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Break-in after rebuild.. Oh the issues are a plenty

jake2077

Jr. Member
Joined
Dec 6, 2018
Messages
95
Finally got around to getting the 71 Bronco with rebuilt SMF 302 running this weekend. I've had two runs of about 12-15 minutes each bringing it up to temp. A few things I've noticed and a video for thoughts/feedback. Here's the video
  1. Had to stop the first test due to air in the cooling system (spectacular failure see related video on the channel) after about 13 minutes.
  2. Got the excess air out of the cooling system and utilizing the overflow tank successfully but still over 215 degrees closing in on 230 with 180 thermostat
  3. Hearing a lot of rocker/valve noise and wondering if the stock DOOE heads and rockers are the non-adjustable type meaning just run them down? I set for pre-load lash originally and thought I was good but maybe not?
  4. Heat is an issue over 2k rpm. The bore is 6 over so I expected it to run hot but geeze. I have a new aluminum 3 core radiator and stock clutch fan (maybe that's the culprit) with the fan shroud in place.
  5. When the engine is at temp there are 'pings and dinks' here and there making it very concerning and prompting me to shut it down. Not sure if this is the heat seating all the things in or a bad omen.
Thanks for the help as always.
 
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jake2077

jake2077

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What is your timing set at? Incorrect timing can cause overheating and pinging

I decided to reset after last night and check TDC and adjust timing to 5 degrees this morning. I also realized the positive stop nuts on the rockers needed to be torqued down to 20 ft/lbs since these are the original heads and rocker etc. Did an oil change while I was at it and now it's running smooth! No more clatter from the valve train and idling is pretty spot on so far. I hope the adjustments helped with running hot and will give it a try again later to check the results. Below is a picture of what I found when I took the valve cover off the passenger side before tightening the rockers down. Yikes.

WDlEBhT.jpg
 

Timmy390

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That picture is an OH SHITTER for sure.

Base timing should be around 10 degrees....I would try 8 and then 10.

Tim
 

bax

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well that looks exciting. could of been much worse.
 
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jake2077

jake2077

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That picture is an OH SHITTER for sure.

Base timing should be around 10 degrees....I would try 8 and then 10.

Tim
Thanks, I'll get the timing light/gun out and take a stab at it. This is my first ever build of an engine, much less a car restoration, and honestly it's got me spooked after seeing and hearing the sounds during initial startup. I ran through two runs of close to 20 minutes at 2k RPM to get through the break-in and 'feel' like things are running well enough at the moment. I'm hesitant to start it and just let it idle while working on other things, is that okay or should I still be cautious on the break-in?
 
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jake2077

jake2077

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Also, here is an updated video with the rockers corrected, timing adjusted and oil changed. Cooling seems to have settled but still watching temp as it seems to creep close to 210 at idle.

 

Timmy390

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Breakin always has a "pucker" factor......That's why I went "roller". I was SO freaked out breaking in my 390FE I never wanted to do that again. The big thing is you never know if the breakin "took" or not. You just have to run it.

What oil did you use during breakin? Any additives?

For the cooling.....many many factors. The blanket statement is "rising temps at idle is an airflow issue". Not always but in general it's true. 215 isn't hot. My rig runs 210-215 with a 195 stat. I noticed your running a 180 so 210 is a touch higher than I would expect but not what I would call hot.

What radiator cap are you running?
What radiator? Thicker is not always better,,,,,
What fan?
I see a shroud so that's good.

Quick test...put a fan in front of the radiator and see if that keeps the temps down. I was advised to do that during my breakin of the 390FE due to limited airflow at idle. I used just a box fan, Wife was pissed :)

Tim
 
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jake2077

jake2077

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Breakin always has a "pucker" factor......That's why I went "roller". I was SO freaked out breaking in my 390FE I never wanted to do that again. The big thing is you never know if the breakin "took" or not. You just have to run it.

What oil did you use during breakin? Any additives?
I made sure to use break-in oil plus zddp zinc additives. Was too scared I'd trash the flat tappet cams otherwise.
For the cooling.....many many factors. The blanket statement is "rising temps at idle is an airflow issue". Not always but in general it's true. 215 isn't hot. My rig runs 210-215 with a 195 stat. I noticed your running a 180 so 210 is a touch higher than I would expect but not what I would call hot.
Yeah, I have a 180 thermostat and the stock clutch driven fan. I noticed during warm up and idle the fan was lazily turning but when it did get hot it seemed to be much faster. Wondering if I should just upgrade to a static 7 blade fan instead? What is too hot and when should I be concerned?
What radiator cap are you running?
What radiator? Thicker is not always better,,,,,
What fan?
I see a shroud so that's good.
Toms Bronco/Offroad standard 13lb cap (https://tomsoffroad.com/parts/66-77-ford-bronco-radiator-cap) and 3-Core aluminum radiator (https://tomsoffroad.com/parts/66-77-ford-bronco-3-core-aluminum-radiator)
Quick test...put a fan in front of the radiator and see if that keeps the temps down. I was advised to do that during my breakin of the 390FE due to limited airflow at idle. I used just a box fan, Wife was pissed :)

Tim
I heard that using a fan helps as well so during the second break-in I propped one right in front of the grill and it did help. Thanks for the help!
 

Timmy390

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Sounds to me like you did the proper steps and oils for breakin. Time for a drive......

If the box fan helped then you know airflow is the issue at idle. The lazy fan you mentioned isn't moving much air. A common issue with bad fan clutches is overheating at idle or slow speeds. I hate throwing parts but I would try a new fan clutch.......

