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AMC360 with Howell EFI - timing issues

D_JEEPER

D_JEEPER

Picked the wrong week to quit sniffing glue
Joined
May 21, 2020
Member Number
870
Messages
745
So I am working on my CJ (1980) with a AMC360 w/mild cam, Howell EFI, MSD 6A (AMC distributor), t176, 4:1 twin stick D300, D44 front and rear with chromos, etc etc etc.

The jeep has the Howell EFI that works pretty well, but the vacuum advance has been disconnected. It runs rather hot though. I have changed the thermostat out and the rad cap seems to function correctly. I do have a water pump on the way because I suspect something funky might be going on there...

So anyways I was trying to tweak the timing to see if that would help some. I decided to toss the vacuum hose onto the vacuum advance and re-clock the distributor. I have never done a whole lot with tuning a distributor with vacuum advance but I understand the concept of ignition timing and how one thing affects the other.

I can get it to run pretty well at idle and rev up decent, but when I shut it off and try to restart it, I am getting some crazy starter kick like it is SUUUUPER advanced. if I roll it back RET I can get it to start but it is unhappy until I advance it again.

I checked vac at idle and it is about ~15.


Any thoughts here?
 
OH, I also have been having a hard time finding specific timing marks on the crank. I have 5 points to use as reference. I have seen some documentation showing center is 0TDC and each one down is 5 BTDC (advance), with each one after being 5 ATDC (RET).

Does that sound right?
 
There should be one slit in the Balancer for TDC, the notches are cast on the aluminum timing cover and there are at least two different versions that I know of. Best bet is to get a wire brush and some foamy degreaser and try to read the letters.

Top dead center

Ok,so it has come to the point of timeing my engine,360,I turn the crank till I can feel the air out...
theamcforum.com theamcforum.com

If the distributor comes with a vacuum advance i'm pretty sure you should be running it, a strictly mechanical dist would not have one I think?. The FSM for a jeep that came with a 360 stock should have the timing curve at several RPMs that you can check against. I have used a timing light with advance to make sure I was in the ballpark through the RPM range.

Are you possibly connected to the wrong type of vacuum port? If I remember right there is one that starts high and goes down with throttle and one that starts low and goes up. Those are the retard terms there are actual names for these things.
 
Bebop said:
Put a timing light on and check timing ?
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Well, I was. It SEEMS ok to me.... like 10-14* BTDC but it wont start like that, only when moved to it while running
 
Google search says stock is 0 deg initial.
 
I think stock is 5 deg advance on the 304s, we usually end up around 12 deg advance with HEI distributors but something is not right if he can't get it to start reliably in the range we are talking about though.

I might start over and verify the timing marks at TDC. I think that high performance ignition was supposed to mess up the stock style amc distributor something about the small diameter cap arcing inside. I have only personally run an MSD box with an HEI on these engines so I can't confirm.

If you have never done it you can watch the vacuum advance working with the timing light, it's easier if you have one that you can set advance on though. The mark should advance out of sight at higher RPMs.
 
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MigGunslinger said:
I think stock is 5 deg advance on the 304s, we usually end up around 12 deg advance with HEI distributors but something is not right if he can't get it to start reliably in the range we are talking about though.

I might start over and verify the timing marks at TDC. I think that high performance ignition was supposed to mess up the stock style amc distributor something about the small diameter cap arcing inside. I have only personally run an MSD box with an HEI on these engines so I can't confirm.

If you have never done it you can watch the vacuum advance working with the timing light, it's easier if you have one that you can set advance on though. The mark should advance out of sight at higher RPMs.
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Yeah, it will drop down and off the scale (advanced) when I rev it above mid range.

I need to just start from scratch.... cyl 1 on compression, TDC, check dizzy and balancer mark, etc etc.

The port I was using was on the throttle body that held 15 psi and would jump on throttle. Maybe that is the wrong one because I figured it would drop off as you cracked open the butterfly.
 
So how much slop is there supposed to be on this rotor. Feels like the weights are not doing the right thing and holding everything tight.
Next step will be to rebuild this I suppose?

Also was able to get a good pic of the notches. Measured cyl 1 at TDC and it matched on the crank as close as I could feel (well within ruling out something got fucked in the timing chain). 20231218_162357.jpg
 

You can hear the squeak of the mechanical advance but the springs feel like shit and do not return fully. I bet this is causing issues. What say yutes?
 
