Timing Marks

[Brian Mills]

I would like to install timing marks on my old motorhome. The old girl is a 1972 dodge van class C style. The power is a 360 with a manufacture date of 10th month 1971, according to the sticker on the valve cover. The millage is 60'000, and I have turffed the 2 barrel for an eidelbrock performer, carter 625 competition, as well as tossing the points distributor in favour of the mopar performance package upgrade with distributor including advance spring all ready installed, new wiring and orange box with .5 ohm ballast resistor. This is fine, but I cannot find any evidence that this machine ever had timing marks on it. I have looked from the top and from the bottom, and I have taken it to the dealer, and it looks like I will have to manufacture a mark. I have timing tape for the harmonic balancer, but I need ideas for the pointer. The harmonic balancer actually has no TDC mark on it anywhere. I've never seen this before, and I have no experience with vans, I have heard that you time them from under the bumper, I guess I'll listen to anything you say.

[Brian Mills]

Just came back from an old out of the way autowrecker, I saw a 727 from a heavy dodge van, (3/4 ton), and the bell housing had a 1" hole at the top just to the right of the center line in the casting. I also saw a chilton manual with a paragraph stating that some motorhomes used this hole to set timing, and that the marks were on the flywheel. Mine has no such hole but the trans could have been changed, maybe I should drill a hole and have a look.

[The Dartman]

I used to work at one of the Midwest's largest RV and camping dealers, Cheyenne Camping Center in Eldridge, Iowa.

You are correct that the 1" hole in the trans to set the timing via marks on the converter.

What's really funny is that when we bought the 727 trans and 340 motor for my Dad's '72 Duster, it was supposed to be the original "matching" motor and trans from this car or one the same year. Lo and behold it had the 1" hole in the trans, and a heated arguement ensued about the validity of his claim.

Anyway - just pop the doghouse off and try to check the timing on the converter. If I remember right, it gets pretty oily and dirty around there due to rear seal leaks. So you may need to put a rag in the hole to clean the flywheel off.

Addon: ooops!! I didn't see that you said you didn't have a hole. I must've been too happy that I actually knew something about your question!

[This message has been edited by The Dartman (edited August 19, 1999).]

[Brian Mills]

I am trying to track down the past two owners and find if the trans. was changed at some point. If it was, I may drill the hole and hope the convertor is original, or, since this is one of the first 360's, there may be something else. I noticed a sticker under the hood claiming this vehicle is equiped with a sears electronic ignition. And again I can find no evidence of this, it had a points ignition when I got it.

[Brian Mills]

Well I took it to a long hill and I removed the doghouse, loosened the distributer hold down, and timed it by ear at 60 mph. It seems much better, no detonation, and it pulls hard even under high speed acceleration. Kinda bites not knowing where it's set though.

[Dave]

I just picked up a factory damper for the 360 I am rebuilding and it is the wierdest thing. The first thing is that instead of having the extra balance weight hanging off one side of the front of the damper, it is level. The balancing is done by having material removed from the outer ring. I was told that, in theory, this one is a better one to have because of a reduction in rotational weight. I'm a bit suspect of this claim because when you consider the total weight of a crank plus all the wieght of the reciprocating assy I would guess the advantage of a couple or three pounds off would be quite minimal.
The other thing that is strange about it actually has something to do with Brian's question. I was wire wheeling the scaley rust and paint off and under the paint I found shallow timing marks. Starting at the main timing groove (the one that goes straight across the damper) there were marks every 2 degrees starting at 12 degrees atdc and ending at 32 degrees btdc.
I've never seen these before so I deepened the marks with a small cold chistle and filed the 10 degree marks all the way across to make them easier to see under paint. Now I won't have any worry about the timing tape flying off. The guy at the machine shop said that it must have been from a 360 truck, which it was.
So Brian check your damper you may have the marks on it. Or add the timing tape to the damper and use packing tape to hold it there.
I can't remember, did you say if the engine had that timing tube thing bolted to the bottom of the timing cover or not

[Bigdodgeram]

when you took you rv out and timmed it by ear that was the best way as how does an engine know if its on a mark or not. with todays gas and you have an adjustable distributor it is better to adjust it to the best performance. the reason i say if you can adjust the timming is because todays vechiles the timming is set by the computor and if you turn the distributor you will change fuel delivery.

[This message has been edited by Marshal Carpenter (edited August 24, 1999).]

[Brian Mills]

Dave the balancer in mine has some small thin valleys that only go half way across, they seem to be spaced evenly apart. There is one very faint mark that goes all the way across, but when I cleaned it up it looked like a casting mark and it is very faint. There are no markings on the timing cover above or below the crank. The motorhomes are supposed to be marked on the flywheel, I've seen a transmission in the junkyard with a hole in the top right side of the bell housing for timing. My trans doesn't have this hole, and previous owners have no recollection of a trans change. I'm looking at a new harmonic balancer anyway, I have an intermittant engine vibration in the middle of the power band. I think the rubber in this balancer has deteriorated and is allowing the weight to shift, but I have no TDC mark to check it with! So I am going to buy a new balancer, timing tape I always have in my little stash, and I am now looking at van engines for a timing chain cover with under the crank markings as car and truck covers with over the crank marks will be hard to get at with a timing light. I have only heard about these under the crank marks, I've never seen one. If you have, I'd like to know what year of a van I am looking for. I thought about drilling the peep hole in the trans, but I am changing the balancer any how, so this seems to make more sense. It's kind of a catch 22, since the mid range vibration could be caused by a hair too much advance anyhow. Ya gotta love this little dilema don't ya! Given age of the beast,1972, I guess the new balancer is in order, but I'll listen to any and all advice.

