www.the351cforum.com

ALL things related to the Ford 351C
It is currently Tue Aug 20, 2019 1:15 am

All times are UTC - 5 hours




Post new topic Reply to topic  [ 13 posts ]  Go to page 1, 2  Next
Author Message
PostPosted: Sun Apr 21, 2019 10:03 pm 
Offline

Joined: Sun Apr 21, 2019 9:09 pm
Posts: 5
Hi,
I'm stuck on what I hope are some tuning issues with my 351 Cleveland, and am looking for some help or ideas from some old pro's. If I set the timing advance to anything less than 20 deg, it will backfire out the tailpipe at idle. This seems wrong, as from what I understand initial timing for a Cleveland is supposed to be around 14 deg. If I bump the idle timing up to around 24 deg, it runs better, but this seems like an insane amount of advance. I have all the vacuum ports on the carb plugged, and the vac advance on this disty plugged. If I put a vacuum gauge on the full manifold vacuum port of the carb (or in the port on the intake manifold) I see the need rapidly bouncing between 6-9 in Hg. Rapidly. This seems really low, but I do have an aggressive cam in it. The rapid fluctuations in vacuum don't seem right though. Here's some specifics on my setup:

There's only about 400 miles on this newly built motor. It seems to pull pretty good on the road, but admittedly haven't pushed it too hard during the break-in period. Idle is very poor and changes from one stop light to the next. Might idle fine at one light, then a few miles away, it wants to die. Over-heating issues at sustained highway speeds (longer than 20 minutes), made me stop driving it to look deeper. I've got a 3-row radiator, and am blaming it for the over-heating, but wanting to get the other timing and vacuum issues resolved before tackling that. Along those lines - thinking about getting a 4-row Champion radiator and a high flow water pump. (using a standard Ford water pump today)

I've got the distributor installed such that the vacuum port is pointing to the drivers side, instead of straight forward. Does that matter, as long as I've got the rotor pointing to #1 at TDC? I've read in forums that this is a no-no, and also that it doesn't matter as long as you observe the correct firing order and point the rotor to the right cylinder.

I'd like to use the vac advance, but when I connect a line between it and the timing port on the carb, it runs even worse than already. Interestingly, if I take the power brake vacuum plug off the carb, the engine runs a lot better at idle.

It looks like MP4 file attachments are not allowed, otherwise I'd post a video which shows the vacuum gauge rapidly jumping between 6-9 in Hg. Is this expected with such a setup?
Any ideas what's going on with my timing? 24 deg initial just seems outrageous.

Sorry for the long post. Congratulations if you've made it this far! Appreciate any ideas. Disclaimer: I don't know what I'm doing! Just learning as I go. I've probably created a mess here, but don't have any Ford buddies to come over and help me with this.


Top
 Profile  
 
PostPosted: Mon Apr 22, 2019 4:58 am 
Offline

Joined: Mon Oct 29, 2012 9:05 am
Posts: 2585
First of all, thanks for joining....

I would recommend a little investigation on your harmonic balancer first. If it's a factory balancer, it's possible that the hub could have spun and then your timing marks would not be correct. If it's an aftermarket balancer, there are lots of them out there, some are for Windsors, and there again, the marks could be off.

The first thing I'd do is check true TDC on your balancer. It will require a spark plug piston stop, some masking tape, a tape measure, and a Sharpie. Pop all the plugs out of the engine, screw the piston stop into #1 plug hole, turn the engine over slowly and carefully until it hits the stop, put some tape on the balancer and make a mark, then turn it back the opposite direction until it hits the stop, mark the tape on the balancer. True TDC should be directly in between those two marks. If it's not, then you have your answer. If it is, then we can delve into some more things.

If the timing is not correct, then nothing will be tunable or work correctly. For right now, I'd unplug the vac advance and plug the hose.

In addition, you are correct. It doesn't matter which way the vacuum pod faces, or where #1 is on the cap, as long as the firing order is correct and as long as the rotor is pointing at the correct spot in relation to it all.

I think you have some other things going on, but we need to get the timing nailed down first.

_________________
Brent Lykins, Lykins Motorsports
www.lykinsmotorsports.com
brent@lykinsmotorsports.com


Top
 Profile  
 
PostPosted: Mon Apr 22, 2019 10:33 am 
Offline

Joined: Fri Jul 08, 2016 2:19 pm
Posts: 60
Location: Odessa FL, Blairsville GA
My bet is on the balancer also. I just resolved the same issue with mine. The factory balancer ring was spinning rather freely, even though the rubber looked good, giving me timing that shifted each time I checked it.


