1986 F-250 XLT 6.9 idi C6 switch to 300 4 speed

[Gary Lewis]

Hi Jim, I imagine you are into the 6.9 work by now. The big rats nest is of course all the preheat wiring other than that it is pretty similar, anyway good luck with it.

Thanks Gary for the site and all the positive feedback, it has been very helpful.

The truck runs very nicely and is operating on the fuel tank. A little bit smokey until I was able to fill up with premium but smooth after that.

The transmission shifts smoothly and is much more fun to drive than the C6.

The truck is definitely underpowered by today's standards but absolutely fine for my needs.

I will probably start another thread on making the tachometer work with the gas engine.

The front suspension rides a little high but I will see how bad the tire wear is before I give that any further thought as it drives nicely at highway speed. It doesn't look bad and I haven't measured it but there is a slight amount of positive camber.

Thanks to all and unless something swap over related occurs I think I will call this done.

Still lots to do on the truck and I will start a new thread on anything I think worthwhile.

Congrat's!! Glad you have it on the road.

[nic55kel]

Congrat's!! Glad you have it on the road.

Follow up after several weeks:

The truck ran beautifully for about a month and I put a couple of tanks of gas through it and couldn't have been happier.

At the end of the long dry spell we had a real downpour and it cooled off.

Went out to start the truck after that and cranked but no fire. I figured the old ignition wires and cap were probably damp and draining off the spark. I sprayed it with ignition spray and it fired right up and ran fine. Ordered wires, cap and rotor.

The next day went out to start it - crank no fire - sprayed the ignition - It started very roughly but evened out and ran fine.

It started even more roughly the next day (shook like a dog) and then ran but had developed a nasty lifter tick and had a miss.

Replaced the coil, plugs, wires, cap and rotor - still did not want to start. Ordered a module and pickup coil.

Changed the fuel pump - did not get rid of the noise.

Pulled the valve cover. #6 intake pushrod out of the rocker and bent, #3 collapsed lifter and bent pushrod and one other bent push rod.

I ordered a set of pushrods and the last 6 valve lifters on rockauto. Seems there is a worldwide shortage of valve lifters!!!

Bad timing on my part I guess. I had been thinking replace the cam, lifters and pushrods but no cam and lifter sets available!! Checked a few other places and no stock on valve lifters.

Still waiting on the the ignition module - once I get that I will see if that fixes the no/hard starting.

Once that is remedied I will decide what to do about the valve train. I am kind of leaning toward changing the 3 bent pushrods and the one collapsed lifter (I know there is a good chance it will take out the cam lobe) just to see if it runs properly. I want to know what the root cause is on this before changing lots of parts.

I am kind of thinking the violent shaking of the engine was enough to throw the pushrods out of place???

Maybe those 3 lifters were compressed when the engine was at rest and had not yet pumped up when the engine shook.

I have worked on lots of engines but never ran into bent pushrods before, I have heard others mention it as a problem on the 300 and now I see it is true.

 

[nic55kel]

Follow up after several weeks:

The truck ran beautifully for about a month and I put a couple of tanks of gas through it and couldn't have been happier.

At the end of the long dry spell we had a real downpour and it cooled off.

Went out to start the truck after that and cranked but no fire. I figured the old ignition wires and cap were probably damp and draining off the spark. I sprayed it with ignition spray and it fired right up and ran fine. Ordered wires, cap and rotor.

The next day went out to start it - crank no fire - sprayed the ignition - It started very roughly but evened out and ran fine.

It started even more roughly the next day (shook like a dog) and then ran but had developed a nasty lifter tick and had a miss.

Replaced the coil, plugs, wires, cap and rotor - still did not want to start. Ordered a module and pickup coil.

Changed the fuel pump - did not get rid of the noise.

Pulled the valve cover. #6 intake pushrod out of the rocker and bent, #3 collapsed lifter and bent pushrod and one other bent push rod.

I ordered a set of pushrods and the last 6 valve lifters on rockauto. Seems there is a worldwide shortage of valve lifters!!!

Bad timing on my part I guess. I had been thinking replace the cam, lifters and pushrods but no cam and lifter sets available!! Checked a few other places and no stock on valve lifters.

Still waiting on the the ignition module - once I get that I will see if that fixes the no/hard starting.

Once that is remedied I will decide what to do about the valve train. I am kind of leaning toward changing the 3 bent pushrods and the one collapsed lifter (I know there is a good chance it will take out the cam lobe) just to see if it runs properly. I want to know what the root cause is on this before changing lots of parts.

I am kind of thinking the violent shaking of the engine was enough to throw the pushrods out of place???

Maybe those 3 lifters were compressed when the engine was at rest and had not yet pumped up when the engine shook.

I have worked on lots of engines but never ran into bent pushrods before, I have heard others mention it as a problem on the 300 and now I see it is true.

I was unable to source lifters here in Canada but Rockauto has sealed power lifters. Not sure if I misread it earlier or if they just updated their stock listings.

[FuzzFace2]

I was unable to source lifters here in Canada but Rockauto has sealed power lifters. Not sure if I misread it earlier or if they just updated their stock listings.

Put some break in lube on the lifters before you drop them in the motor.

