Badly Knocking P38 4.6 V8.....help

Morning all,
I could do with some advice please.
I have recently bought a 1998 P38 4.6 HSE V8 with LPG, (a week ago!!) and it has now developed and really loud knocking from the bottom of the engine, I don't think it's big ends as you can't hear it at tick over, just when the revs rise. The engine has done 105k
Looking at the oil it's very very thick (I assume to try and cover up the issue).
I would really like to fix the old girl as she has the making of a fantastic car, LPG working and certified, air suspension is all good, air con no issues, new wheels & tryes, brakes and disc's etc.
It's just the engine that seems to be FUBAR'd
How easy are they to work on, happy to get my hands dirty just could do with some advise.
Thanks
Duncan.

Engine is simple to work on...electronics not so much!!

The only thing at the bottom of the engine is the crank and bearings.....drop sump, remove s crank bearing cap andtake a look at the shell....

The tappets can tap if the oil is too thick to pump them up....they aren't at the bottom of the engine obviously, but are quite low in the engine bay to make it sound like it is from under the engine....

Hi Saint.V8
Thanks for the reply, where is the the best place to get the big end and main bearings from, any idea on cost ?and what's the best oil to use?
thanks again.
Duncan.

De

wickets said:

Hi Saint.V8
Thanks for the reply, where is the the best place to get the big end and main bearings from, any idea on cost ?and what's the best oil to use?
thanks again.
Duncan.

Click to expand...

Depending on the state of the shells you may need to have the crank reground,engine out job.Saint did a write up,with photos , when he reshelled his P38

Would it be worth replacing the main bearings & big end to see if that fixes it first? Are they easy to replace?

wickets said:

Would it be worth replacing the main bearings & big end to see if that fixes it first? Are they easy to replace?

Click to expand...

If the crank has picked up from the shell then no, Not a bad job if you know what you are doing. Check the technical archive for Saints "how to",if it's not there then it should be.

Just checked and it's there.

Thanks I'll have a read )

I have just done an engine flush, put new oil filter and fresh 10w40 semi synthetic oil in, definite low end rumble now so I think big ends, I take it I can do this without having to take off the timing chain cover etc?
thanks

wickets said:

I have just done an engine flush, put new oil filter and fresh 10w40 semi synthetic oil in, definite low end rumble now so I think big ends, I take it I can do this without having to take off the timing chain cover etc?
thanks

Click to expand...

Big ends knock main bearings rumble.

Ah.... just had a listed again and I think it is a knock rather than a rumble, is there any way I can upload a video ?

wickets said:

Ah.... just had a listed again and I think it is a knock rather than a rumble, is there any way I can upload a video ?

Click to expand...

I think I have uploaded to YouTube in the past and then posted the link here.

Main bearings is front cover off due to location of the cross bolts holding the caps in....also starter off too....

Big Ends can be done by just dropping the sump, removing spark plugs and 1/4 turn loosening the bearing caps to help rotate the crank shaft - look in the Technical Archive for a How To.

Here is the link to the youtube video I up have uploaded

Thanks again for all you advice.

Sound very much metal to metal to me, like a big end has gone south, I hope not for your sake
I think its pull the sump of time and have a look, cant be as bad as the last engine I had make that sort of noise and stopped turning over, that had a snapped crank on no2 bigend, well it was a Renault.

That is a big end.

This forum is fantastic....!!!!
Thank you all very much, big ends this weekend.
I'll keep you posted

Good luck, hope the crank is ok and you can just put new shells in.

Me too

New shells wont fix that, that sounds bad enough to need a rod and crank grind assumeing its not caused by oil starvation