Top
 Profile  
 
PostPosted: Tue Apr 23, 2019 10:48 pm 
Offline

Joined: Sun Apr 21, 2019 9:09 pm
Posts: 5
Thanks for the ideas and inputs! Really appreciated. Thanks to the owner for hosting this forum for the community.

The harmonic balancer is aftermarket. It was on the engine when I inherited it, which my dad ran for a couple years. It's possible he used a wrong balancer, but I'm skeptical he would have missed that. I can't seem to twist it or detect any play in the damping material, so assuming it's not damaged. I don't see any wobble while the engine is running either.

My engine builder told me he had the rotating assembly at TDC when I got it. I also verified this myself before marking the balancer TDC. I found it odd that my actual TDC was off the markings on the balancer by about 4 degrees. Does that tell me the balancer is damaged? I'm using the stock timing pointer/location, as far as I can tell.

Before I changed to the new distributor, I found my old disty had too much end play in the gear. It was out of the specs for this measurement. This was causing the timing marks to jump around when freezing with a timing light. Now with the new 83503, the timing is solid. (just a lot higher than what I'd expect)

I had also reached out to Competition Cams to get their input on what's expected out of this cam. I asked if the 20-24deg advance is expected at idle, and I asked about the manifold vacuum jumping around between 6-9inHg. I received their response today:
Quote:
That is a bigger camshaft and will definitely want more timing. That is just something you will have to play with to see what the engine likes. The vacuum will fluctuate with that big of a cam. So, your vacuum readings seem normal to me.

This seems to indicate that I don't really have a timing problem, and the low, fluctuating vacuum level is expected. Anyone here agree with that?


Top
 Profile  
 
PostPosted: Wed Apr 24, 2019 5:30 am 
Offline

Joined: Mon Oct 29, 2012 9:05 am
Posts: 2585
No, I think you have a timing problem.

How did you adjust when you saw the balancer was off 4°?

That's not uncommon, BTW, and it's corrected with timing tape, or an adjustable pointer, etc.

_________________
Brent Lykins, Lykins Motorsports
www.lykinsmotorsports.com
brent@lykinsmotorsports.com


Top
 Profile  
 
PostPosted: Wed Apr 24, 2019 7:42 am 
Offline

Joined: Sun Apr 21, 2019 9:09 pm
Posts: 5
Not sure what you mean by adjust?
I made a mark on the balancer at the pointer,when I knew #1 was at TDC. I've been timing off of that mark, ignoring the balancer's marks.
I had seen the timing tape for sale, and figured this must be a somewhat common problem. Although wondered how this could happen with the pointer in the stock location. Maybe this balancer is made for a pointer is a slightly different location?


Top
 Profile  
 
PostPosted: Wed Apr 24, 2019 7:47 am 
Offline

Joined: Mon Oct 29, 2012 9:05 am
Posts: 2585
Yes it’s common, and it’s possible that you have a Windsor balancer on it.

Big cams don’t make engines hard to tune.

_________________
Brent Lykins, Lykins Motorsports
www.lykinsmotorsports.com
brent@lykinsmotorsports.com


Top
 Profile  
 
PostPosted: Wed Apr 24, 2019 10:17 pm 
Offline

Joined: Sun Apr 21, 2019 9:09 pm
Posts: 5
It's very possible that it's a Windsor balancer, and he used it to save money or had one sitting around. Other than TDC and the marks being off, will that cause any problems to use a Windsor balancer?

Thanks for the ideas.


Top
 Profile  
 
PostPosted: Thu Apr 25, 2019 3:50 am 
Offline

Joined: Mon Oct 29, 2012 9:05 am
Posts: 2585
As long as the balance is correct and timing marks are right, they work just fine.

_________________
Brent Lykins, Lykins Motorsports
www.lykinsmotorsports.com
brent@lykinsmotorsports.com


Top
 Profile  
 
PostPosted: Sun Jul 14, 2019 11:45 pm 
Offline

Joined: Tue Nov 06, 2012 1:14 am
Posts: 11
Did you find out what your issue was? Mine is doing a very simillar thing.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 13 posts ]  Go to page 1, 2  Next

All times are UTC - 5 hours


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group