Hello everyone, I just purchased a 1968 Ford F-100, 360ci, converted to automatic (4 speed I think...maybe C6?) was a 3 speed manual on the tree, 9" ford rearend. I drove it home and the trans wouldn't shift in "D" but I could manual shift it from 1 to 2 but as soon as I went to "D" it would rev up like it was in a different gear. Would only do 35-40 MPH. I was told the trans is brand new. The fluid is nice...not new but not bad or burnt. I don't know at what time it was installed but it still looks very clean on the outside. The vacuum modulator is rusty on the outside but there is vacuum being supplied. Checked with a vacuum gauge. Not sure what the cause is. Also, the engine ticks...like it's valve train...was told it had a different camshaft installed. Not too familiar with these FE engines. It should have hydralic lifters...I believe anyways. No rocker adjustment. Runs smooooth as can be...purrs like a kitten...it's only when in drive or when i rev it up and let off that the "tick" is really noticeable. Sorry to ramble on. Truck had 69,XXX original miles. Looking for some input...where I can check next. I'll try and post a pic...not sure how. I'll take more pics soon. Any help is much appreciated.

Sam

 

Oh...and do these engines require lead additive? i don't think it has hardened seats. It's a really nice truck. If I posted in the wrong part of the forum..I apologize. Look forward to feedback.

P.S. Vin lookup doesn't work for my '68 F-100

VIN# F10YC94218

 

The C6 is a 3sp auto, and it sounds like your 3rd gear is slipping and may be ajusted out to work. When you put the shifter in 2nd, does go to 2nd gear or 3rd gear? If the trans was replaced, the linkage may need to be ajusted.
The "tick" may be a lifter or a push rod or the rocker arm shaft is worn.
Myself, I have not used a lead additive and I do not have the harden seats, but it would not hurt to do so.

 

Could the tick be an exhaust manifold leak? Very typical with these trucks.

As for tranny, sound like linkage is not adjusted right for shifter. Is it a stock column shifter? Does all the other "marks" line up(like reverse or park)?

 

I agree with the exhaust manifold leak. Mine does the same thing as we speak. Not sure about transmissions though.

 

Thanks for everyones input. The marks on the steering column all line up. That was the first thing I thought....the shift detent was maybe installed incorrectly. All is fine with that though. I checked the vacuum from the manifold and at the Vacuum Modulator on the trans. All checks out good. Fluid is up to proper level and a good color...not burnt or discolored. No leaks as well. The column originally in it was for a 3 speed on the tree. It is now an automatic column. I can manually shift into first...start rolling and then manually shift into 2nd...as soon as I go to "D" it seems like it downshifts to 1st...high revs...but does connect with the rear axel...I thought the first time it was in neutral. I am looking into it possibly being a bad Vacuum Modulator. It's cheap and easy....just threads in...and make your adjustments for shift firmness. Atleast that is what I've come across in my readings. Just a side note...there is no trans fluid in the vacuum line when pulled off of the Vacuum Modulator.

Now the engine...Oil is at full level. It is a little dirty but otherwise good. The guy I got it from has a "WIX" filter on it. I will go with Motorcraft as soon as I change the oil. I am a "DIE HARD FORD/Motorcraft GUY". I hooked up a oil pressure gauge and I am getting 40-45psi warm at idle. Not sure what RPM's it idles at...but seems just a tad high. I will check it tomorrow with my dwell/tach meter. It purrs like a kitten...no abnormal noise out the exaust. Revs up beautifuly. The "tick" gets louder the warmer it gets. I thought it was the exaust also but it seems to come from in the middle of the engine...more toward the front. But definatelty in the engine. By the way...exaust from manifolds back is brand new. I was told the cam was replaced...not sure about the timing set. I beleive these engines originally came with the nylon style? Maybe I am wrong. I did a compression test on all cylinders....I am getting 110psi-120psi. The plugs look real nice...not black, not sooty, not oily, and not white (lean). I took the valve covers off and on the very top of the inside was white sludge....like when oil and water mix. But it is only on the top of the valve cover...not anywhere on the rockerarms or top of the heads. Next I spun it over to TDC for every cylinder...exaust and intake valves closed. There is no excessive play in the pushrods. As there shouldn't be with hydraulic lifters. Provided that the person who swapped the cam used the old lifters or a new set. I will say this however...there is a nice coating if gunky oil all over internally...well atleast in the top of the heads. Pulled 2 pushrods out and the lifters stuck to the pushrods momentarily. Found out something interesting...no holes in the pushrods for oil....looked for a way for it to get up there....can't find out how oil gets to the valvetrain??? I put all the plugs back in and fired it up without valve covers....thinking oil would shoot out all over the place....nope....hardly a drop on the end of the valves....but the top of the heads are wet. I did rev it up and still nothing. Very strange! I am thinking maybe the oil isn't getting to the top of the heads...but when I ran it the "tick" was not evident in the valvetrain with the valve covers off. I heard it could be the fuel pump. It is the original with the cartridge fuel filter. Really neat as I haven't come across one on my other old trucks. Thinking maybe the cam bolt is loose...making the fuel pump excentric clatter. Maybe the old nylon timing set is clogging the oil pump pickup...not getting enough to the lower end...but it definately doesn't sound like a rod knock...well...they seem alot louder to me. I am half tempted to pull the pan and check the rods...and clean the pan out...as I am sure there is sludge in there. Can't say for how long it has sat. But with 69,000 original miles...I am sure at some point it sat for long. I want to pull the front cover...just to check the timing set. I am trying to do all the cheap easy diagnosis stuff first. So tempting to just pull it and go through it. Full gasket set is only $80.00. I could do it in a weekend easy. But I want to take my time and do it all right. I'd hate to have to tear into a engine with such low mileage. But if I did I could clean it and be sure that it was all correct as well as put hardened seats in the heads. I did add some lead additive today. It's such a sweet truck. I wanna post pictures...maybe a video of the truck running with the "tick". Well, sorry to ramble on. Thanks to everyone...and again...any input is appreciated.

