knock in engine

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diymirage

diymirage

HP@idle > hondaHP@redline
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I was out riding today and I noticed a knock in the engine, loud enough to hear it over the exhaust

I babied the car home and listened to it idle
didn't seem to make a racket at idle but when I hit the throttle it sounds like loose bolts rattling around in there
it would slowly quiet down after I let go of the gas, but the noise wouldn't drop as quickly as the RPM

it sounds like it is coming dead smack from the center of the engine

im guessing I broke a connection rod cap but I guess I wont know for sure until I dig into it

any thoughts?
 
Time for a V8 :happy1:

But seriously, bummer...you have a slanty right? Those are great engines.....wonder what went bad?
 
66340SEDAN said:
Time for a V8 :happy1:

But seriously, bummer...you have a slanty right? Those are great engines.....wonder what went bad?
Click to expand...

yeah, that /6 was on its way out when I bought the duster so I dropped in this 360...which is what has knock in it now

what comes after a 360, 407?
 
Check the crank pulley. I just had a knocking noise issue and that's what it turned out to be.
 
340luckyman said:
Check the crank pulley. I just had a knocking noise issue and that's what it turned out to be.
Click to expand...

what exactly should I look for?
loose bolts?

it sounds like it is coming from further back though, closer to the transmission
(but I will have a look)
 
haven't noticed it with different temps, but I sure hope it is the converterbolts
that is most likely the cheapest/easiest fix, considering all that could go wrong

hopefully I can get some time to get the car up in the air and have a look at her soon
 
well, it definitely does not "come and go"
I fired the car up today, being completely cold and it started as soon as I revved it up

sounds like its coming from the back end of the motor
 
Check the convertor bolts as suggested above. I drove mine for years with a ticking noise that we couldn't diagnose from the top. When I pulled it out to put my new engine in, we found one convertor bolt missing and one finger tight. We had been beating on that poor old 340 with two tight convertor bolts.
 
diymirage said:
well, it definitely does not "come and go"
I fired the car up today, being completely cold and it started as soon as I revved it up

sounds like its coming from the back end of the motor
Click to expand...

Did you put a dust shield on the trans, if so, it could be the converter bolts hitting it.
 
I did, its the shield that came with it
im hoping its something along the converter loosening up that I could fix without pulling the motor (or my wallet)

ive noticed this, I don't know if it is related or not, I first chalked it up to a used starter but maybe its related...the starter doesn't always engage
instead of cranking at times it makes the grinding noise, like the sillinoid sticks, or there is a flat spot on the crown

this morning it grinded a lot of times before grabbing it and starting
could that be an indication the converter is loose?

(or does it just mean I shouldn't have cheaped out on a used starter)
 
Its probably a bad ring gear. Or starter.
But, it could also be a sign that the convertor is too far to the rear, due to the thrust bearing being worn, Its an easy test. Just push/pry the crank to the rear. Then pry it too the front. If it clunks, its too much.
Spec is less than .010.
 
thanks for all the advice guys

first change I get I will be trying out these things,
1 checking crank pulley and balancer bolts
2 checking crank for play to check thrust bearing
3 remove and inspect transmission dust cover
4 check convertor for presence and tightness of bolts

most likely wont be until after the weekend though
 
I checked all four points on my list and found nothing wrong
had the car running for about 15 minutes and revved it a few times to see where the racket was coming from
I cant figure it out from here

the only change ive noticed is that the knock is now present at idle aswell
im afraid it sounds like a thrown rod but I would hate for it to be that

worst excuse to build a stroker ever :banghead:
 
What all did you do to the engine before installing it?

I know we had a long discussion about it, but I don't know what the final outcome was.
 
not too much, checked the compression which was good
inspected the bores which looked good (checked with a bore guage)
had the heads rebuild which were a mess (something about different valve, a few guides had previously been replaced and not passing a vacuum test)
new cam, lifters, springs and timing chain
new gaskets where applicable
installed a new rear main seal and was happy with the way that one crank bearing looked and installed a new oil and fuel pump

and new freeze plugs

I know, im kicking myself now for not replacing the pistons and bearings while I had the block undressed but there was no indication it was necessary
(or if it was my untrained eye just didn't spot it)
 
nope,

I did not "touch" the rods, pistons, cranks or caps, except for the one I took of to replace the rear main seal
 
it already ran it without the inspection plate on (but with the larger cover that sits between the starter and the transmission still in place)

it didn't seem to help, and the knock sounds more substantial then something hitting a piece of tin

if you think it is a possibility I can pull the starter, removed the cover and try again next time
 
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