Bullnose Enthusiasts Forum

Engine hard to start hot and wants to stay running with ignition off.

Classic

List

Threaded

16 messages Options

351FUN

Engine hard to start hot and wants to stay running with ignition off.

The issue comes and goes, and has been back pretty bad since the truck sat a couple weeks. The first issue is it turns over real slow if the engine is hot, but once it catches it fires right up. New battery and all connections cleaned except for the starter itself, need to get down there and check that one soon but that means removing the heat wrap and everything and I haven't gotten to it yet. Truck has headers, but also hood vents and a scoop so it doesn't get terribly hot underhood.

Second issue is dieseling when I turn the ignition off. It stops for a moment then tries to spin over a little more. This is even with all power to the truck disconnected via master disconnect. It sounds awful too, like marble in a can.

The engine is not factory, it's a https://blueprintengines.com/products/306-ci-crate-engine-small-block-ford-dressed-longblock-carburetor-bp3060ctc The only change I've made from that is an edelbrock carb, but the issues have existed off and on with both carbs. A smaller but possibly related issue is it does not like to come out of fast idle, and issue both carbs had. Sometimes it will drop to a happy 800rpm, but a lot of times it's around 1500.

I do not know the timing, I had a shop set it but the timing marks on this engine are not the standard ones for a normal light, I don't know what you're supposed to use but the shop recognized it. If it's possibly a timing issue causing all of this I can take it to another shop and have them make sure it's right.

I think that's everything but if you need any more info let me know.

kramttocs

Re: Engine hard to start hot and wants to stay running with ignition off.

Administrator

Does the fast idle cam set and release when you are playing with it by hand?

Matching the timing tape to the balancer is important but I've never heard of the marks not working with a light. What all did the shop do? Meaning is it something you think you should take back to them?

Scott
'Camano' 1986 F250 Supercab XLT Lariat 460/C6
'Chanute' 1980 F350 C&C 400/NP 435 - Gin Pole

But there ain't nothin' wrong with the radio

Gary Lewis

Re: Engine hard to start hot and wants to stay running with ignition off.

Administrator

In reply to this post by 351FUN

At 1500 RPM I doubt you are going to be able to get it to stop properly. And even 800 RPM is pushing the dieseling range. So you are going to have to get the RPM to come down reliably. I have a similar problem with Big Blue and have gone to two throttle return springs, and even that hasn't truly solved it.

As for the hard starting, it can be several different things. But since it happens only when the engine is hot I'll suggest two:

Starter: As the bearings in the starter wear they allow the armature to get closer and closer to the field. Eventually the armature touches the field, causing a huge drag and heat. Heat causes both the armature and the field to expand, exacerbating the problem. So I suspect his is the real problem since when the engine and starter are hot the armature is already starting to expand.

Timing: You didn't say what ignition system you have on the truck, but the good DS-II modules have a feature on them that retards the timing during cranking. This can make a huge difference, but it really shows up when the engine is hot.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

kramttocs

Re: Engine hard to start hot and wants to stay running with ignition off.

Administrator

Good point Gary - when it's idling fast can you reach under there and push the throttle back causing the rpms to drop?

Depending upon what bracketry is being used you have the option of using the stock return or an aftermarket arm that comes out the front (myself and others here use one of these).

Scott
'Camano' 1986 F250 Supercab XLT Lariat 460/C6
'Chanute' 1980 F350 C&C 400/NP 435 - Gin Pole

But there ain't nothin' wrong with the radio

351FUN

Re: Engine hard to start hot and wants to stay running with ignition off.

The ignitions system is the one in the link, it's a coil on top of the distributor. I think it's called HEI, I've never worked with it before but it seems to work well enough. It could be the starter, but I meant to put in the first post that it's only a few years old with not a lot of mileage on it. It's possible it's the culprit but I'm hoping not. It's a powermaster mastertorque pwm-9604, the factory one wouldn't fit with the headers.

I wish I could tell you more about the timing. When I replaced the engine it ran well, but at one point I had it in for exhaust and had my shop do the timing because I couldn't figure it out. He told me the setup was for an old style way of setting timing. I need to contact Blueprint and get some information on that, and I'll try to get a good picture of it tomorrow.

