Jump to content

'25 Starter Chain Noise?


MikeC5

Recommended Posts

I fired up my '25 after sleeping all winter and while it started up fine, I noticed a loud ticking noise (louder than the many others) coming from the front of the engine. Closer inspection with engine stethoscope indicates origin at or very near generator end of starter chain. It is slower in frequency than the other ticking noises which may be something tied to the passing of one section of the chain. I did adjust the chain tension last year and thought I had it in correct range. Any ideas? Engine runs fine otherwise.

Link to comment
Share on other sites

I pulled off the cover and inspected the chain. Nothing obvious, tension appears O.K. I started it with the cover off (makes a mess) and saw no unusual motions in chain or sprocket. The noise was also more random that I remembered, more of a clacking noise and with cover off it sounded like the source was on other side of engine. I found that the water pump has a little bit of backlash, I assume with drive gear meshing with cam gear. When running, and the stethoscope on front gland nut the clacking is very clearly heard. Just standing in front of car with engine idling the clacking noise is very clear... Should there be zero backlash for water pump gear?

Link to comment
Share on other sites

Mike, yes, it IS a big mess with the little cover off and car running. Obviously Dodge of '25 has no problem with front oil circulation. Your question is a good one... the water pump gear will have to have a bit of backlash, .003" to be exact.

Link to comment
Share on other sites

The water pump gear on my '26 has this backlash problem. The key had become so worn in the keyway that it was flopping about. Until I get round to rebuilding the pump (or another one if anyone has one spare for sale) I have brazed the key into place. Backlash has been much reduced but that's all. The knock on effect (no pun intended) can be quite marked in it's effect on timing as the distributor is driven from the same shaft.

Ray.

Link to comment
Share on other sites

Thanks Pete. If I make a guess at the water pump gear diameter and measure the arc traveled on water pump pulley to take up slack, I should be able to get an approximation on backlash. When I rebuilt the pump I don't recall the key being sloppy (and it was a new shaft) but it sounds like it would be worth removing it and getting a closer look. Did yours make a very noticeable clacking sound Ray?

Link to comment
Share on other sites

If your shaft is new I would not expect to find any movement at the keyway but there may be wear in the gears. As my shaft is badly worn it will need to be replaced. Yes, the gears make a clatter which is more noticeable at some revs than others. It's a kind of irregular clatter but when under load the slack is taken up and the noise less obvious. I have my tick over adjusted to run without too much noise but it can return at times. I have learned to live with it along with a number of other noises which don't make for relaxing listening.

What I am trying to understand is how this noise has appeared now when presumably it was not evident before.

Cheers,

Ray.

Link to comment
Share on other sites

Hi Ray, I have been asking myself that same question... It could be it's more obvious when running the car in the garage (door open!). I'll have to see about when driving it. It is definitely an irregular clatter but the engine seems to run pretty smooth so I don't think the timing is jumping around too much. I might put a timing light on there and see if anything is revealed with the strobe.

Link to comment
Share on other sites

Some noises like that can be a worn camshaft thrust bearing, allowing the cam to walk front to rear with an irregular tick or thud. That can be heard at the front of the engine. It sure sounds like a busted link on chain though. It's hard to say when I can't hear it myself. If you're running the engine without the crank hole cover on, you can hear everything going on in the crankcase. It's a direct opening to the bottom end. Have you checked the fan belt for any delaminations? I hope it's one of those simple things.

Link to comment
Share on other sites

Thanks Pete. I will have to try with the crank hole cover off and see if that sheds any light. I'll have to read up on the cam thrust bearing too. Nothing obvious with the fan belt but then it only has a handful of miles and is a modern, serpentine-style flat belt. Maybe I'll drag the laptop out there and try to get a recording...

Link to comment
Share on other sites

Mike, 'got to thinkin' about that noise again and it occurred to me that you had the engine front cover off, could it be that a longer cover bolt went back in perhaps in the wrong place and it's clicking against the chain, or... This wouldn't be the first time I've seen (or rather heard) this happen!

Link to comment
Share on other sites

  • 10 months later...

I've been doing some more listening and poking on this and am 99% sure the noise is caused by excessive backlash with water pump drive gear. In fact, with engine off I can grab the water pump pulley and turn it back & forth a degree or two (shaft moves with it). When running, the stethoscope picks up the noise loud and clear on the front and rear seal nuts. Perhaps the noise was there all along and I just didn't notice it or maybe I bolted it back on in a slightly different position after doing water pump rebuild... It does seem less noticeable when under load too. No way to adjust it short of using a thinner gasket. At least I'm convinced it isn't a catastrophic failure waiting to happen.

