351 swap issues

spierce · Oct 27, 2006

I finished my 351 swap and now the car starts and runs.
put I still have a problem.
I set the timing to 10 deg. base (no plug) and then shut it down and put the plug in. the timing advances propperly now.
If I sit in the car and rev the motor it sounds great like everything is working fine, lifters are a little loud but that's to be expected.
when I drive the car it has no power, it's like putting the car in 5th gear going 5 mph. and that's in first gear with it floored.

Any ideas?

uedlose · Oct 27, 2006

more info is it carb or inj.

vristang · Oct 27, 2006

subscribed, but we need more details.....

9 Deuce GT · Oct 27, 2006

My thought is drive it for a little bit. When I did the H/I on my car it ran like crap. After the computer adapted to the changes, it was fine.

spierce · Oct 27, 2006

car specs

it's EFI
here are some specs:
Custom blower cam (no blower currently hooked up)
GT40P heads ported with larger valves
1.6 rockers on the exhaust, 1.7 rockers on the intake
Typhoon intake
30lb injectors w/ C&L tube
Accufab 75mm TB
New bearings (cam, main, and rod)
new lifters
new stock lenght pushrods
28oz fluid damper
28oz billet flywheel
FMS king cobra clutch and custom pressure plate
it's mated to a T5
the pistons are stock so compression is right around 9:1.

spierce · Oct 27, 2006

more info

now the car did sit for a year with old gas but I pumped it out and put it in my 93 and it ran fine.
So just to be safe I pulled the fuel filters (inline and in tank).

Fuel pressure was set to 39lbs

I have a wide band O2 sensor and it says the car is running nice and fat, I've even tried leaning it out to see if it helps but it doesn't.

it sounds like the motor is under water when it's under a heavy load. I just have no idea whats wrong.
and I know it doesn't have a blown gasket already.

Black1987Stang · Oct 28, 2006

spierce said:
sounds great like everything is working fine, lifters are a little loud but that's to be expected.
when I drive the car it has no power, it's like putting the car in 5th gear going 5 mph. and that's in first gear with it floored.

Any ideas?

mine did the same thing...found out my balancer (outside part) slipped 30 degrees .....new balancer and reset timing n alls good now

vristang · Oct 28, 2006

Run through the diagnostic codes.

That should give you something to go on.

Let us know what you find.

jason

macx · Oct 28, 2006

Just start with the basics - things like - have you adjusted the tps voltage after you set the idle? Have you tried "clocking" the C&L? Have you checked and rechecked for vacuum leaks? All your vacuum hoses hooked up under the intake? Maybe hook a vacuum gauge on and see if it's steady at idle and see what it does under varying levels of acceleration. What do your plugs look like? I've read of fuel pumps putting out plenty pressure like at idle but not enuf flow, although sounds like you've covered the bases with filters etc - have you monitored pressure while you're trying to accelerate? One thing I found on mine was that even though I was careful installing the distributor it ended up pinching the widened fuel rail hose and reducing fuel flow to the driver side somewhat. Maybe check your lines from the tank up to make sure nothing's pinched.

Is your map (or whatever that is) sensor hooked up so it's reading manifold vacuum correctly?

Have you checked your plug wires for excessive resistance?

If you run the codes it should tell you if any of your
sensors aren't inputting correctly to the computer.

That's all I can think of right now.

You can maybe check your damper by turning the
motor by hand till #1 is at TDC (just by sticking a
long wire or something in the cylinder and getting it close) and then see where the marks are, of course turning it a 1/2 revolution if TDC is not near the pointer.

