sounds like a diesel to me

problem... under start up and under load I get a diesel sound start up is bad all started when I did the rear main so...
things I've done...
1.new rod bearings
2.new main bearings
3.checked the water pump and the flex plate
I have done a search on this and everything that's been suggested I have looked at so any new Ideas, after the mains it did improve but is still there oops sorry 1990 with a 4L at 270k yes that's Kilometers I'm a Canadian eh any help would be greatly appreciated and you shall be rewarded with a thousand thank yous...Clint

It's probably your lifters if it isn't the rod bearings.

RyleyF said:

It's probably your lifters if it isn't the rod bearings.

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x2, mine sounds like that and I have 150k on it. I just live with it.

How did you check the flex plate? Maybe try unbolting the converter from the flex plate and pushing it away and then start it and see if the sound is still there. I'm not sure why it would have anything to do with changing the rear main but I had a cracked flex plate once and it did sound like that.
Mike

Thanks mates I will check your suggestions...Clint

I've run out of oil (close enough that nothing showed up on the stick) before, and it sounded like my dad's powerstroke. Thinking you'd have already done this, but occasionally we all miss the little things.

I just pulled an 89 motor out and put in a 87 with low miles. I did all you did and found out the wrist pins were worn.

Gator said:

I just pulled an 89 motor out and put in a 87 with low miles. I did all you did and found out the wrist pins were worn.

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this is the direction I seem to be heading in thanks for the input ...Clint