Slant Six Forum
https://www.slantsix.org/forum/

Help!!! Engine swap problem - possible timing nightmare!!!
https://www.slantsix.org/forum/viewtopic.php?t=44845		 Page 1 of 2
Author:  MattyBrown [ Thu May 05, 2011 1:28 am ]
Post subject:  Help!!! Engine swap problem - possible timing nightmare!!!
Hello! I am in some desperate need of a few questions answered. Hoping someone out there can help.

Me and my dad just did an engine swap. The Slant in my '73 Valiant started knocking so we pulled it and threw in a Slant from a '72 Satellite. The '72 Slant has new rings, bearings, timing chain/gears installed. Almost everything from my '73 engine was transferred over to the '72 (manifold setup/carb, oil pan, oil pump, fuel pump, coil and distributor).

So, we finally get the engine in and go to start it up and nothing. Won't start. Okay. Fine. Pull the distributor and go to the next tooth. IT STARTS UP!! But wait... it's running rough... can't get it in time. Something isn't right. Try the next tooth on the distributor... NOTHING. Won't start. Okay, so we've found a magic tooth on the distributor that actually gets it to start, but why's it running like crap? Why can't we get it to smooth out and set the timing to spec?

NOW FEAR SETS IN. Did we goof up on the timing chain and gears? Are we off a tooth?

And this is where I'm hoping someone can answer some questions. Is there any way I can do a test to see if crank and cam aren't timed properly? Is there any way I can observe the behavior of the valves in relation to the pistons to see if I'm off a tooth? I'm really hoping I can figure out a way to diagnose this situation without pulling everything apart again.

A COUPLE NOTES:

A) I am relatively certain that the TDC mark on my damper is correct. I am going to find TDC again and confirm it, but I'm pretty sure this isn't a problem, so there shouldn't be any issue using it for reference.

B) When my dad was adjusting the valves before we put the engine in, he felt like he had to tighten the rockers a lot more than usual to get them to spec. He was using the coat-hanger method for getting the pistons to the top and then adjusting the valves. I specifically remember he felt like something was off about the whole thing but we ended up shrugging it off. Was this a mistake? Could this have been evidence that our timing chain/gears is off???

We aligned the dots on the gears almost perfectly. I don't see how they could be off, but I'm really starting to fear they might have been. If anyone could please offer suggestions I would appreciate it very much. This car is my daily driver! I'm effed without it.

THANKS!!

-Matt
Author:  wjajr [ Thu May 05, 2011 3:14 am ]
Post subject: 
Quote:
B) When my dad was adjusting the valves before we put the engine in, he felt like he had to tighten the rockers a lot more than usual to get them to spec.
Be sure that when the lash was reset that Intake & exhaust valves were not mixed up. First three cylinders 1,2,3 from front end of block start out EI, EI, EI; last three 4,5,6 are IE, IE, IE.
Author:  sandy in BC [ Thu May 05, 2011 6:41 am ]
Post subject: 
It is relatively rare to find timing gear with dots that are even remotely accurate. Thats why we degree the cam.

You can do a rough degree-in to see if you are even close......
Author:  Doc [ Thu May 05, 2011 8:08 am ]
Post subject: 
Re-adjust the valve lash... set them on the loose end of the tolerance to start with and fine-tune from there. (.012 intakes & .022 exhaust)
Do you have a timing light? If not, get one.
DD
Author:  MattyBrown [ Thu May 05, 2011 11:05 am ]
Post subject: 
Doc, yes we have a timing light.

First step will be to recheck the valves and make sure there was not an error.

But, if that doesn't take care of the problem, I am going to have to degree the cam. The only problem is, I'm not really prepared to do so. I do not have a degree wheel or any of the other equipment shown in Ceej's Degreeing a Cam article.

Sandy, what do you mean by "Rough degree-in"?

If anyone can link me to any articles or topics about degreeing the cam that I might not be seeing, that would be great. That whole process is kind of over my head.

