L31 350 installation questions

[Quikshft]

I received my crate from Jegs - $1899 and free shipping to my door, not a hitch in the transaction and I can recommend them.

I'm putting this in my '71 4WD with an SM465. Staying pretty low tech, no fuel injection and in fact I had a Rochester two barrel on my previous engine that I'm planning to stick with. I have a new flywheel, a melonized distributor gear, a Holley Might Mite electric fuel pump, etc.

Question - I had assumed since this is just a small block Chevy engine that I could put an early timing cover and balancer on it, and then use the original brackets for the alternator and power steering. The new plastic timing cover doesn't have a timing mark and I'd like to put a timing light on it if I want. I believe the balancer is 8 inches diameter, the older balancers are 7 inches? Not opposed to getting a 7 inch balancer if that's what it takes. What experience is out there???

[B. W.]

You can install a steel cover on your L31.

You SHOULD be able to run an early style crank damper so you can use a short water pump & original brackets but I have not done this. If you don't mind, keep us posted on what part # damper you use.

https://www.crankshaftcoalition.com/...er_replacement

[Jrainman]

I am no expert but when I installed my L31 crate engine my timing cover did have a mark as well as my Damper ,I used 8 inch timing tape on the Damper , and went to my local junk yard and pulled a serp setup off a 98 model chevy truck for $80.00

being you got the weighted flex plate for the one piece seal and the rear of the crank is externly balanced you are ok ,but when you change over to a 7 inch stlye damper ,I dont think it will effect the balance of the crank because the front of the crank is internly balance but will this effect your warrenty on your new GM L31.

[Ol Blue K20]

I believe you'll have to change to a newer intake manifold though.

[6T7 C10]

Congrats on the new engine. The L31 does have a timing mark molded into the timing chain cover. Granted it is not all that but it will get you close enough to fine tune later. There is adding timing tape to the balancer route too. Check the cover to see if it has an open whole on the bottom for a sensor. If it does you will need to plug it or a stock OEM cover without the hole is part #12562818 which is what I did.

Other than using an adapter I am not aware of a two barrel carb intake manifold for vortec specific heads. A nice 0-5000 rpm dual plane intake and a 500-600 cfm carb will make a nice combo.

I went this route a year ago and am well pleased. Holler if you run across any more questions.

[truckster]

On my L31 I used a Cloyes double roller chain, stamped metal timing cover with a bolt-on timing tab, and a stock 8 inch harmonic damper for a 72 SBC 350. Everything went together easily. I did use a piston stop to verify TDC on the timing tab..

[dfosh]

67C10 , How did you do heater hoses ? I have heard about a water bypass ,could you post some pics? Thanks

[6T7 C10]

Here is an engine shot. Yes a bypass is needed. In my case the heater core acts as the bypass. Even a looped hose would work or a couple 1/8" holes in the thermostat would work. You just do not want to plug up all the outlets in the intake manifold and totally stop circulation while the thermostat is closed.

[Quikshft]

Originally Posted by truckster

On my L31 I used a Cloyes double roller chain, stamped metal timing cover with a bolt-on timing tab, and a stock 8 inch harmonic damper for a 72 SBC 350. Everything went together easily. I did use a piston stop to verify TDC on the timing tab..

Truckster did you run original accessory brackets with this set up??

[davischevy]

It will be a minor deal once you get to it, but the exhaust manifolds dump at a different angle. The down pipes will have to be redone.

[truckster]

Originally Posted by Quikshft

Truckster did you run original accessory brackets with this set up??

I'm using a serpentine setup, but the difference is in the crank pulley, not the balancer. If you want to use a 72 balancer you need to remove the reluctor.

[Mr_Rich]

Nice! Wouldn't you want to keep the heavy 8" balancer with a heavy flywheel on the back end of the engine? When you mentioned you were thinking about a 7" balancer I went looking in my spare parts. I have a timing tab that I used on an engine with a 6" balancer and it might work on a 7", but it would be close. I'm mentioning the part in case there's a need.

[Quikshft]

Originally Posted by Mr_Rich

Nice! Wouldn't you want to keep the heavy 8" balancer with a heavy flywheel on the back end of the engine? When you mentioned you were thinking about a 7" balancer I went looking in my spare parts. I have a timing tab that I used on an engine with a 6" balancer and it might work on a 7", but it would be close. I'm mentioning the part in case there's a need.

Yes, ideally there's a way to make the balancer I have work with a steel timing cover. I think I'm just going to have to get the engine on my stand and see if I can't add the parts to see what is actually going to be required.

[Mr_Rich]

Originally Posted by Quikshft

Yes, ideally there's a way to make the balancer I have work with a steel timing cover. I think I'm just going to have to get the engine on my stand and see if I can't add the parts to see what is actually going to be required.

This was my truck project 5-6 years ago. I had the timing cover for a long time because I was storing this engine in my garage when I had time for my project. I was able to order the timing tab at the dealer during the project. I don't remember the part number unfortunately. There really isn't much physical difference between these engines except for the Vortec heads. My engine was early '90's TBI 350.

[dell72]

I have converted several L 31 350's to a steel front cover. I drilled and tapped the two missing timing cover holes and installed the dowel pins (pioneer brand) to locate the tin timing cover. I also used an older style balancer to get rid of the reluctor wheel.

[D.PASSMORE]

Did your the reluctor wheel come with the motor? I haven't uncrated mine yet.

[Quikshft]

Originally Posted by D.PASSMORE

Did your the reluctor wheel come with the motor? I haven't uncrated mine yet.

Yes it is already installed. Just pull the balancer and timing cover and you can retrieve it.

I think these are the timing cover options - there is actually a plastic cover available without the sensor hole in it. Then of course you can use the one that came with the crate and plug the hole. Or, you can use a metal timing cover which works fine once the reluctor wheel is cut down.

Since I used a metal cover from another engine I verified the balancer timing mark was at Zero on the timing tab at top dead center, something else to watch for so that you can time your engine accurately.