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08-04-2018, 01:09 PM | #26 |
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Join Date: Oct 2016
Location: Dallas Texas
Posts: 2,875
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Re: Burnt up rockers on sbc
If nobody else chimes in regarding your current set of lifters and/or the video of the lifter valley, I suggest you replace them all with comp's recommended lifters for your cam. I would also replace the rockers since they were not getting oil. A failure of the bearings there would send metal into your block/oil ( potentially ).
I know you don't need this advice, but future readers may: When installing the lifters, follow the directions to the tee, if no directions, go to the website of the manufacturer and download or read them from there. If no directions, return them and buy from a manufacturer that provides instructions for you to clean the hardware and soak in oil before installation. Regarding the lifter valley video: I see oil rising up from inside the bores so the oil galley is pressurized. What I don't know is whether that's the right amount of pressure...enough to make it into the lifters...assuming the lifters are functioning and aligned properly when riding on this cam. Hth, -klb
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67 C10 fleet fuel injected '70 402, 700r4, 3.73 posi 07 335 sport turbo 6sp 94 Trans Am GT LT1 6sp posi -- sold after 22yrs 99 540 sport V8 6sp -- sold 73 240z L24 4sp -- given to friend 68 C10 step 350/350 3.73 open -- sold |
08-05-2018, 11:01 AM | #27 |
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Re: Burnt up rockers on sbc
The upper lifter has the reliefs and the orifice for the lifter should be fine . But still no oil . Could very well be the lower part of the lifter with the roller and the base circle of the cam may not be dropping down in the lifter bore enough to expose the center of the lifter to the galley bore .
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08-06-2018, 11:48 AM | #28 |
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Location: Moraga, CA
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Re: Burnt up rockers on sbc
Yes. Great point. Not a ton of information out there on that one. The few machinists I've spoken to say that they don't normally take out because there isn't too much junk behind it. But I took mine out before I spoke with them and had to track down the part number and the instructions to install it. I carefully put mine in and have good flow through all push-rods.
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(Very) Slow-Going Build Thread: Stock 1970 Short Step with Stock 1970 LT-1 http://67-72chevytrucks.com/vboard/s...d.php?t=567340 |
08-07-2018, 09:48 AM | #29 | |
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Re: Burnt up rockers on sbc
Quote:
Here is a link to what TruckDude and I were talking about: https://www.crankshaftcoalition.com/...ystem_Chevy_V8 And the pic: https://www.crankshaftcoalition.com/...ear_main_2.jpg EDIT: BTW, this is a $1 part. But they might charge you $5 for it. :-) Talk to your machinist first. See if they are familiar with the plug and how confident they are that they put it back in. And see what they say about your symptoms.
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(Very) Slow-Going Build Thread: Stock 1970 Short Step with Stock 1970 LT-1 http://67-72chevytrucks.com/vboard/s...d.php?t=567340 Last edited by mattfranklin; 08-07-2018 at 04:41 PM. |
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08-07-2018, 08:31 PM | #30 |
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Location: Clear Lake, MN
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Re: Burnt up rockers on sbc
GOOD info, I just checked and I get a depth of 8 3/8” from top.
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08-07-2018, 08:37 PM | #31 |
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Location: Clear Lake, MN
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Re: Burnt up rockers on sbc
Here’s another video showing oil flow coming out the #8 exhaust lifter bore. First one closest to the distributor. https://youtu.be/MAv045q55PM
I went ahead and ordered new comp lifters and some full roller rockers. I will give that a try. |
08-07-2018, 10:52 PM | #32 |
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Re: Burnt up rockers on sbc
Sweet! Your oil is being a) pumped through the filter ( wink wink ) and b) nicely pushed with pressure into the lifter oiling galley there!
You'll be cooking with gas again shortly -klb
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67 C10 fleet fuel injected '70 402, 700r4, 3.73 posi 07 335 sport turbo 6sp 94 Trans Am GT LT1 6sp posi -- sold after 22yrs 99 540 sport V8 6sp -- sold 73 240z L24 4sp -- given to friend 68 C10 step 350/350 3.73 open -- sold |
08-08-2018, 11:46 AM | #33 |
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Location: Moraga, CA
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Re: Burnt up rockers on sbc
Glad the plug wasn't missing. So we've eliminated that.
Still scratching my head. Next thought: Comp says their roller-tip rockers have a 350lb max. See p 314. http://www.compcams.com/catalog/comp...12_312-327.pdf The 372lb spring pressure was your "full open" pressure, right? Could your extra 22lb make the difference? <10% Maybe if it's already at the limit. So some oil makes it to the rockers, right? It's just not as much as I'm used to seeing with stock type lifters. Could it be that your lifters assume that you're using full roller rockers?
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(Very) Slow-Going Build Thread: Stock 1970 Short Step with Stock 1970 LT-1 http://67-72chevytrucks.com/vboard/s...d.php?t=567340 |
08-08-2018, 02:28 PM | #34 |
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Re: Burnt up rockers on sbc
Again, scratching my head, but how's the pushrod length? I assume you compensated for the taller roller lifters with shorter pushrods. But if the geometry is way off the oil holes in the pushrod won't line up with those in the rocker. Still scratching my head.
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(Very) Slow-Going Build Thread: Stock 1970 Short Step with Stock 1970 LT-1 http://67-72chevytrucks.com/vboard/s...d.php?t=567340 Last edited by mattfranklin; 08-08-2018 at 03:52 PM. |
08-08-2018, 04:16 PM | #35 |
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Location: Clear Lake, MN
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Re: Burnt up rockers on sbc
I ended up needing .100 shorter pushrods with the roller tips. Yes hydro roller lifters. I ordered up comp lifters and some full roller rockers. I’ll double check pushrods length when they show up, get the correct pushrods and try it all again to see what we got.
How does the oil flow out of the #8 lifter bore look? Ever do that before? |
08-08-2018, 05:39 PM | #36 |
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Location: Moraga, CA
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Re: Burnt up rockers on sbc
I did some more reading because I've never had rollers myself.
According to Comp, many brands of roller lifters need a certain index to align properly with lifter oil gallery for Chrysler anyway -- Comp says their lifters are machined so it doesn't matter. For Chrysler. I didn't dig far enough yet to figure out issues for Chevy Have not primed before with lifters out before. Good luck with this. We're interested in seeing it run strong. Oh, and Go Gophers! and SKOL, Vikings! (I'm a MN native living out in CA these past 20 years).
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(Very) Slow-Going Build Thread: Stock 1970 Short Step with Stock 1970 LT-1 http://67-72chevytrucks.com/vboard/s...d.php?t=567340 |
08-21-2018, 10:54 AM | #37 |
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Join Date: Sep 2011
Location: Ark City, Kansas
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Re: Burnt up rockers on sbc
An engine builder acquaintance of mine has had issues with these specific rockers.
His take on the deal is that the slot in the rocker balls allow the oil to just run out bottom of rocker too fast. He has replaced slotted balls with solid balls. When he has done such, he uses lapping compound between rocker body and solid ball. fairly easy to do, easy to clean lapping compound off after. This has been a fix, for him. Mind you these are ALL customer engines. He refuses to use these rockers on any engine. He advises to only use them on a stock or close to stock build.... |
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