D25 Engine Rebuild thread

[Don Coatney]

I had a water pump leak when I first started my engine. I removed the water pump bolts and used thread sealant on the bolts. My leak was way below the engine head.

[bamfordsgarage]

Thanks for the replies. I'm heading out to the garage now to re-install — again with thread sealant on the bolts but Right Stuff on both sides of the gasket this time. This will make it very difficult to remove next time but it it sure oughta not leak.

_ _ _ _ _

Don or others I need some clarification on setting initial timing... I'm familiar with the factory procedure of finding TDC-#1-Compression and setting the gear on the oil pump for a 7:00 rotor position.

I would rather not take the oil pump off and disturb the seal (or not, thinking of the water pump!) and considered Don's comments in the "Starting Issues #2" thread — engine at TDC-#1-Compression and put the distributor in any old place and start with the #1 wire from there. Seems to me that this method would only be effective if the drive is either at the correct factory position or 180° opposed:

There are 10 teeth on the oil pump drive. For any intermediate position between these settings the engine would need increments of 60° (360°/6 cylinders) but the pump/distributor drive will only yield increments of 36° (360°/10 teeth). Is there actually enough timing adjustment to correct for this differential, and/or I am I misunderstanding something important here?

[Young Ed]

I'm very interested to hear the others thoughts on this. It seems to me that 2 teeth off would put the dist at the next cylinders firing position. And between the two adjustment points there would be enough to adjust out 1 tooth off. However both my flatheads have properly indexed oil pumps so I've never really messed with one that was off.

[james curl]

Since the cam rotates twice for each rotation of the crankshaft would not the difference be 72 degrees not 36 degrees of engine rotation, or am I missing something?

[bamfordsgarage]

Good morning James — sorry, my last paragraph could have been worded more betterly. Try this:

"There are 10 teeth on the oil pump drive. For any intermediate position between these settings the distributor would need increments of 60° (360°/6 cylinders) but the pump/distributor drive will only yield increments of 36° (360°/10 teeth). Is there actually enough timing adjustment to correct for this differential, and/or I am I misunderstanding something important here?"

[Guest P15-D24]

The mounting plate bolts on and can be rotated. Why not do the job right so when the time comes for someone else to work on it they have a valid starting point. The oil pump reset is simple, two bolts and a paper gasket. For start up just set it up for TDC and you can do that by simply turing the distributor.

[bamfordsgarage]

The mounting plate bolts on and can be rotated...The oil pump reset is simple, two bolts and a paper gasket...just set it up for TDC and you can do that by simply turing the distributor.

Thanks. That helps clarify. The engines I have most experience with do not have conventional distributors. And I have never gone wrong with the usual "Ask the audience" reply of doing things the right way.

A question then about indexing. The manual says to set the pump drive so the slot is parallel with the mounting bolts, then turn the gear one tooth CCW and re-install the pump. Fair enough, but the pump shaft will rotate a ways upon insertion — do I need to compensate for this by starting the insertion with the pump part-way rotated, or keep the pump level and the gear-rotation-upon-insertion will put the drive in the correct place (presumably a result of the one-tooth CCW adjustment)?

[Merle Coggins]

Thanks. That helps clarify. The engines I have most experience with do not have conventional distributors. And I have never gone wrong with the usual "Ask the audience" reply of doing things the right way.

A question then about indexing. The manual says to set the pump drive so the slot is parallel with the mounting bolts, then turn the gear one tooth CCW and re-install the pump. Fair enough, but the pump shaft will rotate a ways upon insertion — do I need to compensate for this by starting the insertion with the pump part-way rotated, or keep the pump level and the gear-rotation-upon-insertion will put the drive in the correct place (presumably a result of the one-tooth CCW adjustment)?

I believe that's all taken into account in the procedure. Follow what the manual says and it'll likely work out perfectly.

Merle

[PatS....]

(PatS, I demand a full refund of the absolutely nothing you charged for these brand new motor mounts plus shipping!)

No problem...satisfaction is guaranteed...the check is in the mail!!!!

[bamfordsgarage]

Well, its alive! And about time, too. Better care on the water pump installation stopped that leak completely. The old gal fired up yesterday AM but no test drive until later after some clutch and shift linkage adjustments.

