Chain tensioner
- Thread starter Mopar&vettedude
- Start date
Oldiron440
Well-Known Member
Usually
6thGenImperial
Well-Known Member
Even when they're identified as a "quiet" gear drive, you can still hear them, but I gotta say, I have always enjoyed the whine of the factory gear drive on my '96 Harley Evolution engine. Just loud enough to add to the mechanical ambience. In the follow-on engine, the Twin Cam, they switched to chains, but if I were to ever get one of them, first mod would be a gear drive.
Oldiron440
Well-Known Member
I've seen the timing bounce 4 or 5 degrees at idle with a gear drive, making them hard to time.
I had a question asked me about the police engine oil coolers – that spray oil onto the timing chain.
Here is a picture of the system. This is from my ‘77 and '87 parts manual – sense the pictures make a bit more sense when looking at them, than pictures do (or to me, anyway).
1977 F/M-body
1977 B-body (for reference)
1987 M-body
The oil coming from the oil cooler travel via a hose, then to a short piece of pipe. The pipe then connects to a hollow bolt. This bolt replaces one of the fuel pump mounting bolts – and looks really odd. Chrysler calls this hollow bolt, a “nut” for some reason. Because this hollow bolt does hold on the fuel pump – it is fairly easy for it to break when installing a fuel pump.
Small blocks use this hollow bolt (nut) in the rear bolt hole of fuel pump. Big blocks use the front bolt hole.
The problem is the hollow bolt has a tendency to break and very hard to find and has been out of production by Chrysler sense about 1990 (or so).
In my garage, somewhere, I have a mostly complete police engine oil cooler setup (and part of another), less the hollow bolt. Once I figure out how to make replacement bolts – I’ll install a cooler setup on both cars.
If someone would make some new bolts – I’d buy 20 right away (only I don’t have any bolt parts to use as a pattern).
My ’77 parts manual show the fuel pump bolt (called a Nut, Fuel Pump) to be part # 4071712
My ’87 part manual shows it to be # 6031741 (called a Screw, Fuel Pump, in this book)
Both part numbers have long been discontinued.
BudW
Here is a picture of the system. This is from my ‘77 and '87 parts manual – sense the pictures make a bit more sense when looking at them, than pictures do (or to me, anyway).
1977 F/M-body
1977 B-body (for reference)
1987 M-body
The oil coming from the oil cooler travel via a hose, then to a short piece of pipe. The pipe then connects to a hollow bolt. This bolt replaces one of the fuel pump mounting bolts – and looks really odd. Chrysler calls this hollow bolt, a “nut” for some reason. Because this hollow bolt does hold on the fuel pump – it is fairly easy for it to break when installing a fuel pump.
Small blocks use this hollow bolt (nut) in the rear bolt hole of fuel pump. Big blocks use the front bolt hole.
The problem is the hollow bolt has a tendency to break and very hard to find and has been out of production by Chrysler sense about 1990 (or so).
In my garage, somewhere, I have a mostly complete police engine oil cooler setup (and part of another), less the hollow bolt. Once I figure out how to make replacement bolts – I’ll install a cooler setup on both cars.
If someone would make some new bolts – I’d buy 20 right away (only I don’t have any bolt parts to use as a pattern).
My ’77 parts manual show the fuel pump bolt (called a Nut, Fuel Pump) to be part # 4071712
My ’87 part manual shows it to be # 6031741 (called a Screw, Fuel Pump, in this book)
Both part numbers have long been discontinued.
BudW
I’ve not measured them to know 100%- but I’m 92.7% sure all of the fittings and pipes are normal pipe thread – including the female part of the fuel pump bolt.
BudW
BudW
Mopar&vettedude
Well-Known Member
So im finally getting around to putting the timing chain on the 318. Ive already installed the mp tensioner, but notice trying to put the double roller timing chain on its a super tight fit. the chain is already making contact with the tensioner and i haven't even pulled the pin to set the tension on it. I'm starting to second guess this thing. Any suggestions?
Mikes5thAve
Well-Known Member
It's supposed to make contact with it. The pin is to hold it back to make it easier to install.
When I did my chain it was when the tensioner was just starting to show up as an add-on for older engines and at the time everyone on forums said don't run it. Now it seems to have changed and everyone is using them.
When I did my chain it was when the tensioner was just starting to show up as an add-on for older engines and at the time everyone on forums said don't run it. Now it seems to have changed and everyone is using them.
Mopar&vettedude
Well-Known Member
Are you running a double roller as well or did you just stick with stock?
XfbodyX
Well-Known Member
No need to source any cop parts and do alot of un needed work, folks have been using the easy fix for chains and gear drives for years.
Just drill a small oil hole in the galley plug behind the cam retainer plate as well as the cam retainer plate and you can have pressurized oil to the chain or gear or gear drive. Id have to look at the size most use but its tiny.
Everyone I know including myself do this mod when using a GD. Its the norm.
You can also do the same with a small metal line if you want it in a certain area, all under the T chain cover.
