why would this leak?
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why would this leak?
[After taking this head off i found number 1 head to cylinder was leaking and wondering what would cause it?[image][image]
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Flint
1980 Type 251CT
1980 Type 251CT
- Amskeptic
- IAC "Help Desk"
- Status: Offline
Re: why would this leak?
The most usual cause of leaking between head and cylinder barrel is the typical result of thousands of heating and cooling expansions/contractions. Etremely diligent engine assembly can reduce this. Cleanliness, beautifully cleaned stud threads and cylinder head nut threads correctly torqued and checked after an overnight "settling", and careful break-in during the intense heat generated by parts breaking in to each other, all will help. Any subsequent engine overheat event will relax the clamping forces and require a cylinder head re-torque. I would recommend a prophylactic retorque regardless after about 50,000 miles if you are doing much interstate driving.
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
- JLT
- Old School!
- Location: Sacramento CA
- Status: Offline
Re: why would this leak?
When I'm doing such a head re-torquing, I am working on only the four nuts that are exposed when you're taking the valve covers and valve rockers off, not the other four that are shrouded in the sheet metal. Should I be taking the engine out and removing the sheet metal to get at those upper four? Or would the lower four be enough?Amskeptic wrote: ↑Fri Jan 19, 2024 10:04 amThe most usual cause of leaking between head and cylinder barrel is the typical result of thousands of heating and cooling expansions/contractions. Etremely diligent engine assembly can reduce this. Cleanliness, beautifully cleaned stud threads and cylinder head nut threads correctly torqued and checked after an overnight "settling", and careful break-in during the intense heat generated by parts breaking in to each other, all will help. Any subsequent engine overheat event will relax the clamping forces and require a cylinder head re-torque. I would recommend a prophylactic retorque regardless after about 50,000 miles if you are doing much interstate driving.
-- JLT
Sacramento CA
Present bus: '71 Dormobile Westie "George"
(sometimes towing a '65 Allstate single-wheel trailer)
Former buses: '61 17-window Deluxe "Pink Bus"
'70 Frankenwestie "Blunder Bus"
'71 Frankenwestie "Thunder Bus"
Sacramento CA
Present bus: '71 Dormobile Westie "George"
(sometimes towing a '65 Allstate single-wheel trailer)
Former buses: '61 17-window Deluxe "Pink Bus"
'70 Frankenwestie "Blunder Bus"
'71 Frankenwestie "Thunder Bus"
- Amskeptic
- IAC "Help Desk"
- Status: Offline
Re: why would this leak?
Take the engine out, retorque the heads, replace the oil cooler seals, check end play.JLT wrote: ↑Fri Jan 19, 2024 12:20 pmWhen I'm doing such a head re-torquing, I am working on only the four nuts that are exposed when you're taking the valve covers and valve rockers off, not the other four that are shrouded in the sheet metal. Should I be taking the engine out and removing the sheet metal to get at those upper four? Or would the lower four be enough?Amskeptic wrote: ↑Fri Jan 19, 2024 10:04 amThe most usual cause of leaking between head and cylinder barrel is the typical result of thousands of heating and cooling expansions/contractions. Etremely diligent engine assembly can reduce this. Cleanliness, beautifully cleaned stud threads and cylinder head nut threads correctly torqued and checked after an overnight "settling", and careful break-in during the intense heat generated by parts breaking in to each other, all will help. Any subsequent engine overheat event will relax the clamping forces and require a cylinder head re-torque. I would recommend a prophylactic retorque regardless after about 50,000 miles if you are doing much interstate driving.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
- JLT
- Old School!
- Location: Sacramento CA
- Status: Offline
Re: why would this leak?
It sounds like a spring/summer project for me, but I guess you're right. While I'm there, I should also replace the muffler gaskets.
-- JLT
Sacramento CA
Present bus: '71 Dormobile Westie "George"
(sometimes towing a '65 Allstate single-wheel trailer)
Former buses: '61 17-window Deluxe "Pink Bus"
'70 Frankenwestie "Blunder Bus"
'71 Frankenwestie "Thunder Bus"
Sacramento CA
Present bus: '71 Dormobile Westie "George"
(sometimes towing a '65 Allstate single-wheel trailer)
Former buses: '61 17-window Deluxe "Pink Bus"
'70 Frankenwestie "Blunder Bus"
'71 Frankenwestie "Thunder Bus"