D25 Engine Rebuild thread

[Don Coatney]

The fork boot had pulled out of the hole and the clamp tabs were poor — I drilled three small holes in the bell housing and wired it solidly in place; Inside view of clamp wires.[/i]

I was lucky and found a NOS fork and fork boot on the bay.

The felt gasket on the bell housing pan was dirty and ragged — I replaced it with a surplus Model T Ford hogshead (bell housing) felt. The new felt was a little thinner than the original so I shimmed it out with a surplus 1/16" Model T valve cover gasket, and riveted the whole works together with Model T transmission band brass rivets... nothing like period-appropriate repairs!

I sent the wife to Hobby Lobby and had her buy a couple of 8X11 sheets of felt. I uut them to size and shape and used some brass screws I had to make a new one.

[Don Coatney]

I just remembered if you want to make a new boot there is a templete available in the downloads section of the main web page supporting this forum.

[RobertKB]

Chris, any updated news to report?? We are waiting with great anticipation!

[bamfordsgarage]

I thought there might be a query on this when I posted about the windshield washer... You haven't missed a thing. I haven't touched the project for almost a week. Today I'm heading back to the garage, I expect the new pistons from PatS tomorrow, and Monday, hopefully, stuff goes to the machine shop.

[bamfordsgarage]

Hello all, took a week off from the project but back at it yesterday and today, mostly cleaning engine parts and the engine compartment — no painting of course, just a good cleaning followed by an oily-rag rub down.

Going into the project I expected to replace the three rubber motor mounts. Now I'm not so sure... the rear donuts clean up like near new and feel very solid with no mushiness, the front plate has cracking around the edges but otherwise feels nice and solid. I believe these mounts have been in there since 1947 so from that perspective they oughta go but on the other hand it seems silly to replace parts that look like they could go another few decades without problems. Comments?

Photos: Oil pump body with new gasket nicely proud of the mating face; Flattening the timing cover bolt holes; Really getting into my work; Half and half engine compartment; Rubber motor mounts in question.

[JerseyHarold]

Watch out for that screwdriver on the battery.....BZZZZT!

[greg g]

Getting into your work can be a satisfying experience. That fire wall paint looks pretty nice for its age.

[Niel Hoback]

I hate to think that you would take advice from me, but I think that I would box the new ones up and put them in the trunk. They're not very big or heavy, and its my experience that if I carry a spare of anything, I'll never need it.

[Frank Elder]

Take your old mounts, tag em with the date, put them on a shelf and admire them from a distance.........you'll be happier:)

[RobertKB]

If nothing else, I would replace the front mount. I find they take a lot more s--- and abuse than the rears and tend to go bad. However, if that one is original, it actually looks pretty good but I have seen a lot that go flat or the top will start to separate and go forward. As mentioned, carry a spare or carry the old one as a spare.

[oldodge41]

I would re-use those mounts on my own car, no problem. Were I doing work for someone else I would recommend replacement. I am comfortable with the risk of reusing such things because it would not cost any more to replace if it fails later. If you were paying someone to do the work and then paying to replace them upon failure it would be advisable to do them while it is in the shop.

[Don Coatney]

Were it me I would replace the engine mounts front and rear. That is because I dont like to do things twice.

Are you familur with the "floating" procedure for the front timing chain cover install?

[bamfordsgarage]

...Are you familiar with the "floating" procedure for the front timing chain cover install?

Thanks everyone for your comments. I am going to reuse the rear mounts and replace the front — although it too feels solid, there has been minor lateral "drift" of the two metal plates relative to each other. I see the fronts are only $25 at VPW (the rears are also not expensive, but mine really do look OK).

Don, without looking it up, I would speculate the "floating" procedure involves precision-centering the crank in the cover seal, then fastening down the cover at that point. There is a similar procedure in the Model T world that is often ignored and greatly affects ignition timing (cam gear cover plate holds the timer housing — timer roller is on the camshaft, and non-concentricity makes accurate timing impossible.) Close?

[1940plymouth]

Chris, I see that coffee cup gets around:)

[Don Coatney]

Don, without looking it up, I would speculate the "floating" procedure involves precision-centering the crank in the cover seal, then fastening down the cover at that point.

From GTK

Since the tool mentioned in the manual is no longer available this process has been used instead. Install the cover but don't tighten down. Make sure the cover seal for the hub is installed. Remove the keyway from the crank hub and install the hub on the crank. Verify the seal is spaced evenly around the hub, then tighten the timing case cover. Remove and reinstall the crank hub with the keyway.

[steveplym]

Just my $.02. I thought my engine mounts were good when I rebuilt my engine. Then about two years later got some vibrations I didn't like. I ended up changing them with the engine still in the car, but it was a bit of a pain. If

I would of had to do it over I would have swapped them with the engine out as it is a snap. Just food for thought.

[bamfordsgarage]

Thanks all for the further comments and suggestions, and to Don for the timing cover info. A good reminder to me to review the site technical info from time to time. I looked through Aero3113's engine rebuild thread again yesterday — excellent information and I understand some of the details better now, being in the middle of my own project.

Engine compartment is basically cleaned and ready, just a little finishing needed down around the linkages, pedals and rear crossmember. Nice to have that job done, no hurry whatsoever to do another.

Re my engine mounts, PatS in Calgary has a new set of three he figures he'll never use and has generously offered them up for my project. I'm more than happy to accept, thanks very much Pat.

