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we started up the L72 how hot can it get to before we need to look out. got about 10 min into the break in and i shut it down at about 230 got nervous. will having to start back into the cam break in cause problems like resuming break in after engine cools a bit and we check level? bill
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Re: any body still awake advice needed asap
Even a brand new engine should not run that hot. Did you have coolant circulation? You can normally tell by the upper radiator or hose temps, they should have been jet hot at that time. If not you may have a circulation concern, t-stat or air pocket. We would normally fill a new engine through the thermostat opening in the intake, this ensures the block is full. 230 should not have been hot enought to hurt the engine but you want to get the high temp addressed before moving forward. Do you have adequate air flow through the radiator? Is the fan pulling air? -
Re: any body still awake advice needed asap
we are letting it cool the pull the thermostat. how hot is dangerous hot? i suspect the air pocket. does stopping then starting again affect the cam break in? do i go back to 30 min at 1700 rbm? my nearves are shot i have a small fortune in this motor,apriciate the help billComment
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Re: any body still awake advice needed asap
Bill, I would count the time already elapsed as part of the total run in. The 230 range is about the top of where I would personally feel comforatble with the engine touching. I don't think I would run my engine at that temp for any period of time. We used to run cool water over the radiator at break in sometimes but it can get messy. It is very effective but if you have a lot of time in detailing this will get things wet.Comment
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Re: any body still awake advice needed asap
i watched it carfully it shut it down as it went past 225 ran around 210 for most of the run. i suspect timing off a bit should i let her cool completly before trying again? should i pull thermostat alltogether for break in? billComment
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Re: any body still awake advice needed asap
Bill,
One thing you might try is taking a couple of box fans and place them in front of the radiator and turn them on high. Also,turn the car heater on full.
Doug LeeComment
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Re: any body still awake advice needed asap
Bill,
Let it cool enough to pull the thermostat housing, may take a little while. I would not fully drain the engine either, just enough to get the stat out and refill through the hole. Don't run the engine without the stat either. Normally around 140 or so you can pull the thermostat housing, be careful, 140 is still hot enough to scald you. If you know your total advance you should be able to set the timing during break-in. We used to have advance timing lights that could be dialed in for total advance then just set the pointer on zero at speed, works great if you have one. Good luck, I'll check your post in the AM.
Don YesacavageComment
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Re:set car on fire all is well
ran around 170 to 210 max completed break in set car on fire. side pipe cover front mount came loose and layed on pipe saw in time. are we having fun now. what lash should i set? really apriciate your help, billComment
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Re: any body still awake advice needed asap
all broke in nearves coming down, time for bed, thanks all,billComment
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Re:set car on fire all is well
Bill, don't worry about the engine getting a little hot, as soon as you start the engine set the timing to the spec's, and I guess your carb is still in good adjustment. While it's running check for the proper vacuum, and set idle. If it's running good, then that's fine, you can shut it down and let it cool and try to find that air lock which could be giving you a false reading. I had the same thing happen to me after rebuilding my L-82. It cleared up itself, and when I first started up the engine, my rocker's were too tight and the engine would not start after cranking. I pulled the intake and push rods to check the lifters and camshaft and everything was just fine. Re-installed lifters and intake, and this time I left the rockers a little loose, the engine started and then adjusted the rockers when hot. Tuned them in and gave them a 1/4 turn, if I gave a 1/2 turn it would unbalance the valve timing, so I found the 1/4 turn worked great. Put the valve covers back on and cleaned up the oily mess. I met with Mr. Dave McLellan in 2004 and he told me that Chevrolet (CORVETTE) Division was doing testing in Death Valley and he said "they were running the cars using turbo's in around 75'-76' and they were getting great HP, but too much for the automatics to handle and the motors were operating at about 280o and it was no problem", so don't worry. Ken.Comment
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Re:it was a wild night
rebuilt ebay carb would not pump gas, put on holley i had. starter heats up. solonoid hung up on my last fire up (will look at today) side pipe caught fire. fuel lines had minor leaks. but the engine itself purred like a kitten and TI worked great. idles nice timing right on. murphy's law was with us last night. will lick our wounds and button her up. didn't get much sleep worrying if we forgot somthing and car would burn (hell with my shop)like a good corvetter i lulled myself to sleep reading the chassis main guide,woke up to 2 inches of snow here in VT. the advice here was a god send and in my opinion the reason i joined. you didn't let me down. thanks guys for all the advice and support,billComment
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Re:it was a wild night
Bill,
Glad to hear everything turned out OK. Start-ups can be nerve wracking. I am glad I could provide some support, fixing cars by email is tough. Regarding your valve lash, do you have specs for the cam?
Don YesacavageComment
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Re:it was a wild night
Ha ha, I got a good laugh, thinking about the times I've had the same sort of experiences. Nerve-wracking as can be.
As a matter of course, if I have the engine in the car for start up now, I have a fan blowing in the grill, timing light hooked up and ready, distributor wrench in place, the water hose dragged to the garage door, the garage door open so I can roll the car out if need be, and a heavy old moving quilt to smother any carb fires. The quilt is better than a fire extinguisher if you have ever had to clean that dry chemical off of anything you want to keep.
They often get hot on the break-in. For one thing, you have the assembly lube that can clog the filter. If the filter clogs, you put a real load on the engine, unless you have a working bypass.
Now that you have gotten through it, drain the oil, remove and cut open the oil filter, and check for metal. There probably will be some, but a little glitter isn't hurting, a lot of glitter (or chunks) is.Comment
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Re:it was a wild night
Reconfiguring the vacuum advance control to full time will considerably reduce the tendency to overheat at idle. Teeing it into the choke vacuum break hose is the easiest way.
DukeComment
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Re:set car on fire all is well
Ken, it is possible that you were cranking down the rocker arm faster than the lifter could adjust itself. When the engine is running and you start to tighten the rocker, it takes a while for the lifter to bleed down enough and let the valve close all the way. Just a wild guess as to what was happening. TerryComment
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