Intake Manifold Installation

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Millertime

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So I'm installing an Edelbrock 2750 performer manifold and a new carb, I've got the old manifold out and the valve covers off and I noticed one of the push rods wasn't in place and it was bent. Is this a big issue or is just that it needs to be replaced (I imagine it's best to replace all of the rods at once)? Another question I have is with the videos I've seen of 351C engine intake manifold swaps, they don't have this extra tin gasket thing covering the base of the push rods, so can I remove that and then then just apply my gasket maker around the edges followed by the intake install? Lastly, any general feedback of what you see in the photos is appreciated, the car has never really ran well so if you notice something looks pretty out of whack, I'd love to know haha. Also, if anyone has a very stock engine and could send some photos of how everything is hooked up that would be great, I'm very skeptical of whether the previous owner had things hooked up correctly.

Cheers,

Erik
 

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I would definitely use the valley pan gasket again, get a new one. The valley pan gasket helps keep the intake cooler by keeping the hot oil away from the bottom of it. If you had a bent pushrod that was out of place, then you were running on 7 cylinders, which will definitely kill power. You can just replace that one pushrod, you do not need to replace all of them, but if one pushrod is bent, I would check them all. Please be aware that when you remove pushrods, they must be reinstalled exactly where they were, in the exact orientation that they were in. Pushrods, like lifters, and rocker arms, create a unique wear pattern between one another, they must be installed exactly where they were or you can create wear issues and parts failures if you move them around. Take your pushrods out one by one and check them on a plate of glass, just roll them over the glass, if they are even slightly bent you will see them wobble when you roll them over the glass. Replace any pushrod that is even slightly bent.
I can't see anything else that looks out of place on the photos, the one strange thing is that the last rocker arm on the passenger side of the engine, seems suspiciously clean, and so does the pushrod, may just be the photo. Maybe someone had an issue there before you and changed that rocker and pushrod? That engine has a little too much dried and gunked up oil and dirt in it, which is normal if this is an engine that has been running for decades, with not the best oil changes. I would try and get some rags, something that does not let out small fibers, and very carefully clean as much of the gunk and caked on oil that is there before I closed it back up, clean the insides of the valve covers. If you end up pulling the pushrods, you might as well pull the rockers and clean them all before you put them back in. Also clean the oil passages in the pushrods, and the rockers. If you do pull the pushrods and rocker arms make sure to oil them thoroughly before you put them back on. Check the oil drain passages in the cylinder head to make sure that they are clear of any debris.
After it is all back together I would give than engine a nice oil flush treatment, put new oil in it, and then change the oil at more than normal intervals to try and remove as much of the gunked up oil that is in it as possible. Modern oils have a lot of detergents and just changing the oil more often than necessary will clean the engine up.
 
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Question is: why has any pushrod been bent? If you just replace it the new one could be bend again. So I would determine the problem and perhaps pull the lifters to check them for function. As your engine seems stock but not well maintained in the end it could be a stuck lifter that caused the problem. So I would do the following: make a cardboard or a shoebox with numbers of each cylinder, remove every lifter, pushrod and rocker by one and stick them through the cardboard in exact the direction and order they were on. Now you have them off check them for function, perhaps you have to replace some of the parts. I bet for some lifters and pushrods. If there are are lot of them failing you could replace all of them by once. If you keep the engine otherwise stock without any further modifications keep the original rockers and their parts.
Before reassembly make the above described cleaning process and an oil and filter change afterwards, perhaps you have to flush it with oil because of all the gunk.

Hope that helps!

Tim
 

72351HO

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I would definitely use the valley pan gasket again, get a new one. The valley pan gasket helps keep the intake cooler by keeping the hot oil away from the bottom of it. If you had a bent pushrod that was out of place, then you were running on 7 cylinders, which will definitely kill power. You can just replace that one pushrod, you do not need to replace all of them, but if one pushrod is bent, I would check them all. Please be aware that when you remove pushrods, they must be reinstalled exactly where they were, in the exact orientation that they were in. Pushrods, like lifters, and rocker arms, create a unique wear pattern between one another, they must be installed exactly where they were or you can create wear issues and parts failures if you move them around. Take your pushrods out one by one and check them on a plate of glass, just roll them over the glass, if they are even slightly bent you will see them wobble when you roll them over the glass. Replace any pushrod that is even slightly bent.
I can't see anything else that looks out of place on the photos, the one strange thing is that the last rocker arm on the passenger side of the engine, seems suspiciously clean, and so does the pushrod, may just be the photo. Maybe someone had an issue there before you and changed that rocker and pushrod? That engine has a little too much dried and gunked up oil and dirt in it, which is normal if this is an engine that has been running for decades, with not the best oil changes. I would try and get some rags, something that does not let out small fibers, and very carefully clean as much of the gunk and caked on oil that is there before I closed it back up, clean the insides of the valve covers. If you end up pulling the pushrods, you might as well pull the rockers and clean them all before you put them back in. Also clean the oil passages in the pushrods, and the rockers. If you do pull the pushrods and rocker arms make sure to oil them thoroughly before you put them back on. Check the oil drain passages in the cylinder head to make sure that they are clear of any debris.
After it is all back together I would give than engine a nice oil flush treatment, put new oil in it, and then change the oil at more than normal intervals to try and remove as much of the gunked up oil that is in it as possible. Modern oils have a lot of detergents and just changing the oil more often than necessary will clean the engine up.
A word of caution with respect to "modern oils," which do not contain enough zinc or phosphorous for use in flat-tappet engines. I recommend the use of a "racing oils" that have added ZDDP.
 

