All Small Six 170 issues

[frozenrabbit]

Your timing marks are correct, hard to see the dot on the crank gear, but timing marks do line up with the keys.

With no increase in compression numbers with oil in cylinders, I'm still leaning towards incorrect rocker adjustment.

If you did a 'zero lash' +3/4 turn on dry lifters, it is very likely you are over lashed.

Factory manual specs for adjustable rocker on hydraulic lifters, you should be at 0.067"-0.200" lash measured between rocker and valve stem tip with the lifter in a collapsed position.

Zero lash on dry lifters would never let the valves fully close, and could possibly bend push rods.

 

[Rodders]

Looks correct to me, the fact that it runs, and has some compression would indicate is right, even a tooth out would make it run really bad or not at all. What head have you got on this engine?

It's all original

 

[Rodders]

It's all original

That was my thinking too. That wouldnt run if that far out

 

[ActionYobbo]

Put a vacuum gauge on it

 

[B RON CO]

Hi, so this is what happened to me. I bought a 200 from a guy for $500 who had work done to it by a shop. He bought a two barrel conversion head, Holley carb, and a cam. He was selling the engine, which was at the mechanics shop, because they were doing a V8 swap.
I put the head on my 170, after a while I dug into the 200. Clean inside, everything was standard factory, so I honed it, and got rings and bearings. Since I didn't know what cam they had, and I have a heavy 66 Bronco, I got the mild Comp Cam kit, with their timing chain set. Well some of the guys here probably remember, the damn thing was @ 17* retarded. With the new timing chain set, and with the timing chain set that came with the engine. Off. A lot! And the seller told me it ran, and was a drop in motor! That is why he sold it! It was a dead dog! So with plenty of help from some of the guys here, and the adjustable timing set from Vintage inline, I got it degreed to within 3*s from perfect. When I talked to the tech guy at Comp Cams, he had little to no interest! That is why whenever I see someone is doing a cam swap, I say you MUST degree the cam. Good luck

 

[drag-200stang]

I have posted before that if I degree a small six cam and it is right; I assume that I made a mistake and do again and I find that I did make a mistake. Assume that they are off, as they usually are and by a fair amount.

 

[drag-200stang]

What about ignition timing. have you checked and made sure it is good where it is set to?

 

[Rodders]

Your timing marks are correct, hard to see the dot on the crank gear, but timing marks do line up with the keys.

With no increase in compression numbers with oil in cylinders, I'm still leaning towards incorrect rocker adjustment.

If you did a 'zero lash' +3/4 turn on dry lifters, it is very likely you are over lashed.

Factory manual specs for adjustable rocker on hydraulic lifters, you should be at 0.067"-0.200" lash measured between rocker and valve stem tip with the lifter in a collapsed position.

Zero lash on dry lifters would never let the valves fully close, and could possibly bend push rods.

I set rocker gap as per manual, I will try loosening them off a bit and see what happens.

 

[DON]

I would try to do more than one cylinder at a time. I would do one cylinder at a time, watch intake valve, when it closes, bring that cylinder to TDC, first loosen the adjuster so there is clearance, then carefully tighten until resistance is just barely felt when twisting the push rod. Then do your 1/2 turn.
You might notice how far you turn the adjuster till you get play-to check your previous adjustment

 

[chad]

I say: “Always degree every single cam.” No matter 'dot to dot' or 'previous owner'.
@ minimum it lets me know excatly where I’m @, more data, known quantities, etc.
Ck lash, do full ignition tune THEN think/read bout “What is correct break in proceedure".
(Guy on here just happened to have vid camera on when 1st start-up after a rebuild. He did
the break in & I saw red hot exmanifold, mentioned it. He went on to do more w/the car but
came here to problem solve. Lots of ideas, hi post count, several pages. When mentioning the
hot manny it turned out to have damaged a new engine). Its 20 min, above 1500, 2K RPM, varrying
from there to under 4K, etc....

 

[drag-200stang]

It's all original

Original, what car, van, bronco etc. and what year?

 

[awasson]

I have posted before that if I degree a small six cam and it is right; I assume that I made a mistake and do again and I find that I did make a mistake. Assume that they are off, as they usually are and by a fair amount.

You mentioned that to me last year when I built my 200. It was a relief to know it was normal that my camshaft was off by 10 degrees with the dots lined up.

 

[awasson]

I set rocker gap as per manual, I will try loosening them off a bit and see what happens.

I had a small block Chevy Camaro with solid lifters when I was 18 and just getting into cars and mechanics. It took me quite some time to get the hang of setting the lifters correctly. My first attempts were too tight and as soon as the engine got to temperature, the valves wouldn’t close, I’d lose compression and it would die on the side of the road, half a mile from home. I eventually got it but it took a while. I’d set them looser than optimum just to see if that’s what’s going on with yours.

It would be good knowledge to degree the camshaft to see where it lines up. These engines are notorious for being out.

 

[Frank]

So with the new timing chain set as per photo. The cog on the cam has the groove so is set position and the the cog on the crank has the groove that line up with groove on cam. I did that as per instructions. (I didn't degree it, as thought with these markers it was a set position) The cam is the original.

Is the lack of degreeing the cam causing the issue? Can I do anything with timing etc to get around this problem? Or do I have to strip down to degree the cam??

My laptop is on a 32" TV screen. From my view, the timing marks don't look aligned. Probably the camera angle, etc, -and this is just a comment, not a controversy. . (Does cause me to reappreciate gear drives where the dots are in each other's laps. )


Valve adjustment should always err on the side of loose. If it clicks, it can be reset. If it's holding the valve open, serious problems.

 

[Frank]

Put a vacuum gauge on it

YES, yes, yes. This will tell you AT ONCE if the timing is off.