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Rough idle, Cam off by one tooth?

5K views 26 replies 8 participants last post by  familyman 
#1 ·
Hi, I'm still trying to diagnose rough idle condition and I'm very concerned. Vacuum at warm idle is low (11.7-11.9) and is not a vacuum leak. Vacuum snaps up to 20 over 1000 rpm and runs like a champ. Sprayed carb cleaner all over to locate vac leak and no changes in anything. Besides, fuel trims do not show lean mixture at all. Long term trim is -14% at idle on both banks. I have yet to test fuel rail pressure? All cylinders passed compression test. Tonight I will start motor with new plugs and lead to be certain it is not those items.

I'm afraid I may be a tooth off on cam if possible? ?has anyone heard of this? Is it possble to slack one side of chain and retard or advance cam?
 
#3 ·
Isn't this some strange oddball cam that you've used? It might be possible that someone can tell you what vacuum readings you will get with a standard cam, or even a known one, but the only person that can tell you what it should be for this is the person that made the cam. It isn't unknown if a cam has too much overlap for the idle to be rough anyway, it's a trade off against the extra power it may generate (or simply the extra fuel you will use).
 
#4 ·
Are you serious?
I asked in your last posting about this crap, to post the camshaft card for that cam you saved money on. No reply.
I asked for actual fuel pressure readings.....No reply.
Now you make another thread about the same crap?
After talking to Scotty today, I can certainly prove you wrong in one fact, all injectors are NOT the same. It did however, provide a very good laugh.
So you bought some injectors for cheap, and then screwed up your fuel rail due to them needing "modified" to work with those cheap injectors. Bad.
You bought some off brand camshaft, to save a few $$. Bad
I attempted to tell you what works, and is proven, at the beginning of all this, you wanted to save a few dollars here and there. Down to rummaging through o rings instead of buying the right one. Here is a hint, IT DOESN'T WORK.
Your camshaft is junk for a Range Rover.
Your injectors are either way over fueling, or maybe under fueling, but I would guess over. Your poor computer is trying to compensate for things that are way out of it's parameters, so give up there too.
This reminds me of someone else that tried to save money here and there, and eventually bent pushrods after screwing with it time and time again. Guess what? He sent me his motor to build right, and will have over $6,000 in it by the time he is done. Not my fault, purely his. He should have either listened in the first place and had support, or just sent me the thing to begin with. Like your injector theory though, those pushrods make me giggle every time I look at them....

Martin
 
#5 ·
You can just delete the post.. I'm obviusly not going to get any genuine help from anyone who wants to diagnose engine problems that arent the cookie cutter LR build..
 
#7 ·
There's a good reason for that. The stock Landrover engine works just fine. Every time you change something for a non-standard part you make it worse.

Why do you think that you know more about it than the original designers?
 
#6 ·
Although Martin's post is entirely undiplomatic and rather barbed he makes a very valid point. You were handed part numbers and suppliers names for after market parts to boost your build that are tried and true with guaranteed tested results. You have ignored tried and true advice before, during and after your build. You went with nonstandard parts that have little/no real world use or tested experience. You now have a hodge podged mish mash of parts that aren;t working well together. I can guarantee nobody here has the combination of variables you have created for yourself and thus have no experience or real world input to give. You are blazing a new trail yet asking for directions. Sadly with the limited information you have provided you are on your own. I wish you the best of luck.
 
#8 ·
No one tried to help?
I have asked for the camshaft card, and actual fuel pressure numerous times.
I tried to offer advise of how to build the motor the RIGHT way at the start of this, you wanted to save a few bucks and thus ignored it.
There was a 5% chance of you knowing your stuff enough to go out on your own limb, until you claimed that all injectors are the same. You then lost the 5% chance I gave you.
This is like me asking for advise on my LSx build.....I am on my own and fully understand that. The difference being I actually know what I am doing, and don't ignore advise given by those that know more than me on a specific topic.
A P38 engine is a known quantity though, as well as the parts that are proven to work. Yep, they cost actual money vs a 1980's SBC/SBF engine build. This is why it says "Range Rover" on the hood, and not Ford or Chevy.......
Sheesh, talk about getting your ball and running home with it.

Martin
 
#9 ·
I'm sorry I have not posted the cam card info sooner. I could not find it until last night. It is a Erson p/n E6400, RV10H RV15H 111+4
over lap 62.00
intake open 33 Exh close 29
intake close 67 Exh open 79
Valve lift int .446 Exh .460
Duration 280 288

@.050" lift
overlap -11
intake open -3 ex close -8
intake close 31 ex open 42
duration int 208 dur exh 214
lobe lift int .280 ex .288
intake centerline 107
 
#12 ·
Thanks Martin, I do apreciate you help and realise the path I took is the wrong one. But, is the F-d up path I'm on. So, I trudge on. About the injectors, their resistance, shot and orifice size are the same. Only difference is that they are motorcraft branded and are slightly taller and are grey. Oh yeah and the dont say $$Land Rover$$ on them... They were new and not rebuilt..
 
#13 ·
From what I was told a good vacuum for these motor is up around 20.. With a mild cam I have no idea.. I would assume not to far from 20 either..
 
