Chuck Sea/Tac
Well-known member
If you have the flywheel refaced, the place where the pressure plate bolts has to have the same amount removed. The factory spec is .123” as I recall. I’ve seen them work “off spec” but why not do it right.
Clutch slipping.
- Thread starter Zephyr4
- Start date
Dick M
Well-known member
I would call or go online to Bert's Model A Center in Denver. He sells professionally rebuilt pressure plates. The pressure plate comes with depth adjustment preset. Just bolt on and go. I would certainly replace the clutch disk, throw out bearing, and pilot shaft bearing as well. I agree that you should have the flywheel trued up if it is not perfectly flat.
I would also install the Mitchell Manufacturing Company "Real Deal Oil Seal" in the front of the transmission clutch cover sealing up the shifting rails and install the oil seal cap on the rear of the transmission case sealing up the shafts. Both of these fixes go a long way to stop transmission leaks.
Mitchell also makes a transmission dipstick that makes it really easy to check the oil level in the transmission. I have one and love it.
I would also install the Mitchell Manufacturing Company "Real Deal Oil Seal" in the front of the transmission clutch cover sealing up the shifting rails and install the oil seal cap on the rear of the transmission case sealing up the shafts. Both of these fixes go a long way to stop transmission leaks.
Mitchell also makes a transmission dipstick that makes it really easy to check the oil level in the transmission. I have one and love it.
Zephyr4
Member
Thanks for the replies, guys. I'm still relatively new to these old cars so all advice is welcome.
I shall contact a local machine shop and see what they can do. I have a spare used pressure plate. Will dig that out today and see how it looks. No-brainer to get a new clutch disc.
My other problem: I have a Snyder's 5.5:1 head that I thought I'd fit while I have the engine out, but the stock head doesn't want to let go! I've spun the engine over, but only blew some bubbles out of the head gasket, didn't move the head. I've tried lifting the front of the head using the water pump studs and got no movement at all. It's soaking in penetrating oil now. I guess it's the two long studs at the front that cause most of this problem. The head gasket was always weeping, so it needed to be changed regardless. I guess the leaky head gasket meant coolant got around the studs.
I shall contact a local machine shop and see what they can do. I have a spare used pressure plate. Will dig that out today and see how it looks. No-brainer to get a new clutch disc.
My other problem: I have a Snyder's 5.5:1 head that I thought I'd fit while I have the engine out, but the stock head doesn't want to let go! I've spun the engine over, but only blew some bubbles out of the head gasket, didn't move the head. I've tried lifting the front of the head using the water pump studs and got no movement at all. It's soaking in penetrating oil now. I guess it's the two long studs at the front that cause most of this problem. The head gasket was always weeping, so it needed to be changed regardless. I guess the leaky head gasket meant coolant got around the studs.
Zephyr4
Member
Like this?
Swapped that out a while back when I first put this engine and trans in.
Found my spare pressure plate. Has a very light score on it and a little surface rust. I can scotchbrite the rust off easily enough. Any thoughts on the condition of this one? I know ideally I'd just replace it, but £185 isn't insignificant and if this will work just as well, I could spend that money elsewhere.
Mulletwagon
Well-known member
On this side of the pond most would just send in their old pressure plate for a rebuilt unit at a cost of about $125. Typically the rebuild would consist of new springs and a precision resurface of the plate. Not sure of the additional costs that would be incurred in shipping twice from the UK. New units are also available for less and do not require a core but the quality would have to be determined before going that route.
PS - Have been to Banbury many times in my Upper Heyford days - very nice !
rotorwrench
Well-known member
Clutches have to be properly set up for best function. The best rebuilding of antique clutches is Ft Wayne Clutch in Indiana. I send all my obsolete stuff to them for complete overhaul. They have a quick turn around time and you get your original assembly back unless it is beyond repair. They have exchange services for common clutches but none of the ones I send them are common in this day and age.
Opening up the engine oil pan can lead to a barrel of worms. I won't say not to do that but be prepared for worn out main bearings (especially the center main). Model A rear main seal is just a slinger and a drain back tube set up but they have to be in good condition. Some folks are going to fully sealed transmission input and output bearings these days. The add on seal fixture for the shift fork rails is also a Mitchel upgrade to stop seeps there. Folks also add o-rings to the counter shaft but sealing the shaft with silicon at reassembly can be just as effective. Model As like to mark their spot.
You can make them leak less but I don't now if you can seal them up completely for any length of time. Ford likey used the shrouded clutch design just for this reason. centrifugal forces tend to throw off any oil that gets on the rotating assembly. It's not perfect but they can stay relatively dry even with seeps in that chamber. The old multi plate ones were crap but the later design isn't all that bad.
Opening up the engine oil pan can lead to a barrel of worms. I won't say not to do that but be prepared for worn out main bearings (especially the center main). Model A rear main seal is just a slinger and a drain back tube set up but they have to be in good condition. Some folks are going to fully sealed transmission input and output bearings these days. The add on seal fixture for the shift fork rails is also a Mitchel upgrade to stop seeps there. Folks also add o-rings to the counter shaft but sealing the shaft with silicon at reassembly can be just as effective. Model As like to mark their spot.
