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1971 lemans 350 not started in 20 plus years

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1971 lemans 350 not started in 20 plus years

1971lemanssport 1971lemanssport
New User | Posts: 3 | Joined: 06/14
Posted: 06/23/14
08:16 PM

Hope someone enjoys this saga. I have a 71 lemans with the 250 hp, rated 350, with #94 heads and a 2 barrel on it. It has not run in 20 years or more, but has been in and out of storage at different times. In 1990, I put headers on it, replaced the 2 bbl. carb. and changed the cam and lifters back in 1990 and then the keys got lost. I went on with life and time got away. It has not been started since then. No I am not kidding! I just recently came across a running pontiac 350 with an unknown cam, #46 heads, edelbrock performer intake and carb and believe it to be a 73 or 74 model. The idea was to just swap the running motor for the one I never got started to at least get the thing moving again. 2 weeks ago my neighbor asked me if the car ran. I told him not in 20 years plus. He said I should try to get it started. Just for grins, I pulled the plugs and put some marvel mystery oil in the cylinders. I put a ratchet on the crank and it turned. I fig'd it would be locked up. At the same time, a 2 barrel off of a running motor became avail. from a neighbor with a 67 lemans that did an intake swap. The existing motor was never started with the new cam(now 24 years old), and thus the cam has not been broken in. At this point, I am trying to figure out if its even worth the trouble to swap the running 2 barrel carb, change the oil and flush and refill the cooling system and try to get it started. The hope would be to get it to run at 2000 rpm for 20-30 minutes to break in the cam. It could also be a really poor idea... Looking for thoughts, ideas and opinions.  

shyrgfuh3 shyrgfuh3
Enthusiast | Posts: 496 | Joined: 11/13
Posted: 06/23/14
08:29 PM


ok i'm lost.

is the eng in the car brand new and has never been started until recently?

if so, how long did it run?

what type of oil is in it?

did you prime the pump?

what type of lifters?

how long did you run it?

hoe big is the cam?

what is the spring rate with the valves open?

is it flat tappet or roller?

if its new and you just ran it for a few minutes the cam might be damaged.  

1971lemanssport 1971lemanssport
New User | Posts: 3 | Joined: 06/14
Posted: 06/23/14
09:41 PM

The engine that is in the car is the original with 108K miles. It was not brand new. It ran ok, but backfired through the carb sometimes. I replaced timing chain, carb, plug wires and plugs, but it would still miss when you accelerated. Someone suggested perhaps the cam was flat.  That gave me a good reason to change the cam and lifters and put headers on it. I put a new cam and lifters in it in 1990. The keys got lost, other issues cropped up, and time passed. It has not been started since 1990, so the new cam has never been broken in. The cam was/is a hyd erson tq20, .449 life, 214 duration at .050, 110 degree lobe, and I installed trw lifters. I did not put new springs on, so they are most likely stock and original. I know now that new springs were probably needed, but at this point, if the springs are weak that may be ok if I even try to proceed to break in the cam.

I have only turned the engine by hand and it spins well.  

shyrgfuh3 shyrgfuh3
Enthusiast | Posts: 496 | Joined: 11/13
Posted: 06/23/14
10:02 PM








bigD bigD
User | Posts: 155 | Joined: 05/14
Posted: 06/24/14
03:25 AM

You say the original motor has over 100k miles. Back then, that was considered almost wore out. I would not try to crank it. If the running 350 you mentioned is cheap, I'd buy it and put it in your car to get it running.

Then, you can decide what to do with the original 350. If you wanna restore your car to original, with a numbers matching motor, you can rebuild it to near stock specs or just use the block and build a high perf motor.

But, at this point, I'll have to say, there are cheaper ways to make power, if you are not concerned with originality.

350-400hp is easy with a 400 or 455 block. It just depends on exactly what you want. Smile  

1971lemanssport 1971lemanssport
New User | Posts: 3 | Joined: 06/14
Posted: 06/24/14
03:28 PM

The 350 Pontiac in the car has not been started, only turned by hand to determine if it would spin 2 weeks  ago.

The initial thought was that if the motor spins, then maybe I could get it to start. I think I would like to start it if it is even a good idea. If it turns out it runs absolutely awful

Because I have just acquired a 2 bbl off a running 326 lemans, I was going to bolt it on, to get it running.

I was also going to double check the adjustment of the valves. I don't exactly remember how I adjusted them then.

Concerning the burnt valve possibility:
If a compression leak down test checks out on all cylinders, then what is the downside to trying to get it started?

Is it worth the risk to possibly ruin the cam?

What are the suggestion to get it started?

I remember putting the moly paste on the lifters and cam only 24 years ago, but who knows...

I was thinking get some break in oil and add a zddp additive?

Prime the oil pump, use fresh gas obviously, and antifreeze, new plugs and wires.

Opinions are appreciated. Thanks.  

gtojack1366 gtojack1366
Guru | Posts: 1278 | Joined: 11/09
Posted: 06/24/14
03:46 PM

Go ahead start it up .It sounds like you know what your doing . You could take a cold compression test first to see if you have any dead cylinders .  

76Tranz 76Tranz
User | Posts: 170 | Joined: 01/10
Posted: 06/25/14
07:10 AM

Start it up! Old Pontiacs are tough, it might surprise you and run just fine! What have you got to lose? What's the worst that could happen? Rebuild? You've already found another motor in case that happens, go for it, the fun can only begin, if you don't, the "what if" will worry you to death....go for it!