[Vid]

Soon I’ll be in the happy and fortunate predicament where I need to break in both a new motor with a HFT cam AND a brand new Muncie.

Here’s my question. We all know about how to break in a new flat tappet cam by firing the motor and immediately holding the revs at 2200+ for 20 minutes.

Now - My transmission builder warns that under any circumstances, with a brand new manual transmission, do not rev the engine for extended periods of time as the spinning gears on the stationary main shaft can cause oil starvation and heat issues that could lead to seizure problems and dangerously launch the car forward. This forbidden extended revving would precisely include the HFT cam break in procedure.

Trans builder suggests using my old tranny at first until the cam is broken in and then swapping in the new trans afterward. That or break in the motor on a dyno beforehand which I would love to do if there was only one within 500 miles of Reno, NV.

Obviously I’d prefer to install the new motor and trans in one fell swoop and not have to double swap the tranny.

Any break in tips, tricks, hacks or shortcuts that will get everything properly broken in and won’t ruin the cam and/or the tranny? Thanks fellas.


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[chiphead]

On a cam break-in, I vary the RPMs between 2000-3000 for three rounds of 10 minutes each. Its the heat cycles and varying RPMs that really help seat the lifters. Make sure to use break-in oil and take the inner springs out.

For the trans, that's a new one for me. I can only think of removing the clutch disc for the break-in. Or maybe put the rear axle on jackstands and remove the rear tires, so if the trans happens to grab, the car doesn't actually go anywhere?

[JLMounce]

If it was me, I'd try to find a run stand that I could borrow or rent. Break in the engine on the run stand, then stab everything into the car.

I'd check local hobbyist groups near you or even engine builders. While there may not be dynos specifically, any good engine builder likely at least has a run stand.

[Formulabruce]

The trans should have been run out or dynoed when built.
If worried, add some " motorkote " to the gear oil.
Trans can't starve oil UNLESS its very very cold.

[ID67goat]

Originally Posted by chiphead

On a cam break-in, I vary the RPMs between 2000-3000 for three rounds of 10 minutes each. Its the heat cycles and varying RPMs that really help seat the lifters. Make sure to use break-in oil and take the inner springs out.

For the trans, that's a new one for me. I can only think of removing the clutch disc for the break-in. Or maybe put the rear axle on jackstands and remove the rear tires, so if the trans happens to grab, the car doesn't actually go anywhere?

Agree 100% on the above. Not sure I am convinced about the transmission….as long as you have it filled to the proper level with gear oil it should not damage anything as all the gears will be turning in the gear oil except the output shaft as seen in the attached picture.

[Vid]

Originally Posted by chiphead

Or maybe put the rear axle on jackstands and remove the rear tires, so if the trans happens to grab, the car doesn't actually go anywhere?

You might be on to something here. By securely jacking the car up and removing the rear tires I could theoretically even put the car in gear for break in. Problem solved!

Removing the tires would help me worry less about the car vibrating off of the stands and winding up on the 2nd tee of the golf course directly across the street from my house.

hmmmmm…


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[SRR]

I think your trans. guy has towing confused with engine running? See post #5.

[Vid]

Originally Posted by SRR

I think your trans. guy has towing confused with engine running? See post #5.

No, he was very specific. I completely understand where he’s coming from. If I professionally built manual transmissions for a living I would also want to eliminate any and all possible failure sources that might make me or my work look bad.


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[PunchT37]

Originally Posted by Vid

No, he was very specific. I completely understand where he’s coming from. If I professionally built manual transmissions for a living I would also want to eliminate any and all possible failure sources that might make me or my work look bad.


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Run it with the tires off the ground for 30 minutes or so. Should be good to go. Go through all gears. The no load condition will "polish" the gears and have the tapered roller bearings loosen up a bit. It will get real hot at 1`st without a no load period of time.

[64speed]

Be really careful with jackstand placement running the car while you run it in the air.

[78w72]

really careful...

[Formulas]

If i was going to sweat such a thing i would put trans in 4th and to reduce danger of running on jackstands
just pull wheels off put lug nuts back on backwards to keep drum or rotor on

You think GM did such things ?

Tapered rollers in a Muncie? thats new to me and the rollers that are on the countershaft they are submerged in oil

[TedRamAirII]

Break in of the trans, will happen when you drive it. I suppose you can leave it in 4th gear, no real load, direct drive.

[tjs72lemans]

We can all only think of negative things that can happen on a new build and breaking it in. I had mine on the dyno for the reason that if something went wrong, I wasn't pulling a motor I went through the trouble of installing recently. Luckily, I did that. I reused the harmonic balancer that I sleeved and it leaked. The machinist doing the dyno pulled it and re-sleeved it and it leaked. Had to buy a new one. That in itself would've been a hassle in the car. Undoing things only to re-do.