Ive never seen a cop car bolt deal on any hot rod, drag car or anything but a cop car, just seems like alot of work when the fix is very simple.
But id also ask this question, with no mods, even after they did away with the one hollow bolt on the cam retainer plate can ANYONE post a pic of a gear or chain that physically shows it was overheated? Ive broke one non mopar T chain in my life, it was a oem cheap chain with 40k miles of hard running when the fun thing in town was to be on and off the gas in low gear barking the tires. I will put it this way, I killed three pro built turbo 400-s (broke one case) before I had T chain trouble.
Id understand the cop car deal with some sitting at idle for hours and hours but remember the oil slinger and the soaker gasket/lower gear with it get oil from stop and go. If you ever wonder how much, leave the slinger out and try just running with the front cover seal. Keep a couple extra quarts in your rig, youd need them.
Alot of the oem tech of the 70-s ect has been debunked and changes made.
Just drill a small oil hole in the galley plug behind the cam retainer plate as well as the cam retainer plate and you can have pressurized oil to the chain or gear or gear drive. Id have to look at the size most use but its tiny.
Everyone I know including myself do this mod when using a GD. Its the norm.
You can also do the same with a small metal line if you want it in a certain area, all under the T chain cover.
Ive never seen a cop car bolt deal on any hot rod, drag car or anything but a cop car, just seems like alot of work when the fix is very simple.
But id also ask this question, with no mods, even after they did away with the one hollow bolt on the cam retainer plate can ANYONE post a pic of a gear or chain that physically shows it was overheated? Ive broke one non mopar T chain in my life, it was a oem cheap chain with 40k miles of hard running when the fun thing in town was to be on and off the gas in low gear barking the tires. I will put it this way, I killed three pro built turbo 400-s (broke one case) before I had T chain trouble.
Id understand the cop car deal with some sitting at idle for hours and hours but remember the oil slinger and the soaker gasket/lower gear with it get oil from stop and go. If you ever wonder how much, leave the slinger out and try just running with the front cover seal. Keep a couple extra quarts in your rig, youd need them.
Alot of the oem tech of the 70-s ect has been debunked and changes made.
I used a double roller with the tensioner on my last small block build. Worked fine, but yes, installing it can be a pain.
As already mentioned, make sure you have the oil slinger that slides onto the crank snout. This will toss oil up on to the chain while keeping it off the timing cover seal.
Mikes5thAve
Well-Known Member
Double roller.
The 2 things that I didn't like when I was trying to decide was the chain constantly rubbing on the nylon and what kind of added wear the chain might get always having pressure on it so since the forums said not to bother I didn't.
With a new chain the timing should be pretty solid. It's when they start to wear over time that it tends to jump around a bit and that's where the tensioner helps.
Since you've already installed it leave it and don't think about it anymore. Enough people are using them that if they caused catastrophic problems we'd hear about it.
XfbodyX
Well-Known Member
As long as your under #500 open they are great, a real heavy spring and the cheap bastards will flex, maybe with the 4th drilled and bolted it might not.
The cheap metal will wear before the nylon will. Even the most abused one ive got the nylon didnt tear up too bad and hardly took the ano off the chain. But this is with a rollmaster gearset, the cloyes and sa gear type chains are ok too but not nearly as HD for the small price difference.
On some chain covers if it goes on hard, you may need to trim 1/16 wide x 1/4 long off the bottom edge of the nylon adjuster.
If you use the bolt with the hole dont forget the lil oil ramp to the chain as well.
The cheap metal will wear before the nylon will. Even the most abused one ive got the nylon didnt tear up too bad and hardly took the ano off the chain. But this is with a rollmaster gearset, the cloyes and sa gear type chains are ok too but not nearly as HD for the small price difference.
On some chain covers if it goes on hard, you may need to trim 1/16 wide x 1/4 long off the bottom edge of the nylon adjuster.
If you use the bolt with the hole dont forget the lil oil ramp to the chain as well.
Mikes5thAve
Well-Known Member
How much mileage was on that tensioner?
XfbodyX
Well-Known Member
About 6k street miles, run hard every time out, at times over 7k, 3-4 minutes at a time.
Mikes5thAve
Well-Known Member
That's not much use. It would be more interesting to see what they look like with 50-100k on them.
XfbodyX
Well-Known Member
A stocker will be worn alot more with that many miles 100k, at least the ones ive torn down.
The one I posted is about as abused as one can get with over twice the spring pressure then oem and crazy rpm so lets think, would that put more tension on the chain, I think it would????
The bracket is softer then the nylon, the nylon isnt worn in this pic but the metal is grooved from the nylon.
The one I posted is about as abused as one can get with over twice the spring pressure then oem and crazy rpm so lets think, would that put more tension on the chain, I think it would????
The bracket is softer then the nylon, the nylon isnt worn in this pic but the metal is grooved from the nylon.
XfbodyX
Well-Known Member
Looking at that pic, I wonder where a oem chain allows the nylon tab to sit on that pad?
Mopar&vettedude
Well-Known Member
Did you double up on the oil slinger?
