1275 valve lash adjustment "shade tree"

[mightymidget]

1275 valve lash adjustment "shade tree"

My $500.00 Midget has a lot of noise in the valves. need to adjust valve lash

Need the know proper setting/gap for setting cold.

I want to set them from the top by rolling car in gear to get valves in proper position. I use to do it years ago but for the life of me I cann't remember the system.

Anybody help me out with adjusting them the shade tree way

 

[Hap Waldrop]

Re: 1275 valve lash adjustment "shade tree"

Most use the number 9 system, meaning if # 1 is open completely, you would adjust # 8, 1+8=9, another exmaple, if #2 is completely open you would adjust #7, 2+7=9. Everything add up to 9. Now the cam you have in the engine could reflect the desired valve lash, but if that is unknown, I would shoot for about .015"-.016" hot/warm as for lash. Hope this helps.

 

[mightymidget]

Re: 1275 valve lash adjustment "shade tree"

I adjusted them at 15. they were tighter before I started. but I checked them 2 or 3 times your way and ever other way.

The reason I thought they were loose was they make alot of noise at speed. If it isn't the rocker adjustment what could it be? motor runs fine, starts fine

 

[hooey]

Re: 1275 valve lash adjustment "shade tree"

rocker shaft maybe and or rockers if the noise is coming from the top if the motor

 

[mightymidget]

Re: 1275 valve lash adjustment "shade tree"

will a rocker shaft from 1098 engine switch over?

 

[spritenut]

Re: 1275 valve lash adjustment "shade tree"

1098 rocker shaft will swap over but check the adjustment, some engines had shorter push rods and you may find you have to move the adjustment 1/4 inch or so.
Stock cam valve lash is .012 cold. Noisy rockers if not out of adjustment could be worm rocker shaft bushings. Also look to see that the rocker is hitting the valve close to center, there are shims (washers) on the shaft to move the rockers accordingly. And make extra sure the rocker pedestool with the oil hole lines up with the oil hole in the block.
Some engines have all 4 pedestools with this drilling, some only have one with the drilling. I know a guy who killed an MGA engine because he did not look at the pedestool hole and put in in the wrong spot, no oil and a 6 hour road trip on a brand new engine wiped out his rocker assembly.

 

[Hap Waldrop]

Re: 1275 valve lash adjustment "shade tree"

Well they are solid lifter engines, so some ticking is to be expected. If you have a noise under ccleration, it could be an array of things, exhaust leak, bottom end noise, etc., etc., etc.

 

[Spridget64SC]

Re: 1275 valve lash adjustment "shade tree"

Rocker tips (pads) are prone to wear from PO's lack of attention to valve adjustment. Some can have down right divots. Polished up a set last night heading south to a customer. Loosen the adjuster screw up all the way and pivot arm up as high as it will go. Use mechanics inspection mirror to view pad and see if it has a big divot in it. No amount of adjustment can fix the wear in the pad. Replacement is only option. Shallow marks can be polished out with a dremel tool and a fine (120+ grit) sanding drum.

Shafts, rockers, pads and valve stem tips all wear. Most likely excessive noise is due to a worn out shaft and rocker pad.

Caution on swapping rockers between small bore engines and the 1275. The rocker pads are different with the narrower pads being on the small bore stuff. The location of the rocker is different as well. 1275's have locating washers to help align the rockers over the valve stems. Also, the small bore stuff uses then spring washers on the end to push the #1 and #8 rockers up against the pedestal. 1275's rocker assemblies don't have these.

Cautions on the lubrication hole as well. 1098 shaft has the grub screw on #1 and needs the oil passage. 1275 stuff usually has the grub screw on #2 and the oil passage on #1. Bad stuff if the valve train isn't lubricated.

HTH
Mike Miller

 

[Spridget64SC]

Re: 1275 valve lash adjustment "shade tree"

One other thing I thought of while out for lunch. Some of the small bore engines came with aluminum pedestals. Avoid these completely. They won't take the head stud torque. Put them in the bin for scrap metal/beer money.

 

[mightymidget]

Re: 1275 valve lash adjustment "shade tree"

Think I will pull complete shaft tonight and inspect. I realize some noise is to be expected but this noise is above all other noises

Rocker tips (pads) are prone to wear from PO's lack of attention to valve adjustment. Some can have down right divots. Polished up a set last night heading south to a customer. Loosen the adjuster screw up all the way and pivot arm up as high as it will go. Use mechanics inspection mirror to view pad and see if it has a big divot in it. No amount of adjustment can fix the wear in the pad. Replacement is only option. Shallow marks can be polished out with a dremel tool and a fine (120+ grit) sanding drum.

Shafts, rockers, pads and valve stem tips all wear. Most likely excessive noise is due to a worn out shaft and rocker pad.

Caution on swapping rockers between small bore engines and the 1275. The rocker pads are different with the narrower pads being on the small bore stuff. The location of the rocker is different as well. 1275's have locating washers to help align the rockers over the valve stems. Also, the small bore stuff uses then spring washers on the end to push the #1 and #8 rockers up against the pedestal. 1275's rocker assemblies don't have these.

Cautions on the lubrication hole as well. 1098 shaft has the grub screw on #1 and needs the oil passage. 1275 stuff usually has the grub screw on #2 and the oil passage on #1. Bad stuff if the valve train isn't lubricated.

HTH
Mike Miller

 

[Hap Waldrop]

Re: 1275 valve lash adjustment "shade tree"

Another thing to look at is valve lift, you can test this by placing dial indcator on the valve retainers of each valve, and rotating the egn by hand to see what max valve lift is, measuring valve lift to see if you have one or more vae lifting alot less than the the others, indicating a worn cam lobe, and they do wear out. Another thing to look at as for lost valve lift form a worn cam lobe would be a given valve always get more lash over time, yet the adjusting hardware is properly tightened, that would be a hint that a cam lobe is worn. Also making sure all of your pushords are straight and not bent would be another thing to look at, it's unlikely, but worth a quick look.