4.2 engine build

[skippy3k]

I will be pulling my 148,000 mile 4.2 out in the next couple of weeks and rebuilding it as a winter project. I am just waiting for parts at this point. I've done several head gasket jobs on Rover engines, but never got into the innards before. My goal isn't to build a monster 4.2. I use my LWB for long trips, so I am looking for overall longevity and reliability....with maybe a little extra performance.

Part of what initiated this rebuild is no compression in the #1 cylinder and sketchy maintenance history from the previous owner....but mostly I just wanna do it for fun and some experience.

Here is what I am planning (and what I am comfortable with);
Crower 229 camshaft
Lifters
Double roller timing chain
Valve springs
Valve job
Headers (ceramic coated)
....plus the usual cap, rotor, wires, resurfaced heads, etc.

But what I don't know is does it require any special tools to pull the pistons and replace the rings? Obviously, I will have the engine on a stand. The manual makes it seem like I remove the pistons, change the rings, and put them back in. I just don't want to get into a position where I need special measuring tools, or something like that. I am not good with precision instruments. I know I need to replace the big-end bearings too while I am in there. Anything else?

I am comfortable with engine work, but I know I am headed into uncharted territory with the bottom end of the engine. Does anyone see any "gotchas" or other things I missed that I should do?

Thanks.

 

[mmathews]

I took my crankshaft to the machine shop and had them check it and polish the journals. Only cost me $20.00.

 

[ptschram]

It sounds as though you need to do some reading on engine building before you start assembly. You'll also likely want to buy some measuring tools as well.

 

[Chris-St Louis]

Are you using Rover Spec Valve Springs, or stronger? The OE ones are worth measuring before replacement, they are usually pretty sturdy.

 

[mmathews]

It might be best to wait on ordering parts until the bores are measured and the crank can be measured. If the crank needs to be ground or the block needs to be re-bored it will determine the parts you buy.

 

[lforgue8]

It sounds as though you need to do some reading on engine building before you start assembly. You'll also likely want to buy some measuring tools as well.

X2 and to add to it bearings need to be damn sure they are within spec and you should have measure tools....if you are going to do this once you can find halfway decent outside and inside mics at harbor freight and also buy some plasti guage

good luck and double check all your work

 

[ptschram]

For the love of God Chris!

Let's get this man a book and teach him to rebuild engines, not spoon feed him!

From my experience, the stock valve springs are pretty weak, but amazingly consistent. My machinist who does my head work always checks the springs and he has commented on the consistency of the Rover valve springs, even in engines with MANY miles. That said, if one expects improved performance from the cam (BTW-get the 230, it's well worth it and the desktop dyno simulations bear this out), stronger valve springs may show a benefit.

 

[Chris-St Louis]

They are weakish, but for a low rever, I woudlnt worry too much, plus less spring tension is less stress on the cam.

But, yes, a book is best, and order after a teardown.

 

[skippy3k]

PT - I don't want to understate my abilities. I am not a complete novice with engines, but I am not a mechanic either. Do you have any books that you would recommend?

Chris - I will be using valve springs from D&D that are to be used with the Crower cam. (RV-911)

All - I will send the block and crankshaft out to be checked as well as the connecting rods for balance. But what else would I need to be measuring? I do own a ruler and a really good tape measure.

And beyond measuring, does this project require any of those damn Land Rover specific tools?

 

[skippy3k]

BTW-get the 230, it's well worth it and the desktop dyno simulations bear this out), stronger valve springs may show a benefit.

When I spoke to D&D, I believe they mentioned that the 230 would require some machining to make it work, and there wouldn't be any "seat of the pants" benefit. Keeping to my original plan on not making it a "monster build", I decided to keep it simple with the 229. However, the cam has not been ordered, so I could still change my mind.

 

[Chris-St Louis]

You will need the heads machined to fit the new springs properly from D&D.

