ENGINE NOISE

[Benjamin7]

Well I'm not worried about carnage below... Unless it's been created in the last month.
As far as the noise, I've pinpointed it to the #7 cilinder. I did the plug wires and removed each one starting at #8. Went around the horn removing each wire and then putting the truck in gear, then pushing it until the knock ocures. No single wire affected anything except the #7... I pulled it and put it back in several times to make sure, but the wire deffinitely made the noise go away (wish it could make all the valve train noise go away). Anyways, I'll record it again tomorrow when it's light and I'll post it so you guys can give it a listen.
By the way, don't put your hand on the dizzy to adjust the timing when you've removed a wire.... Learned that one the hard way

 

[Robert Kenney]

Well I May have to rethink your issue if the noise was so discretely associated with #7 only and being a main unless #8 is real week. I doubt a loose rod would go 1000 miles making that racket so May be piston/piston pin related.

You got me on the edge of my seat.

again we have to wait and see.

 

[Robert Kenney]

Listened to your vids again and it does sound an awful lot like a rod.

 

[Benjamin7]

About to jack it up again and use the plasti's on it. Hopefully in a couple hours I can give you guys some more info on it.

 

[Robert Kenney]

The racket you are hearing will be plainly visible. Plasti-gauge upon reassembly to verify clearance.

You will see the gray layer of the bearing worn off and copper beneath showing proudly.

Give us picture whores a lot of pix.

 

[Benjamin7]

Ok, sorry to say buddy (or I don't know if I'm sorry, not too sure what to think...) the bearings showed wear but nothing excesive. This is the #7 rod bearing... I'm sorry but it's as far as I've gotten tonight and I'm headed out with my woman soon so this is it, but I'll post the pics of what I've got. The #7 is the only one I could check. I pulled appart the rod bearing and plastiguaged it. Torqued it to 50 ft.lbs. And got .076... Way more than .0011-.0036 that it's supposed to be. So new rod bearings are in order, but I need to check the main bearings as well. I'll get on it first thing in the morning.
Here are some pics for your viewing pleasure.
Sorry but the pic of the plastiguage messurement did not come out.

 

[Robert Kenney]

Ben,

.076"???? Not possible to measure with your red pg. There is a metric and a inch scale pg available. .076mm is equal to .0029". That is good!!!.. If you purchased metric pg multiply the reading by
.03937 (.076 x .03937 = .00299 which is fine).

The upper rod shell sees all of the loading and 90% of the wear and on the mains it is the lower shell.. You should be able to feel the looseness up and down by hand when you run across the culprit. I would like to see the wear pattern on the upper shell and not the bottom one for the reasons I posted above.

Push the piston up into the bore further and see if you can feel up and down play in the piston pin.you can also rotate the journal to give you room to move it.

I'll be at the nhra winter nationals most of the day tomorrow. I will try to get to the form with my I-phone but May be limited.

 

[Benjamin7]

Ok sounds good. I did check play up and down but did not inspect the upper bearing. I will make sure to take a look tomorrow. And yes, you were right, it is metric... Thanks for the clarification!

 

[Robert Kenney]

The clearance you measured indicates you will see only slight wear on the upper shell. An other bearing must be the bad one. Maybe the rear or #4 main.

 

[Benjamin7]

Ok, I'm gonna just post as I go through this so I make sure to get everything that's important noted down. I went from #7 to #8... #8 looked even better than 7. Guaged at .002. I buttoned it back up and torqued it down, then moved back to #6 pulled it appart and yeah, the bottom of the shell looks good, but the top is wiped out, showing coper and a bit of scorring... So I figured it would guage real high... Nope. Guaged right at .003 (see pics). So now I'm wondering what's the point of guaging at all? If a bearing is visibly wiped out, why would the guage show that the clearances are within spec? anyhoot, I'll keep working forward and post more of what I find as I go. Here's some more pics for ya!
I accidently pictured the mm side of the guage, but like you said before, .076 mm is .003 in.

 

[Benjamin7]

Ok, #5 was not as bad as #6 but it's starting to show some ware on the top half of the bearing. #4 is pissing me off tho. It is wiped pretty well but more than that is how much play the connecting rod has on the piston pin. It is not twisted but it looks like whoever installed the pin into the connecting rod did not use the spacers that limit the play on the pin. I can't describe it very well so I'm going to post a video of it on youtube and you can take a look at it.
youtube - '77 Scout II connecting rod

 

[Robert Kenney]

The play front to back of engine is normal as there is really nothing to stop is accept for the rod bearing play and the piston.

If you find no bearing clearance over .006 and you have feeler gauges, see if you can measure piston to cylinder clearance.

 

[Benjamin7]

Ok I guess I was over reacting all of the rod bearings are within tolerance, #3, 2 and 1 were all about the same, showing some ware but not crazy bad. I realized that #6, #7 and #8 bearings have a line running along them... I believe they are different from the other bearings and maybe they were replaced recently?? But #6 is showing the most ware of everything so possible it's the culprit? Not sure... So I just did the first of the crank bearings and it's looking good... The plasti shows .004. Allowed is .001 to .004. Here's a pic of the plasti on the first bearing. More to follow.

