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11-20-2012, 07:03 PM | #1 |
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Valve Job Options?
I'm helping a friend get his 31 PU running so he can sell it. https://fordbarn.com/forum/showthread.php?t=82064
A compression check and pulling the head revealed all 4 exhaust valve burnt. I have some extra, serviceable, valves and the tools to do a quality valve job. He doesn't want to spend a bunch of money so I thought we could just do a routine valve job, get her running, and see how it goes. This is turning out to be anything but routine! I've taken apart plenty of Model A engines but have never run across this: Removing the valve springs I notice they seem a bit shorter/heaver than stock but don't really pay this much attention. Also, the exh spring retainers have 2 flats, they're oval, not round. Again don't pay this much attention. Now the problem: Lift the valve to insert guide removal tool and the valve won't lift high enough to allow the tool to be inserted. A little hillbilly engineering (no offense to hillbilly's) and I was able to get most (not all) the valves/guides out with a homemade tool. Look at the attached pics of the removed valve compared to a stock and also the lifters installed in this particular engine. The valves are almost ½" shorter than stock and the lifters are an equal distance longer than stock. Also, the valves have a flange on the stem just under the valve head similar to an early V8. As I contemplated/cursed this setup I thought this must have been some kind of aftermarket kit since it uses adjustable lifters and bastard valves. However cleaning the valve head off revealed it's Ford Script. Someone please tell me if they've seen this before? More importantly what are my options as far as doing a valve job on this engine, inexpensively? Does anyone make valves this length? Or does anyone have 4 valves like this they could part with? I've also contemplated replacing the adjusters with machined down grade 8 bolts to reduce to height of the lifters to near stock and then grinding new valves for clearance (a little more work than I'd like to put into this). If someone makes or has some valves like this it seems like a better (and simpler) option. The engine in this PU also has a peculiar SN, one too many digits and no stars. At first I thought this must be a Diamond engine but it is not. It must have been a replacement engine but what's with the extra digit? |
11-20-2012, 07:08 PM | #2 |
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Re: Valve Job Options?
Looking at the valve makes me wonder what is the condition of the seats? They look awfully rough. Is there enough of the valve seats to grind? I'm sorry I can't help with the identification.
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11-20-2012, 07:13 PM | #3 |
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Re: Valve Job Options?
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11-20-2012, 07:16 PM | #4 |
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Re: Valve Job Options?
Perhaps they are V8 flathead valves ---the original lifters were drilled and custom or adapted adjusting screws were added ---V8 valves are shorter, and have the same head diameter as an A valve ---I think flathead 6 valves are somewhere inbetween for length ----take measurements ----post a picture of the whole removed valve next to a ruler--
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11-21-2012, 12:22 AM | #5 |
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Re: Valve Job Options?
They look like Chrysler lifters. Measure the stems. The A lifters are .593 diameter, the Chrysler is .624. The Chrysler lifter base is 1.285 dismeter. Stock lifter base was 1.110-1.125, and the commonly available lifter base now is 1.117, but those are not the common lifters that you have. The Chrysler lifter length is 2.44 to the top of the stem, not including the adjusting screw. The springs and valves are probably the shorter v8 because of the longer Chrysler lifter. There are specs around for the valve lengths, I think the v8 is 4.75 or thereabouts up to 1948, and the stock A is 5.677. The v8 springs are also shorter than the A.
Check the lifter bores before you buy anything to replace whatever is in there. The bore has probably been reamed out to a larger diameter. There is really no reason not to use the Chrysler lifters adn the v8 valves and springs are easily available. However, I would want to do a lot of measuring before using the v8 valves with the Chrysler lifters. They may be a bit too long and not allow sufficient lash which would explain the burnt exhausts. Maybe you could have a machinist grind off the valve stem base a touch to get a little extra clearance if needed. You might also check the cam grind just for fun. Chrysler lifters usually go with hot cams although you can use a stock cam. Last edited by PC/SR; 11-21-2012 at 01:38 AM. |
11-21-2012, 02:06 AM | #6 |
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Re: Valve Job Options?