D_JEEPER said:

You can hear the squeak of the mechanical advance but the springs feel like shit and do not return fully. I bet this is causing issues. What say yutes?
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I sure hope that is in the mechanical advance and not the gear slop. We have had 3 sets of distributor gears go out and it sucks to change the cam gear.

They usually run like shit for a while before they jump time and stop working.

I’d pull the dist and inspect the whole thing.
 
MigGunslinger said:
I sure hope that is in the mechanical advance and not the gear slop. We have had 3 sets of distributor gears go out and it sucks to change the cam gear.

They usually run like shit for a while before they jump time and stop working.

I’d pull the dist and inspect the whole thing.
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Yeah I have read about the shitty quality aftermarket cam gears and such. I guess that is my next inspection point...
 
So I took the distributor out and inspected both the cam gear and the distributor gear. Both look just fine. However I found that the roll pin on the distributor gear was broken when I went to take it out...and seemingly had been for a while.
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(rubbing on the non broken side)
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So are these just your standard oil quenched spring steel roll pins or should I be looking for a special one designed just for distributor gears. Last thing I would want is for this thing to snap and grenade in the timing housing haha.

Also, the front of the jeep fell off. I decided the old 304 radiator had run its course and it was time to upgrade so I have a high flow water pump and a 3 core aluminum radiator coming.
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Your new MSD distributor will come with a roll pin.:laughing:

Are you planning to try to rehab the advance mechanism in the distributor, or get a remanufactured unit? The summit brand HEI's are not too bad but you should make sure you have what you need to work with your MSD box.

Whatever you do you have to use your stock dist gear no matter what if it is in good shape dont use any other gear no matter what the manufacturer says, even MSD or DUI, do not use their gears with the unknown cam gear.
 
I am going to run the stock one for now. I was thinking I could pick up a reman unit (swapping the MSD pickup over in lieu of the points).
But yeah, goal was to swap the gear over to any new distributor. I did tear down the distributor and was able to clean everything else up. It does not seem to be draggy now at least.

Is there SUPPOSED to be slop between the weights and arms on the mechanical advance? Mine has about 1/8" or so slop and they will clatter if you shake the distributor. The arms themselves are not moving but the weights do.

The MSD is a 6a so fairly easy to adapt, I reckon. The DUI is tempting but.... not in the budget right at the moment. I might be selling my two Comanches in the near future which would fund a few more upgrades/fixes.
 
Every mechanical advance I have gotten into has been pretty tight. Since you have it cleaned up I'd run it and see if your ignition problems are better. That is the free-est solution. I'd say get a proper diameter and length roll pin and run it. I have seen the slotted and coiled types of distributor roll pins so I don't think that matters much.
 
MigGunslinger said:
Every mechanical advance I have gotten into has been pretty tight. Since you have it cleaned up I'd run it and see if your ignition problems are better. That is the free-est solution. I'd say get a proper diameter and length roll pin and run it. I have seen the slotted and coiled types of distributor roll pins so I don't think that matters much.
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Yeah that was the plan with the distributor. Get into it, clean it up, reassemble after checking everything. If that isnt right, grab one of the Cardone distributors and put my gear on it and try again.

I am also going to look into going to a different port on the throttle body to see if I can find one that actually DROPS pressure when you rev it. I do have some plugged ports on the intake I can pop onto and see if that has sufficient vacuum at idle.
At least it seems I found the one to use when I go to power brakes! :grinpimp:
 
I know you said DUI isn't on table but that's what I've been running for damn near 15 yrs. Best mod so far. I'm still fairly stockish on the 304 tho besides that, headers, and 3" duals.

I'd stay away from cardone... they got bought out a few yrs ago and most their stuff I've seen being liquidated these days is complete crap.

I've had OK luck with a couple 4WD HEIs but I'd say you're safe with a summit brand too. Their house offerings seem to be decent quality.

Like the setup on your 7, got a build thread on it?
 
NDCjeepsmith said:
I know you said DUI isn't on table but that's what I've been running for damn near 15 yrs. Best mod so far. I'm still fairly stockish on the 304 tho besides that, headers, and 3" duals.

I'd stay away from cardone... they got bought out a few yrs ago and most their stuff I've seen being liquidated these days is complete crap.

I've had OK luck with a couple 4WD HEIs but I'd say you're safe with a summit brand too. Their house offerings seem to be decent quality.