 

[Benjamin7]

Alrighty, I did #2, #3 and #4 mains and it all plastiguaged the same as #1. #2 showed the most ware with some scoring, #3 is worn but very evenly, #4 was better than #2 but did show some ware. I didn't pull #5 as I don't want to have to get a new seal.
So after all of this what do you guys think? I don't have feeler guages long enough to measure clearance between rings/piston wall. I don't really know where to go next. All of the pistons were firm in their bores.
One thing that I noticed when I pulled the main bolts was that the ones in the middle, #3 and 4 in particular, smelled a lot like gasoline. Maybe all of this is being caused by bad valves? Or is it just because I'm running the truck with no #7 wire so the fuel is getting into the oil? Shouldn't it still be ejected out of the exhaust? I think after I get it buttoned back up I'm going to go ahead and work on the carb. I'm still debating changing out the 345/727 combo with the 350 efi/700r4 that I have... Either way I'm going to have to run this thing the way it is until this spring when I can take a week to either swap or rebuild. I know the swap is a can of worms, but right now I have 650 bucks worth of mis. Parts that I can return and have that cash towards the swap, plus I'd have the 345 and the newly rebuilt 727 to sell for extra cash (maybe I can do the SOA at the same time??)
watcha think?

 

[Michael Mayben]

My opinion,...there is no bandaiding that motor, the bearings are wiped just from looking at the pics! This motor was throwed together sometime in the past in a botch job with obviously worn out parts, those bearings are toast, don't care what the plastigage clearance is now.

I'd also bet a sixpak that at least one rod/piston is installed backwards (resulting in gross piston "slap"), and some of the pistons are installed incorrectly on the rods, the pistons must be heated to above 300f to either remove or install on the rods.

It needs to be completely overhauled in a proper manner, or parked. It will not function effectively in it's current state, and will most likely grenade when run. If that happens, ya got nothing and will have wasted whatever parts money has been spent to this point.

We have a tremendous amount of information posted in this forum right now regarding proper engine building practices along with alternative methods to achieve a decent end result.

 

[Robert Kenney]

When you plasitgauge a main bearing like you did the weight of the crank hanging down into the main cap will crush the little gauge strip before forcing the crank up into the upper bearing in the block. It really only works well with the engine upside down like when you are building an engine. The gray/lead alloy layer is at least .003 thick so if you are still gauging at spec while the gray layer is worn away I suspect error in the measurements. But anywhoo as you say. You have an engine issue and just have not found it or quantified it yet. What numbers are on the bearings???



I can't do much more than we have already with out having it in my hands. If you are near mayben ( thought I read you are in oregon) I suggest seeing if he can help you.

 

[Benjamin7]

I think I agree with you michael. I think this thing needs to be parked before more damage occurs.... Lord knows I don't need a thrown rod. What do you think about the swap? Considering that I don't care too much about stock, more than anything I want reliability and fuel economy. My plan for this truck is to be a dd with weekend warior capabilities. Want to be able to do light trails and get up into the mountains for hiking. I can see myself taking this thing to the coast as well... Where I live is 4000 ft. So it seems like the efi will be the best there. I really think I'm just gonna swap the 350. Just gotta figure out if I wanna keep the transfer on it and find a different front axle (the GM is a driver side drop) or keep my Dana 20 and fork out 600 for the adapter... What do you guys think?

 

[Robert Kenney]

I think mm has his hands full in his shop so I'll chime in on the swaparoo.

You have a good engine and drive train that works. If you put teh time it would take to swap in a GM you would have a great running IH motor. The IH can make a good mile per gallon like the GM so no real gain there. The Scout is still a brick and hard to push through the air.

I suggest getting trevor to help you out and go through the engine. That is ofcourse if that sounds doable.

 

[Scoutboy74]

The other option which is quite workable if the proper steps are taken, is to look for a known runner sv motor, buy it and swap it in. This isn't something that you'd want to rely solely on any seller's word for. You'd need to hear it run, perform your own compression tests, etc and the price would need to fit within your budget, but that would get you up and running without fear of engine-pocalypse. Then if you wanted to, you could take your sweet ass time going through the current engine with a fine tooth comb. Complete, running sv motors aren't like trying to find bigfoot out here. They actually do exist. And in this case I wouldn't turn my nose up at any size 304-345-392 just so long as it met the criteria already set forth. The final call is up to you ben. It's your ride and your dime. All we can do is make sure the options are on the table for you to consider. Sorry about your luck on this one.

 

[Benjamin7]

Hey trever, I was wondering when you were gonnna chime back in! So ya, that's what I've started doing since michael gave his opinion of the reliability of that motor. I have already been looking for a decent used motor... So far I've only had much time to search this site and binder bulliten. I still need to check binder planet and binder bench and see if anyone has anything out there that will work.
Thanks for all the help and the info here guys. I know that without it I would have done a botch job on this. Now I know exactly where to go, I just have to decide which "where" I should follow! I realized something else last night... My Dad has an '82 Chevy that was creamed by a semi a few years back. It's been sitting in the back forty for at least 5 years... It has the 454 and an auto tranny... Hmmmm... 454 would be pretty bad ass in a Scout...