In all honesty... a case of the nerves - 49 Plymouth Engine reassembly

[nbn]

I was planning on reassembling the engine from the 49 Plymouth Spring 2023 as it had just made it back from the machine shop. Things got busy and the engine was pushed to the corner until this week.

Going through research and the service manual, I'm still feeling a bit nervous. Quite a bit nervous, actually. I'm sure I'm overthinking and creating my own drama.

 

Any step by step guides you use you care to share? And for those more proficient, how long does it take you to reassemble an engine ready to fire?

[Sniper]

Assuming everything is already all cleaned and laid out and ready to assemble doesn't take more than a day and not even a really long day. There are lots of YouTube videos out there showing you how to do things. And it also depends on how detailed you want to get. I don't know what your machine shop is already done for you but it's not a really difficult job

[Doug&Deb]

Keith’s Garage on YouTube. He’s a member of this forum and did a series on rebuilding a Plymouth flathead. I did my first one not long ago and if I can you can. 

[keithb7]

I took my time assembling my flathead engine. I checked and re-checked all my work. It was a first time flathead rebuild for me and I took it slow. I thoroughly enjoyed the process. I suppose a flat-rate mechanic back in the day would have done so many rebuilds, he could do it in a day. Not me.  I did it when I had spare time.  Between my full time job and honey-do lists.  Everything that I was unsure of I stopped and researched. Even when I was sure it had it right, but didn’t grasp the why, I stopped and researched some more. I considered my engine to be a self taught correspondence course in flathead rebuilding. I learned a ton.  If I recall I dragged the block home from the machine shop in about mid-June. I let it sit all summer. I believe I started reassembly in early Oct. i flashed it up about Jan 1 or so.  A very memorable, enjoyable period in my life.  Out to the shop to tinker and make a real man outta myself. Lol. 

[plymouthcranbrook]

Although I have never built a complete engine from scratch I will suggest that unless you trust the machine shop completely be sure you check that all the oil and coolant passages are clean and clear.  You might already know this and thus can safely ignore my post but I felt it needed to be said

Edited October 18 by plymouthcranbrook

[Sniper]

Hmm, I guess we all have a different idea of what ready for assembly means.

 

To me that means all the cleaning, painting, measuring etc is done.  All that is needed is putting the parts in,

 

That shouldn't take more than a day. 

[Dave72dt]

since it's been sitting for a year you'll need to clean it again and inspect for flash rust on all the machined surfaces including the parts, tap all the threads again so your torque readings will be accurate.  I'd suggest reading the service manual on the section you're working on, then watch the video which may make it easier to understand what he's showing and telling you.

 

Take your time with it, enjoy it and learn from it.  Don't worry about taking multiple days to assemble or how fast someone else can do it.  There's very little in the car hobby that beats the sound of an engine you built yourself firing up for the first time.

[Sam Buchanan]

23 hours ago, nbn said:

................how long does it take you to reassemble an engine ready to fire?

 

It doesn't matter....it'll be finished when it is finished. If someone asks when it will be ready to run, just tell them "Thursday". No need to specify which Thursday. 

 

Enjoy your new engine!

[Dartgame]

Do you have a friend thats done a re-assembly of an engine ? That would be a great help to you. Otherwise as stated above take your time and I'd measure all your clearances as you go. check this guys video.

 

[nbn]

7 minutes ago, Dartgame said:

Do you have a friend thats done a re-assembly of an engine ? That would be a great help to you. Otherwise as stated above take your time and I'd measure all your clearances as you go. check this guys video.

I've done several engines in the past (everything except Flathead), but had a mentor close by if I had questions. Sadly, he's no longer around and this is the first unsupervised, that's why I've got the jitters.

The known potential issues with the oil pump has me concerned.

And thanks for the reference video.

7 minutes ago, Dartgame said:

 

 

[Sniper]

What's the issue with the oil pump?

[Doug&Deb]

Some of them have been known to seize no matter how well prepped they were. I don’t remember what the issue is. Mine has lasted about 4000 miles knock wood.

[Sniper]

The Freewheeling Tony Smith has a pretty good go thru on oil pumps and their issues on facebook.

 

Someone put together a post on it here.

 

 

[rustyzman]

I had one of those new pumps that locked up after about 15 minutes.  Very odd failure and no indication that it was going to happen beforehand.  Properly primed, spun freely etc.  Knocked two teeth off the drive gear and nicked the cam gear a little.  Not the best day...  

