Seat pressure and break in. Hyd flat tappets

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Mopar92

Mopar92

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About to crank my rebuilt 360. Flat tappet hyd setup. New cam and lifters. It’s primarily a Mopar engine shop. Cam is basically a 340 lift and duration with a little more ramp speed. I used the springs recommended by the cam manufacturer. I’m around 130 on the seat. I’m fairly nervous... as is the engine builder. Cam builder says no problem. It’s primed, Brad Penn break in oil, hoping it fires right away. Does this amount of seat pressure scare you guys or no?
 
Rip it! I’ve broke 3 in with recommend valve springs and no issues. I’d doesnt sound like a big lift cam so Don’t over think it. Just run through all the precautions you can, timing is crucial to instant start and as long as you’ve poured some fuel in the bowls you should be good to go.

Jake
 
nope, fire it up, 1800 rpm for 20 min, should be good to go
 
That’s what my plan is. That and keep good zinc oil in it after breakin. Timing is set, carb is primed, mighty vac’d fuel through the pump and up to the carb log.... triple checked hose clamps etc so I don’t have that 4 min in shut down. I’m probably worrying over nothing. The last one I had done was a roller and I didn’t worry as much.
 
Mopar92 said:
That’s what my plan is. That and keep good zinc oil in it after breakin. Timing is set, carb is primed, mighty vac’d fuel through the pump and up to the carb log.... triple checked hose clamps etc so I don’t have that 4 min in shut down. I’m probably worrying over nothing. The last one I had done was a roller and I didn’t worry as much.
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Stop future trippin, and like I say at the golf course "tee it high and let it fly"...
 
Mopar92 said:
About to crank my rebuilt 360. Flat tappet hyd setup. New cam and lifters. It’s primarily a Mopar engine shop. Cam is basically a 340 lift and duration with a little more ramp speed. I used the springs recommended by the cam manufacturer. I’m around 130 on the seat. I’m fairly nervous... as is the engine builder. Cam builder says no problem. It’s primed, Brad Penn break in oil, hoping it fires right away. Does this amount of seat pressure scare you guys or no?
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Wait a minute, real this back for a second LOL did you say the engine builder is nervous? About what? a relatively stock cam? Ooookey....
 
IMO, 1800 is low for break in. I prefer varying between 2500-4000 for 15 minutes. The two biggest reasons are first, obviously you don't want the engine to idle or RPM too low, because you have the risk of wiping a lobe. 1800 is not much above fast idle when the choke is on.

Secondly, you want to sling a LOT of oil around and you're not going to accomplish that by letting the engine run slowly.
 
RustyRatRod said:
IMO, 1800 is low for break in. I prefer varying between 2500-4000 for 15 minutes. The two biggest reasons are first, obviously you don't want the engine to idle or RPM too low, because you have the risk of wiping a lobe. 1800 is not much above fast idle when the choke is on.

Secondly, you want to sling a LOT of oil around and you're not going to accomplish that by letting the engine run slowly.
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I was thinking 1800 was a little low. (I sould know because someone called me a Mopar good today)
 
Let ‘er rip. I broke in my solid Clay Smith cam for 30 minutes between 2000 and 2500 with Shell Rotella and Redline Engine Break-In Additive. The cam is a little hotter than the 273 Formula S cam. No problem. Enjoy the moment.
 
Let her rip... my new cam will have a bit more on the seat so I'll ditch the inner springs until it's broken in... I don't think you'll have any issues. Good luck...
 
At least 2500 or above with varying RPMs like rustyratrod said.
Of course when I broke mine in I just let it idle..... it's a roller cam. :p:p
 
130 is pretty low and it is not the seat pressure that will wipe the cam, it is the over the nose pressure!
 
  • with that cam and springs, 1800 - 2800 will do just fine, or just go 2000 - 2800. I would slowly walk it up to 2800 and then slowly walk it down to 1800.
  • Don't overheat it.
  • Have someone there. My last cam I broke in, I had my wife stay in the car, she started it, I kept it revved and set the idle to about 2000, then I slowly picked it up and brought it back down. That way I could look for leaks and check gauges.
 
