Post by: henrycj5 on August 07, 2006, 10:07:41 PM
Started the engine up and it sounds like a sewing machine with no power at all. the lifters and rocker arms have been replaced twice and the camshaft is new but the rattle is definetely coming from the top end. Makes no difference once the engine is hot or cold, (although I swear it's ever so slightly better when the engine first starts although I could be wrong)
Any ideas - please feel free to pass them on. And apologies for the moaning!
Post by: Anonymous on August 07, 2006, 10:27:04 PM
Post by: trent on August 07, 2006, 10:32:36 PM
Do you have good oil pressure?
Post by: henrycj5 on August 07, 2006, 10:40:06 PM
Post by: trent on August 07, 2006, 10:48:46 PM
It also may be worth inspecting the exhaust manifold for cracks!
Post by: henrycj5 on August 07, 2006, 11:00:45 PM
exhaust manifold is new and I've also fitted performance exhaust headers.
someone mentioned replacing the pcv valve? never heard of a pcv valve, have you?
Others have mentioned changing the grade of oil in the engine. I'm currently running on 15/40, should I change?
Post by: Anonymous on August 07, 2006, 11:04:05 PM
Post by: MK1 on August 07, 2006, 11:10:24 PM
It could be that the tappets are not 'charged'. Take the rocker box off and run the engine, you should be able to see the valve action. You will however make a bloody mess.
Post by: Ric Jacques on August 08, 2006, 08:35:03 AM
Anyway seems you have a strange one. Has your rocker cover been replaced? The reason I ask is that I just replaced mine.......however some of the rockers were actually making contact with it. Had to identify which ones from the marks they made on the inside then beat it out a bit with a ball pein hammer, just enough to get some clearance.
If you have a spare distributor shaft you can pull the dizzie out and put the spare shaft in the hole, engage the oil pump drive, and spin the shaft with a drill. With your rocker cover off you will see if the oil is reaching the rockers without making such a bloody mess as you will if you run her with the cover off!
Post by: Mike Pavelin on August 08, 2006, 09:01:05 AM
Post by: MK1 on August 08, 2006, 09:11:38 AM
Quote from: "Mike Pavelin"
Is the cam timing correct?
You'd struggle to get it wrong, it's just a matter of lining up the dots. (But you never know).
Post by: isle of man on August 08, 2006, 09:12:53 AM
Quote from: "henrycj5"
someone mentioned replacing the pcv valve? never heard of a pcv valve
"positive crank ventilation" basically it's a flame trap filter....if blocked the oil is normally pushed out of the rear main seal.
peter henry
Post by: elvis on August 09, 2006, 10:54:01 PM
Post by: Anonymous on August 10, 2006, 09:42:37 AM
you have a very similar writing style
Post by: henrycj5 on August 10, 2006, 10:04:36 AM
The engine (head & block) are from the same unit and have never been swapped.
Any of you guys local to me (Thorpe, Surrey) would be nice if I could show it to one of you.
Thanks
Henry
Post by: MK1 on August 10, 2006, 10:30:57 AM
Quote from: "She Devil"
wow elvis.......you and bubba could be one :?
You never see them together in the same place.
Post by: Anonymous on August 10, 2006, 10:37:47 AM
Post by: Bubba on August 10, 2006, 08:57:20 PM
Post by: eastryjeep on August 31, 2006, 01:19:34 AM
You don't say which engine you have, is it the 6/232 (3.8 litre) or the 6/258 (4.2).
The fact that you say you have a top end rattle confuses me as the cam followers are in the block, more or less behind the distributor. So I would probably rule them out as the source of only a minor rattle, a heavy hammering is what you get when they fail, it's so bad I thought I'd run a bearing when it happened me!
You said that this was the second rebuild, if you've had the head and block skimmed on both occasions it might be worth checking that you are still within tolerance for the pushrods you are using.
Did you install valve seat inserts that are perhaps not machined to the correct height in one of these rebuilds? Just need to find out if any of the followers are bottoming out for some reason, you don't have some wild cam in there do you?
Hope you are already fixed up or that this helps, Have rebuilt my 6/258 umpteen times now so give me a yell if you need any more gloom on what can go wrong on these simple but bullit-proof engines!
