[Nyairguard]

Drippers or no drippers what you guys using? 68 400 engine
Roller tip comp rockers


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[KEN CROCIE]

your poly locks will act as drippers

[steve25]

X2 with that.

[Vid]

Originally Posted by Nyairguard

Drippers or no drippers what you guys using? 68 400 engine
Roller tip comp rockers


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I am finishing up a hydraulic flat tappet 455 build and have two sets of rockers on my bench. Your basic Comp 1.52 roller tips and a set of PRW 1.65 full rollers. I’ve read that the 1.65’s should NOT be used for hft cam break in, so I’ll likely start with the Comp 1.5’s and see how I like them. If I feel like it needs “a little more” after break in I’ll switch for the full rollers.

Has anybody reading successfully used 1.65’s on a hft break in? Just curious.


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[OCMDGTO]

Vid,
The engine in my sig was broken in with 1.65s

[78w72]

Originally Posted by Vid

Has anybody reading successfully used 1.65’s on a hft break in? Just curious.


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i'd be more concerned with push rod clearance of the heads using 1.65 rockers than cam break in. have you checked the heads for clearance.

curious to hear what the reason is to NOT break in a cam with 1.65 rockers?

[Schurkey]

Originally Posted by 78w72

i'd be more concerned with push rod clearance of the heads using 1.65 rockers than cam break in. have you checked the heads for clearance.

Quoted for truth.

I went nuts grinding clearance for 1.65 rockers on Father-In-Law's 455. It was WAY more extensive than what I was reading in books.

Originally Posted by 78w72

curious to hear what the reason is to NOT break in a cam with 1.65 rockers?

Higher ratio rockers increase the pressure on the lifter compared to lower-ratio rockers. If the valve springs are stiff enough, the higher ratio makes for excess pressure on the cam lobe/lifter interface.

[Vid]

Originally Posted by 78w72

i'd be more concerned with push rod clearance of the heads using 1.65 rockers than cam break in. have you checked the heads for clearance.

curious to hear what the reason is to NOT break in a cam with 1.65 rockers?

Heads aren’t on the block yet so haven’t measured push rod length or pushrod to head clearance yet.

Just got the crank in last weekend. Fits real nice and all journals clear at .0025. I’ll be installing the pistons and hopefully the pump, dipstick and pan this weekend.

Heads are Edelbrock round ports #61529’s for flat tappet cam (not for roller cam). Uncle Vic says they’re good up to .575” lift. My UD cam is nothing too drastic, just a good, healthy street performance cam something like an enhanced 041. Exhaust lobes open the valves to .507 @ 1.5 and .558 with 1.65’s. Intakes just 485 and 533 respectively. 231/239 @ .050” on 112. Should be a whole lot of fun on the street until some EV pulls up next to me and ruins the party, haha.

Back to the 1.65’s. So many of the stories we’ve all heard or seen surrounding hft cam break in and flattened lobes, pushing the envelope even further with 1.65’s does make me a little extra nervous.

My concern is exactly what Shurkey said. 1.65’s will add extra pressure on the lifter face during the brief but critical period when you actually want it slightly reduced.

However it is encouraging to hear that you guys have done it successfully. Frankly I love hearing ANY successful hft break-in story these days.


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[grivera]

The PRW RRs have been mentioned by Cliff and others on here for failure at the roller tip. Apparently wearing to the point they put metal in the oil.

[78w72]

thanks for the info on the 1.65 rockers, wasnt aware that was an issue for break in. some articles ive read about using 1.65 rockers says they put less side loading force on the lifter/lifter bore in the block, wasnt sure if they helped cam/lifter wear or created issues with cam break in.

as mentioned above, ive heard of & know people that have used 1.65 rockers for cam break in without issue. with the small stock 041 sized cam, you would probably be OK with 1.65 for break but since you have 1.52 those would be best, then swap to 1.65 if you feel the need & you confirm they will clear, from what ive read most say the heads will need some grinding.

the older E heads come with standard springs for flat tappet cams but its easy to just swap to a spring for a roller cam if/when needed, i have the same heads but in 72cc and changed the springs to what dave at SD suggested for his OF roller cam.

[highway star]

Back to post: OEM drippers! On the W72 chrome valve covers & using Comp Cams 1.52 roller tips. More oil direction up there is a good thing.