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Open valve pressure is what I think about. If it is under something like 300 lbs, then I have less concern. (But thinking about your increased ramp seed is on the mark as far as force on the lobes.)
 
I'm lucky enough to have a break in cycle test on my dyno. I use it every time I have an engine with a new flat tappet camshaft. I set the low rpm and high rpm and the number of seconds per cycle and number of cycles/time. 1800-2500 rpm is what the engine will cycle between with the throttle open about 30-40% and the dyno does the rest. Its pretty cool to have the engine running up and down and be able to walk away from the console and check timing/leaks/fuel etc.. It also puts about 200 ft/lbs of load on it and that helps the rings as well. FWIW I would want your engine with those springs to fire immediately but it should be fine. J.Rob
 
j par said:
I was thinking 1800 was a little low. (I sould know because someone called me a Mopar good today)
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It probably is a little low, when you're using Walmart tech 2000 oil. lol You being the one who doesn't believe zinc is important with flat tappet cams. 1800 rpm varying to 2200 has worked for me / us without any failures. ANY !
 
RAMM said:
I'm lucky enough to have a break in cycle test on my dyno. I use it every time I have an engine with a new flat tappet camshaft. I set the low rpm and high rpm and the number of seconds per cycle and number of cycles/time. 1800-2500 rpm is what the engine will cycle between with the throttle open about 30-40% and the dyno does the rest. Its pretty cool to have the engine running up and down and be able to walk away from the console and check timing/leaks/fuel etc.. It also puts about 200 ft/lbs of load on it and that helps the rings as well. FWIW I would want your engine with those springs to fire immediately but it should be fine. J.Rob
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Right! Sure, just rub it in!! LOL!!
Yeah, 130# on the seat ain't nothin', unless there's only 3 coils & the spring rate is 800#/inch.....then I'd worry lol!
 
I forget what the open pressure was. I guess it's the ramp that made me nervous. I worry too much I guess. Hensley racing built me a bad *** 360 in the mid 90's. .509 cam etc. I was 18 at the time and saved my pennies for that engine, which still runs strong to this day. Anyway... I cranked and cranked and cranked. Finally got it to crank, had a water pump gasket leaking. Shut it down. No telling what oil I used, probably mobil1 at the time. Engine has a lot of passes and miles for a toy car not driven. I guess ignorance is really bliss.
 
fishmens67 said:
It probably is a little low, when you're using Walmart tech 2000 oil. lol You being the one who doesn't believe zinc is important with flat tappet cams. 1800 rpm varying to 2200 has worked for me / us without any failures. ANY !
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That Walmart oil was bought for this old junkyard 360 with a million miles on it likely. Now of course I believe in zinc it's in all oil LOL. And of course I broke my new motor with 350 lbs open rate with penn grade break in oil and I've only used penn grade since. I'm not going to take a motor that's had 40 or 50 thousand miles on it that's been taken to Jiffy Lube all its life all of a sudden now you need some special oil with extra zinc in it LOL
 
j par said:
I was thinking 1800 was a little low. (I sould know because someone called me a Mopar good today)
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What's a mopar good?

Damn all this new lexicon crap. Just a few days ago I learned idle screw is derogatory. Now I have to learn what a mopar good is.
 
yellow rose said:
What's a mopar good?

Damn all this new lexicon crap. Just a few days ago I learned idle screw is derogatory. Now I have to learn what a mopar good is.
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First why are you all over the forum quoting me? And 2nd I didn't know I was a Mopar God till yesterday, I didn't even know there was such a thing LOL like I said none of this is self-acclaimed and it was challenged heavily!
 
j par said:
First why are you all over the floor I'm quoting me? And 2nd I didn't know I was a Mopar God till yesterday, I didn't even know there was such a thing LOL like I said none of this is self-acclaimed and it was challenged heavily!
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Ahhhhhhhhhhhh...mopar God. I'll agree you are a mopar God.
 
Anyways I don't have time for this crap I've got to go get your motor mounts from O'Reilly's and get this motor in my truck.
 
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