Buying a LT1 motor what should I listen and look for

1249 Views 6 Replies 2 Participants Last post by Workman, Mar 10, 2013

gvincent

Discussion Starter · Mar 8, 2013

I am thinking about buying this Lt1 motor and would like some advice on what to look for and what to listen for that would indicte a serious problem.
This is the motor description and what it is currently doing.

Lt1 350 with ported heads and intake. Lt4 hot cam, 1.6 roller rockers. Pacesetter mid length headers and magnaflow cat back. Msd optispark, Taylor ignition wires, recent spark plugs. Cold air intake. PCM4less tuned ecu. Car put 319 horsepower to the rear wheels on a mustang dyno. Was told motor had about 10k on a rebuild when I bought the car and we've put another 20k or so on it.

and now being New England these cars sit all winter and was recently started and run. This is what the owner said:

Fired it up this year (2013). Was going to trade it whole for a truck but started running hot and drinking coolant this morning.

It's never overheated but always ran at 160, was a pretty constant 210 Sunday when we had it out. Not dripping anywhere, puffs white at idle, and pressurizes the coolant hoses right away on a cold start. Not positive but I'm pretty sure it is a head gasket.
I'd compression test it if it wasn't such a pain to get around the headers. I'm just at the point where I've had enough. If you are still interested I'll let it go very cheap if we get to that point.

for now the oil still looks clean but who knows. I'd advise going through it to be safe but entirely up to you. If it comes to a part out I'd probably ask $500 for it. Heads, hot cam, roller rockers, I'd give the harness, ecu, all accessories, everything. At that price I'd include the msd opti too. It's not on it. Needed a cap/rotor so I put an eBay opti on it for the end of last season.(2012)

So what do you guys think I should expect?
Puffs of white smoke =New head gaskets?
I there is Coolant in the oil would mean trashed bearings right?
Take a valve cover off and look for rockers? what should I see? Aluminum rocker arms? are there stamped steel 1.6 rocker arms?
Need help, I just wanted to do a straight swap of the stock LT1 in my 280Z

See less See more

Save

1 - 7 of 7 Posts

Workman

· #2 · Mar 8, 2013

Okay If i were you,
1) Take off the valve covers, I know its a little time consuming but you need to look for burnt up valves, Youll be able to tell bcuz they will be black as tar and while the valve cover is off you can look for scratch marks on the push rods and also metal shavings and also you can see if any lifters are loose(Kinda hard to hear that slight tick with headers)
2)Check the coolant itself, Take off the radiator cap (when the car is cool) and check for Browness in the coolant and also check for Bubbles. ALOT of bubbles can mean a BAD BAD head gasket.

Honestly if the oil still looks clean, (Like no shavings, no slight motor knock etc....) Then i would say that your bearings are okay right now.
But if you are sure that it does have a bad head gasket and it meats the criteria, replace it.

And puffs of white smoke dont always mean head gasket, could mean possibly worn piston rings as well.

Save

Workman

· #3 · Mar 8, 2013

And to add to that, The LT1 motor in my humble opinion is one of the best motors out they're. I would buy it and fix it while its out of the car. Its block is stronger than an LS1 witch means, NOS. I dont care what anyone says, My friend had a STOCK LT1 with a 100 shot of NOS and ran it HARD for 50k miles before selling it. And that motor is still running STRONG today. I know the owner personally. Lt1 is also Crazy torquey. ALOT of fun.

Save

gvincent

Discussion Starter · #4 · Mar 8, 2013

Thank for the help Workman, I am trying to educate myself quickly.

Workman said:
Okay If i were you,
1) Take off the valve covers, I know its a little time consuming but you need to look for burnt up valves, Youll be able to tell bcuz they will be black as tar and while the valve cover is off you can look for scratch marks on the push rods and also metal shavings and also you can see if any lifters are loose(Kinda hard to hear that slight tick with headers)

So should all the lifters be tight or is some wiggle ok just not real loose floppy like.
Also is it easy to tell the difference between 1.6 rocker arms and the stamped steel factory ones? there is no way to check to see if it does have an LT4 Cam without removing the OPTI and chain drive cover right?

2)Check the coolant itself, Take off the radiator cap (when the car is cool) and check for Browness in the coolant and also check for Bubbles. ALOT of bubbles can mean a BAD BAD head gasket.

The Bubbles also when cool or when running with the cap off and thermostat open and up to temp?

Honestly if the oil still looks clean, (Like no shavings, no slight motor knock etc....) Then i would say that your bearings are okay right now.
But if you are sure that it does have a bad head gasket and it meats the criteria, replace it.

And puffs of white smoke dont always mean head gasket, could mean possibly worn piston rings as well.

Piston rings on 30K+ motor according to owner? Would a broken ring do puffs of smoke or continuous smoke.

Is replacing a head gasket hard to do? I read the intakes need a lot of sealer in the rear where they are prone to leak when re-assembling. Have heads checked for flatness and valves checked for seals and seats while they are off, Make sure that I number push rod tubes while removing or leave them in place.

Save

Workman

· #5 · Mar 8, 2013

Yes your doing fine,
AND NO! do not bring it up to operating temp and remove that cap lol, talk about hot.
Remove the cap when cool and then start it up, and just keep an eye on it for a few. If alot of bubbles start coming up, head gasket is leaking. AND I DO NOT recommend head gasket stop leak at all.
And Honestly, In my opinion you can probably replace it in a weekend. But its not a task for the Novice change your own oil and wiper blades kinda mechanic.
If you have a book or a good referenced website that guides you step by step then go for it. Itll be a great learning experience for you.

The lifters should not be able to flop around like, you shouldnt be able to pull both sides up and see under the touching points. They should be fairly tight, BUT NOT TOO TIGHT.
And yes, 1.6 rockers do look different then factory. A great way to tell in your situation is think with your head----> what would an old rocker arm look like with the mileage this engine has on it, and then think what would a good new rocker arm look like on here. ORRRRR (take a picture and post it on here for us to see)
And honestly man,
to answer your question about the cam, rockers wont make that car have that amount of horsepower a cam will. Drive it and see.
Unless you just want to take the cam out and check the stamps on it.
and a broken ring would make your horsepower suck, and blow smoke smoke and more smoke. Trust me from experience.

I hope im helping you out friend.

See less See more

Save

gvincent

Discussion Starter · #6 · Mar 9, 2013

Thanks Workman, yes you have been a ton of help, I am going to pop the valve cover off the Stock LT1 I have with the bad knock and take a picture of the stock lifters to have with me. I'll take pictures of the engine and post them.
I also will cut a paste the all the things you mentioned and put them on a checklist to take with me next weekend

Save

Workman

· #7 · Mar 10, 2013

Sweet!!! I hope you find great sucess with your motor!

Save

1 - 7 of 7 Posts

This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.

Top Contributors this Month