Part Selection for Rebuild

[Mike1291]

I wanted to put out a feeler (your opinions) on a few items I am looking into for rebuilding my Model A engine. Specifically the crankshaft and the pistons. For the pistons I could go with Snyder's or an aftermarket like Egge. For the crankshaft I was given the option to either counterbalance my current one or get a new counterbalanced one.

My use case is my Coupe. Rebuilt about 50 years ago and current sitting at .030 over bore. I drive it seldomly, but most of my driving is done between 35 and 50-55 mph.

My price cap for my rebuild would be prohibit me from getting a Burtz long block built by someone (going price is ~$9500 w/o shipping) so please don't suggest this.

 

[gdmn852]

Hello, not so much about part selection, but trying to find an engine rebuilder willing to work on older engines. Tryed to use two different rebuilders, on two different projects, a 912 Porsche, and 1949 Buick, neither were in any hurry and neither would read any of the manuals I sent them. In case of the 912 , they cracked the 3rd piece of the engine and faced off the flywheel, without maintaining the distance to clutch pressure plate, had to take engine back out and have the mount area faced .Still waiting on the 49 Buick head . Attempt to find someone that can personally recommend a machine shop if that work is needed. Only seen to want to work on Chevy big blocks.

 

[J Franklin]

Does your engine need a full rebuild or maybe just a ring and valve job with adjusting the bearing clearances?

 

[alexiskai]

The bearing clearances will be the tricky part. You have to match the existing bearings to the crank and the crank pins to the pistons. If the existing bearings are worn unevenly or too far, putting a new crank in there could be a waste of (a lot of) money.

 

[Mike1291]

I was torn with just doing a valve job and a rebuild (extreme, I know) but I keep blowing head gaskets and exhaust gaskets. The real problem is that the block is not straight and needs to be resurfaced after a few overheating events. I figure if I have to take everything apart and put it back together again I may as well rebuild it, even if it doesn't burn any oil and has low mileage.

The rebuilders I talked to all have worked with Model A engines and are willing to take my engine.

 

[J Franklin]

You might just need a quote on the work that needs to be done to keep gaskets from blowing. The shop can dissasemble whatever is needed to do the job.

 

[nkaminar]

A previous engine had welded on counterweights. Worked well and no indication of cracks or otherwise failing. Of course you have to get it straightened and balanced after welding on the weights.

 

[JayJay]

I was torn with just doing a valve job and a rebuild (extreme, I know) but I keep blowing head gaskets and exhaust gaskets. The real problem is that the block is not straight and needs to be resurfaced after a few overheating events. I figure if I have to take everything apart and put it back together again I may as well rebuild it, even if it doesn't burn any oil and has low mileage.

The rebuilders I talked to all have worked with Model A engines and are willing to take my engine.

Before thinking about new pistons, I'd take the engine apart and thoroughly mic it. It might be that your cylinders are OK and you won't need new pistons. I did a "refurbish" on an engine a couple of years ago, valve job, new rings, new camshaft, new lifters, but the bearings were OK so I just reshimmed. It's worked out fine. If the babbet is OK, the bearings clearance out OK, and you will reuse the babbet then don't even think of a new crank, balance the old one if you wish but babbet bearings MUST be fitted exactly to the crankshaft, so a new crankshaft would require replacing the main bearings at a minimum, and likely the connecting rods as well.

But if you are going to the extent of replacing babbet with inserts, then I'd be inclined to balance your existing crank. The cost of a new balanced crankshaft will put you into Burtz territory compared with balancing the old one.

Obviously there are other considerations, like the condition of the main and rod journals. But you can't make any meaningful decisions until teardown and you can see just what you have. Starting out with a 0.030" over block is not really a deal-breaker as long as it's otherwise sound.

 

[Synchro909]

There are so many engine rebuilding options out there that this thread is like asking how long is a piece of string. I will assume you are using Babbitt bearings. Others have already mentioned you should mic everything after disassembly, then decide. Maybe you can get away with adjusting the bearings, a set of rings and a valve grind. If you only use the car rarely, that should do for a long time. Adding counterweights and a harmonic balancer will add life to any Model A engine but they all cost $.
How deep is your pocket?

 

[old ugly]

maybe in todays world there is too much information out there? (and a lot of us don't know what to use out of it) KISS

if the car is used just for short runs and icecream i would do the minimum amount required. no need to build a bullet proof engine. especially if the car is running ok now.

maybe you can
-shim the bearings
-de-glace the cyls
-new rings
-lap the valves
-check and replace only stuff that needs replacing.
as far as machining always make sure the head and deck are flat and maybe magniflux the crank.
do a basic farm rebuild.

save you money for date night.

 

[Mike1291]

I don't drive more than 800 miles a year so really not an engine I would put miles on. I am assuming it has Babbitt bearings. I will take the suggestion and do a partial disassembly and see what I find. Hopefully nothing much so I can save up for someone/something special

I'll create another post if I have any questions. Thank you for the advice!

 

[Bruce of MN]

maybe in todays world there is too much information out there? (and a lot of us don't know what to use out of it) KISS

if the car is used just for short runs and icecream i would do the minimum amount required. no need to build a bullet proof engine. especially if the car is running ok now.

maybe you can
-shim the bearings
-de-glace the cyls
-new rings
-lap the valves
-check and replace only stuff that needs replacing.
as far as machining always make sure the head and deck are flat and maybe magniflux the crank.
do a basic farm rebuild.

save you money for date night.

I did that and it ran fine for 15+ years.

 

[Wick]

Watch marketplace for a running driving chassis where a hot rodder has removed the body. Usually cost $1,500-$3,500 or check with some rebuilders for a short block that wasn't paid for.

 

[nkaminar]

Fresh engine paint always helps.

 

[old ugly]

Fresh engine paint always helps.

I love it when i can do one of those rebuilds.

 

[Mike1291]

I finally got my engine out of my car and pulled some of the bearings. I have the rear main, rod #1, and rod #4 pictures, in that order. The cylinder walls look good (with no notable wear) and the cam looks good.

I am sending it to a local engine rebuilder for inspection, but your comments are appreciated.

To go back to the original inquiry, I don't believe I will bore out the cylinder walls but may/may not need Babbit and crankshaft work. I understand there is some wear, but is it truly that bad?

 

[Joe K]

Fresh engine paint always helps.

Red makes it go faster...


Joe K

 

[alexiskai]

Visual inspection is helpful but you don't actually know how much an engine is worn until you measure the clearance between the moving parts with micrometers, which your rebuilder will do.

 

[nkaminar]

The scratches on the journals concern me a little. It looks like dirt has gotten into the oil at one time. I suggest adding an oil filter. Crocus cloth will polish the journals and yellow Timesaver will bed the bearings to the journals. But check for out of round on the journals with a micrometer.

 

[Fullraceflathead]

I also would recommend polishing the crank journals a little bit but the babbitt doesn't look bad, shim to the proper clearance. Have the block deck surfaced and the head surfaced. I would reassemble it and your Gasket problems will be solved. I would also use grade 8 studs!!!
A basic valve job while it’s apart or if on a serious budget lap the valves. A quick lite cylinder hone will improve the engines performance dramatically. The amount of mileage that you’re driving it that engine will last another 25 years easily, but keep fresh clean oil in it.