I dont know much about the 229, but if its pretty close to spec, I cant see a advantage to the stronger springs. Tighter springs help with float at high RPM, Rovers dont see that high rpm for more then a few seconds at a time.
Plus, you have to pay more to have the head machined.
Also, they are REALLY much stronger...TOugher to install and will increase cam wear, even with a ACEA C3 oil.

Just my .02$

 

[ptschram]

OK, the springs that Mark suggests , IIRC, have a seat pressure of 90 lbs, the stokcers run in the range of 60-65 lbs, a significant increase, but not a huge amount on an absolute basis.

WRT the 229 vs the 230, Mark and I have discussed them at length and he won't sell me a 229 as he is so strongly in favor the 230, even moreso after my research last year, using readily available camshaft profile data and the wonderful application, Desktop Dyno. In what will no doubt not surprise anyone who knows me here, MArk commented that I was the first person to have gone that far and he was pleased that I shared what I'd learned. The Rover engine sees the greatest benefit from the 230, but none from any of the others I could find profile data for. The 230 really is the best currently available cam profile for our engines.

I have installed many of the 230 cam and have yet to need to do any additional machining. Also, I've never had to have the heads machined to provide an acceptable valve spring geometry. The cam I have for MY 4.2 is the 230 and has not required any additional machining-although, to be honest, that is about the only thing for which this block has not been machined for.

Buy a book before you begin the teardown. Knowing things to look for and things to avoid can save you from costly mistakes. The Smokey Yunick Small-Block Chevy books are where I learned most of what I needed to know to get started. Hotrodding the Small Block Chevy is another great reference and I still cannot believe I left it and most of my engine machining texts in my old house when I moved!

WRT measuring tools, buy a set of telescoping gauges (mine are a set of Mitutoyos I bought 30 years ago) and micrometers (obviously, Starrett is the best here and worth every stinking penny, IMO)for crank journals and piston sizes. The pistons are 3.7" and I don't have the crank dimensions handy (well, I do, but I'm being lazy) but I think a 3-4" and 2-3" micrometer will get you covered. You'll want mics that can measure to 0.0001" as the crank clearances are tiny (well, up to 0.002") and you'll want some dynamic range to be able to adequately measure the dimensions. You'll also want a piston ring compressor.

 

[t77911s]

Two other things you might consider are: 1)The ARP main bearing stud kit, and ARP Head studs. The "mains" stud kit supports the crank much better than the OEM bolts (much more critical on a 4.2), and on the head studs if you ever have to remove the head again, the studs will have paid for themselves. Also much easier to torque. D&D sells both, you can talk to them about additional benefits. I'll never build another engine without either of these.

Tim

 

[mmathews]

One thing to check into is the proper break in rpm and time. Also, from what I gather engine oil needs to have an additive for the proper break in. Ask Mark when you are buying parts.

Based on past experience I am adding an oil pressure gauge, so that I can make sure I have oil pressure before starting the motor. The oil pressure light on the Rovers I have owned have not been reliable.

I just opened my box from D&D and I received the 229 cam. I just went with the one Mark recommended.

I went with the ARP head studs on a 4.0 block.

 

[landrovered]

Has anyone had any experience with the Rimmer Bros. Stroker kit that takes a 3.9 and makes it into a 4.8L?

 

[skippy3k]

Thanks PT, for the book recommendation and the advice on measurements. As for machining for the 230 cam, I swear that's what he told me on the phone. I might have got it wrong, but it seems likely that we were talking about the subtle differences between the 229 and 230. Maybe you and Chris will have to arm wrestle for it.

Tim - I was considering the ARP head stud kits as well, but wasn't aware of the kit for the main bearings. Thanks.

MMathews - Yes, I was also planning on installing an oil pressure gauge while I was in there. Mounting the gauge itself without it being obtrusive might be a challenge, but it's the least of my worries at this point.

I'll include pictures as I go, for those who are interested.