#14 ·
Having nothing better to do, well that's not strictly true, I've got lots of better things to do but thought I would see if I could see what you are talking about anyway. The Erson online catalogue quotes your cam as being suitable for 3.5, 3.9 and 4.2 litre Land Rover engines up to 1994. That's a 14CUX engine, as fitted in a Triumph wedge, but you don't have a 14CUX engine, you have a 4.6 with engine management that is two generations newer. The spec for the RV15H grind also says "Rovers and TR-8s with lightly modified cylinder heads, aftermarket aluminium intake and free flowing dual exhaust system, increases low end torque and mid-range hp. Fair idle" So, do you have an aftermarket aluminium intake and free flowing dual exhaust? I suspect not because you probably have the cats still fitted so that throws any free flowing properties out of the window. You put it together so you should be the only person that can tell if it is one tooth out. Why not have a look? And if you've changed the injectors for something other than stock then it's surprising it runs at all.

I'd say take the cam and injectors out and bin them, then fit stock ones.
 
#15 ·
Just looked at your two videos. The horrible noise in the first one sounds like rockers running dry. Did you somehow plug the oil feed to the front rocker pedestal when you put the engine together? Did you check the preload on the cam followers? You may need shims if the heads have been skimmed.

The second video shows that it is running rich, the pre-cat lambdas are about shot because they are updating ridiculously slowly and the cats are shot too as the post cat sensors are showing permanently rich too.
 
#16 ·
Your injectors are probably junk, to that motor anyways. They are measure in Lb's, not by their resistance etc.
Your camshaft is positively junk for a stockish P38.
Your numbers are quite a bit higher than the level 2 performance cams I use.
They are the following specs.
INT/EXH - Dur @ .050” Lift: 196°/202° RR: 1.6/1.6 Gross Lift: .430”/.446” LSA 112°

Multiply your cams lift at .050" by 1.6, and see the difference. Too much lift, too much duration, and that in turn screwed the LSA. I think someone mentioned that days or weeks ago......Now who was that guy.....
As an example, jsut your gross exhaust lift at .050" is .4608", and your intake, and duration are equally screwed.
This isnt even considering your pushrod length is probably to crap too, or that you no doubt didnt measure the valve to piston clearances, work out your CR, and so on.
There are parts that work, and parts that need work. I think you figured out which one you have there.
Your insults to the guys that posted here wont get you much help. I know myself and Gilbert have more than enough experience to diagnose your problem. So the vailed insults need an apology in short order IMHO. I can promise you that we know what works in a P38 a whole lot more than that "reputable" engine builder that stuck that cam to you.
There are two ways for you to go, after sincere apologies get handed out freely.....
One is retarded, the other makes sense, as is the case in life.
Retarded:
Send your ECM to England for a custom tune.
Measure for valve clearance, CR and pushrod length. Get the pushrods custom made, although solid lifters and TVR rocker assemblies with tappets would make more sense at that point.
Dump the rigged up injectors and try to save the fuel rail. Install the Ford Motorsport injectors that I have used in the past. Search for part numbers.
Put it on a dyno, along with installing a wide band o2 sensor to keep a close eye on the AFR. 13.4-14:1 is ideal for a naturally aspirated small V8 like this one.
The sensible solution:
Dump the camshaft and install the kit I told you to a year ago.
Install the injectors that I do.
Break the camshaft in.
Go drive the thing and enjoy a smooth idle and great SUV performance.
I have another motor in my shop now, that someone tried to save money on. Didn't end up too well with 5 bent pushrods, chipped pistons, and so on. He will have about two THOUSAND dollars more into it, than he would have if I had rebuilt it to begin with. Some just aren't cut out to do certain things in life........
Your call, but everyone but you knows that the cam kit is 90% of your problem, with at least 10% being the junk injectors you rigged up. There are no quick fixes for this one. You made a bad call, now it's time to pay the piper so to speak. After sincere apologies all round of course.....

Martin
 
#17 ·
I'm flattered by the compliment Martin, thanks, but like you, my experience comes form doing things, sometimes getting it wrong and learning from it. Like you, not from Googling and finding rubbish posted by people who don't know what they are talking about. But, a little story relevant to this thread. Along with a couple of friends, I'm involved in importing cars from the US that are destined for France. It is impossible to register anything in France that doesn't have an EU Certificate of Conformity. Anything we import pre-dates this scheme so they are shipped to the UK and registered here first. Cheaper to ship to the UK and when the cars are finished, they have UK plates so can easily be transferred to French or other EU country plates.