[Brian Mills]

Marshal you should check the balancer to ensure the top dead center marks line up when the #1 piston is at TDC. If the balancer slipps on the rubber and changes weight distribution, it can set up a vibration that will break your crank shaft over time, you may not even notice this vibration till it is too late. All you need to do is pull #1 spark plug, put the piston at TDC, Mopar Perf makes a tool to do this, I bent mine and now I just use a screw driver. When #1 is up, the timing marks on the balancer and timing cover should line up, if not, replace the balancer. This is easy to check, and it costs nothing. However if you run your engine hard, this is something you don't want to overlook.

[Dave]

The bottom timing mark deal that I have seen is a bolt on thing that hooks onto the lower side of the timing case. At the bottom of the bracket there is a tube that points directly up, toward the balancer. The center of the tube gives you your "0" timing point. What I am not sure of is whether you can still use the #1 plug wire for your timing light or not. I am going to see a friend of mine that knows more about this tomorrow and I'll let you know what he said next week. Unless anyone else out there has used one of these things? ???
It does seem strange to me that your damper doesn't have a mark that goes all the way across. It surprises me that Chrysler would actually have a different damper for a motor home. But Hey! stranger things have happened. (Did you know, that is what happens when you fall in the loft in the barn? You get "Butt Hay").......LOL!! LOL!!
I know, I know...Don't give up my day job!

[Christopher]

The tube everyone is refering to sometimes on these truck timing covers and on the balancer ,you will see what looks like two TDC marks.The other one is for use with a magnetic timing probe that would be used on a machine like a Sun or Allen scope at a tune up shop.That's what the tube is for.FYI.Also the "missing" weight from the 360 balancer,is the later model one that is from a different vendor to Chrysler.I see no problem with using one of these.

[This message has been edited by Christopher (edited August 26, 1999).]

[This message has been edited by Christopher (edited August 26, 1999).]

[Brian Mills]

Right on Dave! I don't know what you do in the daytime, but stay on the bosses good side, unless you know a joke about butt stay! On the business side, I am familiar with the tube your refering to, no, I haven't seen one on this motor, but I will climb under it and under the hood of it one more time in the morning. Looking forward to your buddies info.

[Dave]

Well it sounds pretty easy. Use #1 cyl. for your timing light and have a timing tape on the damper mounted in the normal position. Aim the timing light at the tube thing and away yu go! You will not get the PERFECT timing accuracy but it will be not too bad.
The other way is somewhat harder . Lie on your back and aim your timing light up into one of those tiny adjustable mirrors and look onto the mirror to see the marks. You will be looking at the normal timing marks. He swears to me that it can be done....but it is not easy. Good luck
The biggest thing is if you only power time it is to be sure to back off the distributer a little extra to be sure you don't have too much timing. SB Dodge does not show knocking bad like a Chev. You could have a bit too much and not know it, and this could be doing damage all the time. Check your plugs to help show. This is especially true with a van because of the lack of airflow aroung the motor and the higher load with your class C chassis. So Don't Fight With the Detonation Gods! They will win ! Good luck!!

[Brian Mills]

Thank you very much Dave. There is no tube or any other mark on this motor, so it is power timed at present, and I will back it off slightly. What do you think of my latest idea, I figure if I drill a hole in the transmission bell housing, put #1 at TDC, scratch a mark into the tourque converter and a corresponding one into the outside of the bell housing at the hole, and then just use my digital advance timing light. Crude but effective? I'm not even starting it till I hear your oppinion. Brian

[Dave]

Sounds like an okay idea. The only question I would have is on the dial back timing light. Some (I have heard MOST) dial back lights aren't too precise. Whether or not this means a terminal error I do not know. I would try it and keep an eye on the plugs and see what happens!
FYI We once ran my old 360 Dart with 48 degrees total advance (slipping dist. hold down) and only noticed that the power was down. No knock or clatter.

[Brian Mills]

You know that is the second time I have heard that from a reliable source, the thing about the dial back timing light that is. I will keep an eye on the plugs. Am I looking for any little pick marks in them as a sign of detonation, or am I just watching the color?

[This message has been edited by Brian Mills (edited September 02, 1999).]

[Dave]

Yup .Specks are the deal. If you see silver specks on the plug you have chunks of molten piston splattered up to bond to the plug and the inside of the chamber.
Colour should only tell you the mixture as far as I know.
See what happens

[Brian Mills]

Well I bit the bullet today. After trying everything else, I measured the trans bell housing and drilled the hole. I used a rag in the #1 plug hole to find TDC, then I played around with the ring gear till I was close. I chiseled a mark in the tourque, and another in the trans housing.

My crude marks showed timing to be at 0, I bumped it to 5 BTDC, went to a quiet stretch of road and played with it for 2 hours. I settled on 2 BTDC, then adjusted the vaccum advance and man what a difference! The engine is a heck of a lot quieter than it was. Power is smooth and very responsive. I can now cruise over 60 MPH without being into the secondaries, used to be in them anywhere after 50MPH.

Driveability is excellent, it was always good, but this is the best result I have ever had with the electronic ignition upgrade. Can't get over the improvement a little time well spent has gotten me.

Thank you for all the advice and information guys, couldn't have done it without all of you. Kudos to Dartman and Dave for the RV info. Can't wait to test economy, I know it will be improved!

Brian