic and one often overlooked The fact that springs can and often do lose some pressure after run in and use.

Here is one example documented in a build done by the noted Ken Crocie. In use was a Comp hydraulic flat tappet cam. The valve spring pressure was set at an initial setting of 130 pounds on the seat, with 320 pounds open pressure.
After running on the dyno, he knew the valve spring pressure would ease down toward Comp Cams rated value of 117 pounds on the seat. The actual pressure after a day on the dyno was 122 pounds.

Another nice example from mgarblik who posted a few years ago with a build using dual springs with 135-140 on the seat. However on this particular build the cam was broken in on the dyno with the inner spring removed.
His posted comment..."BTW, also consider if the springs are new, after running the engine for an hour, the outer springs will lose 8-9 Lbs of seat pressure as well. (10%) is typical so when the inner is reinstalled in my case, the seat pressure will be 127-132 broken-in."

And related, always check new springs at their intended installed height with their actual intended retainers on a calibrated spring tester. Never trust catalog specs ! I've had new springs that did not come anywhere close to their catalog rated specifications. And from a valve spring catalog.... "Note: spring tensions often vary measurably within the same production runs; therefore it is recommended that EACH SPRING be tested on an accurate spring tester and the springs installed at the recommended SEAT PRESSURE."

And someone posted that the retainers being used can be a key player in this deal as the inner can vary some from one part number to another. This affects or changes spring checking pressure(s) and coil bind as well.

.

[chuckies76ta]

Are you looking for info just on this: Flat tappet cam and or lifter failure ?

[67Lemons]

Originally Posted by Apache Warrior

Well, I’m certainly not an engine builder but I spend time learning and/or trying to learn.

All things considered, I believe I’m on the right track to get this engine fired and ready to go.

125-130 seat and 330 open for my HFT is my target.

Using good lifters (mix of Rhoads and Johnson’s). Cam already has some runtime. Removed inner springs for first fire-up. Washed the liters thoroughly in hot, soapy water, then a mineral spirits bath, then back to a hot, soapy cleaning and compressed air blow-out, to now soaking in 10/30 oil with a little GM EOS added.

Very thorough job & well done. Did you mean that you disassembled the lifters to clean in soapy water then mineral spirits then soapy water & then assembled again to soak in oil? That’s a ton of work but you can’t be too safe now a days I guess.

[Apache Warrior]

Originally Posted by 67Lemons

Very thorough job & well done. Did you mean that you disassembled the lifters to clean in soapy water then mineral spirits then soapy water & then assembled again to soak in oil? That’s a ton of work but you can’t be too safe now a days I guess.

I did not disassemble the lifers.

Is that best practice? Because I certainly can. I have a good snap ring plier set.

[67Lemons]

Originally Posted by Apache Warrior

I did not disassemble the lifers.

Is that best practice? Because I certainly can. I have a good snap ring plier set.

Smarter folks than me will hopefully respond but I believe disassembling them to clean is a best practice.

[Dragncar]

Originally Posted by 67Lemons

Very thorough job & well done. Did you mean that you disassembled the lifters to clean in soapy water then mineral spirits then soapy water & then assembled again to soak in oil? That’s a ton of work but you can’t be too safe now a days I guess.

Not sure why anyone would use soapy water to clean a lifter. Some sort of oil based solvent would be my choice. The oil them up.

[Apache Warrior]

Originally Posted by Dragncar

Not sure why anyone would use soapy water to clean a lifter. Some sort of oil based solvent would be my choice. The oil them up.

I always do a soapy water clean with most new parts, then a mineral spirits soak (bucket #1), or brake cleaner soak (bucket #2), back to hot soapy water, and then to an oil soak (bucket #3), if needed. If not oil, I’ll bag with a liberal WD-40 blast.

It’s an old Dan Whitmore process that he once shared with me, so I’d say it’s validated.

[455Darren]

Two Summit 2802 failures. Seat 120#, Open 230#. Taking the inner spring out on next cam Comp 270H 224-470.

[Formulajones]

I used a 2802 not that long ago with a set of Johnson lifters on it. The springs were 68404's set at 1.6 install height, and they had 128-130 lbs. on the seat. I don't recall the open pressure off the top of my head but anyone can do quick math if they wish for a rough ball park. I topped them off with a set of 1.65 harland sharps.

I broke it in just like that with 1.65 rockers and didn't bother removing the inner springs. All went just fine and that engine still runs perfect to this day.

Don't know why you guys are having so many problems.

[67Lemons]

HFT failures at break in or shortly thereafter seems to be one of the hot rod worlds greatest mysteries. Some folks don’t have issues while others doing the same exact thing do, it’s no wonder why a lot of folks go roller.

[PAUL K]

Originally Posted by 67Lemons

HFT failures at break in or shortly thereafter seems to be one of the hot rod worlds greatest mysteries. Some folks don’t have issues while others doing the same exact thing do, it’s no wonder why a lot of folks go roller.

All that guarantees is a bigger disaster if something fails .... But I agree that is the most popular reason folks go roller

[P@blo]

Originally Posted by 67Lemons

HFT failures at break in or shortly thereafter seems to be one of the hot rod worlds greatest mysteries. Some folks don’t have issues while others doing the same exact thing do, it’s no wonder why a lot of folks go roller.

Rollers have the same faulure maybe worse. If the problem went away with a roller I would say yes. But new problems filled the place of the old but take blocks with them. Not good for the hobby.

The industry will push roller because it is a big cow to milk as far as parts sales goes. Not much money to be made on the HFT stuff really so obviously they will want to sell you 2-3 grand of stuff instead of 2-3 hundred.

Just wait until guys won't buy your blocks because you ran a roller lifter it's coming...

[Formulajones]

I go roller for different reasons, none of which are any worries over flat tappet cams. It has more to do with what the goals are for the engine and it's intended purpose.
I've said it a million times, most failures that I've seen, and ones even posted on this forum have been self inflicted. Like I've said, stay away from the cheap china parts and fleabay deals and your chances improve greatly. With that said, even with the subpar parts, It's such a small percentage of failure overall when you consider how huge the market is that it's really only a hand full of worry warts preaching the whole gloom and doom thing.

It's not like this is a new thing, it's been going on for decades, the only difference now is we have the internet.

[EksCelle]

Originally Posted by Formulajones

I used a 2802 not that long ago with a set of Johnson lifters on it. The springs were 68404's set at 1.6 install height, and they had 128-130 lbs. on the seat. I don't recall the open pressure off the top of my head but anyone can do quick math if they wish for a rough ball park. I topped them off with a set of 1.65 harland sharps.

I broke it in just like that with 1.65 rockers and didn't bother removing the inner springs. All went just fine and that engine still runs perfect to this day.

Don't know why you guys are having so many problems.

I threw a 2802 with the cheap Summit brand lifters in my 455 last summer, also with 68404 springs but 1.5 rockers. I pulled the inner springs for break-in, and while I like to think it helped, it likely wouldn't have mattered. Runs great! I didn't know people were having issues with Summit cams.

I would like to see what kind of oil people are running when they experience a cam failure. I haven't lost an FT cam yet, but I always run a proper break in oil like Lucas. How many cam failures are due to running a cheap oil with an additive rather than a proper non detergent break in oil?