Timing chain touching block 440 ?

Upon inspection of a C440 I noticed the chain was very close to the block. I pulled the gear and you can see in pic on the left only it is hitting barely and where gear itself touches block at cam it seems to be only riding on the left half 1/2. I don't build lots of engines so not sure if this is something terrible block shift deal or if there is an easy fix.

Suggestions?

Thank you

Some moron didn't get the gear seated and bolted it on cocked.

I just went out and tried another gear set and same fit.

I couldn't tell much from the pic (I had the same prob with my hi tech Samsung mini camera till I engaged the flash function but at least it ain't ever caught on fire (yet), the picture looked OK on the camera screen for the split second it shows when snapped but then when later transferred to the computer it is dark. You are saying with the crank gear on by itself (no chain) that it is tilted, with it seated all the way in on the crank snout? EDIT I reread & you're talking about the cam potentially tilted and yes I can see the shiny left half. I dont have much to add but I would continue with a small straightedge to try & see see what surface is tilted. I would suspect the cam and or gears before the cam bore alignment. If the rest of the valvetrain is out/loose I would rotate the cam to 90 intervals & see if that tilts a straight edge on the front face of the cam itself. Keep us updated

Had this issue on a couple of builds with double roller chains.
I just grind those casting 'circles' flush to the rest of the block.

You could check proper alignment of upper and lower gear.

Problem isn't the kiss at the casting flash circles, that's a common issue easily fixed.

The problem is the poor machining on the front cam journal where the gear is rubbing on the pass side ONLY. Does the cam turn freely in the block? If so then it's probably not a journal alignment issue.

Or the face of the front cam journal isn't machined square with the centerline of the cam.

That was my thinking as well.

Well here's another thought. I'm not sure if that gear face is level with the timing cover surface but if I was designing and engine for mass production I'd want one pass with the grinder to hit both surfaces. That said, it's possible there wasn't enough material on that gear surface to be machined completely so the grinder only hit the high spot. So the gear still turns properly it just doesn't have a full thrust face to ride against. But you can't change that because that surface determines proper gear/chain alignment. Another problem is the gear is supposed to be lubed by that small slot but since the gear doesn't come near that slot its only going to get splash - probably the cause of the excessive wear on the thrust face.

As for the outer marks from the chain, possibly just high casting flash. Grind 'em down and be done with it.



I'd be bolting a gear on there and making sure it has no wobble when the cam is rotated.

Thanks I will jump back in tomorrow and check all suggestions.

I would buy one of the better racing timing sets that have the built in Torrington bearing and thrust washer to prevent the cam gear from rubbing on the block

Not the fault of a cocked gear or the face of the cam not square with the journals, the gear would be hitting the thrust surface all the way around. Looks like the face of the block is machined wrong.

THIS ^

http://www.manciniracing.com/mabhethbowit.html

That /\ looks like a nice fix , will this fit behind a stock cover still?
Thanks ozy / cab

http://www.manciniracing.com/manbrbhemthr.html
This is the one I just bought and it hits also, not its fault either.

I believe NANKET is right on there about the block

My Australian made Romac Rollmaster timing chain came with the torrington bearing. Superb quality. Its not listed on the website but I believe summit racing sells them

Chrysler Big Block

CS5150 Gold Series V8 361-440ci
3-Bolt cam with Torrington Bearing and Nitrided Sprockets

With the face of that journal improperly machines a torrington setup will not work properly either.

It'll ride on the pass side just like the regular gear did.

Will do thanks for tips. Never have had luck with taking quality pics.

If the cam of gear face was off somehow, the wearmarks would show up on the other circles to as the 'wobble' would rotate around with the cam/gear.

I have never had the cam/crank area or the block machined, is this a normal process when machining/boring a block?

not at all. EDIT as in it is extremely rare to have an issue there

Did ya check to see if the bolts were bottoming out and letting the cam gear a hair loose?

Only if the other surfaces are the same height as where its contacting now. And since its a casting, they probably are not.

Bottomed out gear bolts is possible but I would think the chain would keep the sprocket in line.

The machinist that bored the cam holes into that block did not have the boring bar square to the block so all the cam bearing supports are drilled at a slight angle. This causes the cam to be installed not square to the block face causing your problem. If it were mine I'd grind the casting off where it is rubbing, then cut an oiling line at the front of the block where the gear is rubbing to facilitate lubrication. Look at the 3 o'clock area of the front bearing support, you'll notice a line cut into the block for oiling of the gear. Cut another line like that in the 11 o'clock area to let oil into that area.

