Re-build

Hi all...Merry Christmas

Anyone rebuilt a 100,000 mile engine with success, i.e got a good deal of mileage out of it thereafter as mine has let me down and i am planning to rebuild it.

If you did, can you suggest a quality parts supplier or any other advice on what to definately change and what not to worry about.

Cheers, Nick.

After a pretty poor start and hours under the bonnet, fiddleing around, curseing and other abuse thrown at people who make simple things very,very difficult (incomparison to the two P38's ive done it seemed much more tricky....not sure if this is due to doing this one on my own or not) the engine is out and winging it's way to V8 developments to be checked out and re-worked with top-hat liners and other parts......

A very good friend lent me his workshop (He can make or help with most enginneering projects in the area around junction 13 (Stroud) on the M5 for parts cleaning and refurbing various parts and he is replacing parts of the gas system that were shoddy.....on dismantling i found that the gas injectors which they had rightfully put next to the petrol injectors, but had drilled the inlet whilst still on the engine!.....i have found the swarf in the heads, along with all of the bits of the rocker arm pads which fell off which would appear to be from too high a pre-load on the cam followers when the engine was built...but at least it didn't have chance to screw up the engine completely and i would mention that there was no noise from the valve gear even with six pads missing which is a fair gap for the followers to make up!

So now to clean out the engine bay ready for installation of the spangly lump when it is returned and tidy the bomb site that is my car port...

well done mate, good luck!

Thanks for that Mr Fett (did you get the info on the heads?), i have also found on my travels info on Bison's 4x4 site which may help others who are uncertain with what they are dealing with regards the many myths around 4.0 & 4.6's and lpg....

cool , yeah I did thanks. I know my 3.9 would benifit froma rebuild, especailly the top end but I am not gonna do it as all cash and efforts now into 72 project!

I will build my spare 3.5 carb motor into a stroker motor for it, wonder if a 4.2 crank will do that in a 3.5 block? I dont fancy spending £1600 on a stroker kit from rpi or real steel :doh:

Not sure, did they have to make the skirts in the newer pistons shorter to allow for the bigger crank throw and would it need the extra strength from cross bolting to hold it together.....not too sure about these things, i suppose you can pretty much do anything with a bit of thought.........still waiting for the transport company to collect!!

plenty of myths actualy millions of myths only a few concrete problems even then those that supposedly know dont know

I agree that it is a minefield of mis-information made worse by some people who embellish a story for the sake of it, backed up with the wrong info from a conversation with a mate who had a mate that said........

I am going to ask the company to take pickys if there is anything to see, but i suspect there will nothing noticeable........hey ho perhaps i'll buy the fiat Panda next time.

Nick.

preload will not cuase the ends to fall off the arms more like they were cheap patterns not gen parts all the engines i do it is coman with aftermarket stuff only get rattly arms for gen ones

Hi......i don't know the actual answer but if there is such a thing as preload, then this suggest's that a certain amount of static force (!?) is applied to the rocker arm by way of the valve gear/adjuster so if it was higher than intended would it not wear through the pads as it has.......if it is a duff batch then they were never fit for purpose....some of them (six) have actually worn all the way through and then fallen off.....and judging by the nuts and bolts i suggest that this engine hasn't been apart before but of course i can't be sure.

How many have you seen worn like this?

Nick.

Nightmare path to go that! If its a stock 4.2 crank set then you need to build it on a 3.9 - in which case cross bolting is not a bad idea as long as it is very late block, (ARP studs are nearly there), I've just about finishing a TVR 4.3 (same as 4.2 but higher comp ratio and valve cut outs on pistons), and to find pistons for 4.2 is almost impossible - I did find a few but they where £130+... EACH!!!!!!!!!!! Turns out 4.2 where a special by JE.......



Anyway before spending loads of cash on it, I would whip off mains and a couple of pistons have a look at crank, if major gouges/scratches (feel them with finger nail) you will need it reground you can exchange with real steel at around £150, then you will need bearings £80ish quid, next take a look at bores, important to check if any scratches, again finger nail test is good for indication, and finally if there is any feelable step in top 5mm of bores, if there are any you can be looking at a £400 quid bill, at which point your looking at £600 -£700.....



