8BA compression issues

[Kurt in NJ]

On post 70 , the picture of the valve it looks like the (if it is one that is lapped in) it looks like the seat is very wide

[mrlaser]

You're correct. When I was lapping that valve (#4) I was leaning over the '51 front fender with one foot in the air and fighting the heater motor.. At the time I didn't realize that the valve guide had slipped down into the gallery. It was only for a few strokes. After realizing what had happened, I covered the valve with Magic Marker and checked the pattern. It yielded the same narrow band as the others. I would have replaced the valve itself. But I don't know who the valves were originally purchased from. Thank you for catching that mishap

[Bored&Stroked]

Can you take a close up picture of a couple of the cylinder bores? Close as you can, with some light and good focus? I'd like to see what the cylinder walls look like. Thanks!

[mrlaser]

B&S, These are the best pictures that I can get with my phone. There are some residual bits of the head gasket on the walls and the pistons which I haven't removed.

[mrlaser]

B&S, it doesn't appear that there is any significant cross hatching. As I mentioned above, the records of the build were lost by the movers and the builder has passed away. I did notice a significant jump in compression, on repeat testing, with added oil. From 65 psi to 90 psi. What would you suggest might be my options? Thanks for your help.

[mrlaser]

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It's a bit frustrating, coming at the end of an 8 year restoration project. But. As they say "you need to play the hand you've been delt"

[Sid]

If you're running close to 90 lbs on all cylinders button it up and start it. as long as there is not much over 5 lbs difference between cylinders. Once the motor is run and warmed up the compression will be even higher. Also the elevation plays a slight role in compression. The compression will be slightly lower a say 5,000 ft. as opposed to sea level.

[mrlaser]

Will do. Thanks. Unfortunately, ( except for the weather) I'm at sea level.

[Bored&Stroked]

Hey Mr. Laser - do you see any hone cross-hatch marks in the cylinders? I don't think I can make any out (might just be the pictures)? As this engine is new - was wondering if the rebuilder did the "normal" stuff that we always do . . . which is all about getting the new rings to seat.

[flatford8]

That’s a beautiful car!!!...what ever it takes to get to the end result.......will be well worth all your efforts.....Congratulations!!!......Mark

[Bored&Stroked]

If you're getting 65 - 90 lbs at cranking speed, I'd get it back together, get it started (check for leaks and retorque the heads) and then I'd put it under highway load as soon as possible. It will be key for the rings to seat and it kind of looks like there isn't much cross-hatching or honing in the cylinders.

Don't make the mistake of letting it idle/run for a long time in the garage - get it on the highway and do some heavy acceleration runs. The last thing you need is to glaze down the cylinders - the rings will never seat and you'll have perpetually low compression and low power.

Once you've done that at least a half dozen times, then drive it for a good length of time (couple hours) - with varying speeds and accelerations. Then take it home, let it cool down and do another compression check - you'll then know if things are in good shape or not.

Best of luck - you've been working your butt off on this - we're all hoping for a great outcome!

B&S

[cadillac512]

B&S has the same opinion as I do...Get everything ready to drive, fire it up, do a quick check for leaks,noises and check the ignition timing. Then get on the road and drive it as suggested. Nothing wrong with fairly heavy load for short bursts-it'll help seat the rings. Idling is bad so keep that to a minimum at first. Monitor the gauges and enjoy the ride!



Terry

[mrlaser]

Thanks everyone for all your help and suggestions. I will keep posting with any progress. Happy Thanksgiving to all.

[Sid]

With that being a fresh engine and I might assume a reground cam or new it may be wise to use a break in oil in the beginning. Due to the lack of Zinc in today's oils. And add a dose of additive at each oil change. I realize flatheads don't have the valve spring pressure a ohv has but it is good insurance. I myself use Royal Purple break in but I'm sure there are other brands just as good. Just be sure it states fortified with a healthy dose of Zinc

[mrlaser]

Will do. I am hopeful that there will be a need for the break in process. I appreciate everyone's thoughtful suggestions and help. I have learned a lot.

[tubman]

I have a '51 Ford with a 255" Mercury and Edmunds heads, which should be as hard, if not harder, to spin over that your engine. An Optima spins it over just fine. Before resorting to a 12 volt jump, I would spend some time inspecting and cleaning ALL of the connections, Including grounds. A 12 volt should not be necessary.

[Ross F-1]

Are the battery cables #00 gauge, very heavy duty? Common cables carried in auto parts stores are #2 or #4, made for 12v systems, nowhere near up to the 600 amps a 6v car draws in cold weather.

[mrlaser]

Thanks for the input. I will , of course, try with just the 6 volt alone and possibly with the 6 volt boost. I did notice, before the latest tear down, that the compression readings were 10-15 PSI greater when the 6 volt boost was applied. That's why I wondered about the use of 12 volts to aid with starting. The cables are less than a year old and were purchased from a major early ford supplier. Unfortunately no description as to the wire gauge was listed in the catalog. They were, however listed for the '50-'53 V8. I will check on all the connections prior to attempting to start the engine. Should it actually start, I will only run it for a few minutes since the rings are not seated and it will not be under varying loads.

[mrlaser]

Oh, and as to the question about the starter, it was rebuilt at an auto electrical shop before it was installed.

[Sid]

Any news on the 8BA?