Like the setup on your 7, got a build thread on it?
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The DUI would replace everything with the MSD (coil, box, distributor), wouldn't it? I mean, if I were to drop $400ish on a Distributor, why not get an all-in-one right? Sorry, just not super familiar with how it works.

Its a 1980 CJ5 :)
It was built by a friend of mine who got out of the wheeling scene. I was around when he built it though... he put a lot of good work into it. Many people know him by the bumpers he made (Groundpounder Fab).

It was a frame-off rebuild. He put a scout D44 rear and a narrowed Waggy D44 front in, alloy shafts, 4.56 gears. It has the AMC360, RemanT176, short shaft D300 with 4:1, twin stick. It has a custom cage, bumpers, fenders. I just replaced the tank and fuel system this year so that is all fresh too.

It was sitting for many years so when I came into it, I started going through some of the issues plaguing it.
 
Technically any HEI will replace all your multi component ignition.

It's got some good stuff on it. 37s?

My 1980 CJ7 will get a refresh next year or two. It's got the same drive train minus 56 cubes and no 4:1.

WT CJ D44 and stock D30 up front still surprisingly. 456s, SOA and 35s

I picked up an LJ and I'm tired of wheeling a stick but I can't get rid of her. Had it since I was 12 and did all my first things on her.
 
NDCjeepsmith said:
Technically any HEI will replace all your multi component ignition.

It's got some good stuff on it. 37s?

My 1980 CJ7 will get a refresh next year or two. It's got the same drive train minus 56 cubes and no 4:1.

WT CJ D44 and stock D30 up front still surprisingly. 456s, SOA and 35s

I picked up an LJ and I'm tired of wheeling a stick but I can't get rid of her. Had it since I was 12 and did all my first things on her.
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Currently on 35s so it tends to scream down the road at 55mph LOL. It crawls nice though :grinpimp:...however I need to put 4.56s in the front.

Tempted to try 37s but it does pretty well on 35s and everything is beefy enough for a little stupid pedal. I would probably have to lift it a little more. It is currently running YJ springs and shackles. I recently built some front shackle mounts and welded them to the frame for strength (since no track bars) and it really helps tightened up the steering a bit. It has a bent leaf so it kind of does a passenger lean. One of the many things I need to run down and fix. My problem is I want a streetable and wheelable rig whereas this jeep was not really built for "road manners" in lieu of "offroad capability". I also plan to get some rocker and quarter panel armor as well. I need to not neglect Project Iron III Oxide as well (Red TJ in the background of the garage pics).

I DO wish they had a T176+1 for the overdrive option haha.
Fun pics
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You can still run your MSD ignition box with an HEI but it does replace your coil, If I remember right you pull out the module in the HEI distributor because it is not needed. I'd check the manual for your MSD box, it should tell you what, if anything, you would need. The DUI HEI is just known to be better quality but if you were to be replacing the dist gear and removing the module the only advantage over a summit HEI would maybe be the coil quality.

Check page 13 of the below:


Nice 5 by the way! I roll with a crew of them and it's never boring:lmao: It's weird being in a TJ and feeling like the longest rig on the trail.:lmao:

IMG_5428.JPEG
 
MigGunslinger said:
You can still run your MSD ignition box with an HEI but it does replace your coil, If I remember right you pull out the module in the HEI distributor because it is not needed. I'd check the manual for your MSD box, it should tell you what, if anything, you would need. The DUI HEI is just known to be better quality but if you were to be replacing the dist gear and removing the module the only advantage over a summit HEI would maybe be the coil quality.

Check page 13 of the below:


Nice 5 by the way! I roll with a crew of them and it's never boring:lmao: It's weird being in a TJ and feeling like the longest rig on the trail.:lmao:

IMG_5428.JPEG
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Haha sweet! You and your luxury coil springs and what not :-p


Yeah I would have to do some research on the Howell Fuel Injection system to get a feel for how to integrate the DUI stuff. It is probably easier that I am fearing.


I will see where this latest change gets me. My new Aluminum 3 core radiator is going to be here Saturday and my water pump will be here tomorrow. I have some work to do to get this all back together haha.
 
Ok, well I have been messing with this for a while and I give up on the vac advance lol. I just put it back together without it. Runs just fine.