Link to comment
Share on other sites

Bill. One thing I didn't mention about the rebuild of my pump is that with the new shaft the fan pulley ends up slightly further to the left than it where is was originally. This has caused the edge of the belt to fray slightly due to rubbing against the retaining shoulder of the pulley.

Mike. Do you remember if your pump has a distance piece/washer next to the distributor worm drive?

Ray.

Link to comment
Share on other sites

I don't remember any thrust washer in the water pump drive, if that's what you meant Ray. The belt is not riding against the edge of pulley either. It looks like Romar sell the WP drive gear but is says 'call for price' (gulp)...

Link to comment
Share on other sites

There wasn't one in my original pump either, Mike. The washer was in the replacement pump which Ron Lawson very kindly located for me. I can only assume that it was necessary to take up the wear to the blades of the impeller because without it the shaft would move from side to side rendering the pump ineffective. The problem I had was that with the washer in place (although there was no lateral movement of the shaft) I was unable to get the two halves to meet. I could have fitted a thick gasket, I suppose, but in the event I turned down the shoulder of the end bushing and solved the problem that way. I enquired about a new impeller from Myers but they hadn't got one.

The new shaft was flawed in that the keyway and peg hole which locate the distributor worm gear were not at 90 deg's the result being that with the worm gear keyed in, the holes wouldn't line up! Perhaps I am expecting too much.:confused: Anyhow, the pump is now rebuilt with rubber lip seals courtesy of Machinist Bill (thanks again, Bill) and fitted to the car with no more leaks.

Ray.

Link to comment
Share on other sites

Hi jacks are welcome Bill as long as DB related... I wish I had paid more attention to the impeller clearance... It has no fore/aft play though so I'm hoping it's working. I brought the radiator to a friend's house who has a mechanic's flexible bore scope and we looked around in there. The bottom of the tubes (long, thin rectangular- honey comb style core) looked clean and open while some of the upper tubes we clogged with what appeared to be fibrous material. I suspect the rad sat for a long time with no caps on the ends and varmints built nests in there. As such, I wasn't surprised the vinegar didn't seem to do much. Next up, sodium hydroxide... I'm also trying to come up with a way to test the pump. I'm thinking disconnect the upper pump hose and rig up a longer hose to dump water overboard, rig up a lower hose to feed water in somehow and run the engine for several seconds. Hopefully it will be obvious....

Link to comment
Share on other sites

Had my '25 Dodge running and I can hear that odd noise too. Last year I took the chain inspection cover off and saw "nothing" out of the ordinary going on. Buttoned it all back up and passed it off as gear/chain noise only. Car runs great, water circulates great- IT SEEMS ALL THESE DODGES sound like this?

Mike, it sounds like your water pump is OK to me, without seeing it though. Even with half rusted away impellers, if yours were, it would circulate enough when the water gets hot, with the natural help of the convection circulation like the old Fords had--"no water pump at all".

Edited by Pete K. (see edit history)
Link to comment
Share on other sites

Mike. I don't know how long my car was run like it; but the water pump had been bypassed presumably because it leaked. Now that the pump is working as it should and the radiator is clear, the engine runs too cool unless the fan belt is removed. Thermo-syphon was commonly the norm on many British cars of this era but then we don't generally have that many really hot days. Sunday was a hot day and I took the car to a show driving about 30 miles round trip and the temperature remained cool.

About the noise. There is a general clatter from the pump drive which as you say might improve with a thin gasket. I didn't have a gasket to hand so I sealed it with a line of silicone. I can't be sure but I think it has improved the noise level.

I have a suspicion your block may be silted up. This is a common problem on the smaller engines of many British cars; my baby Austin engine was completely clogged! I suppose it could be a problem with some larger engines? I found that a pressure washer worked well after giving it the acid treatment. Good luck!

Ray.

Link to comment
Share on other sites

I suspect the rad sat for a long time with no caps on the ends and varmints built nests in there. As such, I wasn't surprised the vinegar didn't seem to do much. Next up, sodium hydroxide... I'm also trying to come up with a way to test the pump. I'm thinking disconnect the upper pump hose and rig up a longer hose to dump water overboard, rig up a lower hose to feed water in somehow and run the engine for several seconds. Hopefully it will be obvious....

