Engine Guru's...need your oppinion!

[AllZWay]

I put in another engine I bought used without much information known about it.

The engine itself sounds great.... as long as you don't listen to exhaust from the rear of the car.

As the exhaust exits, it sounds just like it has an exhaust leak around the exhaust manifolds. However, it only sounds this way at the back of the car. Under the hood, the car runs and sounds perfect. No miss, no knock....just nice and smooth from idle to redline.

Dad and I reset the valves tonight hoping to mabye find the cause of the sound or stop it, but adjusting the valves had no affect on the exhaust sound.

Throw out your oppinions. I am kind of leaning to maybe a burnt valve...what do you think?? The problem with this theory is that the engine sound so good.

I am close to pulling the heads now and will likely miss Hallett, since my schedule is pretty filled between now and race weekend.

[Casey_SS]

James - sorry to hear this. You're right - could be a burnt valve or hole in a piston. A compression or leakdown test would confirm / deny this theory before you go to the trouble of pulling the heads though. Is it throwing any codes? If you can get a datalog (there are several free programs out there for OBDI) that would also be helpful....a burned valve or piston should show up as a big difference in O2 readings from side to side. Happy to look through the logs for you if you're able to get them.

[AllZWay]

Thanks Casey.... I am going to do a compression test, but it will probably be on Monday before I get a chance to get back to work on it.

I have a 93 computer so I can pull codes and nothing other than the egr codes were showing.

The car seems to run so smooth is what is throwing me off on a burnt valve or piston... I would think it would have a slight miss.

[Adam Ginsberg]

If the compression test comes back normal (or relatively normal).....RACE IT!

:)

[Casey_SS]

x2! :)

Heeeyyy.....waaaaiiittt a minute....you're not trying to pull whole that McLaren / Redbull F1 thing where the exhaust gas generates downforce but sounds all weird are you? GLENN.....GLENN!!

[Fbody383]

I am close to pulling the heads now and will likely miss Hallett, since my schedule is pretty filled between now and race weekend. Wouldn't think it would run "well" and have no codes with a hole in a piston. There have to be enough parts floating around this group, besides how hard is it to put the top end of the motor back together? Glenn can change the valve springs out in about an hour.

Come race the thing.

[AllZWay]

If the compression test comes back normal (or relatively normal).....RACE IT!

:)

The thought has definitely crossed my mind. I just wonder what would happen if it is a burnt valve.

[marshall_mosty]

+3!!!

If it's an "unknown", it's a ticking time bomb!!! RACE IT LIKE YOU STOLE IT!!!

[ShadowBolt]

Vacuum leak will make the exhaust sound funny at the tailpipes. If the compression is good obviously you don't have a burnt valve.


JJ

[BryanL]

I think you should go to the seller and ask about the warranty. Seriously I don't have a clue of how to help you and hate you are having an issue. Have you tried listening with a stethoscope or screwdriver all under the motor and down the exhuast? Maybe its from all those flames coming out of your exhaust. Compression and leakdown would help for sure.

[Rob Liebbe]

An uncle of mine who was a car salesman used to check the exhaust pulse with a dollar bill. If the bill only blew away from the pipe, then the engine was fine. If it pulsed funny or even got sucked back toward the pipe, then he would suspect a valve. I don't know if there's any truth to it or not.

[AllZWay]

I think you should go to the seller and ask about the warranty. Seriously I don't have a clue of how to help you and hate you are having an issue. Have you tried listening with a stethoscope or screwdriver all under the motor and down the exhuast? Maybe its from all those flames coming out of your exhaust. Compression and leakdown would help for sure.

Yep...tried that trick and everything sounds perfect from valve train, intake, block, and oil pan. Nothing wierd at all.

[AllZWay]

An uncle of mine who was a car salesman used to check the exhaust pulse with a dollar bill. If the bill only blew away from the pipe, then the engine was fine. If it pulsed funny or even got sucked back toward the pipe, then he would suspect a valve. I don't know if there's any truth to it or not.

I have been told about this little trick and plan to try it and see what it does.

[mitchntx]

An uncle of mine who was a car salesman used to check the exhaust pulse with a dollar bill. If the bill only blew away from the pipe, then the engine was fine. If it pulsed funny or even got sucked back toward the pipe, then he would suspect a valve. I don't know if there's any truth to it or not.

I'm sure it worked way back then. But today, it requires a $20.


James ... a spare motor is sitting here. It'll take 1/2 hour to load and be on the way.

[AllZWay]

I'm sure it worked way back then. But today, it requires a $20.


James ... a spare motor is sitting here. It'll take 1/2 hour to load and be on the way.

You know I really appreciate the offer... but I can't seem to keep my crap from breaking.. I sure don't need to break anyone else's stuff.

[Al Fernandez]

Compression test followed by driving to grid for warmup. Dude, you have to redeem yourself at Halllett!

[AllZWay]

An uncle of mine who was a car salesman used to check the exhaust pulse with a dollar bill. If the bill only blew away from the pipe, then the engine was fine. If it pulsed funny or even got sucked back toward the pipe, then he would suspect a valve. I don't know if there's any truth to it or not.

Well this test failed miserably. I am going to start pulling the heads on Monday or Tuesday and see how bad it is.

It would try to suck the piece of paper completely into the pipe...of course it would then blow it back out, but it had a major pull back into the exhaust.

I tried on my truck and street car and neither of those even appeared close to pulling the paper back in.

[mitchntx]

James ... a spare motor is sitting here. It'll take 1/2 hour to load and be on the way.

Ahem ....

[RichardP]

James ... a spare motor is sitting here.


Swap first, ask questions later...


Richard P.

[BryanL]

Hate to hear that. What about disconnecting the exhaust to see if you can identify which side has an issue? Then maybe pull only one head? I'm hoping its just a head and then you could just swap one off your other motor.

[AllZWay]

Hate to hear that. What about disconnecting the exhaust to see if you can identify which side has an issue? Then maybe pull only one head? I'm hoping its just a head and then you could just swap one off your other motor.

Dad thinks it is from the drivers side based on what we heard during the valve setting. We are going to start with that side first. It runs too good to be something really bad, but I don't want to blow it up to find out how long it would last like this.

[Alien]

If you end up pulling off the head, (it's junkyard engine, right?) I'd at least get whatever one you put back on it resurfaced. I've never seen an aluminum head with more than a few thousand miles on it not need resurfacing. Should be a quick turn around at a machine shop just to do that since it's not 100% necessary to tear it down.

[BryanL]

I talked to my engine builder and he said it's probably a valve. Said to do a compression test to identify the cylinder to check. Be a good idea anyway to check the health of the motor too