Engine wont start after cam/head swap

[LONN17]

I just completed my engine upgrades and cannot get the car to start. I need help trying to figure out what the problem may be. To start, here is what I installed:

-Worked 1970 351W Heads
-Crane roller rockers
-Comp Cams XE274H cam
-Comp Cams double roller timing set (set on -4*)
-Rebuilt carb (holley 1850)
-Crane Fireball points conversion (in a brand new accel blueprint series dist.)
Note: I set up the crane ignition before the work and ran the stock engine with it so that it could be ruled out after the major work was done)

The engine cranks over pretty easily (tired battery w/ charger connected on 55A start). I only got two small pops/backfires through the carb after a lot of cranking so it doesnt even seem that I am close. The following is what I have tried so far:

-Filled carb bowls prior to start up. Verified I was getting fuel and sprayed started fluid to ensure easy combustion.
-Verified spark at coil then plugs.
-Pulled plug #1 and reset distrbutor when I felt the air from the compression stroke.
-Turned rotor 180* to make sure I wasn't 180* out.
-Tried both the 289 firing order and 351 firing order.
-Compression test on #1 yeilded 145psi.

What should be my next step? I want to get this thing running as soon as possible. Can someone please confirm the 289 firing order for me? I think I was using 1-5-4-2-6-3-7-8 in a counter-clockwise direction around the cap. I have fuel, spark, & compression so what could be keeping this thing from running?

Thanks for the help,
Trevor

 

[Jon22]

It sounds like you are 180 out with your timing but, since you have checked that, try retarding the timing a bit. A pop through the intake can only mean too early or 180 timing if the intake valves are seated. Hope this helps.

 

[LONN17]

Now that I think about it I had my firing order going CW rather than CCW when I checked to see if I was 180* out. I'll check again as soon as I get a chance with the firing order correct. This is a possibility. The couple of backfires I got through the intake were pretty random. When it does this is the intake valve opened when it gets spark?

Any other suggestions - my garage is 2+ hrs away from where I live so I want to be able to try as many things as possible when I get there.

Thanks,
Trevor

 

[Spoofty]

Sounds like timing issuse.
But here's something else to think about if it's not.
Are you using the positive stop style rockers?
If so did you check the pushrod legth?
I put in a cam once tightend all the rockers down to the stops and it wouldn't run. It turned out the push rod were too long and it was holding all the valves open all the time. Not enogh to hit the pistons. Just barely enough to loose all compression.

 

[SoCalCruising]

1-5-4-2-6-3-7-8 is correct firing order. Yes, CCW on dizzy. Make sure you are at TDC #1 using timing mark and compression test (you sound like this was done properly, but please verify). In my experience, it is very easy to think that you have the dizzy in correctly (pointing at #1 plug at TDC #1), but actually have the dizzy retarded. After verifying the above, try to start motor. If it pops, advance the timing while someone cranks the engine. Popping (or flame) through the carb usually means you are too retarded (ha, ha), assuming the firing order is correct. Good luck.

 

[LONN17]

I moved the distributor as far as I could either way until the vacuum advance stopped to from going any further to see if I could get any better results and it didnt sound any different either way. I advance by turning CW and retard by going CCW correct?

I thought it may have been a pushrod/rocker problem at first but I am running crane al. roller rockers with trickflow pushrods that are the correct length (set up with trickflow adjustable rods). I adjusted a couple times to make sure they were set up correctly. Also I ran a compression test on #1 and got 145psi after cranking for 5 seconds.

This seems to have come down to a timing problem I guess. I was working on it by myself last time and need to get someone else to go down and help on the next trip. Its too hard to bridge the starter solenoid while trying to shoot the timing light. I also made a stupid mistake of putting the timing tape on in the wrong direction (TDC comes up at 90*).

 

[Pakrat]

I agree it sounds like a timing issue also. I am not familliar with your CAM choice but it's not uncommon for a Cam to have a different firing order (like the 351) than stock and it should have come with a recommendation. I know you checked your points coversion on the stock engine but that doesn't mean something hasn't happened to it since then. Prior to switching to my pertronix I had an old school dual point upgrade and when I was off by even a hair it would pop out the carb big time.

 

[Jsprint68]

Maybe try restabbing the distributor one tooth forward or backward? You could also try reinstalling the points just to make sure it’s not the point’s conversion. I know the pertronix can quit without any notice.

 

[Pakrat]

Maybe try restabbing the distributor one tooth forward or backward? You could also try reinstalling the points just to make sure it’s not the point’s conversion. I know the pertronix can quit without any notice.

