The Worst Part of an Engine Swap

jikelly

jikelly

Dirt-Old 20+Year Member
Jul 9, 2003
872
54
99
Lubbock Tx
#1
So I've been working on putting a rebuilt 351w roller block in my 73 and now I'm to the worst part of every engine swap I've ever done...

Getting the engine to start for the first time.

Of course I got spectacular backfires on the first try. So I was a bit excited. Played with it a while and it wouldn't start, so now comes the troubleshooting. Check the firing order.

I installed a Trick Flow Stage 1 cam so I checked their site to see what the firing order should be. 1-3-7-2-6-5-4-8 which is what it is for the 351w. I think before my cam was the 302 firing order.

I rechecked the cap, it looked right, took of the distributor and guess what, it turns counter clockwise. Oh, I got that wrong. Turned it around on the cap running the wires counter clockwise form 1.

Still it didn't start. :bang:

So now I'm wondering did I do something wrong still? I mean it should start somewhere withing the swing of the distributor (advance/retard) right??

What I've done in the past is simply walk the plug wires around the cap until I found where it would start. I guess that's what I'll do next, but of course I've got to wait for my battery to charge.

My fuel pump is another little problem. Either I installed it wrong and it's really pumping backwards (it blew bubbles out into a cup I used to see if it would suck fuel), or the pumps diagram is done.
 

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#3
rbohm said:
get back to the beginning. start by bringing the engine to tdc compression stroke, then wire the dist. by the way, the fuel pump=toast.
Click to expand...

Good advice on the TDC - the times I have seen backfires on a new engine start, it has been because the distributor was 180 degrees out. Lighting off the fuel in the cylinder w/ the exhaust valve open causes the backfire.

Wes
 
#5
Yeah the ecentrics is on the cam. Maybe I got it on top of it.

I lined up the engine at TDC and dropped the distributor in so that the rotor would be pointing at #1.

Didn't work, but that's alright.
 
#6
Not quite enough info, but here's some tips

Hi, jikelly--

From what you've said, it seems like you're close, but not quite there.

First off, I haven't read any other threads where you've perhaps posted information regarding what kind of distributor you're running.

You also didn't indicate whether you're aware that the cylinder numbers are 1-4 on the right (passenger) side, and 5-8 on the left (driver's) side, but I'll assume that you are.

Most everybody these days is running some type of electronic distributor, so I'll gear my comments toward that.

Here are the steps that have always helped me get my distributor in correctly:

1.) Pull the #1 plug (passenger side, first plug)
2.) Remove the coil wire from the distributor
3.) Place your thumb over the spark plug holehole, and with a remote start switch, bump the engine over until the force of the compresson blows your thumb off the hole
4.) Using a socket, turn the crank clockwise until the timing mark lines up
5.) Pull the distributor cap and check the location of the rotor

The rotation of the rotor is COUNTER-clockwise, so if your rotor is on or past the # 1 spark plug wire location (when rotating in that direction), try rotating the distributor counter-clockwise a bit.

If the rotor is exactly at the location for the #1 plug wire, then follow these steps:

1.) Turn your crank until the timing mark is exactly at 10-degrees
2.) Put the distributor cap back on the distributor
3.) Re-insert the coil wire into the distributor cap
4.) Insert the #1 plug into the #1 plug wire, and ground the electrode
5.) With the key on, slowly move the distributor body clockwise until the #1 spark plug fires
6.) Lock down the distributor, and your initial timing will be set at 10-degrees (you can change it with a timing light later)

If the rotor isn't even close, remove the distributor and try inserting it again, and then follow the steps above.

If the timing *IS* currently correct, then you probably have some lifters that are too tight . . . you might try loosening them up a bit (if they're adjustable, of course), and see if the engine will start.

Just some stuff for you to try from an old-timer . . .
 
#7
stonecoldtx said:
Hi, jikelly--

From what you've said, it seems like you're close, but not quite there.

First off, I haven't read any other threads where you've perhaps posted information regarding what kind of distributor you're running.

You also didn't indicate whether you're aware that the cylinder numbers are 1-4 on the right (passenger) side, and 5-8 on the left (driver's) side, but I'll assume that you are.

Most everybody these days is running some type of electronic distributor, so I'll gear my comments toward that.

Here are the steps that have always helped me get my distributor in correctly:

1.) Pull the #1 plug (passenger side, first plug)
2.) Remove the coil wire from the distributor
3.) Place your thumb over the spark plug holehole, and with a remote start switch, bump the engine over until the force of the compresson blows your thumb off the hole
4.) Using a socket, turn the crank clockwise until the timing mark lines up
5.) Pull the distributor cap and check the location of the rotor

The rotation of the rotor is COUNTER-clockwise, so if your rotor is on or past the # 1 spark plug wire location (when rotating in that direction), try rotating the distributor counter-clockwise a bit.