This http://www.ebay.co.uk/itm/Beautiful...=&orig_cvip=true&rt=nc&_trksid=p2047675.l2557 is the latest one that we finished. When first put together the idle was rough and it smelt rich. No amount of twiddling with the carbs would get it correct so new jets for the carbs were ordered thinking that they may be worn. New jets fitted and it still idled rough and smelt rich. At that point it was left for for a few days as my friend had no way of accurately setting the timing as he'd driven over his timing light. I was taking the next import down (a motorcycle this time) so picked up a new timing light for him and took it down with me. We checked the ignition timing and it was correct but I knew he had fitted a fast road cam so pointed out that the timing may need to be different to standard to suit the cam. Tried adjusting it by ear and with a few degrees more advance, it idled a lot better. Still not perfect but a lot better although it still smelt rich (who needs a gas analyser when you've got a nose?). By now everything was new. The engine had been rebored, new pistons and rings, new bottom end, every bearing, bush and gasket had been replaced and the only unknown quantity was the cam. At this point the decision was made to try a standard cam. Swapped them over, set the ignition timing to standard, fired it up and it ran like a sewing machine. So smooth and quiet that you could hardly tell it was running.

So the moral of this story is that even 50 years ago engine designers knew what they were doing so if it ain't broke don't try to fix it. In fact, I would suspect that cams from 50 years ago are maybe better than ones now, in those days they concentrated on proper running rather than emissions and economy. The car actually sold for the asking price, which we reckon may be a record for a P1800.
 
#18 ·
I can normally tell when someone has learned from experience, rather than Google etc, so the compliment is well earned mate. From bloodied knuckles, bleeding limbs, and a lot lower of a bank balance.......rofl
There are some motors that respond VERY well to a mild cam upgrades, and others that do not. Over the past 15yrs, this number has got higher IMHO, due to emission junk and MPG being the two main goals in "normal" vehicles. The thing to remember is, in my book, that one thing normally leads to another. New cam and lifters normally require the push rods to be measured, and so on. The good news is, the cams I normally use dont require anything else to be done. Bolt them in and enjoy. Go with more lift and duration though, and you're on your own.
Would be like me asking why my 4L60E isn't shifting right, when it sits behind a LSx motor....:lol:

Martin
 
#19 ·
I can normally tell when someone has learned from experience, rather than Google etc, so the compliment is well earned mate. From bloodied knuckles, bleeding limbs, and a lot lower of a bank balance.......rofl
I started at the age of 11 helping my stepfather stripping and decoking the flat twin, aircooled Onan engines that used to be used to drive a generator in the back of ice cream vans and I'm now 59 so I've got a few years experience. Had the bloodied knuckles, had the bleeding limbs (and the seized back from leaning into an engine bay for hours at a time) but the one you missed out was the permanently black fingerprints and nails. Admittedly I've now started wearing latex gloves when working on a car to keep my hands clean but, as I discovered a number of times while doing the engine in my 4.0SE, you don't always notice when the glove splits so end up with black fingertips anyway! Age isn't helping either. I whacked my elbow on an axle stand while changing the engine in a Toyota MR-S we bought for my daughter 2 months ago and I can still feel it now.

Once the 4.0SE is 100%, that will be sold to fund an engine rebuild on my everyday car. Driving the SE has made me realise just how tired the engine in that is now. I'll have to get top hat liners fitted by someone that knows what they are doing (and has the facilities to do it) but I'll do the rest myself. I estimate that it should cost me just under half what it would cost to simply buy a complete engine already done. Not to mention the satisfaction of doing it and getting it right. For that reason I will be sticking with a stock cam and injectors.......
 
#20 ·
I started when my Dad bought me a FS1E......in boxes! The deal was, if I could put it together and pass an MOT, it was mine. Deal done and it was rode for a year or so.
The Crower camshafts are a nice upgrade, and not too expensive. The fact they need no other modifications is why I stick to them myself.

Martin
 
#21 ·
Thats the problem with performance cams I have found, if they can use the standard gears and keyways without any mods then they should be ok. but if the lift and duration becomes too much and you need to start filing the keyway or fitting vernier pulleys then your going beyond comfortable road use and need proper setting up which is time consuming and should best be left for sport or track cars, not really a 4X4 road car with an auto box.

Knee high to a grasshopper was my dad's comment when started working on cars with him, Always remember he was fitting a recon engine to our HA Viva, he goes in for lunch leaves his toolbox open, comes back from lunch and i have a very satisfied look on my face while he is looking at a stripped recon engine in bits on the grass lol I remember putting it together was a lot harder than taking it apart hehe.
 
#23 ·
Younger than me then. By the time the Fizzy came out I'd gone through numerous assorted mopeds and a couple of BSA Bantams that were ridden round a field, 250 Ducati (first road bike at the age of 16), Triumph T100SS and had moved onto cars...... First car was a Citroen ID19 Safari, talk about leaping in at the deep end!
 
#24 ·
Man those were the days! I remember getting my first car at 14, it showed up on a flatbed, all my dad said was, " when you put this thing together, I'll buy you a motor!" The motor showed up the same way!! ( Love you Dad)..
 
#25 ·
FS1E, then the air cooled RD's, then the liquid cooled RD's. Ahhh the smell of 2 stroke in the morning!

Martin
 
#26 ·
Never had a 2 stroke for the road but raced 3 seasons of motocross in the early 80's. All 2 strokes, all run on a 30:1 mix of Castrol R30. That really is a smell to wake you up in the mornings. Stayed with Yamaha though, got a 600 Fazer these days for when a Range Rover just isn't fast enough.
 
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