Oh, was your car originally a mass air? I converted mine and when it
didn't run right I found I had not inserted one of the wires quite far
enuf into the plug so it wasn't making good contact and the reference
voltage to 3 sensors (I think EGR Position was 1 of them) was low.

spierce · Oct 29, 2006

351 issues

the car is a mass air car, It was all installed before I bought it.
I double checked everything, TPS is set right.
I left the new fuel line a little long for the driver side fuel rail and it doesn't pinch.
I've watched the fuel guage and it shows the fuel pressure rise properly.
I have a stock style balancer that I may try. I did notice that on this balancer there are two sets of timing marks, one set is about 45 degrees clockwise of where the set I'm using now are. I matched the balancer up with a stock one and use the timing marks that looked like they lined up with the stock ones. maybe I'll just swap the balancer and try using the stock one to see if that makes any difference.

thanks for all the good ideas, I'll let you know what I find out with the balancer.

spierce · Oct 29, 2006

and the computer isn't showing any codes, I'll have to check it again to make sure but I've run it for about an hour now just going around the block but there hasn't been a check engine light yet.

vristang · Oct 31, 2006

spierce said:
and the computer isn't showing any codes, I'll have to check it again to make sure but I've run it for about an hour now just going around the block but there hasn't been a check engine light yet.

Pulling the codes is different than the CEL.

The computer can be throwing codes without ever triggering the CEL.

I have a link in my sig for checking codes.

Or do a search for codes and the member 'jrichker'. He has posted very good info on pulling codes.

jason

spierce · Nov 4, 2006

I tried using the jumper wire again and there isn't a single code stored in the computer. I'll disconnect the battery to clear it then run the car for a while and check again.

thompsonsd · Nov 4, 2006

We have almost the same exact combo. I just did the swap myself, with the same symptoms... I just replaced the stock 351 distributor with an MSD and OMG what a difference! Timing is way different too, not at all where it was with the old distrubtor.

spierce · Nov 6, 2006

I am running a ProComp billet distributor
Do you have any pictures of how yours is?

I really need to pull the distributor again and re-stab it.

I also noticed a large oil leak from somewhere... now I need to get under there and find it.

thompsonsd · Nov 6, 2006

I can take some pictures maybe tomorrow, just need some daylight time to do it.

Sounds like you have a good distributor already. I have my timing set at 13 to 14 degrees without the plug, that little advance helped me a little.

What lifters do you have and how did you adjust them? With me it made a big power difference on this part. When I adjusted them just to where the clatter stopped it ran like a dog, then at no clatter + 1/4 turn it ran a little better, but at no clatter + 1/2 turn it's alive! Once I had it there I ran through the sequence several times to make sure I had it right. I also plan to do it again once I get a few more miles on it.

spierce · Nov 7, 2006

I'm running stock replacement hyd. roller lifters, stock pushrods, 1.6 rockers on the exhaust and 1.7 rockers on the intake, both are pedistal mount.
now they do make noise, but I adjusted them per the Crane instructions and there is still a little play in them but since the lifters are new I don't know if they are fulley primed yet.

spierce · Nov 7, 2006

another question I have is about the lash on the rockers, the 1.6's are nice and tight, the 1.7's are a bit loose, by loose I mean they have about .010 play in them. if you shim them it just makes it worse, I thought about taking about .005 off the bottom of the pedistal portion of the rocker to lower it down and make it tighter against the push rod. anyone have this problem?

txstang84 · Nov 7, 2006

you should have between 0.020" and 0.060" lifter preload...if you've got 0.010" play (lash) then you probably need some slightly longer pushrods by at least 0.030" to take up the slack since you're running non-adj valves

thompsonsd · Nov 7, 2006

I'd say you definitely have a valve problem alright... Do you have a local machine shop? I'm pretty sure that one of those guys has seen this before and may have your answer.

351 swap issues

spierce

Member

uedlose

vristang

9 Deuce GT

Member

spierce

Member

spierce

Member

Black1987Stang

Active Member

vristang

macx

New Member

spierce

Member

spierce

Member

vristang

spierce

Member

thompsonsd

spierce

Member

thompsonsd

spierce

Member

spierce

Member

txstang84

thompsonsd

Similar threads

351 swap issues

Member

Member

Member

Member

Active Member

New Member

Member

Member

Member

Member

Member

Member

Similar threads

Privacy & Transparency

Privacy & Transparency