I'm hoping someone out there will have a good used emergency brake cable to suit my car. Once all the gunk came off the original, it looks perilously close to failure. These might be available new — I haven't checked and would very much prefer a used/rusty/patinated one to match the car. Anyone?

My brand new 52-year old pistons and rings arrived this weekend from PatS, and they are everything I was expecting — and 1/16" more! My D25 long-block has 3-3/8" bores, and the replacement pistons are 3-7/16"+0.030 oversize. My understanding is that there is sufficient meat in the block to accommodate what is in effect a 0.0925 overbore. Can those folks here more experienced than me confirm this before I turn the machine shop loose on my block?

The wrist pin height is exactly the same as my 3-3/8 pistons, so head clearance will not be an issue. I calculate a 5.5% increase in swept volume with the larger pistons, increasing displacement from 218 to 230 in3.

[Young Ed]

Anyone know if his Ebrake cable is the same as a 46-48 plymouth? I might have one.

[greg g]

Should be the same. To get the packing goo off the pistons, I have heard that warming them up in the oven for a while will speed the process. Unless of course you are just going to leave the mess to the machine shop.

Edited January 9, 2012 by greg g

[bamfordsgarage]

G'morning Ed — My 1940-47 Canadian DPCD Parts book shows brake cable #953755 fits RHD P14, P15, D23 and D25 (the larger D22, D24, C34 and C38 cars take a different #). I'll send you a PM on this.

Thanks for the tip, Greg. My beloved will be out of the house for a few hours today...

[greg g]

Some piston souffle on the menu for lunch perhaps??? You can probably use the BBQ grill, but with indirect heat. Pistons on one end, low burner on the opposite end on. I believe Warm Cosmolene in a closed enviroment might have a lasting fragrence tell tail.

Warm mineral spirits is a good rinser.

Chemically, cosmoline is a homogeneous mixture of oily and waxy long-chain, non-polar hydrocarbons. It is always brown in color, but can differ in viscosity and shear strength. Cosmoline melts at 113-125 °F (45–52 °C) and has a flash point of 365 °F (185 °C).

Since the temp is so low perhaps a nice soaking in 120 degree mineral spirits.

again probably and out door job.

[Joe Flanagan]

If that is Cosmoline, hot water worked for me.

[Dodgeb4ya]

On some engines a too large of over bore causes too fast of heat transfer trough the cylinder walls to the coolant and can cause higher running temps. Not sure on the MoPar 6 flatheads about this issue though. I think.060" is the biggest OS I've seen in any 218/230 engine teardowns that I have done over the years..

Bob

[bamfordsgarage]

Interesting — I've often heard of WW2 motorcycles or similar being preserved in Cosmoline, but never seen the stuff.

I've got some questions about replacement valves and hope someone can provide input from experience.... my intake and exhaust valves are not particularly worn, and may be re-usable after a touch-up grind. There is no burning evident and the stems are not worn to where one can see or catch a nail on a wear ridge. I'll have the machine shop make a proper assessment once they have the parts.

If new valves are called for, or maybe even if they are not strictly required, I would like to install ones with larger heads for improved breathing. Model Ts are typically rebuilt with Ford small-block V8 valves which are 0.100 larger diameter and there is ample meat in the block to accommodate the larger seat and the bigger valves do not hit the head.

In November, Tim Adams posted this link to a Melling Engine Co valve size chart listing hundreds of valves by diameter, length, retainer type etc., making it possible to select suitable replacement valves without referring to a specific engine type: http://www.mellingengine.com/Portals/5/Valve%20Progressive%20ID%20Chart%20291-293.pdf

I found a couple valves in this chart that are the same as mine for stem length and diameter, but with slightly larger heads. So my query to the forum is about the ability of the D25 long-block to accept the larger seat size without cutting the casting too thin or contacting the head

Specifically, my exhaust valve is 1.527" head dia, and Melling valve #V1324 is 1.622" diameter (0.095" improvement) with other dimensions same as my original. My intake is 1.721" diameter and Melling #V1393 is 1.840" (0.121" improvment) with other dimensions the same. Alternatively, Melling #V0947 is 1.780" diameter for an improvement of 0.060".

Strangely, my P15 workshop manual lists the exhaust and intake valve head diameters as 1.406" and 1.531" respectively — both of these much smaller than what I have now. This manual covers the 23" short-block of course, so engine info is not necessarily transferrable, but I am surprised to see that much difference in valve size.

Comments, suggestions?

_ _ _ _ _ _ _

And as a supplemental question, does anyone here have detailed specifications for the D25 long-block Canadian engine? If so, I would very much appreciate a copy. Many thanks.

Edited January 9, 2012 by bamfordsgarage
Add'l question.

[Plymouthy Adams]

Chris..when facing valves...pay close attention to the reserve metal left on the head..this LIP has to be of X thickness to ensure the edges do not get hot and burn...next..larger valves..if you are not upgrading your cam to a deep breather there is little need to increase the size of the valves both intake and exhaust..don't you consder the fact that 65 years later this baby stillhas good valve train, goes alot to enigineering from the get-go....check the valve stems for a wear taper as it rides in the valve guide..if this is extreme you may want to replace the valve for this reason also the guides themselves are to be checked close...it is not economically wise to allow a machine shop to kurl as it is a guaranteed short life process..it will actually speed up the wear but will show instant short term oil consumption control..