Post by: henrycj5 on August 31, 2006, 10:34:33 AM
I will definetely pass your comments on although he has just given me one of the lifters which he thinks are incorrect. (too short) So I'm off to my US car parts firm to check and compare to ensure they have given me the right one.
Oh my inline 6 is a 258, (I think)
Post by: eastryjeep on August 31, 2006, 02:56:19 PM
Does your engine backfire through the carb by any chance?
What carb do you have fitted and what distributor type, (points, electronic or hybrid; ie 'Lumenition' or similar), as the different cam profiles for the mechanical advance systems may cause your engine to over-advance. I mention this as I had endless problems when I first fitted headers to my 6/258 and wondered if you had done your engine mods incrementally or all in one big hit.
What I'm getting at is that the vacuum through the carb throat and vac. advance need to be within specified parameters or you just get next to nowhere with high fuel consumption and very little power.
Once upon a time, I had a competition distributor and a Webber 38 DGAS carb fitted and running nicely, I then broke the cast exhaust manifold and replaced it with a set of headers, & that was where the problems started. The long and short of it was that the increased air flow and reduced inlet manifold pressure unbalanced the air fuel mixture and caused the distributor to over-advance the ignition so much that the engine only ran on full choke and then died when the automatic choke cut out! It also sounded like a bag of nails and couldn't pull the skin off a rice pudding. I eventually had to ditch that distributor and go back to the stock Motorola set-up and get the carb seriously re-jetted, took a day on a rolling road before my mechanic was happy enough to let it go!
Post by: henrycj5 on August 31, 2006, 05:53:42 PM
The engine was rebuilt once about 8 years ago but sat in my garage before I finally completed the restoration job. Everything was stock and when we first got it running it didn't run right and had a similiar tapping sound as to what it has right now. The oil pump then packed up whilst driving and a lot of damage was done to the bottom end.
I have then had the engine rebuilt again.. early this year and whilst waiting for the engine to be rebuilt by the local mechanic (I regret now not taking it to someone will real experience) anyway whilst it was being finished I went shopping in the US and brought myself exhaust headers, a performance inlet manifold and a 4br Holley.
The local mechaninc could not set up the timing that well and didn't know his way around a holley carb either. So I have been driving with terrible fuel ecomomy and a nasty tapping/rattling from the engine for a few months.
Anyway to finish the essay, I now have an American Car specialist looking at the engine. He immediately set the carb and timing in a matter of seconds giving the Jeep loads more power!!! He is now looking into getting to the bottom of the rattle which he believes are being caused by incorrect lifters! (apparently they are not long enough according to him)
But all your suggestions sound very interesting so I will be passing them on asap! Many thanks, Henry
Post by: isle of man on August 31, 2006, 06:01:44 PM
peter henry
Post by: eastryjeep on September 01, 2006, 12:31:54 PM
Post by: eastryjeep on September 01, 2006, 01:39:13 PM
Back in the dark days of history I installed a simple mod which anyone who doesn't want to risk a siezed motor can do!
Install a brass or steel Tee piece and pressure switch, either before or inline with, the oil pressure sender, then wire it in or have it done by a pro, so that if the oil pressure drops the feed to the ignition is cut!
I don't consider it a down side, but it does mean that the engine won't fire on start-up until it's got sufficient oil pressure, so your battery does need to be in reasonable condition. Just make sure your sparky tells you how to over-ride the mod incase you ever need a jump start, and then replace when you have a nice healthy battery again.
This also has the added advantages of protecting you from upset bank managers, the wrath of her indoors and could even be considered cheap wallet insurance!
As ever, all vehicle modifications are done at your own risk.
Post by: henrycj5 on October 11, 2006, 04:15:07 PM
For any of you that are curious as to what was wrong, it turned out that slightly longer push rods solved the problem! I'm no technical expert but after 3 engine rebuilds it's now perfect!
Hope to see you all at a Jeep event soon, although now the engine is running quietly I've noticed a whine from the rear axle.. oh well! ha ha
Just
Empty
Every
Pocket!
ha ha
Post by: Ric Jacques on October 12, 2006, 09:25:19 AM
Post by: eastryjeep on October 13, 2006, 01:27:27 PM
Only a bit of rear axle whine, you should hear my Jeep whinge if it doesn't get the attention it thinks it deserves, struth, if I forget to get it something nice for Christmas I'm sure the sod would fail it's MOT just to spite me!