Millertime

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Thanks for the feedback, really appreciate it! Which oil do you guys run your 351 Cleveland's? I read some guys use 10W30 but others recommend 10W40 and it's roughly 5 quarts to fill?
 

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Cleveland engines are known to bend pushrods. The heavy valvetrain, somewhat dodgy geometry and RPM potential will do that. My first task would be to inspect the lifter that the bent pushrod was on. Pull it out and inspect the face to make sure it's not worn or damaged. Post a couple good pics of it here for second opinions.
 
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I run Valvoline ZR1 10-30.

Us the pan gasket but while the intake is off the car place it upside down on a table and slip the pan gasket into place. Make sure the runners line up correctly. I had one manifold way back when that had a runner that stuck down just far enough to push the valley pan gasket down just enough to cause a leak. Drove me crazy figuring out what the problem was. I used some tin snips and cut out a hole for the runner and that fixed my problem.

So it's an easy and simple thing to check.
 
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The intake manifold on the 351-C Ford engine is critical as far as torque rate and sequence are concerned. Intake leaks, although very slight, will affect engine performance and may result in oil burning. Apply the manifold with care, making sure it is aligned correctly, front to rear and side to side, and adhere to the following instructions in three steps.

1. Torque all bolts in sequence to 8 ft. lbs.

2. Torque all bolts in sequence to 15 ft. lbs.

3. Torque all bolts in sequence to final specifications:

5/16" bolts should be torqued to 18 ft. lbs.

3/8" bolts should be torqued to 25 ft. lbs.

If the Edelbrock torque instructions are different, use them, but still use a 3-step sequence.

Be advised that the manifold requires retorquing in sequence to full torque after the engine has reached normal operating temperature.

Installing long studs in the four center holes (9, 10, 11, and12) will assist in getting the manifold aligned correctly. After torquing the rest of the bolts to their initial torque value remove the studs and install the bolts to their initial torque.
351C Intake Sequence.JPG
 
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I am not an engine builder, so take what I say with grain of salt. I try hard to keep it simple and avoid extra work. I think you can check all of the other pushrods without removing them or loosening the rocker arms. I would pull all your spark plugs. Set your vibration damper timing mark on TDC. You should be able to spin at least four of the pushrods with your fingers. You will see and feel resistance change if any rod is bent. Then simply rotate your motor one revolution using the nut on the damper back to TDC and check the others that are somewhat relaxed. I think if you repeat this eight times you can accomplish checking for bent rods using this method of spinning them using your fingers to see if you feel resistance changes or rocker arm movement. I’m sure someone with more experience than me will know the exact pushrods to check each time you rotate the engine, or possibly tell me I’m wrong.
 

72351HO

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Thanks for the feedback, really appreciate it! Which oil do you guys run your 351 Cleveland's? I read some guys use 10W30 but others recommend 10W40 and it's roughly 5 quarts to fill?
I use Summit 10W-40 ZDDP.

Stock oil pan 351C engines hold 5 qts, except for the BOSS 351 and 351 HO, which hold 6 qts.
 
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I'm with Tim...you need to find the reason for the bent pushrod. Have you over-revved the engine to the point the valves could have floated? Weak or insufficient springs will allow the very heavy cleveland valves to float sooner than most engines. Valve float and/or a seized valve in guide are the common causes for bent pushrods. They can result in a bent valve, damaged lifter/lobe, or a galled valve/guide.

With both valves closed (or rockers removed) there should be little to no leakage from either valve. Use the adapter from a compression tester connected to your air compressor and pressurize the cylinder to test. Excess leakage from the port which has bent pushrod will quickly tell you if you have bent the valve.