I followed the break-in instructions that came with my piston rings: After starting, run at the equivalent of 25-50 mph road speed (took this to mean in high gear, so 1,500 rpm) until the engine warmed up to 180°, then shut down and retorque head bolts. Further break-in instructions are no driving over 50 mph, and no lugging from 5-10 mph in high. for the next 200 miles. Six miles on it so far.

On the plus side, there are no troubling noises from the engine, only one leak, it feels peppier, and the compression readings are consistent within 6% across all cylinders.

On the downside: that one leak is oil from the flywheel bottom pan so I am expecting rear seal trouble, the temperature gauge no longer works and neither does the one from my parts car, oil pressure still only 42-43 psi at fast idle cold start, the engine is not running smoothly — kind of "hunts" a bit up and down in rpm, the starter struggles somewhat, and I had an overheating event yesterday after climbing a long neighborhood hill.

I did a compression test this morning with dry readings about 5-10 lb above pre-rebuild numbers and wet readings about 5-10 lb lower. I hope these low wet readings (and some visible blow-by out the draft and oil fill tubes) is to be expected before the rings have had a chance to seat. Does this seem reasonable?

The overheating is also a puzzle. Checking today with a non-contact thermometer, the 'stat seems to open properly after a few moments and the top of the radiator warms up soon after. I don't think there is any brake drag as the car will push easily by hand on concrete. Could this also be related to tight clearances pre-break-in?

Photos: On the road again; My helper suspects the coil — it smelt a bit funny; One hot car; Very little spit, no polish.

[T120]

Glad to hear you got it running Chris. Regarding the starting issue and overheating under load -Is your timing a bit advanced maybe?

[greg g]

oil pressure would seem good to me. Mine runs about 30 at idle and 45 at cruise. this with 12K on my rebuild. Is the over heating actually a over hot conditioin or just the normal puking out of unneeded coolant? for the hunting rpm, check your intake to block and carb to intake areas for air leakage. an unlit propane torch works to indicate this by speeding, smoothing rpm.

[Don Coatney]

What position was your winterfront in during the overheating incident? Is the smoky engine bay related to the overheating or the blow-by? If I recall I did not have any blow-by on the initial start-up after the rebuild on my engine. Bob T is witness as my engine is running in this picture. I ran it about 10 hours on this stand prior to installing it in the car.

[bamfordsgarage]

Thanks all for your comments. Ralph, I probably need to further sort out the timing, there is a bit of ping on acceleration. Greg, I will do that. Don, the cloud in that photo is all coolant — the blow-by is only noticeable from the filler and draft tubes when the car is stopped and the light is right. There's not much but there is some.

[bamfordsgarage]

What position was your winterfront in during the overheating incident?

Forgot to answer this. Same position you see in the photo — hardly ideal for the record-setting 55° we had yesterday. I'm putting the incident down to tight clearances, hill-climbing and winter-front forgetfulness. There was about 2 qt of coolant lost. Just picked up an aftermarket gauge this morning which will be a welcome addition.

[Don Coatney]

Forgot to answer this. Same position you see in the photo — hardly ideal for the record-setting 55° we had yesterday. I'm putting the incident down to tight clearances, hill-climbing and winter-front forgetfulness. There was about 2 qt of coolant lost. Just picked up an aftermarket gauge this morning which will be a welcome addition.

I assume you know (Greg G already mentioned this) that the vented cooling system in your car will seek it's own level. As in it will puke out all excess liquid not needed once the correct system volume has been established with temperature expansion. I notice from your pictures that your radiator differs from an American P-15 radiator as pictured below. My vent is positioned at the higest point in my radiator and my fill cap is on the far left drivers side. Yours appears to be different.

It is possible to repair your temperature gauge. Forum member Tod Fitch has posted a great how to on his webpage. You can use your new aftermarket gauge to make this repair.

I may have mentioned this before but I once owned an International 1600 series truck that I used when I was an Ice Cream Distributor back in the 70's. I had a winnterfront on that truck. One day in the middle of the winter I was driving that truck from Columbus, Ohio to Fort Wayne, Indiana and had the winterfront blocked way off due to the cold ambiant temperatures. I stopped for fuel and while checking the oil I noticed a small stream of antrifreeze escaping from a small pin hole leak in the front of the radiator. I foolishly removed the radiator cap and peeked inside. This was a pressurized system so the boiling point was well above atmospheric pressure. A few seconds after I removed the cap I was hit in the face and chest with boiling coolant as the pressure inside the radiator equalized and the boiling point was lowered to atmospheric pressure.