....A lot of money for a 3.5.... At that point it would be worth considering going down a 3.9, easily found from most of the V8 people, if you shop around, JUST MAKE SURE YOU GET A PRESSURE TEST CERTIFICATE with it.....



Other thing to bear in mind is on the heads, biggest thing that robs power is poor valve seating and gerneral sh 1t build up, again before spending a lot of time, get the heads vac tested, a great contact to speak to is this guys:



HEAD SEATS & VALVES
176 ARGYLE STREET
B7 5TE BIRMINGHAM , WEST MIDLANDS

Phone: 0121 327 2232

He will talk you through it, but your looking again at around £250 ish quid for getting both sorted, mind you at a bit more price Ray at V8 developments could sort you out a very, very nice stage 2 head, with double valve springs, etc, 6500 rpm!!!!!!!!!!

Other thing to watch is rockers, I went on a mission to try and find a OEM set of thoose, (plenty of steel, don't quite fit, MGB stlye ones around, some are ok, but just be really carefull!!!!!!!!!!!), but ali ones are almost imposible to get now, again found some at a LR dealer and they where asking £35 each!!!!!!!!!!!

Other thing to check is front cover and oil pump cover, if these are knackered, figure £500 - £600 for OEM parts and £350 - £400 for repro, (V8 tuner where selling these repro, but at last check he could not get them....)

Anyway my point is this, I would think really carefully about doing a rebuild on 2 engines as it will became very apparent that over the last 4 years, parts are getting SERIOUSLY hard to find, and stupid expensive (just check out all of the omissions real steel have made between 2009 and 2011 catalogue). End of rover v8? well future is not looking good.....

.....Not great when you can buy a complete NEW LS3 motor for £3K.....

Oh cannot recommend Ray and Shaun at V8 dev more highly!!!!!!!!!!

Hi.

Have already spoken to Shaun, having looked at my engine i gave them an emither and they are doing the rebuild for me.

Just got sit around till it comes back ......rubbish!.

Cheers for the info, Nick.

There is a very good book that comes highly recommended from engine builders - its called how to power tune a V8. There is quite a lot of stuff in there about racing modifications to the rover engines but there is also a large amount of information about the engines themselves, development, wearing points, failure points etc and a good guide on just generally rebuilding the engine.

If anybody is thinking about doing this (as I am in the process of) I'd highly recommend it.

There is such a thing as pre-load on the lifters too. Not a lot but enough to stop the arms rattling.

Hi.

The pre-load issue was brought to my attention by V8 developments as a possible cause of premature wear to the pads at the valve end of the rockers....as i said before, six of them had worn through completely and fallen off....something i've never seen or heard of before.

Thanks for the info, i have a 4.6 here that is waiting for re-build so i will get that book i think.

Nick.

I am reading that book at the mo

So apart from efi heads to get the better vlave stem seals what would you recommend for a pre 76 3.5 with very low miles on it. I have dont magnecore leads so far and lumenition kit to go in soon.

I'm no expert and I'm only telling you what I have read from the book and picked up from the web. However, the ARP stud and bolt kit on the main caps is recommended to prevent the registers fretting (especially on the earliest blocks), drilling the over pressure release cap (tap it and put a bolt in it to restrict opening) on the oil pump to increase oil pressure to 60Psi when hot which will reduce bearing wear and ensuring cooling is kept about 80 deg C are a good start.

The other thing I think that is recommended is only to use 10 bolt head retention rather than 14 to prevent head gaskets blowing.

I should have said, the book is written by Des Hammill.

Jon

Also Changing oil pump for deeper type, about £40 nicker v8tuner and rimmer bros... And big valve heads from late SD1 -flea bay job...

are the old ones even supposed to go that high for oil pressure? lol, I think thats as high as the gauge goes

my 72 has v low miles and has about 20-25psi at tick over when super hot and thats with tickover at about 500 rpm. it goes up alot when revs come up or when cold. I have been told that the system is designed to work on volume not pressure.

Thats what i was told, as it is fairly historic in design.....

I've just taken mine to the machine shop (£1,500 for all the work - not yet sure it is worth it) and his experience is that they do run very dry at the top and it was very common and a good idea to increase the pressure to get more oil up to the rockers and rocker shafts. 60psi comes from the Hammill book so can't say more than what I have read!