modified engine troubles need help!!!

[jayson427]

well i have a 420a built motor im having troubles with the valves staying open in the first cylinder. i have a toga high volume oil pump and its in a machine shop and they are having trouble figuring out why the valves wont work properly. they just put an oil restricter in but they still stay open above 2000 rpm and before it was doing it at an idle. any suggestions or answers would help thanks

 

[Black420RS]

you should post your mod list... to get some idea of whats happening under your valve cover...

 

[BogusSVO]

Well if it is only on the front cylinder, and you say the eingine is built, I would guess the head was rebuilt, including a valve job.

I would check valve tip height and see if it is in spec, high to low spec on most cars is .030

If the valve tip is to high, when oil pressure reaches the HLA and pumps up it can crack the valve off the seat.

Since the problem moved from idle to 2000 rpm after the restrictor was installed, I would really look at the installed height of the valves.

 

[bullettdsm]

I've spent some dyno time debunking the oil aeration myth. Believe me, I have yet to see a reason to have the restrictor in the 2.0. The 2.4, possibly, but not the 2.0.

While valve tip height is possible, you might want to look at a sticky valve. Simply knock the rockers off in that cylinder with a screw driver (by pressing down on the valve and spring) and have them do a leak down. Simple enough to see if valves aren't seating.

I do wonder how they verify that it is the valves in one cylinder. The reason I wonder that is because if the timing is off, it can give you the idea that the valves aren't closing (because they really aren't at the right time). Believe me, plenty of mechanics have done the timing wrong on our cars.

No offense to those engine machinists, but I've always gone by the opinion that a machinist adjusts/makes the parts and a mechanic puts them together

MB

 

[Slo2gen]

nvmd

 

[jayson427]

i have crower springs and retainers, sbi litfers and rockers, i think ferra valves, crower camshaft stage two, toga high volume oil pump, je pistons 10.5 compression the only thing stock is the crank. the shop told me when they do a leak down test and compression test everything is fine and when they bleed off the lifters on the first cylinder it closes while running. i have a stainless header and u can see that the fuel isnt burning ### its not changing color like cylinder 2, 3 and 4. but the second cylinder is like half dead but its still burning fuel. i have obx cam gears and they did have the timing way messed up i had to take it back to them ### i had zero compression in all cylinders, then they told me they had to time it with the valve cover off and made new marks ### they couldnt line it up with the timing degrees but it has compression its been my project nightmare

 

[bullettdsm]

i have obx cam gears and they did have the timing way messed up i had to take it back to them ### i had zero compression in all cylinders, then they told me they had to time it with the valve cover off and made new marks ### they couldnt line it up with the timing degrees but it has compression its been my project nightmare

Yeah, I think here is your problem. have them take a look at this;

2GNT.com - PROPER_TIMING_MARK_ALIGNMENT

and this;

2GNT.com - Timing_Belt_Replacement

and tell them to line up the two holes in the cams (so they are both up). Its obvious to most mechaniocs that you need to include the crank marks, but I'll reiterate that.

I don't like the idea that they are making new marks. I suspect that is part of your problem.

MB

 

[DSMBanditFZ6]

Would you not just turn the cam in time pointing up and then tighten your cam gears so the notches line up? What is this about making new" marks" ?

 

[bullettdsm]

Hmm, information deleted. Did you figure it out?

Well, let me just post this up for future searchers.

The Crowers will have the holes in the cams like stock. I happen to be doing a head right now, so I took some pics (stock cams);

The holes should be up like this;

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Make note of the location of the lobes (how they are pointing away from each other). That is the correct position with the correct cams.

I point this out because it is possible that either Neon cams are installed, or the cams were ground incorrectly (I note this because a few years back there were a batch of Crower cams that went out as Eclipse cams, when they were actually Neon cams. Took a bit to figure out. Also, I have seen a set of Crower cams that had lobes that matched nothing).

Another trouble spot; here's a pic of the stock cam gears and location;

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The belt's not on yet, so the lines aren't quite exact. But if you look at the front of the gears, you will see "front 2.0" on it. if you were to flip those gears over, it would say 2.4 on them (because the 2.4's use the same gear). So if someone times it with the 2.4 showing, it will obviously be wrong.

Not that they did that, just pointing it out.

MB

 

[jayson427]

well i was just looking at it with the vavle cover off and thats how its set up just like that picture. they say when they start it up its ok but when the lifters pump up the valves hold open in the first cylinder but the others are fine. i guess they are going to take the head off and check it out. but thanks for the info

 

[bullettdsm]

Hmm.......so valve tip height is verified. Timing is verified. Correct cam is verified. Static valve seal is verified. And it happens when lifters pump up, even with a restrictor on it?

I think I would move the lifters from that cylinder to another and see if the problem moves with it, before I took the head off. If all the above verification is correct, that's a bit of a sticky wicket They would do themselves a disservice to take it apart without verifying the lifters vs the cylinder.

Speaking of sticky, possibly a sticky valve? Fine when cold, but when it warms up (even just a little), it sticks. Simple way to check that would be warm it up and then do a leak down without rocker.

Also, not familiar with the oil pump you installed, but I am running a Melling and I get right around 85 psi on start up. I would imagine you would have to have much more than that to affect the lifters that bad.

MB

 

[jayson427]

well they have moved the lifters around already and the problem stayed in the same cylinder. i brought them my stock camshafts so they can measure the back side of the lobe i think. after that i guess they are pulling the head off to figure it out.