My 5.7 converted itself to a 4.3 today

[rbezdon]

Well guys, back to the drawing board. Remember the post we had a wekk or so ago where we were all trying to decide which two cylinders of a 350 were cut off to make the 4.3. Today I found out it is 6 and 8. I was just cruising along a WOT at about 4500 rpm just fine. Came down to idle speed and the engine was rtunning REALLY rough. I had no loss of power, no over heat, no loss of oil pressure, no smoke, knocks or nothin. I just throttled down and the engine was running like crap. Pulled plug wires and found 6 and 8 are dead. The engine is still running on the last 6 pretty well. No somke of water in the oil. Quire a bit of steam coming out the breathers when running at cruising speeds but it disappears after a couple of minutes at idle. I am thinking head gasket, but there is no water in the oil. I havent had time to do a compression test and I am not sure if I should bother. Definately something major is wrong and I am not sure what the compression test would tell that pulling the head wouldn't. Any other ideas before I go out there and get greasy again. Not fun. I dont mind doing as bit of work on the boat but I am definately working more than riding and I am getting tired of it. Oh, I am in a bad mood after a bad day on the water!!!

 

[rattana]

Re: My 5.7 converted itself to a 4.3 today

I would do a compression test if you have the time. Do you have fire at the plugs?

 

[Reel Poor]

Re: My 5.7 converted itself to a 4.3 today

Sounds like you may have blown the head gasket between the two cylinders. No water there.

 

[rbezdon]

Re: My 5.7 converted itself to a 4.3 today

Well, got dirty and got my answer. Sure enough, between 6 and 8 the head gasket is burned through right under the head bolt there. Seems to be a marine gasket (metal seal around all cylinders) but I can't tell for sure. This is a year ols reman long block (suposedly) marine block from a rebuilding outfit down in Texas. The cam was not marine (I measured the lift and compared to specs Ralph got for me) and now I wonder about the rest. Does anyone know how to tell if this gasket is marine or not?? Remember, it is used (and burnt). Bet I got steel freeze plugs too. Never recommend or buy something from them again. At least I know I got the 4 bolt mains I paid for!! (long block came no oil pan). <br /><br />I am considering pulling the other head now and just replacing both. Also, it seemed that the head bolts came out fairly easy. About 40 ft lbs on my VERY poor torque wrench (old beat up needle bend type). Some seemed even less. I am sure the shop torqued them down but do you guys Locktite them too?? I never have but this gasket burned right under the bolt. Maybe it loosened due to thermal stress (cool/hot/cool etc). Any inputs, I'd appreciate them!!

 

[rbezdon]

Re: My 5.7 converted itself to a 4.3 today

By the way rattana, I was pretty certain something major gave way. I did do a poor mans compression test though. I grounded the coil wire and turned over the engine with all the plugs in. I could hear the low compression in at least one cylinder by the load on the starter. I knew this is NOT as good as the real thing and can't tell me which cylinder or how many are low for sure but I knew which ones were dead from pulling the plug wires when I was still on the water so once I knew I had low compression I just went ahead and pulled the head figuring I'd find the issue and sure enough.

 

[Reel Poor]

Re: My 5.7 converted itself to a 4.3 today

The difference between marine and automotive headgaskets is the marine gasket has a stainless metal sealing ring around the cylinders and the auto has steal. Try a magnet on the metal sealing ring.

 

[rbezdon]

Re: My 5.7 converted itself to a 4.3 today

Thanks reel poor. I think these are steel, they dont look like stainless but I'll try the magnet to make sure. If its steel, I think I am going to pull the other head too.

 

[rbezdon]

Re: My 5.7 converted itself to a 4.3 today

Well, went out to the garage and did the magnet test and it won't stick so must be stainless. Guess that wasnt the problem. Maybe the bolt torque??

 

[KaGee]

Re: My 5.7 converted itself to a 4.3 today

I empathize with you man. Where did you buy the engine?<br /><br />If it burnt through, I'd think maybe it was a torque issue or bad gasket. Some schools of thought feel you should re-torque after a few hours on a re-newed engine. You should use thread sealant, but NOT Locktite on the headbolts.<br /><br />BTW... what are you doing 4500 RPM on a new motor for??? Hmmmm??? Need some breakin time before getting up there boy!

