Help ASAP! Motor gone?

[ChrisDSM22]

Okay, I have looked for the answers and found nothing. Also I'm not sure where to be posting this but, sorry in advance. I have also tried posting on another site but no one will respond. So here is my problem. The wife was driving the mirage 4G15 to work when she got off the off ramp the car stopped and a little smoke came out from under the hood. Being inexperienced in this sort of thing she tried starting a bunch of times and it wouldn't start. So a nice guy towed her to a parking lot. I drove down there and popped the hood to find that the crank pulley came unbolted and was just laying there with the bolt in it. The timing belt was all chewed up. I was pissed because I just had the head rebuilt last summer. I figured the worst and towed it back and found a guy willing to sell a whole motor for $75. I picked up the motor mainly for the head and started tearing into the motor on the car. When I got the head off I could see no damage to any of the valves except a sliver mark on one like it just got grazed on one valve and no marks on any of the pistons. Well I posted this question on another site and a guy told me to remove the rocker arm assembly to close all the valves and fill the combustion chamber with oil and let it sit overnight to see if any oil leaks out. Well over 24 hours later the oil is still at the same level as when I filled it but, there is a small amount of oil in all of the exhaust ports and two of the intake ports. What I don't understand, is the head still good because the oil hasn't drained hardly any in 30 hrs and is still at the same mark as when I filled it or should I replace it with the used head? Sorry for such a long post. Thanks.

 

[5150DSM]

Regular oil is too thick to give you any accurate idea, try using kerosene for better results. I'm not sure if the 4G15 is an interference engine or not but it would be fairly obvious if your valves were bent. (Usually) Re-try the leak test with kerosene and see what you have.
Are you sure the other head is in working/good shape? If so, maybe just swapping it over would be your best bet.
Aloha

 

[ChrisDSM22]

Yes, it is an interference engine. When I took off the head almost all of my valves where closed except the one that looked like it was grazed. I will try kerosene instead. I take it absolutely nothing should get by the valves? If that being said couldn't I use anything thinner than oil, like water? Thanks for your reply.

 

[SexperT]

He just said try using kerosene. You bought a motor for 75 bucks, why dont you just use the head from such motor?

 

[laserspeeddemon]

The first thing you should have done was a compression check and a leak down test. Too late for that. There is really now way of determing the cause of the problem without tearing down the motor. I think you are getting yourself way in over your head. You need to find someone in your area that can give you a hand.

 

[ChrisDSM22]

I know he said try using kerosene but, couldn't you use anything else? Like water? Does it have to be kerosene? That is what I was asking. Also, how am I way over my head? I have done this about five or more times now on this car and many others with interference engines where there timing belt had snapped and every time you could clearly see contact with the valves. This is the first time I've taken off the head and there was no or little contact and I have never heard of someone filling up the combustion chambers with oil to see if the valves where bad. I am just going to switch the head. Thanks for all your help 5150DSM.

 

[92awddsm]

I know he said try using kerosene but, couldn't you use anything else? Like water? Does it have to be kerosene?

You can use anything you want, as long as it is a thin fluid. Kerosene or mineral spirits are usually the norm to use because they will break down any deposits that may be accumulated around the valve or seat. Water can give a false results if there is any type of oily substance creating a false seal around the valve.

I have never heard of someone filling up the combustion chambers with oil to see if the valves where bad. I am just going to switch the head. Thanks for all your help 5150DSM.

You are supposed to fill the intake and exhaust ports, not the combustion chambers. It is easier to see the leak out of the ports into the combustion chamber, not the other way around. We always used this technique along with vacuum testing as long as I have been an automotive machinist(13yrs)

 

[ChrisDSM22]

Oh, okay so your kind of killing two birds with one stone with the kerosene or mineral spirits as so it shows you how well your valves are sealing and cleaning at the same time. That is what I wanted to know about the kerosene. This guy on another forum told me to try the oil in the combustion chamber but, it makes more sense to fill the ports instead. I don't have a compression tester. I just usually take it to my buddy who is a mechanic to do the compression check. I suppose it's time to invest in one seeing is that I do this so much. The lack of a compression tester on my part is why the guy suggested the oil in the combustion chamber trick in the first place. Thanks a lot 92awddsm for clearing this up for me.

 

[JungulSouljah]

Thanks everyone for answering the question at hand, its e-x-a-c-t-l-y what I was needing.
Kudos to all.

 

[92awddsm]

One thing I didn't mention is that when you try to fill the #4 exhaust port, you will find that the fluid will pour out of the egr port on the intake side of the head. I have always used a rubber or cork stopper in the egr port when checking the #4 exhaust for leaks.

 

[ChrisDSM22]

Okay, I was going to try this today. Thanks again for your help.

 

[laserspeeddemon]

If you have done this before, then you shouldn't have a problem. From your first post, it seemed that this was your cherry.

 

[ChrisDSM22]

Nope, popped that a long time ago. Well, I found out that the one valve that had a little mark on it was bent. I took off the head on the other motor, slapped it on and we are good to go. Also, I got a compression tester seeing as that I do this enough times and everything checks out. Thanks again guys for the help.