Hello,
This is basically a reply on a before thread called Timing Upsetting. I am now completely lost. I blew a head gasket on my 1978 400, so I tore it down to replace the head gasket. I had the heads checked by a local FORD guru and he said all was well to reinstall, other than valve seals so he replaced them. So I put it all back together with a Edelbrock performer 2171 intake and a Edelbrock 1405 Carb. I also put different lifters in it that were supposed to be stock replacements. So I broke the distributor that came out of it, and ordered a different one off e-bay that was off of a 351M it was in alot better shape than mine in the first place the only problem I saw was the Advance was unhooked from the tab held on by that C clip so I rekooked it. Now then I also put new rotor, cap and wires on this distributor. I checked number 1 cyl for compression and had around 40lbs, at this stroke I sat the balancer at TDC mark installed distributor with rotor touching the #1 post. So then tried to start the engine with tons of backfires coming out of the carb. I played around all over the place with the distributor to no avail. So I thought maybe the cheap valve covers I bought might have been keeping a valve open. I checked and they were rubbing the rockers on cyl 4 and 5 so I fixed them. I then reinstalled the distributor, tried to start it and now I am backfiring out of the exhaust as loud as a shotgun blast. Did I fix anything? I am highly doubting it. I am now at a loss, I checked my old distributor, and the gear on it had been redrilled with a new hole for the pin som time in its life. Out of all this can anybody tell me what the hell to do to get this truck running. I hope I am close, but I don't think I am. I mean it won't really start to try and run it just cranks over and backfires. Thanks

 

You're getting spark and gas - or it wouldn't backfire, that part is not an issue. If the cam gears and chain weren't touched, that's not an issue. I would take the #1 cyl valve cover back off, take the plugs out, turn the engine over by hand till ytou see both intake and exhaust valves closed on #1 and with someone else turning the crank hold a thin long scewdriver in the #1 plug hole till it reaches full top (if it starts to go back down, don't worry, back turn it till it's full top again) then check the rotor under your dist cap and make sure it's at least very close to the #1 plug terminal. If its 1 terminal off or so you can just move all your wires 1 spot over. If its way off the dist needs to be reset. 9 times out of 10 the plug wires are off 1 or 2 spots from the rotor placement. Good luck.

 

XLMAN thanks for the reply, but I have tried that also. Unless I can't tell that the valves are closed. Is there a for sure way of telling with just the valve cover off.

 

Did you preoil the new lifters?

Did you reinstall the rockers correctly?

You may have valves that aren't closing completly.

 

As far as preoil all I did was soak them in 10w-30 then put them in there hole. I put the rockers in there seat and set them all to there torque setting ( can't remember the setting , whatever Chilton manual said). I think there might be something wrong with the valves I just don't know which one. Should I do a compression test on each cyl. Its just weird the motor was running before, with the only changes being the Carb,intake, lifters and valve covers.

 

Just a coupla quick things to check--. I'm guessing you are sure about the timeing chain and gears and the timing marks.

You mentioned the "tab" and a "c" clip, I suppose thats the vacuum advance arm into the plate you are talking about. Make sure the advance plate is fully retracted and not frozen into some kind of advance. Curious why it would have been disconnected---maybe by accident. Also on an old vehicle, verify that both valves are closed and its at TDC. Your bonding rubber for the timing ring on the crank balancer (harmonic balancer) has not started to slip.

The roll pin for the dist gear could have sheared because of an oil pump problem or dist shaft problem. If that were the case, a new pin and drilled hole wont hurt, (long as any problem was fixed) as long as you are pointing at #1 at TDC of the compression stroke.

Backfire out the tailpipe makes me think you are missing on the firing (or firing order) and pumping fuel mix into the exaust, which will ignite eventually.

I've had to back away sometimes, take a breather with a beverage of choice and start over checking even the smallest of things you have checked before

 

Well guy, ya haven't tried all that - if ya didn't watch the valves with the valve cover off when ya checked TDC. It's obvious when the valves are closed. Only got to watch them once. You'll see. The rockers can only be installed one way. It's on (torqued to 30 ft lbs) or it's off. No adjustment with factory rockers. Hope ya get it!

 

No I am not sure about the timing chain and gear and/or marks. I just wish I wouldn't have broke my distributor pulling it out, after marking it to the block. Heck, your right its probably something that I need to check on the third time. It just don't make sense why it won't fire up.

 

dobber97, i just realized you stated you only had 40 lbs of compression? Not good. Open or stuck valve or broken compression ring. You didn't say you disturbed the cam gears or chain. Right?

 

Was the dist gear broke? you could have a broken tooth or 2 on the cam also.

 

Sorry for the double, but I just paid attention to something danlee said about valves not closing---.

Did you put new lifters on an old cam or did you replace both? Because of replacing lifters--valvetrain--, lifter preload could well be off, keeping valves from seating. Did you also do anything about the rockers. Those sled type rocker arms can really wear and if you did anything with them, theres also a problem.

A higher lift cam, even an RV grind with more lift than stock will cause the rockers to raise ****. Been there done that!!

 

XLMAN i did watch the valves just wasn't sure when both were closed.

I took a sharpie and wrote on my dist the firing order in counterclockwise position. Then I have the wires, from each # on the Dist going to corresponding cyls. The #1 cyl is the cyl closest to the fan on the passenger side with 4 being the closest to the exhaust manifold. #5 is the cyl closest to the fan on the driverside and 8 closest to the exhaust on the drivers side. Is this all right

 

I did put new lifters on a used cam, with no preload (wasn't aware I had too) I just knew I had a noisy lifter when i used to drive it, so while I was in thought I would replace them all. I didn't check the teeth on the cam, there could be on missing. Is it ok to rotate the engine with out a dist in.

 

What should the compression check out at on #1?

 

[quote=benshere;6103729]

Did you put new lifters on an old cam or did you replace both? Because of replacing lifters--valvetrain--, lifter preload could well be off, keeping valves from seating. quote]

Good point. Hope ya find out dobber97. Gets frustrating!