You can make them leak less but I don't now if you can seal them up completely for any length of time. Ford likey used the shrouded clutch design just for this reason. centrifugal forces tend to throw off any oil that gets on the rotating assembly. It's not perfect but they can stay relatively dry even with seeps in that chamber. The old multi plate ones were crap but the later design isn't all that bad.
Zephyr4
Member
So I took the flywheel and pressure plate to a local machine shop (MulletWagon - about 1.5 miles from Upper Heyford!) and they're going to reface the flywheel. They took a look at the pressure plate and said they'd seen much worse. Hasn't been overheated just needs a clean up. Now that's not to say the springs haven't gone soft, but I guess the slippage was consistent with the oil contamination.
I managed to get the head off. It wasn't pretty or the recommended way, but it worked with zero damage to block or head. I wouldn't have tried this if I wasn't replacing the head and studs anyway. Basically I hit each stud sideways with a hammer, thinking a little sideways movement would break the rust bond. I had the engine on a homemade stand. I hoisted the water neck end very slightly off the ground from a bracket attached to one of the water pump studs and gently tapped a 1.5" wood chisel in just above the copper gasket, with the flat side of the chisel downwards. My thinking was that the gasket would save the block from being damaged. As it turned out even the head has no marks at all from this. So the chisel simply acted as a wedge and pushed the head up. Once it had moved an 1/8" or so it moved reasonably easily. I've built a few engines in the past and I fully appreciate that I've taken a bit of a heavy-handed approach to this, but like I say zero damage. Maybe I was lucky this time. I wouldn't recommend anyone copy this!
And what joys lurked beneath? Well quite a lot of black carbon - I think I must have been running it rich. Not nearly as much rust as I'd found in two previous Model A engines. The bores are shiny and have a negligible wear lip at the high point of the top ring. BUT looking down all four bores you can see quite a lot of shiny piston ring. If you bring a piston to the top of the bore, there's quite an alarming amount of slap.
Haven't had a chance to put a bore gauge on it yet, but now I fear I'll have to go the whole way with tearing it down. If it's even salvageable. Not sure what it's like in the US, but finding someone to redo the Babbitt bearing over here isn't easy and the conversion to insert bearings is really expensive. Maybe the bearings will be OK, but that would seem unlikely given the state of the rest of the engine.
I managed to get the head off. It wasn't pretty or the recommended way, but it worked with zero damage to block or head. I wouldn't have tried this if I wasn't replacing the head and studs anyway. Basically I hit each stud sideways with a hammer, thinking a little sideways movement would break the rust bond. I had the engine on a homemade stand. I hoisted the water neck end very slightly off the ground from a bracket attached to one of the water pump studs and gently tapped a 1.5" wood chisel in just above the copper gasket, with the flat side of the chisel downwards. My thinking was that the gasket would save the block from being damaged. As it turned out even the head has no marks at all from this. So the chisel simply acted as a wedge and pushed the head up. Once it had moved an 1/8" or so it moved reasonably easily. I've built a few engines in the past and I fully appreciate that I've taken a bit of a heavy-handed approach to this, but like I say zero damage. Maybe I was lucky this time. I wouldn't recommend anyone copy this!
And what joys lurked beneath? Well quite a lot of black carbon - I think I must have been running it rich. Not nearly as much rust as I'd found in two previous Model A engines. The bores are shiny and have a negligible wear lip at the high point of the top ring. BUT looking down all four bores you can see quite a lot of shiny piston ring. If you bring a piston to the top of the bore, there's quite an alarming amount of slap.
Haven't had a chance to put a bore gauge on it yet, but now I fear I'll have to go the whole way with tearing it down. If it's even salvageable. Not sure what it's like in the US, but finding someone to redo the Babbitt bearing over here isn't easy and the conversion to insert bearings is really expensive. Maybe the bearings will be OK, but that would seem unlikely given the state of the rest of the engine.
john charlton
Well-known member
Check your private message from me .
John in Suffolk England .
John in Suffolk England .
Zephyr4
Member
I got the flywheel and pressure plate back from the machine shop.
I cleaned the carbon off the top of one piston and found it's already 0.070" over. Bore gauge showed an additional 0.0165" clearance in the bore. So rebore and bigger pistons.
Babbitt on one big end had crumbled. So new con rods to go with the new pistons.
Then I noticed this on the centre main:
Crank has to come out anyway so I kept going:
And that's where I'm at. I'm on the trail of a newly rebuilt engine fully converted to insert bearings. Pretty much the same cost as getting this engine done, so that's where I'm heading.
Moral of the story: don't look!
I cleaned the carbon off the top of one piston and found it's already 0.070" over. Bore gauge showed an additional 0.0165" clearance in the bore. So rebore and bigger pistons.
Babbitt on one big end had crumbled. So new con rods to go with the new pistons.
Then I noticed this on the centre main:
Crank has to come out anyway so I kept going:
And that's where I'm at. I'm on the trail of a newly rebuilt engine fully converted to insert bearings. Pretty much the same cost as getting this engine done, so that's where I'm heading.
Moral of the story: don't look!
Mulletwagon
Well-known member
Zephyr4,
Great pics, thanks for sharing. Sounds like all good decisions and a solid recovery plan. Looking forward to a success story when it is all back together.
Great pics, thanks for sharing. Sounds like all good decisions and a solid recovery plan. Looking forward to a success story when it is all back together.
ryanheacox
Well-known member
Woah. How’s the crank look?