How Hard Is A Rebuild (Hot Air)

[Kaine Beedenbender]

Just got a car that needed a bunch of work to get it running just to find out the engine is shot. Going to have to rebuild. Whats parts can be done at home and what do you recommend having a machine shop do? I am very mechanically inclined but just haven't built out a motor yet.

Any recommended threads showing the rebuild process?

 

[Nick Micale]

...... but just haven't built out a motor yet....

Since you have never rebuilt an engine, this is not the time and place to start to learn how-to.

Just the R&R on a hot air car is very difficult, especially going back into the car.

It is best you take pictures in detail as you remove parts, as some items are very hard to figure out how they all go back together properly.

 

[Squid4life]

Remove everything yourself, tagging every fitting and connector, put hardware in a ziploc bag and mark what all they go to and take a ton of pics of how each bolt/ stud goes, how the harness is routed, how fuel lines are routed, etc.

For the actual rebuild, find a reputable BUICK V6 person/ shop to do it. These motors are very finicky with clearances. You can't just set everything up like your normal v8. You will have no oil pressure and all that work will be for nothing.

Post up where you are at and someone will point you in the right direction.

 

[Grumpy]

$$$$$ pit is goin to be way more than what the car is worth !! BUT I believe we already went down this road when ya got the car. Good luck.

 

[Kaine Beedenbender]

Well i finally got it "running" but it stumbles and misses all over and smokes after it warms up. I guess a last ditch effort before scrapping it would be valve springs and seals. I have replaced everything that should be and it runs like its on 3 cylinders. I have checked that all cylinders are firing. I cant do a compression check if the valve springs are bad or broken, i just don't know if that would cause poor running in the manner that it is.

 

[BRAD_PADGETT]

I am one of the few people who went down the road on rebuilding an Hot Air. All the advice above is dead on. The key for me was the condition of the body and interior. I now have a really nice Hot Air that runs perfect, looks good, and is pretty quick as well. I would be lucky to get back 10 cents on the dollar spent. I obviously am not selling. I do not recommend doing this. I do have all the manuals and the experience beating my head against wall. Eventually the light did go on. Brad

 

[Nick Micale]

....I have checked that all cylinders are firing. I cant do a compression check if the valve springs are bad or broken, i just don't know if that would cause poor running in the manner that it is.

Just the opposite is true, you NEED to do a compression test to find out the condition of the internals in your engine?

I have seen many "shot" engines that just needed minor work to get them running good.

Since you have no experience with these turbo cars, it may be a smart idea to have a knowledgable person check it out first which may save you $$$ in the long run!

 

[Kaine Beedenbender]

Just the opposite is true, you NEED to do a compression test to find out the condition of the internals in your engine?

I have seen many "shot" engines that just needed minor work to get them running good.

Since you have no experience with these turbo cars, it may be a smart idea to have a knowledgable person check it out first which may save you $$$ in the long run!

Very good, i will indeed perform this and report back. Maybe i can get some guidance as this engine seems to be a little different from an NA as all have said. I also read that a vacuum test can determine allot as well. Got some work to do. I have a scope as well so i will get to it next week. Thanks for the advice.

 

[Kaine Beedenbender]

Well looks like good news as far as compression (below). Now each plug had a bit of oil on it, the car smokes especially when warmed up. I get rough running across all cylinders tested. I have pulled each wire and i notice a difference on each cylinder so they are all firing. I am wondering if this is a case of valve springs and seals. Anyone had bad springs cause real rough idle? Thanks!

(1) 146
(2) 150
(3) 145
(4) 146
(5) 148
(6) 149

 

[Nick Micale]

....... I also read that a vacuum test can determine allot as well. Got some work to do. I have a scope as well so i will get to it next week. Thanks for the advice.

Your compression numbers look good, so like you said put a vacuum gauge on it and that will give you more info.

There is a vac line on the back end of the intake that is hard to see and reach down low by the dipstick tube. This is a common place for a leak so you could also spray carb cleaner in that area, and others, to check for a vac leak.

 

[Kaine Beedenbender]

Your compression numbers look good, so like you said put a vacuum gauge on it and that will give you more info.

There is a vac line on the back end of the intake that is hard to see and reach down low by the dipstick tube. This is a common place for a leak so you could also spray carb cleaner in that area, and others, to check for a vac leak.

I decided to take the driver valve cover off and have a peak and test. I read somewhere that a good test of the valve springs is to see if you can spin them by hand, in which i can spin all of them. I read this means they are bad. I have nothing to lose by doing the valve springs and seals. A few bucks versus scraping the car. So i will give it a go. Will report back. Thanks for the help again.

