Roller rockers with no compression

limp · Jan 22, 2025

DPORTER0729 said:
Is there any way that my timing is off? I'm 99.9% sure that the engine was at top dead center on cylinder 1 when I installed the timing gears but I always end up second guessing myself... I feel if the timing was off cylinder 5 would not have accurate compression each time and it would throw off the whole geometry.

If your dot to dot on your timing gears, thats it.... Unless you have a gear set with multiple keyway settings..
Its your distributor setting that can be off.....
BEST way to make absolutely sure is to remove your valve cover and watch #1 intake valve go down and up while hand cranking it... when the timing mark lines up with the pointer, your at #1.... when the intake valve is fully up slow down on the cranking because the line must be very close...

DPORTER0729 · Jan 22, 2025

I loosened the rockers on cylinder 1 to where there was no clearance between the roller and the valve stem and tried the “wet Willie” test and sure enough it had great compression, feels the same as cylinder 7… i tried to tighten them a bit to see where it loses compression and around 1/4 turn the compression is lacking massively, anything after and there’s none at all. Tried it with cylinder 2 and it’s the same results but it loses full compression around 1/2 turn. Both rockers took over a full turn to reach 20 ft lbs but cyl 2 was closer to 2. Is there any way I can use shims to level them out or am I going to need shorter pushrods? Also if I am able to use shims, is it best to shim all rockers evenly or shim based on the preload of each one? Appreciate all the help! First times always the hardest and I couldn’t do it without yall.

limp · Jan 22, 2025

DPORTER0729 said:
I loosened the rockers on cylinder 1 to where there was no clearance between the roller and the valve stem and tried the “wet Willie” test and sure enough it had great compression, feels the same as cylinder 7… i tried to tighten them a bit to see where it loses compression and around 1/4 turn the compression is lacking massively, anything after and there’s none at all. Tried it with cylinder 2 and it’s the same results but it loses full compression around 1/2 turn. Both rockers took over a full turn to reach 20 ft lbs but cyl 2 was closer to 2. Is there any way I can use shims to level them out or am I going to need shorter pushrods? Also if I am able to use shims, is it best to shim all rockers evenly or shim based on the preload of each one? Appreciate all the help! First times always the hardest and I couldn’t do it without yall.

You can try the shims, a box of them is pretty cheap.... The shims are more to adjust the valve geometry so watch where contact is on the top of the valve stem when you get done.... With any luck it will be the same size or amount of shims but its OK if they are different..... I dont get too concerned if the contact mark is a smidge off center, I think looking at the rocker for good valve/ rocker geometry is more important.... If your building a big Horsepower motor it might be more critical...

https://lmr.com/item/M6529A302/1979-95-Mustang-Ford-Racing-Pedestal-Mount-Rocker-Arm-Shim-Kit

mobilly · Mar 23, 2025

DPORTER0729 said:
Is there any way that my timing is off? I'm 99.9% sure that the engine was at top dead center on cylinder 1 when I installed the timing gears but I always end up second guessing myself... I feel if the timing was off cylinder 5 would not have accurate compression each time and it would throw off the whole geometry.

timing goes dot to dot, check with straight edge. you shouldn't have to worry about tdc. actual tdc of the piston should have already been checked and marked. after the chain is on then you check to see if the cam is running advance, retarded or right on with the crank. if you lined it up dot to dot you should be fine.

Roller rockers with no compression

limp

wrap a little cheese around it and its a done

DPORTER0729

New Member

limp

wrap a little cheese around it and its a done

mobilly

Member

Similar threads

Roller rockers with no compression

limp

wrap a little cheese around it and its a done

DPORTER0729

New Member

limp

wrap a little cheese around it and its a done

mobilly

Member

Similar threads

Privacy & Transparency

Privacy & Transparency