[Stan Weiss]

Originally Posted by Formulas

If i was going to sweat such a thing i would put trans in 4th and to reduce danger of running on jackstands
just pull wheels off put lug nuts back on backwards to keep drum or rotor on

You think GM did such things ?

Tapered rollers in a Muncie? thats new to me and the rollers that are on the countershaft they are submerged in oil

Have not built one in years, but isn't there needle bearings inside the input shaft where the output shaft goes into?

Stan

[Dragncar]

Originally Posted by Vid

Soon I’ll be in the happy and fortunate predicament where I need to break in both a new motor with a HFT cam AND a brand new Muncie.

Here’s my question. We all know about how to break in a new flat tappet cam by firing the motor and immediately holding the revs at 2200+ for 20 minutes.

Now - My transmission builder warns that under any circumstances, with a brand new manual transmission, do not rev the engine for extended periods of time as the spinning gears on the stationary main shaft can cause oil starvation and heat issues that could lead to seizure problems and dangerously launch the car forward. This forbidden extended revving would precisely include the HFT cam break in procedure.

Trans builder suggests using my old tranny at first until the cam is broken in and then swapping in the new trans afterward. That or break in the motor on a dyno beforehand which I would love to do if there was only one within 500 miles of Reno, NV.

Obviously I’d prefer to install the new motor and trans in one fell swoop and not have to double swap the tranny.

Any break in tips, tricks, hacks or shortcuts that will get everything properly broken in and won’t ruin the cam and/or the tranny? Thanks fellas.


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There has to be a engine dyno in Sacramento. Not too far a drive from you.
Of all the thousands of cams broken in on 4 speed Muncie equipped cars, not one person has ever had a problem hurting the trans that I know of.
Does it exist ? Has you trans guy ever really had that happen ?
If it were me and I was that worried about it I would overfill the trans with 30WT. Leave it in neutral the whole time and break the cam in. Then dump it out and fill with the proper amount of gear oil.
You biggest worry is getting the cam broke in with the highest quality lifters you can find.
I mean, I used to use white grease or STP and never had a issue until we got miss-manufactured butter lifters.

[Stan Weiss]

Originally Posted by Dragncar

There has to be a engine dyno in Sacramento. Not too far a drive from you.
Of all the thousands of cams broken in on 4 speed Muncie equipped cars, not one person has ever had a problem hurting the trans that I know of.
Does it exist ? Has you trans guy ever really had that happen ?
If it were me and I was that worried about it I would overfill the trans with 30WT. Leave it in neutral the whole time and break the cam in. Then dump it out and fill with the proper amount of gear oil.
You biggest worry is getting the cam broke in with the highest quality lifters you can find.
I mean, I used to use white grease or STP and never had a issue until we got miss-manufactured butter lifters.

Have you ever broken in a flat tappet cam with a 4 speed? Yes I have. No I did not have any problems. But I built my own 4 speeds. If the OP doesn't follow what the trans builder says and has a problem he may have no warranty.

Stan

[Vid]

Had another thought since I’m worrying about the new motor spinning between 2000-3000 rpm with the car up on jack stands. Why not leave the rear tires on the ground, simply disconnect the driveshaft and plug the tail shaft. If the plug doesn’t cause any issues or go flying out it should be okay. Just not sure how the little red plastic plug would endure the friction, and I don’t want to be taking the brand new trans apart looking for red plastic shrapnel inside the case. However if it works, it’s one less potential nightmare of the car falling off of the stands and me winding up on one of those FAIL video compilations.

And yes, I agree that the whole worry about the main shaft ceasing is probably a long shot, but I respect the advice of my trans builder too.


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[Stan Weiss]

Originally Posted by Vid

Had another thought since I’m worrying about the new motor spinning between 2000-3000 rpm with the car up on jack stands. Why not leave the rear tires on the ground, simply disconnect the driveshaft and plug the tail shaft. If the plug doesn’t cause any issues or go flying out it should be okay. Just not sure how the little red plastic plug would endure the friction, and I don’t want to be taking the brand new trans apart looking for red plastic shrapnel inside the case. However if it works, it’s one less potential nightmare of the car falling off of the stands and me winding up on one of those FAIL video compilations.

And yes, I agree that the whole worry about the main shaft ceasing is probably a long shot, but I respect the advice of my trans builder too.


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If you want to go that route I would use a drive shaft yoke and not the red plastic plug.

Stan

[Dragncar]

Originally Posted by Stan Weiss

Have you ever broken in a flat tappet cam with a 4 speed? Yes I have. No I did not have any problems. But I built my own 4 speeds. If the OP doesn't follow what the trans builder says and has a problem he may have no warranty.

Stan

What kind of question is that ? I used to be such a die hard 4 speed guy I put a Ford Top Loader in my GTO. Even came up through the stock console.
You have a better chance getting struck by lighting than his main shaft seizing up and the trans somehow going into gear.
Just overfill it for the cam break in and there is zero chance of anything not getting oiled.