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11-21-2012, 11:40 AM | #7 |
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Re: Valve Job Options?
Looks like V8 valves, and probably V8 springs with Chrysler lifters. Measure spring pressure before re-assembly to be sure there is enough. Too little pressure will burn valves in a hurry. The keepers are also V8, I use them because they are lighter. You need 38-40 lbs. of spring pressure on a stock cam, which would be 2.125" installed height.
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11-21-2012, 01:15 PM | #8 |
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Re: Valve Job Options?
Without removing the engine and cam so that the lifters could be replaced, the easiest and least expensive repair would be, either grind or replace the V8 exhaust valves. The longer lifters won't work with longer model A valves. the lifters also appear to be larger in diameter than model A lifters. For best results, now that I have the equipment, I always grind the seats.
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11-21-2012, 04:04 PM | #9 | |
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Re: Valve Job Options?
Quote:
After a little more research this morning I'm more bewildered. SBI International (a major valve train component manufacturer) has a search function by which you can search their valves by spec i.e. head dia, stem dia, length, etc. Once a search is done you can select an individual component and it'll give detailed info on that part including manufacturers/models/engines that component fits. Doing so revealed the Ford 2N, 8N, 9N(tractors), and early V8 engines all use the same valve which has a slightly smaller head (1.51 vs 1.537) but a much shorter length (4.819). This is another ½" shorter than the already ½" short valve (5.25) removed from this engine. So apparently the valves removed from this engine (although Ford) are not from a tractor or early V8). Also, the early V8 valve has a stem dia is .003 oversize compared to the A. Did the GAZ or Germany "A" motors use valves like this perhaps? I haven't (but will) measure the head/stem dia of the odd valve. On Dec 7th I have a date to meet with him and work on it again. At that time I'll take some measurements of the lifters. I'll continue to explore options but I think he may have to cut his losses on this. He already thinks this A is worth about 4 times what it really is worth because the person he got it from (many years ago) told him someone offered him $8k for it. Plus it needs a lot more work than just the engine to even be driven. The attached pics is of the O.L. of the bastard valve. Last edited by MALAK; 11-21-2012 at 05:40 PM. Reason: Added pic showing AOL compared to stock |
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11-21-2012, 04:39 PM | #10 |
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Re: Valve Job Options?
How about a 6 cylinder. 1GT 6505-A 1.51 x 5.18" or 7HA 6505-A 1.51" x 5.36"
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11-21-2012, 05:11 PM | #11 | |
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Re: Valve Job Options?
Quote:
There are several valves (including the one you mentioned) that I may be able to adapt. |
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11-21-2012, 06:51 PM | #12 |
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Re: Valve Job Options?
What are you getting for stem size? My Dana catalog shows .311 for the Model A, 9N tractor,
and the 6 cylinder. Bob |
11-21-2012, 07:18 PM | #13 |
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Re: Valve Job Options?
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11-21-2012, 07:56 PM | #14 |
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Re: Valve Job Options?
I was going to say 9N tractor valves. Measure your valve length and head dia. and stem size. I will tell you tomorrow what the 9N valve size is when I go out in the shop. Walt
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11-21-2012, 08:11 PM | #15 |
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Re: Valve Job Options?
I think you may be looking at the later valves. For the 6cyl I show 1947-50 .341 and 1941-47 .311.
The numbers I gave in post #10 are Ford numbers. For the 9N I show intake 1.547 x 4.672, exhaust 1.281 x 4.688 .311 stems update The 7HA 6505-A is the 1947-50 valve. Bob Last edited by Bob C; 11-21-2012 at 08:31 PM. |
11-26-2012, 12:18 PM | #16 | |
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Re: Valve Job Options?
Quote:
Kind of pricey but this is exactly what's needed. Thanks all. Last edited by MALAK; 11-26-2012 at 12:26 PM. |
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