Also, does anyone have any reference material that could tell me the correct specs for the degree of my cam on a '72 225?

THANKS!!

-Matt
Author:  Chuck [ Thu May 05, 2011 11:08 am ]
Post subject: 
Don't forget that there is another bolt UNDER the distributor that you can't get to when the dist. is installed unless you have a special wrench. You can loosen this bolt to give you a wider range of motion when adjusting the dist. A timing light will let you know if the timing is in the "ball park".
Author:  Doc [ Thu May 05, 2011 12:26 pm ]
Post subject: 
While the valve cover is off for lash checks, you can also check the cam position as follows:
Turn engine to TDC exhaust stroke. (this is the cam's overlap period, for cylinder #1, both the intake and exhaust valves are open at the same time for cylinder #1 = no valve lash)

Rotate the engine counter-clockwise (backwards) and find the place where you start to feel where the lash comes back. (intake valve clearance = intake valve is now closed) Mark this place on the damper.

Now rotate the engine clockwise to find the point where the exhaust valve starts to have clearance & mark this position on the damper.

If the cam is installed correctly, the two new marks should be just about equal distance, on each side of the factory TDC mark, on the damper.

This check is pretty accurate if the factory TDC mark and the lash settings are correct.

Note... if a cam is "out of phase" but everything else is set correctly, you will have an engine that idles fine but does not make good power in the high / lower RPM ranges... depending if the cam is too far advanced or retarded.
DD
Author:  sandy in BC [ Thu May 05, 2011 3:50 pm ]
Post subject: 
Do what Doug said.
Author:  MattyBrown [ Thu May 05, 2011 9:25 pm ]
Post subject: 
Thanks to everyone for the advice and a VERY BIG THANKS to Doc for explaining how to check the cam.

I made a graphic of my damper to show my results:

Image

So it would seem that the cam and crank are not in time. My next question is, which way should I turn the cam to correct this? My initial thought was to turn it one tooth counter-clockwise because it seems the cam is advanced too much. WOULD THIS BE RIGHT?

Here's a pic of the dots which seem to be almost lined up on the gears. The way the dots look makes it seem like the cam should turned clockwise one tooth, but I don't want to rely on the appearance of the dots. I looked at the old gears from this motor and the dots seem to be in the exact same place. So why do these gears put me in the wrong timing?

Image

Any further advice or suggestions are appreciated. THANKS!!

-Matt
Author:  Doctor Dodge [ Thu May 05, 2011 10:00 pm ]
Post subject: 
Nice drawing but...
The intake valve will start to open before TDC Ex (overlap event) and the exhaust valve will close after TDCEx. ( Intake label should read "Intake Opens")
If this is true, you should be OK where you are... the intake is opening a little sooner then the exhaust is closing, this tells me that the cam is slightly advanced and that is what you want.

One note: Having 2" (inches?) and 3" (inches?) on either side of TDC is a lot... for stock cams, with the lash adjusted to spec, this is usually 15 to 20 degrees. (about 1 inch)

Re-adjust the valve lash... on the loose side and check again. Aslo look for other causes for the rough running, like a vacuum leak.
DD
Author:  MattyBrown [ Thu May 05, 2011 10:29 pm ]
Post subject: 
Doc, I'm so confused! The way I did your test was to line up the TDC mark on the damper and then check that both valves for cylinder #1 were open. By which I mean that both of the rockers were solid, couldn't be shaken, or moved. The rockers on #6 could both be jiggled freely. This would mean I am at TDC on the exhaust stroke, right?

When I rotated the damper counter-clockwise I shook the rocker arm of intake until it could be moved slightly. Made note of the position.

Then I rotated the damper clockwise, past TDC mark until the rocker arm freed up a little on the exhaust valve. Made note of the position.

And the graphic shows my results (I traced my damper after pulling it).

Providing I did the test correctly, are you really quite certain that I don't have a timing issue? To get the car to run, my distributor has had to be advanced one tooth past what I'm pretty certain it is supposed to be at. My intentions have always been to set this engine to "stock". We had hoped to set the car to run at 0 degrees TDC with the timing gun and then maybe advance it a hair if needed. Currently, the gun shows the timing mark (sometimes erratic) usually hovering way way in the BEFORE.

