Bend pushrod on #4 intake

[zeroaxe]

Originally Posted by Moog

I would say those readings are OK as far as making sure the pistons are not going to tap the heads while revving, BUT...

Variation from piston 1 to 2 is quite a bit - why is this? Is it piston variation, or are the cylinders sitting at different heights. Both cylinders on each side must be perfectly matched in order that the head sits square - if not then it sits askew and you blow out of one side of each chamber - as at least one of the heads seems to be blowing on one side of each cylinder only, maybe this is part of the problem?

Moog, I get what you are saying. I am going to torque down the cylinders and re-measure, at least once to see if I get the same reading/s. I suspect that the head is not sitting straight. There is too much evidence to ignore the facts.

Originally Posted by Moog

With these deck height readings what does the compression ratio work out at - have you cc'd the combustion chambers to work it out?

Ok, so I just CC'ed the heads today. And what a surprise. I must eat *some* of my words. This guy actually had a good eye for machining those heads. Here are the readings:

48,48,48,49cc !! The 49cc reading is on the head where the valve hit the piston(#3). But this doesnt make sense to me. If it was machined 49cc, that means he took 'too little' off. And the piston doesnt come up that high compared to #4. So I dont get that, that should be the problem. Or am I missing something obvious?

According to this site's calculator I calculated the compression ratios per cylinder as follows:
#1 - 1.26mmDH 48cc = 8.9CR
#2 - 1.5mmDH 48cc = 8.69CR
#3 - 1.26mmDH 49cc = 8.76CR
#4 - 1.22mmDH 48cc = 8.93CR
They are all over the place!

Originally Posted by Moog

Of course, there is still the possible issue of coil bind, and at least one valve tapping a piston - put some thin layer of plasticene / blu-tack on each piston crown, do a dry build, turn the engine over by hand, then take it apart to see the marks the valves leave in it - slice it carefully and you can measure how close the valve is getting to the piston crown.

Hope this helps...

Moog

After rechecking deck height, I am going to clean the piston crowns and do the blu-tack thing. following that with the coil bind check.

I also want to ask... Under the rocker shaft, do I need some kind of washer/spacer? I have been told just to assemble it with the little rubber ring/washer underneath to prefer an oil leak

[zeroaxe]

Ok, so I mocked up the #3&4 side with blu-tack and torqued the head properly. I put in the cam lifters with the pushrods and turned the motor a few times to see if the lift-n-fall smoothly on their own steam. #3 exhaust side lifted but didnt go down on it's own steam(with the weight of only the pushrod), so added some oil and 'aided' down a few times turning the engine. After that it would lift-n-fall fine. Next, put the rocker arm on, back the adjusters out all the way and bolt it down securely. Again I turned the motor a few times, and then commenced with valve adjustments. Turned the engine a few times and there were no obvious 'counter force'. No resistance at all.

Disassembled everything(while saying to the wife:"Stay here. Before you leave I want to show you something") and went ahead making a fool out of myself in front of her(oh, the humiliation. There goes the ego! ). No marks on the blu-tack at all!? Huh!? What the heck? The blu-tack was about 3mm thick on the piston head!? At first I thought that I didnt place it well on the piston, BUT, where the intake valve hit the #4 piston the blu-tack was on the mark!?

Now I am at a loss. the only thing I can think of now is that I had a coil bind on that valve, causing the bend PR(but saying that, I should've felt it turning the motor over by hand). Or, it slipped out of the rocker's cup and on the way out the edge of the cup caught it and added +/-5mm of lift, pushing the valve too far? I understand it like this: The valve got hit when the piston came up for the compression stroke? How else can an intake valve be hit? Valve float? It should never be open when the piston is on it's way to TDC, no?

I will do this same excersize AGAIN tomorrow, just to make sure I wasnt a moron. I will (hopefully have time to) do the rocker geometry measurements, if they check out, then I dont know what the reason would be for 2 bend pushrods? It cant be badly adjusted valves, because by nature(when it comes to these kind of things) I am paranoid and re-check measurements 3 or 4 times!

More later.

[Moog]

If you have hydraulic lifters, then i wonder if turning the engine over by hand will lift the valve its full amount. The lifter has a ball check valve which shuts when under pressure and effectively turns it (almost) solid, but will this work when turning over by hand, so the valve doesn't lift fully as the lifter drains down?

Don't know if this is what is happening, but just an idea?

Moog

[zeroaxe]

Moog,

Checked SSP but didnt find a pic of the ones I have got, however, found them on another site:


The site states:
"This cam follower (also called lifter) is for 1972-77 Vans with 1700, 1800cc, 2000cc NON-Hydraulic engines."

Does this help to clarify some things?

[Moog]

Externally 1.7(CA), 1.8(AP) & 2.0 (CJ) Solid lifters look the same as 2.0 (CU), 1.6 (CT) and WBX hydraulic lifters, and they can be swapped from case to case, but only used with the right cam.

Look at the end where the pushrod sits - do yours have a spring clip inside them with an internal piston? Remove the spring & the piston comes out to release a ball & spring.

What length are your pushrods? 272mm (hydraulic) or 282mm (solid)

Moog.

[zeroaxe]

I had a look at the cam followers and there is no sign is any clips/springs/internal pistons. I also put some oil in the 'cup' and it syphoned through the hole out the two holes on the oposite sides. I think we can safely say that these are solid lifters?

As to the PRs, I measured 4, and all of them measured 281mm ( ). I can only assume that these are rods that started their life as 282's and wore off a bit?

Hope this helps.