The point being a closed winterfront works well as long as you have some air flowing through the rediator. Once you slow down or stop the air flow does the same (slows down or stops). Once it does the coolent superheats and rapidly expands. I believe that may have been your problem.

If the ambient temperature was 55 degrees on your drive how come the ground is white with snow? At that temperature a winter front is not needed.

[55 Fargo]

Yup I would agree with Don, and total restiction with a winter front or cardboard in front of rad can make these old girls hot quick.

I totally blocked my rad 1 time on a cold day, then was driving on the highway, the temp gauge quickly rose, I pulled over and pulled out the cardboard.

Chris I would go for a ride again, without the winter front, you do not need it with the temps were having, heck I had my pressure washer outside today, have never done this on March 10th ever.

Hills wind, and that winterfront are a recipe for high engine temps, especially when it is really not that cold out....

[Young Ed]

Tight engines will run hot until broken in. That could also explain your starter struggling.

[bamfordsgarage]

Fred and Don, I didn't have the winter front on because I figured it was needed — I just didn't think about it. Probably too much excitement about getting the old heap on the road again. It doesn't come off easily as the extension cord holder bolts right through it, so I just rolled it up to the passenger side and clipped it in place, Photo 1. I don't think it was a matter of of just puking out excess coolant — the coolant level prior to the event was at the usual point — about 1" below the filler neck.

Don, there is snow for the time being but we are really getting into the spring melt now so it is going away fast. The spring weather really has me wondering about my fancy new studded knobby tires... I have to make a decision soon about whether to mount them now and drive the whole trip on them, or bring them along and have them mounted along the way when we get near big snow. Thanks also for the tip about the temperature gauge repair (and of course thanks very much to Tod Fitch for publishing the procedure on his website http://www.ply33.com/ ). I have done the repair — I think — using epoxy instead of soldering so we will see tomorrow if it was successful.

Photos: Winter front out of the way; Set of Allstate chains purchased at Hershey 2010 for $8.00; Jerry doing a successful test fit on our 6:00x16 Firestone Knobbies.

Edited March 11, 2012 by bamfordsgarage

[aero3113]

Bam, when you retorque the head you should do the intake and exhaust manifolds also. This may help your issue.

[bamfordsgarage]

Bam, when you retorque the head you should do the intake and exhaust manifolds also. This may help your issue.

Yes. I tried the unlit propane torch but couldn't detect much change in sound/rpm. I tightened the manifold and carb nuts anyway — manifold nuts varied from zero to 1/6 turn, one carb nut took a half turn, the other one a full turn plus. I'm using a new plywood carb-to-manifold insulating spacer and it may want to be tightened occasionally until it settles in. Anyway, there seems to be a definite improvement after all the tightening. My main issues now are sorting out the timing and trying to address the rear main leak.

The temperature gauge repair was a failure. I probably got too creative with my splicing technique, as there was a scent of ether at the joint when the bulb was in boiling water. Back to the auto parts store for another donor...

[T120]

Hi Chris,Maybe not worth mentioning, but I guess my only concern with using a plywood spacer is that it might compress and block the little orifice in the base of the carburetor.Phenolic spacers are available for these carburetors.

If you need any gaskets for the base,I have lots...

[plyroadking]

Why would you use plywood?

[T120]

Used as a spacer/insulator to avoid direct heat transfer from the manifold to the carburetor body and help avoid the fuel from percolating in the carburetor fuel bowl when the engine is hot

[Joe Flanagan]

Chris, I made three attempts at the temp gauge repair. All were failures. On one, I did not get the ether bulb cold enough ahead of time and I could smell the ether leaking out as soon as I cut the donor tube open. On the second, I managed to block off the tube with solder while attempting the graft. On the final try, I almost succeeded. I tried the gauge in boiling water and watched the needle rise only to get the telltale smell of ether and see the gauge slowly sink back down. Incomplete soldering job.

Hats off to those who've been able to do it. I wound up sending the gauge off to be repaired.