I've really been banking on the fact that I have a timing issue because everything else under the hood has been swapped over and everything was working great with the old engine.

One thing we've noticed is that to get the car running steady (the way it is currently with no valve cover on) we have to completely block the PCV valve. If we let go of the valve the car stalls and dies almost immediately. Is that normal? Everything else on the carb is either blocked off or connected.

THANKS!!!

-Matt
Author:  Fopar [ Thu May 05, 2011 10:30 pm ]
Post subject: 
Looking at your picture, the cam looks to be 1 tooth retarded.

Richard
Author:  Doc [ Fri May 06, 2011 8:40 am ]
Post subject: 
One tooth moves are a lot (about 13 degrees) so when in doubt, go ahead and try some other positions and retest.
Again... triple-check the valve lash settings, that has a major influance on the readings you see. (and what the engine "sees")

For a cold valve lash adjustment, rotate the engine clock-wise, while you watch the #1 intake valve, as it goes down, then starts to come back up, stop when the #1 intake valve is almost back to closed, then adjust the #1 exhaust valve.

Then continue to rotate the engine until the exhaust valve just starts to open, stop there and adjust the #1 intake valve lash.
Re-run your "split overlap" test.

Also... if you need to plug the PCV valve to get the engine to run, you most likely have a vacuum leak somewhere.
DD
Author:  MattyBrown [ Fri May 06, 2011 10:50 am ]
Post subject: 
Okay Doc, I'm going to do the test again. And yes, the inches labeled above are correct. There's a chance that the valve lash could have been slightly over tightened. It was adjusted first when cold and then again while we had it running to .010 and .020. I will double check it on cylinder #1 the way you specified and at .012 and .022.

Luckily, I also have another Slant in my yard. Another '73 Valiant I use as a parts car. I believe the engine to have low mileage (and hopefully be unmolested) so I'm going to prepare it for the same test and compare the results to the engine in my car.

I'll let you know how today's testing goes.

THANKS FOR THE HELP!

-Matt
Author:  MattyBrown [ Fri May 06, 2011 8:28 pm ]
Post subject: 
I'm really starting to zero in on a solution to my problem of not being able to confirm correct cam/crank timing.

Doc, Before I re-administered the test today, my dad found a dial gauge that he had. It was incredibly useful. We used it to find absolute Top Dead Center which I can now confirm IS exactly where it is supposed to be on the damper. That is a relief.

We readjusted the valve lash, it was a little tight previously. We then attempted to do the test you recommended. Things came in closer to the TDC mark this time, but it got frustrating because I kept feeling like I got slightly different results each time we turned the damper back and forth. At this point, my damper is covered in bunches of little pen marks on each side of TDC. All within a close proximity, but nevertheless it has become very difficult for me to determine the results and what they mean or whether they favor one side or the other.

I did a search online and found a PDF degree wheel which I've printed out on cardstock. I posted a thread a little while back asking for the Valve Timing specs for my engine. Ceej posted them in a reply. So, now I'm wondering if it would make sense for me to just rotate the engine and make note of the degrees where the events happen, and see if they happen where they are supposed to. Joshua Skinner said he would use an intake centerline method, which I don't know anything about (I sent him an e-mail inquiring about it and the specs needed).

Doc, if you're still reading, there's one thing I'm hoping you could clue me in on:

When the specs says Intake Opens and Intake Closes, does Intake Opens mean the valve STARTS to open? Does Intake Closes mean is has closed all the way or just begun to close?

Does this course of action make sense? Have I neglected to realize anything? Any advice is appreciate as always. Sorry I'm such an amateur at this stuff. Got myself in over my head.

Thanks!

-Matt
Page 1 of 2 All times are UTC-08:00
Powered by phpBB® Forum Software © phpBB Limited
https://www.phpbb.com/