Also connected the compression tester hose up with a compressor to cylinder 1 and the air is leaking out at a good rate. Not sure if this is normal.

 

[earlbrown]

That's not a good test.... BUT!... If you're never changed valve springs, they are too weak.

 

[John Larkin]

Rotate the engine so that both valves are closed. You can see when both rockers are at their highest point. You'll rotate the engine via the nut on the alternator.

Just use a nylon rope to hold the valves up when changing the springs. Disconnect the battery so it doesn't start unexpectedly.

Get the valve spring tool that looks like a rocker arm. Get a good one. The one back by the airconditioner box is a biotch without it. Actually you need a good tool regardless.

 

[Kaine Beedenbender]

Well a good day turned into a not so good day. I thought the piston was all the way up but nope! And away goes a valve...... !@#$%. Officially shelved.... ho hum......

I suppose in some way it isn't the end of the world. The rear main was leaking bad and there was terrible low end noise. Might take the drive train out and build it at a later point for a new shell. We will see.

 

[earlbrown]

put a hose over the valve guide and suck on it. That should pull the valve back up where you can get a clothespin on it.

DO NOT try and push it up with the piston. No matter how careful you are, it will bend the valve and require the head to come off!

 

[novaderrik]

take the engine out...

pull it apart...

drop the motor parts (block, crank, rods, heads) off at the machine shop...

let them do their thing...

get the parts back..

put them together..

put it in the car...


it isn't rocket surgery- they slammed these things together by the thousands on assembly lines almost 30 years ago... anyone with basic hand tools and half a brain can do it in their garage...

 

[Kaine Beedenbender]

Ya actually i am a BMW guy and i have my 550i engine apart on a stand and going to do some major PM so it lasts a long time. I can tell you that that is a complicated engine. Going to try and rebuild the trans as well. So i guess if i can do a complex car like that i can muddle my way through this. I just don't know turbo engines nor do i have the tools for all of the tolerances, etc. I have a bit of experience in general though.

My thought was to toss the stock heads for Champion and have the block and internals done at the local machine shop. I would assemble the rest and do the heads since its basically bolt it on, etc. Even though the body is trashed i figure until i find a good donor body i can use it and eventually swap the good drive train over.

 

[baby6]

Man you can rebuild it yourself. Novaderrik has the right idea. Here is what I did (just rebuilt mine)

Pull the damn thing out.

Tear it apart to just a bare block, take the pistons, rods, crank and block to a machine shop. tell them to check it all out, and do what they ask.

Get it all back, depending on if and how much your crank needs to be cut, order main and rod bearings accordingly. (Mine was a stock rebuild with another crank, it was turned 10/10 so I ordered 10 under bearings all around. I had the block line honed, bores honed, crank /rods balanced, hot tanked and....thats it. I plastigaged the mains and a couple rods, made sure everything was fine and dandy and put it back together very carefully and made sure everything was PERFECT.)

Before you put it back together, make sure all of the "flash rust" is removed from the block after they give it back to you after being hot tanked.

Make sure the crank spins nice and neatly inside of the journals with bearings (line honed or not do it anyways)

If all is good, put it back together, make sure everything lines up nicely, take your time on it, and put it back in the car. Make sure cam sensor is set properly and heads are torqued correctly. Also make sure to check the thrust play on the thrust bearing. wack it a couple times back and forth to seat it.

This is what I did with my car, VERY SIMPLE procedure, anybody that has a basic knowledge can do it, and if you don't understand something call someone that knows about these cars or look online.

Fired mine up, 20 psi at hot idle with 10w30, stock cover and an oil pressure plate on the housing (it is time for me to get a timing cover, but as of right now oil pressure is great)

The only issue I've had with it is my transmission took out the thrust a couple times since rebuild, have figured out what the problem was and already fixed it. It had nothing to do with the machine work or assembly.

If a 21 year old kid can do it, you can do it.

The only thing that I would be concerned about, is that it is a H/A motor. same interals, quite a bit different on the R&R procedure like Nick previously stated. Make sure to take LOTS of pictures and number everything accordingly, putting bolts and nuts/accessories into seperate grocery bags.

 

[Squid4life]

Agree with above, but be sure you the machinist what clearances you need. Be very specific.

 

[Kaine Beedenbender]

While i greatly appreciate the advice, you guys are looking at it from the other side. If you have never done a rebuild, don't know what tolerances are needed and how to get them, how to tell the machinist what i need, and other items. Setting the internals of an engine like this, it seems you need to know what you are doing and what to look for. You cant just parts swap. I would rather have them build the bottom end and figure that out, i can do the heads and such.