It is not a very big sending unit if it is just the low-pressure activating switch (for the dash light). I am not positive but I think the threaded end of this sending unit is 1/4" (npt) and is expanded to 3/8" at the rear opening of the pump housing (below and to rear of filter base). It is not that hard to find but the opening is kind of tucked underneath. You can get adapters from most auto parts outlets OR local hardware store that has plumbing fittings. Hope this helps.
We got it running smooth and quiet, then when I started it the next day it was clattering and soon missing. The hydraulic lifters wont stay pumped up. My engine guy put in a new set again and hand primed them and they were quiet again. Then next day clattering and not opening the valve causing a bad miss. He's a little at a loss, was considering just putting in solid lifters, but with the cam for hydraulic lifters that I bought would that be ok? I don't see why the hydraulic lifters arent staying pumped up. Are we missing something. Oil pressure is good at idle, just under 50 psi so the should have enough pressure to work properly,
Well, is it the lifters or is it the adjustment of the rocker arm adjusters themselves? Are they backing off, and what year is the engine? The early engines were solid, the later ones were hydraulic, not sure what year it changed.
The only reason a hydraulic lifter will will bleed off is it is not getting oil or it is getting air bubbles in the oil (pickup tube issue). I have eliminated the possibility of them being worn out which is really rare anyway. Rocker arms backing off is a possibility but one day seems quite a short time even for that.
Well its a 63 so it originally had solid lifters, I just bought the cam kit from Clifford performance with the cam for hydraulic lifters. When he takes the lifters back out to check them they are compressed and he can prime them again but somethings got to be wrong. He's never experienced this and he's done engines for years.
Nice call Dana. I was thinking the same thing. Learned long ago about being 180 degrees off when I helped by brother rebuild a (Yuck) 55 Chev 265. Messed with it for 3 days, and other than us getting rip snorting drunk on beer, nothing seemed to work. Then my Dad popped in the garage, took a look and changed the wires. Yeup. Snorted right off! Sigh!
Oil flow to the lifters is opposite of most engines in hydraulic lifter slant six's. They have grooved cam bearings that send oil up through the block, rocker shaft assembly and down through hollow pushrods to the lifters. Solid lifter versions had non grooved cam bearings and pushrods that were not hollow.
Good call, which confirms why I asked the change of years of the solid and hydraulic cam change. The problem will be fixed when the lifters are swapped to solids, chaging the cam bearings is a complete teardown to swap.
It's not the pushrods getting oil to the top to the rockers that is the problem, it is the volume of oil in the gallery that feeds the lifters themselves, solid lifters require less oil volume and pressure so the updated cam bearings to feed the lifter gallery is the needed component. I don't think anything was damaged, but, it is actually the opposite, the solid lifter camshafts are usually more radical than the hydraulic cams, so the solid lifters on the hydraulic cam should work fine for a stock application. So basically, if you want to keep the hydraulic cam you have to pull the camshaft, remove the cam bearings and install the fully grooved bearings to feed the lifter gallery oil feed (no way around it), or simply install the solid lifters and pushrods, or if you really want to be safe, the solid cam and lifters and pushrods. In fact, installing oil feeding pushrods would make your situation worse, the problem is there isn't enough oil going to the lifter gallery oil rail to begin with and oil leaving the lifters extra would make the problem worse.
putting in the solid lifters sounds like the easiest fix if you think it won't hurt anything. I had gotten impression from other peoples opinions including Larry from Clifford Performance, that the cam was steeper on the hydraulic because the hydro lifters had more" give" and could handle the more radical cam. With solid lifters they said that the hydro cam would more less slap the solid lifter up instead of rolling it up, causing wear on either the cam or the lifter or both.
I'm tempted to try the solid lifters with the hydraulic cam at least for a while to see how it performs. I just want to drive my car......
Compare the profiles of the two cams and you will see they are pretty much alike in stock form. As a matter of fact, I just did a ten site verification just now and there are profiles that are identical between the hydraulic and mechanical grinds so there should not be a problem. This is stock, not racing, and believe it or not, the racing solid cams are usually the more radical of the two on the strip, so make sure you adjust the rocker gap properly and you will be fine.
Solid cams typically have a more gentle ramp to absorb the valve lash impact. I've run solids on hydraulic cams in the past with no problems so you're probably O.K. Like Dana says, set your lash carefully and recheck a few times to keep tabs on wear. I always dab wheel bearing grease on lifters to avoid premature cam wear.
Sounds like you have it correct, flat on top at the front of the engine. This has the rocker oiling holes in the shaft pointing down towards the valves. This way it lubricates the rockers at the place where friction/loading would be greatest.