I'll try pushing back on the linkage. I'm using the factory brackets now, it didn't seem to bind up but it may be just that simple.

Gary Lewis

Re: Engine hard to start hot and wants to stay running with ignition off.

Administrator

Your ignition system probably does not have the retard feature. So you'll be limited on the amount of initial timing that is used.

As for the starter, the "factory" starter for a Bullnose truck is the old, large style. But in the 90's Ford changed to a modern permanent magnet gear-reduction starter. Those are smaller and much stronger then the old style - and are the same size as your Powermaster, but a whole lot less expensive.

I have a Powermaster in Big Blue, but it was on the truck when I got it. And I won't buy another one since PMGR starters are available in your local parts store.

Gary, AKA "Gary fellow": Profile

mat in tn

Re: Engine hard to start hot and wants to stay running with ignition off.

the heavy start could very likely be too much timing. having a non std method of setting timing makes matters much more complicated. love em or hate em ,the hei usually work well, as to the rpm, i think a proper carb tune and set up are in order.

Gary Lewis

Re: Engine hard to start hot and wants to stay running with ignition off.

Administrator

Yes, too much timing can certainly cause problems. Which is why I like the DS-II since it has the retard feature. I think some HEI modules have it, but not the ones most of these distributors use, and even if it has it no one wires it up that way.

And I don't understand "having a non std method of setting timing". Spark is spark regardless of what module generates it. So why can't you use a timing light and dial in the initial advance?

Gary, AKA "Gary fellow": Profile

mat in tn

Re: Engine hard to start hot and wants to stay running with ignition off.

before you start pushing back on the throttle linkage, I suggest snapping it off the carb and get the carb isolated from the linkage to narrow down whether its carb or linkage related. "Divide it in half to narrow the path" and so on.

Gary Lewis

Re: Engine hard to start hot and wants to stay running with ignition off.

Administrator

That's an excellent idea!

Gary, AKA "Gary fellow": Profile

351FUN

Re: Engine hard to start hot and wants to stay running with ignition off.

In reply to this post by mat in tn

"So why can't you use a timing light and dial in the initial advance?"

I'll get a picture soon, but the marks are not the standard kind you expect. It doesn't have the normal indicator either, it's all hard to explain. Timing is something I've considered, I need to see how it cranks with the ignition unplugged and see if that changes anything.

Gary Lewis

Re: Engine hard to start hot and wants to stay running with ignition off.

Administrator

Unplugging the ignition is a good idea. If you do that when the engine is hot and not wanting to start you'll know immediately if too much advance is the issue.

As for the timing, if you don't have marks nor an indicator then that could be a problem. Who installed that?

Gary, AKA "Gary fellow": Profile

351FUN

Re: Engine hard to start hot and wants to stay running with ignition off.

The marks as in rough shape now, but from what I was told there's a machine you hook up in that "tunnel" to set the timing. That's how the engine came. I'm starting to think the right choice is to replace it with a normal setup that I can easily time.

mat in tn

Re: Engine hard to start hot and wants to stay running with ignition off.

it is certainly hard to tell for sure, but it looks as though the top edge of the "bracket" is approximately where the std timing pointer would point to. if you were to "assume" that, does the timing scale on the damper show say 10deg, 15deg , ??? when using a timing light.

Gary Lewis

Re: Engine hard to start hot and wants to stay running with ignition off.

Administrator

If the damper has timing marks you can make your own pointer. Or, as Matt was suggesting, look down one edge of that bracket and add/subtract whatever is needed to get to 0.

Get a piston stop, which screws into the spark plug hole, gently rotate the engine clockwise and note where the edge of that bracket points. Then gently roll it back the other way and see where the bracket points. Half way between those two readings is 0, or TDC.

Gary, AKA "Gary fellow": Profile

mat in tn

Re: Engine hard to start hot and wants to stay running with ignition off.

that type of timing cover is one have seen where that bracket holds a crank angle sensor or crank position sensor. typically, on a car which may have had more electronics than our trucks would. I think you may have acquired someone's re-engineered machine. I see this all the time from those making "improvements."
the damper looks to be a good one and one I have probably used myself. but its only half of the info when trying to read the scale.