Hopefully that fibrous material is all in the radiator and not throughout the engine and tangled in the pump.

Link to comment
Share on other sites

I had the head and water pump off soon after I got it and dug a load of upholstery remnants out of the block. I had the head hot tanked and rebuilt the water pump. I also had the radiator check out by a rad shop but not very well apparently... I'm going to try the pressure washer on the block and while I have the radiator off. I think I've made some progress though. I used some nasty potassium hydroxide liquid and left it in there for a day. I poured some how water through the rad tonight and the whole core felt warm, not just the upper portion. The water pump drive gear didn't look very worn when I had it out. I'm going to price a new one and if not too expensive, change it out.

Link to comment
Share on other sites

  • 3 months later...

Update: Pulled the head, pressure washed the block cooling passages (there was still a lot of crud in there) and installed re-cored radiator. Overheating problem solved! In addition, to try and decrease the water pump drive gear backlash, I removed the drive gear housing-to-block gasket and used some permatex gasket maker instead in an effort to decrease the distance between gears. This appears to have eliminated the noise even though some backlash still exists....

Link to comment
Share on other sites

Hello Mike. Glad to hear you are making progress. I have been wondering if the head gasket is hardly used can it be used again on these very low compression engines? I know the Austin 7 you can but not sure about the Dodge with only 50 psi.?

Ray.

Ray if the gasket is a double copper that is copper all pver on both sides an no breakes around the fire ring than clean with mineral sprits spray a generous coat of silver paint let tac an than another while wet install and tighten in usal way and retightin after engine is hot. I have done this many times with out any problems but the gasket must be clean and unmarked around the fire rings,40 to45 lbs is usally enough than after 300to 500 miles tighten again . Bob

Link to comment
Share on other sites

That sounds sensible, Bob. They don't come cheap these days. In my youth when head gaskets were much cheaper (even in real terms) I didn't have to buy them because my Dad worked for a firm who made them! Of course that place was closed down long ago over fears of using asbestos and the firm wouldn't invest in non hazardous alternatives because there was no money in it.

Do they still mine asbestos on Oz, Bob, or has it all been stopped? Some of my Dad's workmates who handled the stuff died from it.

Ray.

Link to comment
Share on other sites

Just to show how delicate the baby Austin 7 engine is by comparison the head is bolted down with only 18 pounds per sq. inch! Then again it's only 7 hp and produces just over 10 bhp max and couldn't pull the skin off a rice pudding!

I hadn't heard of the silver paint method either. I guess re using a head gasket could be a contentious issue with some guys applying present day practise to these ancient machines. Early cars may have their drawbacks but I think they were a lot more user friendly than now.

It's all a trade off I guess.

Ray.

Link to comment
Share on other sites

That is interesting Ray. It reminds me of the little engines in Crossley cars that were built over here. Did you mean 18 in-pounds torque above? Or maybe 18 ft-lbs? It's hard to imagine a head being torqued to only 18 in-pounds. I figured at the cost of a new HG (~$100) it was worth trying to re-use the not very old one on there.

Link to comment
Share on other sites

That is interesting Ray. It reminds me of the little engines in Crossley cars that were built over here. Did you mean 18 in-pounds torque above? Or maybe 18 ft-lbs? It's hard to imagine a head being torqued to only 18 in-pounds. I figured at the cost of a new HG (~$100) it was worth trying to re-use the not very old one on there.

I thought that might get a response! Of course I meant lb ft not psi!

The recommended max. torque tension, on dry threads, for 5/16" EN16T cylinder head studs and nuts @ 90% yield is 18.53 lb. ft. An old hand at A7 engines says he never exceeds 15 lb. ft. which equates to about 80% yield stress and that seems to be enough. Most Austin Seven engines suffer from having been over tightened in the past so head studs/nuts are generally renewed as a matter of course.

Talking of Crossley in America I would think of Willys Knight etc through the tie up with Willys Overland.

http://www.crossley-motors.org.uk/

Everyone thinks Henry Ford invented the production line but he got the idea from Crossley who were the first to have one up and running in Manchester. They were also pioneers of the 4 stroke engine in England having obtained the Otto Patent rights.

Ray.

Edited by R.White (see edit history)
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...