The one I got for the full rebuild this time is fine, no issues.

 

That being said...

I always check all clearances myself during reassembly regardless of who did the machine work.  I check all bearings, gap every ring in it's appropriate cylinder, check valve contact, adjust valves, etc. 

 

Be sure your engine stand is secure and preferably has 4 legs.  These are heavy buggers especially once the bellhousing is on and stability is key.

 

Make sure the pistons are facing the correct direction and the rods are in the correct spots.  Oil hole faces the cam.

Make sure all the rod caps are matched to their attendant rods.

 

Put rubber hoses over the rod bolts as you put them in the block so you don't nick the crank and damage it.

 

I dip the full piston assembly into a coffee can of oil before I put it in the block.

 

Clock the piston rings 180° apart when you put the pistons in.

 

I also do a rotation check after each piston is installed individually to see if there are any binding issues.

 

Prime the oil system before startup, I use a syringe plumbed into the gallery until I see oil at the bearings.  Good assembly lube on bearings, seals and valvetrain sliding components.

 

I also plumb in a mechanical test oil pressure gauge.  Reassurance that everything is good with a good gauge you can trust.  

 

Don't forget the oil relief plunger and spring!

 

 If it's a new cam, I put Rev Lube on the cam lobes and tappets along with actual break in oil (for flat tappet cams).  New flat tappet cam for me also means prep all ignition, fuel and cooling system for immediate fire up and 30 minute break in run on first startup at 2500 rpm.  That oil is changed after the 30min break in and a new filter is installed too.

 

fill the cooling system as far as I can before I put in the thermostat and housing.  Helps prevent air pockets and overheat on that break in startup.

 

Make sure you put all the oil gallery plugs back in and sealed.

 

Make sure you coin all your freeze plugs in place.  I also seat them in 599 grey silicone myself, but do as you see fit.

 

Be sure the coolant petcocks (both) are closed.

 

Make sure you put the timing chain oil tube back in!

 

Don't forget the oil slinger before you bolt on the timing cover.

 

Center the timing cover seal to the crank.  Make a tool or use the crank pulley.

 

Make sure you attach the oil pump transfer pipe back in the correct way or the crank will hit it!

 

Disassemble and clean the oil pickup screen thoroughly if that was not done.

 

I always paint the timing pointer and timing marks on the crank pulley with my favorite bright colors before assembly.  Makes tune up work much better later on.

 

Don't reuse any hardware that looks suspect.  If it feels funny when you tighten it and torque it, stop and find out what is wrong.

 

Paint everything you want painted now.

 

Replace the water distribution tube and reinstall it with the opening slots facing the valves.

 

Remember to install all the seals.

 

Use your favorite version of thread sealant on all headbolts, manifold bolts and timing cover bolts that pass into water jackets.  They will leak if you don't.

 

I personally seal all gaskets.  I have never trusted paper alone once something has been apart.  Your choice on this, but my rebuilds are leak free.  Use whatever sealer you prefer.  I like 599 grey.

 

Torque the head in sequence and in steps.  Remember head studs have a lower torque than the bolts if you have any studs.  Torque them all again hot at the end of your first warm up, they will be loose.

 

Spray copper sealant on the head gasket, one side or both according to your feelings on the matter.

 

That covers most things I can think of.  

 

I can reassemble and run in a normal day once all the machine work is done, but each person and each engine is different.  I would prefer to spend more time and be absolutely sure it is correct if in doubt.  It's just careful work, not crazy complex stuff, but missing a nut or bolt in the wrong spot can end the engine. 

 

Just go slow and double check your work.  Work without distractions and don't entertain anyone while your doing it.

You have the wherewithal to be cautious and ask these questions, and that alone makes me feel like you will do a good thorough job on it.   

 

Most of all, have fun!

 

 

 

 

[Los_Control]

I say a good warm bottle of MD 20-20 will give you all the courage you need to dive in and get the job done .... never hurts to have a backup bottle just in case.

 

You have previous experience doing this in the past, you simply had a safety net you could reach for if needed.

Just do not get lost in the weeds during assembly, use common sense and same procedures as always .... you still have a safety net here on the forum .... I can always hand you a cold beer if you get stuck ... others might have advice.