If the rotor is exactly at the location for the #1 plug wire, then follow these steps:

1.) Turn your crank until the timing mark is exactly at 10-degrees
2.) Put the distributor cap back on the distributor
3.) Re-insert the coil wire into the distributor cap
4.) Insert the #1 plug into the #1 plug wire, and ground the electrode
5.) With the key on, slowly move the distributor body clockwise until the #1 spark plug fires
6.) Lock down the distributor, and your initial timing will be set at 10-degrees (you can change it with a timing light later)

If the rotor isn't even close, remove the distributor and try inserting it again, and then follow the steps above.

If the timing *IS* currently correct, then you probably have some lifters that are too tight . . . you might try loosening them up a bit (if they're adjustable, of course), and see if the engine will start.

Just some stuff for you to try from an old-timer . . .
Click to expand...
Good info. Instead of using my thumb to plug up the #1 plug hole, I stuff a shop rag in the hole with a screwdriver. When the cylinder comes up to the top compression stroke, the rag pops out and makes quite a loud sound. There's more ways to kill a cat than one. :D
 
#8
Thanks for the replies!!

I haven't played with my car since my last post. I hope to spend some time with it tomorrow.

To find TDC I tried using my compression tester. I figured when the numbers went up and stopped rising the engine would be at or near TDC. Course I got barely a reading probably because the engine's rings are not sealed to the cylinders yet and there is no oil on the cylinder walls either.

So I modified my approach and simply pulled the #1 plug and stared down into the engine. I could see the top of the piston come up, course there is not just one time when the piston comes to the of the cylinder and I changed my harmonic balancer with an after market one that has three sets of timing marks so it's not much help. I could be looking at BDC I recon.

Walking the plug wires around on the cap has always gotten me results, so I'll probably try that tomorrow.

Dang I don't wanna take the valve covers back off, but the rockers being too tight is a thought. That would defiantly cause a couple problems. Course I followed the instructions for their adjustment to the letter when I installed the rocker arms.
 
#10
65fastbackresto said:
Just a thought, its too long to fall all the way in, and its too flimsy to hurt anything.
Click to expand...

Ditto on the straw and NIX the screwdriver idea...


As for compression, even with brand new rings you should still get enough of a seal to get a compression reading. It wouldn't be expected to to be reliable but it should be able to measure. The rings would seat and the compression would rise after some break-in.

My thoughts are that if you aren't seeing much of a psi from the compression tester, then you're valves are staying open too long or not long enough. Check you lifters and rockers and even the push rods to make sure everythings working as it should.

And even some random oddball thought, how much overlap do you have on you cam? Or even an incorrect gap on the rings. But check the easiest fixes first.

Example on compression: My most recent engine build was my jetski engine. Fresh build started with 100psi and after 10 hours of breakin reached it's final and correct high of 150psi. So as you can see, even a fresh build should show compression.
 
#12
Please take no offense, but this is not my first Bar-B-que.

Yes I got matching pushrods, and lifters for the roller cam I added.

Yes I measured to determine what length pushrod I needed.

No I didn't get new valves, but they are on a set of heads that came complete which I ran on my old engine just under 10,000 miles.

Maybe my rockers are too tight, or maybe I had the engine in the wrong spot. I'm gonna go find out tonight I hope. We went mountain bike riding yesturday after work so that day was shoot for car workin'.

Oh, yeah I had spark, and the car would not continue to run after the backfire. In fact the engine tried to turn the wrong way in one spot so I know the timing ain't right. Dang it almost makes me wish I had a distributorless ignition system. Then it'd be a sensor on the crank and a comp controlling it all. (even more of a headache I'm sure :))
 
#13
It sorta started today, but no gas in the carb=not run long.

I took off the valve cover to check the rockers. They were fine, but having the covers off allowed me to see what the cam was doing. Then I used the straw idea to nail down TDC. It was where I thought it was when I first set up the distributor. so I looked at the rotor's position and it was way, way off where it should have been.

What happened was when I set it up the first time I was wrong in thinking the dist turned clockwise, and I set up the plug wires and the rotors position with that in mind. DUH!! Stupid me I put the dist in wrong and never changed it position after I figured out the rotation was counter clockwise.

After I figured out what I did wrong I felt...
A) dumb
B) really thankful for you guys suggestions
C) Like Kirk in Wrath of Khan "You go right ahead quoting regulations."
C) like I wish I had a working fuel pump

Thanks!!!!!!
 
#15
glad to hear you got it figured out J. Dhearne, you do need to make that trip so you can see the 69 GT coupe in all it's glory. she's running and driving now but i have some work to do on the suspension to get it aligned right, need to play with the shims i put on the UCA's to be able to get the alignment right, it's close but we ran out of adjustment a little shy of the caster numbers it needs.
 
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