HEI TDC help working on truck

[NicoSlam]

I'm in the process of installing an HEI distributor on my 250. I haven't removed nor loosened the current original distributor so that I can identify TDC. the egine ran very well and started quickly. Well, the problem is that I'm able to position the rotor facing #1 cyclinder and the piston at TDC but the mark on the crank is 180 degrees off. If I install the new distributor how will I time it if the mark on the pulley doesn't hit where it supposed to. is it possible that someone install the pulley 180 off? Is there something I'm not seeing. Any help thanks

[PanelDeland]

The rotor may not face the # 1 plug at TDC.Only if it was installed that way will it point that way.When the dist is dropped in it may point any direction when the engine is #1 TDC.As long as that terminal ( where the rotor is pointed)on the cap is used as #1 it will work.

[haysonj]

Originally Posted by NicoSlam

I'm in the process of installing an HEI distributor on my 250. I haven't removed nor loosened the current original distributor so that I can identify TDC. the egine ran very well and started quickly. Well, the problem is that I'm able to position the rotor facing #1 cyclinder and the piston at TDC but the mark on the crank is 180 degrees off. If I install the new distributor how will I time it if the mark on the pulley doesn't hit where it supposed to. is it possible that someone install the pulley 180 off? Is there something I'm not seeing. Any help thanks

There are two TDC's one on the compression stroke and one on the exhaust stroke. You need to rotate the motor 180 degrees and bring it to TDC and your mark should line up. I would say someone has installed the dist wrong or moved the plug wires for some unknown reason.

[NicoSlam]

I went ahead and set my distributor where the rotor faced #1 and i felt the piston @ TDC using a screw driver while ignoring the location of the mark on the crank. The engine starts and runs great but when I put the timing light, I see the mark 180 degrees (about 7pm). I used a piece of tape on the face of the crank pulley to see where the notch was as it was running. Now although it starts and runs good, I have no idea what the timing is as the notch is 180 off from the timing tab. Now, I can bring the notch on the crank to "0" (Manual tranmision) and #1 pistion to TDC but the rotor will not face #1 spark plug. Its more like facing the radiator cap. I can then turn that wire on the cap as #1. would that be okay? thanks for all your help. It runs good but I dont want to continue driving when I dont know actual timing. thanks again

[haysonj]

You need to get the engine to TDC with the timing marks lined up. Now the rotor has to point at the dist cap tower that goes to the #1 spark plug. Make sure you keep the wires in the proper firing order. After doing this you can set your timing.

[NicoSlam]

I understand. I guess its more important to get the mark on the tab and #1 TDC then to worry if the rotor is pointing at #1 cylinder. Thanks for everyones help.

When I purchased the HEI, the manufactures instructions mentioned not to use the felt washer they supplied as it would not allow the HEI to ground properly thus voiding warrenty. I didn't install it and now I have a little oil seeping thru. I prefer to install it. what do you think.

[unclewatts]

Originally Posted by NicoSlam

I understand. I guess its more important to get the mark on the tab and #1 TDC then to worry if the rotor is pointing at #1 cylinder. Thanks for everyones help.

When I purchased the HEI, the manufactures instructions mentioned not to use the felt washer they supplied as it would not allow the HEI to ground properly thus voiding warrenty. I didn't install it and now I have a little oil seeping thru. I prefer to install it. what do you think.

On my truck there is a separate ground wire going from the body of the HEI to a tie point on the intake manifold so I don't have to worry about using a gasket. You might do that too.

[FRENCHBLUE72]

I always install the dizzy gasket...

[highperf4x4]

You will want to use the gasket for the dizzy. It may not make much difference on an older vehicle but the worm gears on the dizzy and the cam will be tighter than what they're meant to be as you're actually lowering the dizzy about 1/16 of an inch which amount's to .060.

[NicoSlam]

After taking everybodies advice into consideration, I removed distibutor completely and focused on aligning the notch on the crank pulley to the timing tab on the block at 0 degrees (MT) at the same time as having #1 at TDC. NOT possible. Every time I got #1 to TDC, the mark was 180 degrees off (at 7pm). Do you think my truck has the wrong pulley that would have the notch in the wrong place? Since the pulley can only be positioned on the crank one way, Is it possible that the pulley has both a TDC and a BTDC marking and I just can't find the TDC mark? The truck is running great but its bugging me not knowing why I have this situation. Thanks for everyones help.

[PowerPro]

yeah at 180 off, the piston would be at BDC (bottom dead center)... This would have nothing to do with the camshaft. Suggest getting a new harmonic balancer. (the mark is on the balancer, not the pulley)


The following story may or may not be related, but it's worth telling: The harmonic balancer weight is pressed on with a rubber gasket in the middle, so it can vibrate. I had an 88 Jeep Cherokee where it had actually moved a bunch and was off about 70 degrees and it started creeping back into the timing cover... I didn't realise it had creeped back towards the engine until it started squeaking and I ended up having oil flung all over my engine bay... that repair sucked. Needless to say, i went to Chevy after that...