 

[Trent]

Re: My 5.7 converted itself to a 4.3 today

Was a head bolt re-torque done after the first run?

 

[rbezdon]

Re: My 5.7 converted itself to a 4.3 today

No, there was no retorque done. I thought from what I have read needing retorque was a function of the gasket type used. I bought this as a long block so the heads were mounted (from a place called Thunderbolt near Houston http://www.tbolt.net/marineengines.htm ) The rebuilder did not include a retorque instruction with the other "break in and install" instructions. Since the gaskets are stainless, maybe they did it right after all. <br /><br />I bought it last year May so I did the engine break in in last year. If you remember my posts I had a severe bogging issue which prevented me from hitting WOT so I boated all last year and the first half of this year and couldn't open it all the way or it started dropping rpm. So far this year I did replace the cam with a new Comp Cam so if anything I am guilty of finally running WOT with the cam having only about 10 hours on it but since cams are broken in at higher rpm, I don't see that as the problem. <br /><br />Well, still pondering pulling the other head. I guess pulling the valve cover and doing a retorque may be adequite. And thanks for the advice on Loctite. I have never used it before (although MOST of my engine rebuilding was admittedly automotive, BUT this dang boat is giving me enough experience that my marine time is catching up fast). I'd definately rather be out on the water than in the garage pulling the engine apart AGAIN!!

 

[bigbrownbuku]

Re: My 5.7 converted itself to a 4.3 today

i generally use perfect seal on my head bolts. you arent going to get another chance this good to pull the other head now the intake is off. i would do it.

 

[Reel Poor]

Re: My 5.7 converted itself to a 4.3 today

Be sure to have the head surfaced and check the block deck with a straight edge (especially where the gasket blew out) the air that passes thru the blown area will eat away at the block and head.

 

[lakelivin]

Re: My 5.7 converted itself to a 4.3 today

Ignorant question, but is all stainless steel non-magnetic, or are there different grades? I bought some stainless washers & cotter pins from HD, and was surprised to find out that I can pick them up with a magnet...

 

[Reel Poor]

Re: My 5.7 converted itself to a 4.3 today

I bought some stainless washers & cotter pins from HD,

Yep there are different grades. The stuff from HD will rust.

 

[rbezdon]

Re: My 5.7 converted itself to a 4.3 today

Reel poor, you anticipated my next post. I see a slight "marking" where the gasket burned through but what is the point of machining the head if I don;t do the block too?? Doesn't look like any metal is gone but there is definately a mark in both the head and block. Also, if I get the one head machined don't I have to do the other to balance the compression side to side??

 

[Reel Poor]

Re: My 5.7 converted itself to a 4.3 today

Vatter, check the surfaces with a "machinest"<br />straight edge. With the straight edge on the surface to be checked use a 2 thousandths feeler guage and see if it (or more) will slide under the straight edge. If it will, it should be surfaced.<br /><br />

if I get the one head machined don't I have to do the other to balance the compression side to side??

Idealy, yes, but its not absolutly neccessary. Alot of this decession would be based on how much is removed during surfacing. <br /><br />Also be sure its surfaced with a milling machine and not on a grinding rock. By milling you know exactly how much was taken off.<br /><br />If the deck of the block has to be surfaced, the motor will have to be disambeled and basicaly rebuilt.

 

[rbezdon]

Re: My 5.7 converted itself to a 4.3 today

I nreally cleaned up the surfaces with some cleaning solvents. After cleaning you can not even see where the burn was. I have put the straightest edge I can and there is no way .002 will fit under. I am pretty sure I'm OK as is. Don't forget, this happened quick after a hard runof less than 5 minutes and shut down a few minutes later. Maybe the short time gave less burning that is common.

 

[Reel Poor]

Re: My 5.7 converted itself to a 4.3 today

Good news and Good luck

 

[RandyJ]

Re: My 5.7 converted itself to a 4.3 today

Just a note here for all of us poor boaters... you can do a flat test with a newly machined head by laying it across the block as if it was a straight edge then try to slide a feeler gauge under it.