If you decide to change it out.....Do a test......see if a $1 bill will stick to the front of the radiator before and after the clutch change. That will give you a good indication if airflow is better.

Tim
 

Viperwolf1

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Yeah, I have a 180 thermostat and the stock clutch driven fan.
There is no stock clutch driven fan. All EB fans were direct driven. You have a clutch and fan that's been adapted from something else. It may not work well.
 

bmc69

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There is no stock clutch driven fan. All EB fans were direct driven. You have a clutch and fan that's been adapted from something else. It may not work well.
I've had the best luck with cooling my modified EBs using the 7-blade fixed-pitch fans on the HD clutch. FWIW... Obviously those parts were from a pickup truck application.
 
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jake2077

jake2077

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There is no stock clutch driven fan. All EB fans were direct driven. You have a clutch and fan that's been adapted from something else. It may not work well.
Thanks, that's good to know. I was skeptical of it anyway and not sure if it was working optimally. May just go with the $100 7 blade fan from Wildhorses4x4
 

Viperwolf1

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I've had the best luck with cooling my modified EBs using the 7-blade fixed-pitch fans on the HD clutch. FWIW... Obviously those parts were from a pickup truck application.
My best is explorer serpentine with '96-'97 metal fan and trailblazer severe duty clutch (4 seasons #46049).
 

DirtDonk

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I would do a little more break-in if this were mine. Not because you did not do enough the first time normally, but with not all of the valves and springs and pushrods doing their thing, the lifters and cam lobes on the affected cylinders were not being given the full treatment I do not think.
Yes, the lower pressure on those lobes might have been a good thing, but then again, it might not have allowed the parts a proper bedding or seating-in of the mating surfaces.

So now that all the rockers are set properly I would continue to do what you did for another 15-20 minutes at least. Then go for a drive or idle it any amount you want.
And get that timing back up to what the others were saying. They tend to run better and cooler with more timing advance. No guarantee of course, and every engine build is different. But it's a good direction to go unless you have excess pinging.

And check your header bolts while you're at all this. They tend to work loose, especially after the first few heating/cooling cycles. And exhaust leaks can mimic ticking in the valvetrain.

Paul
 

Broncobowsher

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I don't worry that much about a slow temp rise during break in. The extra friction of the rings seating in the bores tends to make them run a little warm during break in.
 
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jake2077

jake2077

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I would do a little more break-in if this were mine. Not because you did not do enough the first time normally, but with not all of the valves and springs and pushrods doing their thing, the lifters and cam lobes on the affected cylinders were not being given the full treatment I do not think.
Yes, the lower pressure on those lobes might have been a good thing, but then again, it might not have allowed the parts a proper bedding or seating-in of the mating surfaces.

So now that all the rockers are set properly I would continue to do what you did for another 15-20 minutes at least. Then go for a drive or idle it any amount you want.
And get that timing back up to what the others were saying. They tend to run better and cooler with more timing advance. No guarantee of course, and every engine build is different. But it's a good direction to go unless you have excess pinging.

And check your header bolts while you're at all this. They tend to work loose, especially after the first few heating/cooling cycles. And exhaust leaks can mimic ticking in the valvetrain.

Paul
Took your advice, Paul. I purchased a timing light/gun and started the 20 minute break-in procedure again. Almost immediately found that I was advanced close to 30 degrees! That would certainly explain the heat from the previous run and thankfully I shut that down quickly so hopefully no damage was done. This run, with corrected 10 degree timing and the other fixes, sounded much better and overall performed better. Heat was 190-210 at most and idling was great. Next will be some work on checking vacuum pressure and adjustment if needed after setting the mixture screws to default. One thing I noticed is my ammeter is only barely nudging while the engine is running. I'm getting close to 13.75 at the battery when running and just under 12 when not running. Going to test the multi-meter on something else and make sure it's not reading incorrectly. Another issue for another day..

 

DirtDonk

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Well if that reading was taken at 2500 RPM, the 30° reading is fine. But yes, if that was at idle you did well to lower it back down!
Sounds like everything‘s working out.

The ammeter should only show a slight positive reading with the engine running when the battery is fully charged.
It’s only immediately after start up, or if the battery is lower than normal that you will see the higher readings.
So even that sounds good for now.
 

sprdv1

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Took your advice, Paul. I purchased a timing light/gun and started the 20 minute break-in procedure again. Almost immediately found that I was advanced close to 30 degrees! That would certainly explain the heat from the previous run and thankfully I shut that down quickly so hopefully no damage was done. This run, with corrected 10 degree timing and the other fixes, sounded much better and overall performed better. Heat was 190-210 at most and idling was great. Next will be some work on checking vacuum pressure and adjustment if needed after setting the mixture screws to default. One thing I noticed is my ammeter is only barely nudging while the engine is running. I'm getting close to 13.75 at the battery when running and just under 12 when not running. Going to test the multi-meter on something else and make sure it's not reading incorrectly. Another issue for another day..


there will always be one.. Good luck
 

sprdv1

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Well if that reading was taken at 2500 RPM, the 30° reading is fine. But yes, if that was at idle you did well to lower it back down!
Sounds like everything‘s working out.

The ammeter should only show a slight positive reading with the engine running when the battery is fully charged.
It’s only immediately after start up, or if the battery is lower than normal that you will see the higher readings.
So even that sounds good for now.

better than before for sure
 
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