With the vac advance I was getting a vicious pop out of the throttle body when I would stab the accelerator. Also when I would go to start it I would get pretty bad starter kick again.

Maybe it just isnt meant to be. Oh well.

In other news, I bought a 3 core aluminum radiator to swap out my stock radiator. Well, the radiator was a full inch too narrow and there was no way to make it hit the mounts so back it goes. As a positive note, my current radiator, apparently is a 3 core already. I cleaned it really well and flushed it out. I can now hold 180 degrees (my t-stat temp) when idling/revving. The bad news is the current wiring for the taurus 2 speed fan is fucked up. I need to redo everything.... so that will be fun :(

Anyone know of a good prefabbed wiring kit for the taurus fan to utilize the 2 speed function? :grinpimp:
 
D_JEEPER said:
Ok, well I have been messing with this for a while and I give up on the vac advance lol. I just put it back together without it. Runs just fine.

With the vac advance I was getting a vicious pop out of the throttle body when I would stab the accelerator. Also when I would go to start it I would get pretty bad starter kick again.

Maybe it just isnt meant to be. Oh well.

In other news, I bought a 3 core aluminum radiator to swap out my stock radiator. Well, the radiator was a full inch too narrow and there was no way to make it hit the mounts so back it goes. As a positive note, my current radiator, apparently is a 3 core already. I cleaned it really well and flushed it out. I can now hold 180 degrees (my t-stat temp) when idling/revving. The bad news is the current wiring for the taurus 2 speed fan is fucked up. I need to redo everything.... so that will be fun :(

Anyone know of a good prefabbed wiring kit for the taurus fan to utilize the 2 speed function? :grinpimp:
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That is weird about the vacuum advance, them mechanical alone should not be enough for high RPM.

Aftermarket CJ parts are ass, nothing ever fits. :mad3:

Does the Howell EFI do fan control? My brother’s contour fans are now controlled by his sniper. Before that we had a three way temp switch hooked up to two big ass relays. There is supposedly a harness and relay kit in a BMW that is supposed to work really good but I don’t remember years and models.

Edit to add link to my brother’s build thread where he talks about the fan some with part numbers.

Build Thread - Jr's 74 CJ5 "fix" and build as I go...
 
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I do not think the Howell does any fan control, unfortunately.
Currently on the jeep there is a non-weatherproof mechanical temp sensor/probe that has seen better days. It was somehow wired in with 2 relays that would definitely not be enough for the high draw.
I am looking at the Volvo relay option right now. I like it all together like that. Would just need to get the connectors with it haha.
Volvo_relay.jpg

However if someone out there already has a solution for this I wouldn't mind turnkey....depending on the convenience charge tacked on lol. The hard part comes in with the 2 speed functionality of the fan. Kick on low at 180 and high at 200 or something like that. Testing the jeep in the shop, it seemed to hold 180 fine with the LOW hardwired on... but it is also like 40 degrees outside and not under load.


Anyways... I might start a new thread specific to the cooling bit of this and just copy-pasta. Feel free to follow along! :grinpimp:
 
Ok going to revive this thread to make a note. I have been struggling to get this thing timed after rebuilding and replacing the distributor. It seemed like it always wanted to pop out of the intake. The cam is a Edelbrock performer so it has a little more overlap, thus requires like 10* more timing.

However, it seems like I would have it ok-ish but it would pop through the intake when I stab it. Adjusting it more advanced or retarded it would still pop out of the intake, and sometimes out of the exhaust. Come to find out, my distributor cap has some rotational slop. It isnt easy to make it turn, but there is no 'detent' to hold it in place, it seems. So with the MSD, it was arcing across multiple posts at the same time sometimes. I noticed this with my timing light first when the rhythmic flashing would stutter from time to time. When I noticed this I grabbed the distributor cap and gave it a little twist and to my surprise, it moved a few degrees and everything cleared up. WTF.

Oh well, I reset the spring arms on the cap and everything seems happy now, aside from needing some valve guide seals, it seems (engine sat for like 6 years without being ran so I am sure they are bad).


Check out the change is idle just by messing with the cap. The distributor is locked down and does not move.
 
Obviously that’s not good. Going to have to start looking for what needs to be replaced starting with the cap first cause it’s cheap.

I have had caps go down and look straight when they were not in the detent before but I’ve caught it before it ran. I’ll look around and see if I have a stock distributor to take some pics.
 
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