[haysonj]

Originally Posted by NicoSlam

After taking everybodies advice into consideration, I removed distibutor completely and focused on aligning the notch on the crank pulley to the timing tab on the block at 0 degrees (MT) at the same time as having #1 at TDC. NOT possible. Every time I got #1 to TDC, the mark was 180 degrees off (at 7pm). Do you think my truck has the wrong pulley that would have the notch in the wrong place? Since the pulley can only be positioned on the crank one way, Is it possible that the pulley has both a TDC and a BTDC marking and I just can't find the TDC mark? The truck is running great but its bugging me not knowing why I have this situation. Thanks for everyones help.

I'm not quite sure what you are doing but there is two TDC one on compression and one on exhaust. There are a couple ways to find which is which. One you can hold your finger on the spark plug hole and as the piston comes up it will push your finger off. The other is to pull the valve cover and watch the valves on no one cylinder they should not be moving as you come to TDC. Your crank shaft makes two revolutions to one for the cam so the piston has to come to TDC twice. Once you find TDC on the compression stroke just drop your distributor in pointing to your No. one spark plug wire. you will have to turn the engine over a complete revolution to get the distributor to drop into the oil pump. don't try to force it or tighten the bolt until it has dropped in. Also I would use the gasket and run a separate ground wire. It is possible that someone replaced the timing chain and did not line up the marks properly which could make your damper mark off. If that is the case you can find TDC on the compression stroke and file a new mark in your dampner or put a degree tape on it.

[haysonj]

After thinking about this a little more i think you may have the wrong dampener or it has slipped really bad I have never seen one slip 180 degrees. You might try looking to see if there's more than one key slot in the dampener. My after market dampener has three different key slots

[NicoSlam]

thanks haysonj. I'm also thinking the balancer has slipped. The truck is currently running good. I did find #1TDC and dropped the distributor in properly. And it starts from cold on the second-third crank but when using a timing light its at 7pm. I would like to know where the standard location of the notch is in relation to the key slot on the balancer. That way I can compare and see if mine has shifted over the years. I looked for new balancers on the net but could not find a pic showing the notch and the slot.

[wzuke]

It is not he harmonic balancer!. Like others have already written, there are two "TDS". One will be correct relative to the timing mark and one will be 180 degrees off. Follow directions by haysonj.

[highperf4x4]

Originally Posted by wzuke

It is not he harmonic balancer!. Like others have already written, there are two "TDS". One will be correct relative to the timing mark and one will be 180 degrees off. Follow directions by haysonj.

Actually bro anytime the piston reaches TDC the balancer should be lined up with the timing marker. Pistons can't move faster than the balancer as they are both connected to the same crankshaft. If the balancer is 180 from the mark then the piston should be BDC.

Since he's stated that the piston is TDC with the balancer 180 off then the only solution is that the balancer is either spun or not the correct balancer assuming it doesnt' have an adjustable keyway. (although I've never seen one that would adjust 180 degrees)

[NicoSlam]

I called Damper doctor yesterday and they specified that when you position the key way at 12noon, the notch on the balancer should be 45 degrees to the right (2pm). I checked my balancer last night and found that the notch is at 8pm not 2pm. I still need to confirm if the balancer seperated or if its even the correct one. Regardless, at least now I know why. Napa had the balancer for $79. Next question is how to replace it. My crank is not drilled in the center so I can't use the tool to install it. I hate to beat it in. I was reading how some have drilled and tapped, which to me sounds like the more correct way of doing things but I could not find how deep one should/can go.

thanks for all the great help and ideas.

[highperf4x4]

Originally Posted by NicoSlam

I called Damper doctor yesterday and they specified that when you position the key way at 12noon, the notch on the balancer should be 45 degrees to the right (2pm). I checked my balancer last night and found that the notch is at 8pm not 2pm. I still need to confirm if the balancer seperated or if its even the correct one. Regardless, at least now I know why. Napa had the balancer for $79. Next question is how to replace it. My crank is not drilled in the center so I can't use the tool to install it. I hate to beat it in. I was reading how some have drilled and tapped, which to me sounds like the more correct way of doing things but I could not find how deep one should/can go.

thanks for all the great help and ideas.

By a balancer bolt and then you'll know how far to drill.

[NicoSlam]

Thanks makes sense. I guess I should actually install the bolt and washer after the install.

[highperf4x4]

Originally Posted by NicoSlam

Thanks makes sense. I guess I should actually install the bolt and washer after the install.

Yeah, you'll never get the same tolerances they had at the factory so the bolt is insurance. You don't want the balancer to come off.

[NicoSlam]

Being that I'll be doing the switch out soon. Is there anything else I could should replace while the balancer is off? crank seal, timing chain, cover gasket, water pump etc. All is goo know but I'm trying to look ahead.

[highperf4x4]

I would definitely replace the seal. I don't know that I would worry about the rest.