Ive got a hemi that has been sitting for approx 20 yrs in a heated shop that I am going to be using in a restoration car right away.Everything is clean and lots of assembly grease inside,Ive got all the tin off the motor right now for inspection.2 things concern me,should i replace the valve springs because some of them have been compressed all this time? the other thing is I removed the double roller timig set to check for numbers on the camshaft (none were found) and it was really tight coming off,no deflection at all in the chain,its been a while since I put a motor together(years) ,but the timing chain seemed abnormally tight.Should I change the springs and timing set?The car is a trailer queen /weekend cruiser so its not going to be turning 7000 rpm at the drag strip if that matters.

What do new gaskets cost? 50 to 100 bucks? If it was a 318 id say fire it, but take a hemi apart that has been sitting that long.

anything that has sat for 20 years must come apart. the fact that you didn't assemble it back then and have no knowledge of it's internals make it a double must.

Pre-oil it and run it.

I don't like the idea of some valve springs being compressed all that time. I take the rockers off every time my motor sits for more than 3 months.. If it wasn't for that I would prime it and fire it.

20 years is a fairly long time. It might be fine, but I wouldnt take the chance. Heck, a mouse could have found its way and made a nest somewhere, you just dont know. The biggest concern I would have would be a valve seizing in a guide, a ring sticking/breaking, or a lifter not rotating. The chain issue is probably no concern. Soak it in a container of oil. Usually they loosen a bit when they "break in" anyway.

Just tear it apart and take a look. Especially on a resto, you dont want to have to do it twice.

MB

On the timing chain, I know the shop that assembled my B engine liked to see them real tight on a new engine. That's how mine was set up and no problems.

The chain will loosen up in the first 5 mins it runs.

Did you biuld it or know for sure it came from a know shop. I am with Fred on this one. beening that its 20 years old its going to be Vintage parts who knows what someone has gone they dont make 64-71 parts anymore. The new stuff dosent look the same as the old parts Ken

Any more thoughts on the if the valve springs will be okay? I will try and remove a couple tomorrow and have them checked at a local race shop so I can try and figure out what would be a suitable replacement if neccesary,they are light green in colour,double spring with a dampner.The intake manifold is not cooperating as to its removal at this point.How do I prevent or check to ensure a valve doesnt sieze in the guide? completely dissasemble the heads and have the clearances checked? there are no hemi familiar shops in my area ,the one race engine guy in town here can be slow and very,very,spendy.

Run it.

I have twin 454's in my boat, its been together for 20 years. I run it up to an hour at a time at max torque. Been sitting for 3 years, I just started it up 2 weeks ago and it ran fine.

Heat & fatigue kills springs, not static compression.

I'd at least pull the heads and disassemble them. If they were rebuilt there is a very good chance that the valves will stick after all these years. Whaty's the engine worth?, as stated above, gaskets are cheap. Dave

Deep down inside i know it should come apart I suppose,I dont like the idea of running an unknown camshaft in a resto either,the front of the cam didnt have numbers,maybe the rear will?
I'll pull the heads and take them in,how much clearance should the guides have on a hemi?
Are the headgaskets reusable? they are steel shim and I have several new sets here so it doesnt really matter,I had heard as long as the engine hasnt been run they can be reused.Anything else I should specificly check?
The cam gear on the timing chain has a casting date of 1982,maybe its even been close to 30yrs its been sitting, the former owner of the engine as well as the engine builder are both deceased now so I have no way of knowing.

Use new head gaskets. Make sure and coat them too.
I would really like to know what the exact time is that a compressed spring will be expired at. 1 day? 1 week? 1 month? 4 months 2 weeks and 5 days?
Whatever the # is, I'd turn my engine over before that.

a good machine shop will have a cam profiler, that will measure lift and duration, which will tell you if it's a stock replacement or a race cam. then you will know if you want to use that cam, or buy a different one.

A lot of cams have the numbers on the rear of the cam.
As far as stem to guide clearance goes,


.001-.0014 on intake new .0016-.002 on exh new depends on application

my big concern would be the crankshaft plus rod and main bearings being new ,used or incorrect clearances.That can get very expensive if they are wrong or bad. Another factor to consider is the valve seats being corroded or pitted when it sat all those years with the valves open. It would not be a stretch for the rings to be stuck especially with a cast pistons

I had a shortblock that sat for over 20 years. For peace of mind I tore it apart and re-assembled it. I didn't bother checking clearances, etc. because I'd done all that way back when but I did want to make sure the rings were still good and the bearings were still well lubed, etc.. The cylinders needed to be cleaned up but otherwise everything was ok.

I'd try cranking yours over by hand before taking it apart but I think I'd definately be tearing it down. What do you have invested in this car versus the cost of a quick check and re-assemble ?!?!

let me tell you guys a little story, back in the mid 90s I seen an old dodge truck I think it was like a mid 70s. was setting under a tree close to salt water inlet. I stopped and asked about it. I ended up getting it for free. the truck body had rusted off of the chassis almost but the interior looked like new. come to find out it had a 360 in it and thruck had like 6k miles on it when it was parked. the old man had died and it hadn't been moved in over 15 years setting out in the elements close to salt water. I got it home and the motor turned over freely. the gas tank had rotted off. I took the dist out primed the oil pump, cleaned the carb, hooked up a fuel cell. the thing started the first hit, never smoked a lick never made a single noise and ran like a brand new motor. put it in gear and the truck moved. jacked it up and the tranny shifted gears with no problems. this thing ran like a top and I ended up selling the drive train and interior. made a bunch of cash off this old truck. still don't believe it to this day that it ran so good.