Carefully inspect the lifter and lobe for damage. The lifter must be convex...put the surface that rides on the cam lobe (face) on flat glass or something very flat. It should rock very slightly. The edges of face should not be rough/jagged/sharp. A concave lifter means the lobe is flat or going flat. I've seen a lot of flat lobes accompanied by bent pushrods.

Remove the valve spring with the bent pushrod and check for excess valve to guide wear. Excess wear will indicate that the valve may have seized in the guide. Secure the valve from dropping down into the cylinder and move it through it's range of motion and feel for any roughness. It should move smoothly and side to side clearance should be consistent from top to bottom of it's range of motion.

When you work with the retainer and spring removed, keep the piston at, or near, TDC. I've used a rubber band wrapped at the keeper grooves as a safety net to keep the valve from dropping into the guide/cylinder. The valve seal will help with this too.

The above is what we'd do for a customer's car...once you've done it a couple of times it doesn't take long. In your case, you could take a chance and install a new pushrod and put back together, but you'd still want to watch for signs of the potential issues that caused the bent pushrod.

Let us know what you end up doing. Best wishes.
 
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I am glad to see other fellow enthusiasts, other than just myself, "sounding the alarm" re: older flat tappet valvetrain assemblies needing to have Zinc in the engine oil, whether in the oil blend or added. I have seen far too many posts by folks about their cam lobes and/or lifters been worn very quickly due to an oil with no Zinc in it. And I am betting everyone here in this forum and thread had seen more than one report of a new cam/lifter kit getting wiped out quickly despite using the proper break-in lube and engine oil with Zinc, where the suspicion is the new cam lobes and/or lifter faces are not being properly hardened during manufacturing. Cheap Chinese manufacturing, perhaps? No matter, it is best, IMHP, to use an oil with Zinc already in it, as opposed to adding Zinc to a modern Zinc-free oil.

Like 71ProjectJunk, I also use AmsOil Z-Rod on all three of our vintage Mustang/Shelby engines (1969 428CJ, 1984 302 2v, and a 1974 351W 4v transplanted into our 73 Mach 1). But using the Valvoline ZR1 10-30 or Summit 10W-40 ZDDP oil with Zinc in them already is also a fine way to go. In our case all three engines have low enough miles (and wear) on them to be able to use 10/30. At the first glimmer that the 10/30 is being consumed a bit faster than expected I will move the affected engine to AmsOil Z-Rod 10/40. Z-Rod is available in 20/50 also, but if I get to the point where I need that much viscosity I think I would be looking at an engine rebuild anyway.

With luck I will not need to rebuild any of our vintage engines. But if I do I am certain I will be doing a few things to help ensure a long life, and terrific power, for the rebuilt engine. Things like Bronze Wall Valve Guides, Perfect Circle valve guide seals, hardened valve seats, forged aluminum pistons with 9.5:1 - 10:1 compression to handle the 90 octane ethanol-free gasoline we have in our area, double roller timing chain and gears, hydraulic roller based valvetrain, long tube headers (no external changes on the 69 Shelby), etc.
 

Millertime

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All great info, I'll start with just cleaning everything out a bit more then start checking over the other push rods and valves to see if anything seems off. When I pulled the bent rod out, I looked over the others but none of them looked bent and they were all firmly in place. Once I look over anything I'll think about taking them out and doing the glass test etc. If the engine was ever over revved, it would've been by the previous owner, the best I've had it running after rebuilding the carb was idle around 1000 rpm and it bog down and die when thrown in gear. When I took the manifold off and the valve covers, the gasket was in pretty poor shape so I wouldn't be surprised if I was getting a vacuum leak from that.

For the push rod, what length rod should I replace it with and is the diameter 5/16 inch? I'd measure the rod but even if I bent it back close to straight I wouldn't feel 100% certain of the measurement and from what I can see online, they're all within about 0.010 inches of each other in length.
 
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Don't try to straighten a bent pushrod....just get a new one and use the stock length. 8.408 is stock, I believe. You've got the intake off, you really should inspect the lifter and make sure you don't have a bent or galled valve. Pushrods don't just randomly bend...I suppose if someone had straightened one and tried to use it that could happen, but seems unlikely.

EDIT: I'm seeing 8.408 and 8.412...this would indicate possibly 8.410 +/-.002. Somewhere in that range will be fine for stock application.
 
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Millertime

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Ya definitely not using the bent rod, just meant I could bend it and then measure to see what length it was and then buy a new one that's the same length. Just with bending it you never get it perfectly straight to get an accurate measurement.

When you filter results for push rods on Summit for a 351C 2V, you get 8.346, 9.680, 9.590 (says OEM replacement even). Might even just call them up and chat.
 

Ron Tanzi

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The installation instructions for the Edelbrock 2750 intake manifold specifically state not to use the stock "turkey pan" intake gasket set.

Ron
 
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