I would also add a bottle of zinc to the oil and do a cam break in and fingers crossed it will not hurt the cam.

Dave ----

[nic55kel]

Put some break in lube on the lifters before you drop them in the motor.

I would also add a bottle of zinc to the oil and do a cam break in and fingers crossed it will not hurt the cam.

Dave ----

Yes I will take a good look at the lifter I remove, if it is still convex then I will probably take a chance on replacing it and do the full break in procedure. If it is at all concave then I guess I will be replacing the cam and lifters. I just want to make sure that I have the hard starting solved before I think of changing the cam.

Thanks for the input.

[StraightSix]

Yes I will take a good look at the lifter I remove, if it is still convex then I will probably take a chance on replacing it and do the full break in procedure. If it is at all concave then I guess I will be replacing the cam and lifters. I just want to make sure that I have the hard starting solved before I think of changing the cam.

Thanks for the input.

I swapped my lifters a while back. sprayed them down with carb cleaner 3-4 days before attempting to remove them, and then lifted them out with an old cpu magnet. I know that getting the lifters out can be a pain but for me it was mercifully easy. There are after market stock grind cams available. Im using a sealed power cs1230 in my rebuild which is a stock grind. it was about $55 off ebay. good luck! sorry for your troubles.

[nic55kel]

I swapped my lifters a while back. sprayed them down with carb cleaner 3-4 days before attempting to remove them, and then lifted them out with an old cpu magnet. I know that getting the lifters out can be a pain but for me it was mercifully easy. There are after market stock grind cams available. Im using a sealed power cs1230 in my rebuild which is a stock grind. it was about $55 off ebay. good luck! sorry for your troubles.

Thanks, hopefully they are not varnished in there too badly. There is definitely something going on regarding the lifter supply, I just got a message from Rockauto saying there would be a delay on my order.

Still waiting for my ignition module that I ordered from Amazon.

Luckily this is just a project vehicle and I don't need it to get around.

[nic55kel]

Thanks, hopefully they are not varnished in there too badly. There is definitely something going on regarding the lifter supply, I just got a message from Rockauto saying there would be a delay on my order.

Still waiting for my ignition module that I ordered from Amazon.

Luckily this is just a project vehicle and I don't need it to get around.

Well I finally got a full set of lifters and also the ignition module from Amazon.

I changed out the module and no immediate difference.

Embarrassingly it seems that the engine is not starting because it is flooding - however this does not explain why on at least 3 previous occasions it did start immediately after spraying the ignition down or other ignition related changes.

I guess it is a long time since I fought with automatic chokes and I had forgotten that I usually always backed off the choke and would use the accelerator pump to get it going.

Having done that it now seems to start easily again. Just to be sure I will do a couple more cold starts before addressing the pushrods and lifter(s).

I have been researching this issue of breaking in flat tappet lifters and I have come across a very compelling argument, by a mechanical engineer, that counters the generally accepted method of camshaft break-in procedure and lubricants to use.

I would suggest not opening the link unless you have some free time as it is a fairly long read.

https://540ratblog.wordpress.com/2013/06/20/motor-oil-wear-test-ranking/

Not trying to start any arguments.

Anyway I plan on following the advice in the above when I try just changing only the bad lifter(s).

I will report back on the outcome.

[Gary Lewis]

Well I finally got a full set of lifters and also the ignition module from Amazon.

I changed out the module and no immediate difference.

Embarrassingly it seems that the engine is not starting because it is flooding - however this does not explain why on at least 3 previous occasions it did start immediately after spraying the ignition down or other ignition related changes.

I guess it is a long time since I fought with automatic chokes and I had forgotten that I usually always backed off the choke and would use the accelerator pump to get it going.

Having done that it now seems to start easily again. Just to be sure I will do a couple more cold starts before addressing the pushrods and lifter(s).

I have been researching this issue of breaking in flat tappet lifters and I have come across a very compelling argument, by a mechanical engineer, that counters the generally accepted method of camshaft break-in procedure and lubricants to use.

I would suggest not opening the link unless you have some free time as it is a fairly long read.

https://540ratblog.wordpress.com/2013/06/20/motor-oil-wear-test-ranking/

Not trying to start any arguments.

Anyway I plan on following the advice in the above when I try just changing only the bad lifter(s).

I will report back on the outcome.

I assume you mean his statement of "For traditional flat tappet engines, no matter how wicked they may be – use a highly ranked oil from my Wear Protection Ranking list, no matter how much zinc is in it, for break-in to protect against wiped lobes, and a side benefit is that no elaborate break-in procedures will be necessary. Then continue to use the same oil after break-in."

So what oil are you going to pick?

[nic55kel]

I assume you mean his statement of "For traditional flat tappet engines, no matter how wicked they may be – use a highly ranked oil from my Wear Protection Ranking list, no matter how much zinc is in it, for break-in to protect against wiped lobes, and a side benefit is that no elaborate break-in procedures will be necessary. Then continue to use the same oil after break-in."

So what oil are you going to pick?

Hi Gary,

Pennzoil platinum made from natural gas. It is readily available here.

I thought his arguments and methodology quite convincing. Interested to see how it works out in practice.

As I said once I am sure that the starting issue is resolved I will then replace push rods and lifter(s) and report on how it works out using his method.