RT keep us updated on the situation

If the bolts were not holding the gear tight then the bolts or pin would break before long. Also the gear would be hitting all over from accel to coast and engine braking.

what is the location of the face of the cam with respect to the face of the block.[ does it go in past the edge of the block ?] sitting recessed or is it fwd of the front journal ? what does the rear cam plugs location look like ?

You're kidding, right ?!?!? If this were the case, by the time you get to the rear of the block the lifters would be so out of whack they probably wouldn't last a break in let alone thousands of miles of operation. And I suspect that even back then the boring process was automated, not performed by some guy with a brace and bit!

Hahaha Yeah and the rear end of the cam would be splashing around in the water jacket and rubbing the #8 cylinder bore .

This rubbing is just a sloppy chain or lose gear, no big deal just get a gear set with Torrington bearing. All good.

Check the runout of the face of the cam, or just a straight edge across the front of the cam and make sure it is square. A bit hard to tell from the photo, but it looks like the end of the cam extending from the front cam journal is sticking out different amounts around the front of the cam?

Anyhow, something is not square, if you look at the thrust surface of the block, it looks like the timing chain gear was rubbing more in that 11-O clock position than the rest of the thrust surface.
It really looks like the gear was either cocked, or the cam face is not square?

We're only talking of a few thousandths of an inch here, not 1/8 or 1/4 inch. If it was a loose or crooked cam gear it would be rubbing all the way around where it travels, not just in one location. Since it IS rubbing in one location, there are only two possibilities, either the block is not square to the cam centerline (faced at an angle) or the cam centerline is not square to the block ( drilled at an angle).

It's probably just a machining screwup from day one. I've seen a couple over the years, and it probably had a pretty fat aftermarket chain-gear set on it at one point to dig into block like that. It probably is just a matter of a couple of thousandths. Not sure if I'd put the flat torrington in there either.

a torrington will get lube from splash. much better than steel on steel!

if it were mine, and i didn't want to remove the engine for whatever reason, i would clean up the casting with lacquer thinner till it was squeeky clean, then tape off every surface, especially holes that would lead into the internals. tape a shop vac nozzle close to the area rubbing, then get out the grinder. fire up the shop vac, remove some material, then paint with machinist's dye. install the cam gear and rotate [you will have to remove the rocker gear to do this] a couple of rotations. if there is no indication of the dye rubbing off, you are done. if rubbing is still present, you will have to repeat as necessary. just take a tiny amount at a time. an 80grit 2" disc should work nicely. when done to your satisfaction, vacuum the face thoroughly, give the tape a good wipe with thinner, remove the tape, wash the area again to your satisfaction, then reassemble. if done correctly, no grit will have entered the engine. i'm not sure you need the torrington bearing. just my opinion, nothing more.

Try to picture this, if the front of the cam was not square, the timing gear would hit the block all the way around the face of the block.

This block is being rubbed by the gear on one side only, telling us the block face is machined at an angle to the cam bearing bores.

You're assuming that area behind the gear is the same height everywhere. Its a casting so the chances of that are slim. Its probably just a high spot in the casting, nothing more.

Look closer there is a scrape on the upper left
(11:00 o'clock position) machined surface where the cam gear rides.

The O.P. needs to find out if that machined surface is square.
If it is then the cam bearings are not.

That area is machined, that's where the timing gear is designed to make contact. That's why the factory put the oil slot there.

But if the circular area surrounding the cam was machined at a slant the result would be that the sprocket would not contact the area full circle. The sprocket would STILL be 90 degrees to the cam centerline as its bolted to the face.

I agree with a casting issue. Just clearance the area and move on.

67RT be SURE! to conclude this

Your right, it it was the cam face or timing set not being square, then it would run all the way around. I was not thinking this correctly, have a migrane headache.

That being the case,the cam would have to not be parallel with the block and everything else would be out of whack.If the cam bore is parallel with the block,it would make no difference if the front mating surface was square or not.Since it is a 1967 C440 with a later three bolt cam I seriously doubt those marks were there with the original cam.Also,ever see a cam gear on backwards,I have.

This is going on way too long. OP needs to get his butt in gear and figure this out.

I would grind the 2 high spots and be done with it. The motor has been running for years that way and will run for many more.

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if it was not making noticeable shiny metal in the oil when you drained it don't worry about it now Some things are worth worrying about, some are not