P.S. I want to drive it soooo bad. Especially to see if the Vacuum Modulator is the cause (stole one out of another C6 trans in my garage). But I live in Michigan and there is a snow/ice storm moving through. Plus all the salt....AHHHHH!...Oh well. no driving for now.

Sam

 

Make sure the kick-down linkage is not locked down at the carb linkage and at the transmission. Also there is a metal rod in behind the vacuum modulator. Make sure it is in place and not stuck, you will loose fluid when you take this loose.

FE feed oil through the rocker shafts to the valve tops. If you remove the rockers play close attention to the bolts. And make sure the pushrods go back to the same hole they come from. They come in different lengths, you do not want to mix them up.

 

blue68f100....isn't the kickdown linkage only for when you step into the gas....it will kickdown a gear?....well unless you mean it may be stuck and won't disengage from the "kickdown" position.....I'll take a look....cause the carb is quite rusty...frozen up...well the steel parts of it anyway. Seems to work well....just frozen up....like the choke. Sprayed a little WD-40 on it the other day....seems to have helped slightly. I beleive it could use a rebuild...(2 BRL) ...rebuild kit at napa? The carbs are Autolite correct? Thanks.

Sam

 

I'm thinking it may be stuck.. Forcing it to down shift. If the pin does not float or missing in the modulator it impacts shift points.

All linkage is outside the carb.

 

blue68f100....yeah, the linkage is rusty on the outside of the carb. The "pin" that the vacuum modulator pushes on is there and good. I'll check the kickdown linkage tomorrow. Kinda worried about the ticking engine. Hope it's nothing serious. Your help is appreciated.


Just a bit of info....when the cam was installed....a new set of bearings were NOT installed according to the previous owner.

Sam

 

Well everyone, I did some more tinkering with the truck. The kickdown is a lil froze up so I believe it is the culprit to why my trans will not shift. The "tick" or maybe even knock is definately inside the engine....wrist pin?....broken piston skirt?....rod bearing? But definately inside. Most evident noise at the oil pan...using a long skinny screwdriver as a stethescope. Only evident when the engine is warm. I changed the oil thinking it was way too thin....that was not it. Besides....it leaks oil at the intake and is all over the engine. So, I have decided to just pull the engine and inspect everything thouroughly when disassembling. I am going to have the hardened seats put in the heads when I do. There is a nice little coating of sludge in everything so when the machine shop does the heads they will be cleaned obviously but I am going to ask if they can throw the block in the washer and get it sqeeky clean for me. They have a big washing machine like device that they wash the blocks with before they start any work on them. I just don't want to have to re-hone the block or put any cam bearings in again....but maybe I should change the bearings....just as long as there is no re-hone of the cylinders. Anyways, it'll be a little bit of time before I can get it done. If I find anything I'll definately post it up here. Atleast it'll look real pretty when done. Wish me luck. Thanks to everyone with all your input.

Sam

 

Ok guys, I narrowed it down. When the engine is cold I get 50-55 psi of oil pressure. When the engine gets up to temp the oil pressure drops to 20-25 psi....ouch. I beleive the oil pump is shot or the pickup is full of sludge. My brother and I removed the "dizzy"...which was very difficult...why u ask? There was a very nice build up of sludge. So....as of now I am going to pull the pan and oil pump and take a look. I have a oil pump with less than 100 miles on it from another 360 that I am going to check before I throw it in this truck. Then maybe I'll be ok....but it will still need to be pulled and hot tanked. Oh, by the way...the transmission shifts now...after freeing up the kickdown linkage for the trans....thanks BLUE68F100. I'll keep everyone posted.

 

Those pressures are fine and normal between cold and hot if the rpm is under 2k, spec on a FE is 10psi/1000rpm. So if those are idle rpm no problem. You can desludge an engine without telling it apart. It may take several treatments if it's that bad. So expect some more oil leaks once you clean all of the sludge plugged holes.

 

OK everyone...I found out what was wrong with the engine. The engine originally came with the nylon upper timing gear. This was replaced by a previous owner. Unfortuneatly when they replaced the timing set...they forgot to leave out the spacer between the cam gear and the end of the camshaft. This caused to much slop or movement of the camshaft. The camshaft thrust plate was cracked as a result on both ears and when it was reinstalled for some reason the lower driverside bolt was missing the lock washer which caused the bolt to back out, which caused the cam to push on the thrust plate cracking the plate in several places. I was able to find a spare thrust plate in a parts bin from another engine and installed it. I put the engine back together and everything is perfect. Truck purrs like a kitten. I appreciate everyones input. All I have to fix is the slight exaust manifold leaks. I'll try and put up a picture of the broken thrust plate in my gallery in the next week or so. Thanks again everyone. I hope this thread comes in handy to someone in the future.

 

to me that small nock sounds like your timing is off my truck did that to that sound you heir is called pree fire and it will slowly burn a hole in your piston if you dont fix it.