That's all too true, I keep my old dual points and condensor in my roadside bag just in case I ever get stock while I'm out. A flat blade screw driver or leatherman and a match book cover for a quick gap gets you up and running in minutes.

 

[LONN17]

I still have my old distributor laying on the workbench with points still in and set. I'll throw that in and check too.

Can I be 180 out if I stop and stab the dist. when I feel the air blow out the spark plug hole? This only happens on the compression stroke, correct?

I plan to call comp cams tomorrow since I cannot find the cam card. It is rather aggravating that their tech line is not open on weekends. When do they think people work on these things?

Trevor

 

[truck90278]

The advice everyone is giving you is on the money. I would suggest going thru the procedure one more time. But this time pull the valve cover so you can watch the rockers open and close in addition to the compressed air coming out of the cylinder. turn the crank with a socket and watch the intake valve close, observe the timing mark on the dampner. turn the crank until the timing mark (tdc) is at the pointer, then check what wire the rotor is at. The rotor should be just at or slightly past the number 1 terminal/wire on the cap. This will tell you pretty quick if you are 180 degrees out. Being off one tooth can also give you the same problem. however.

 

[BarnStang]

You've said a couple times that you are finding TDC by feeling air blow out of the No 1 cyl. I hope you are then moving the crank to exact TDC by hand afterwards? Just wanted to clarify that. If your timing tape is messed up then that is unreliable. If you turned it around I would still not trust the timing tape untill you prove you are really at TDC. You can use a flashlight to look in the No 1 spark plug hole and see the piston. You can rock the crank back and forth with a ratchet and socket on the crank bolt until it's at the highest point of travel. May take a few minutes to get it exactly at TDC. THEN you can look at the timing tape and see if it's right or not. And of course reinstall the dist with the rotor pointing at the No 1 wire.

 

[65Stang200]

Alright, start over! Pull the distributor. Pull the #1 plug. When you feel compression in the number one cylinder, then put a pencil, eraser side down, in the #1 plug hole. Hold it there while someone else turns the engine over. Once the pencil is at it's highest height that it will possibly go, there will be a little play in the top dead center area, but if you are really close it will fire. Look at the mark on your harmonic balancer, it should line up with the TDC mark. Then you are in business to stab the distributor with the rotor pointing towards #1 plug node. It will fire. =)

 

[302 coupe]

50/50 chance of it anyway. Air pressure exists on the exhaust stroke and the intake stroke. Pull a valve cover, watch the rockers on #1. Watch the intake valve close, as soon as it closes, the exhaust will start to open. Then look at your balancer, should be close to TDC, the correct TDC. Put the valve cover back on, set the rotor to #1 position, and you should be real close. You may be a tooth off in either direction, but at that point its pretty easy to figure out.

 

[LONN17]

Thanks for the info guys. I hope to get down there one day this weekend to try all these suggestions. I need a second person w/ me to make this a lot easier. I cannot wait to hear the fury from this thing when it starts with my old turbo mufflers clamped right to my new tri-y's. Should make the neighbors happy but whatever - my lease is up next friday anyway.

Trevor

 

[SoCalCruising]

302 Coupe: your advice is generally really good, but would you please review your valve event description above. I don't think you meant that the exhaust valve is open/opening at TDC. Both valves should be closed at TDC compression stroke.

Here's what I would do to get to TDC:

One of two things will be happening as the piston approaches TDC.
Exhaust stroke - exhaust valve is closing as piston approaches TDC and intake valve begins to open right around or just before TDC and continues to open as the piston passes TDC and moves down the cylinder bore. This is NOT the TDC you want.
Compression stroke: both valves are closed, and stay closed, as the piston approaches TDC. Use the pencil method (described a few posts above) to determine when the piston is at its highest point. This is TDC-compression stroke. At this point, your rotor needs to be pointed just past the #1 spark plug wire.

If you are looking at your timing tape, it should read TDC at both TDC-compression stroke and TDC-exhaust stroke. If your tape is wrong (as you mentioned), retape it after you are confident of finding TDC.

If it still won't fire, you can remove your spark plugs and turn the engine over using the starter. It will spin fairly fast without plugs and you can use your timing light to see where the timing is set. This won't mean jack, however, unless your timing tape is corrected. Good luck.

 

[LONN17]

It runs!

Thanks for all the help guys. Timing tape was correct. When I initially set it I was running the wrong firing order. After messing with it a bunch I wasn't getting it all the way to TDC. Pulled the valve cover and dropped in the distributor and was @14* and she ran beautifully.

Now see the new problem in my latest post pertaining to freeze plugs....

Trevor