 

[hendrik]

Hi,

about books:

this one is made by Rover
http://www.amazon.com/Rover-3-5-4-6...=sr_1_3?ie=UTF8&s=books&qid=1230978227&sr=8-3
it?s not too user friendly but fort hat price it?s a good backup. All the data?s in there.
The official Workshop manuals do cover the engine overhaul as well, with including the ancillaries:
http://www.amazon.com/Range-Rover-W...=sr_1_2?ie=UTF8&s=books&qid=1230978428&sr=1-2
that should be the one for you. IIRC these are available on CD ? you?ll be able to get one from the LR-parts dealer. I think there even ? illegal ? server on the web where they can be downloaded. Up to each own whether the cost for the item is reason to seek for that.

http://www.amazon.com/Power-Tune-Ro...=sr_1_1?ie=UTF8&s=books&qid=1230978267&sr=1-1
This book I like a lot. It is no repair manual. Many pics. And very intimate info about the Rover V8. Helped me in choosing where to upgrade and where to stay with standard parts. Even though I rebuilt the engine for road use mainly. I will nowhere race it and rarely rev it beyond 3500Rpm.


PTS,
What is the difference between the 230 cam and the Rover-OEM type ?

When I rebuilt the engine 2years ago unfortunately I had no info about the 230 cam.
Obviously it is very easy for a manufacturer and has no downside in tooling or production costs to make a cam with different timing or different shaped lobes (?steeper? or ?bigger lift? ? which possibly has disadvantages in terms of wear or can create an engine that yearns for higher RPM).
Therefore I wondered why Rover hasn?t made it first time like the aftermarket items do it now. I thought that Rover had exactly the universal use in mind that my RRC has to face, i.e. road, towing, economy (errmmm) and long-term reliability. I thought the OEM cam is very much THE compromise that suits MY use.
I felt safe by doing so because I do not know enough about the art (I think it is somehow) of choosing cams to assess whether any aftermarket cam really is an improvement ? the ads tell me so but that needn?t be true. With only that info in my head I would have felt lost in choosing any other cam. It was cheaper, too.
So I am asking out of curiosity now but (as I never witnessed you made any nonsense-recommendation) there will be some point in the 230 cam so I might choose it when the now-in cam is worn away. Hope it will take many years though

 

[Cambo]

Not directly related, but you should look into gettting some of the mustang injectors and rebuilding those to add to your "new" motor. I have also heard there are some advantages to shortening the ram horn thingy-ma-bobbers. Also, are you going with an aftermarket distributor?

 

[ptschram]

PTS,
What is the difference between the 230 cam and the Rover-OEM type ?

WRT the books, I was suggesting very basic engine building books, rather than Rover-specific books as the OP sounded as though he needed a generic intro to how to carefully tear an engine down and put it back together. I felt he needed to know things like how to not scar the crankshaft, remove piston rings and camshafts without tearing things up. Once he has the basics-which apply to every engine on earth-then, we can start on the specifics of Rover engines.

A "Mentor" of mine once told me that "once you get the heads off, they are ALL Small-Block Chevys! So far, I've found this to be pretty much true.

 

[t77911s]

Not directly related, but you should look into gettting some of the mustang injectors and rebuilding those to add to your "new" motor. I have also heard there are some advantages to shortening the ram horn thingy-ma-bobbers. Also, are you going with an aftermarket distributor?

I shortened my velocity stacks, I thought I felt more low end torque at first, but after driving it for over a year now, I don't really think there was a real seat of the pants difference. Now, on a modified motor, with headwork, flowed intake and exhaust ports, and headers, that may be different.

Lately, the biggest improvement I have made is with a MSD distributor from Summit Racing. Starts better, idle's better, and just over all more reliable now. I can pressure wash the hell out of the engine while idling and does not miss a beat, before with the OEM POS, it would choke out and then took for ever and a day to get it fired again. Even in heavy rain it would stall. I also used the button type cap just for a better/firmer connection for the plug wires to the cap. I also use Magnecore wires. My mileage appears to have improved, but I'll know more over the next several months to average it all out.

Just got back from 1500 miles in the mountains and truck/engine did not "burp" once!

Tim