V8 Questions

iwish

Active Member
HI i am currently restoring my 3500s, the engine compression ration is 10.5.1 it was last on the road in 1986 the speedo shows 26k which i assume is 126k as i have no service history for the car, only the log book and the tax disc that was in the window.

I have started to inspect the condition of the engine which i can turn freely but have a couple of questions:

Would this suggest it was re-built at some point?
1. The end shells are in very good condition and marked 010
2. The piston linings are very smooth with no signs of scoring, but a couple are showing a few blackish discoloration marks as if there were spots of surface rust, some of the marks are the size of a 20p, the marks feel smooth and there is no pitting?
3. The pistons and cylinder head has a very thin and even deposit of soot.
However:
4. The oil is very black and sludgy, almost like tar and feels gritty but not metallic looking.
5. The rockers are coated in a thick coat of dried on black tar?
6. The Con Rods are covered in a thick layer of surface rust, but there is no sign of water in the oil?
7. The cam shaft wear looks a little uneven.
8. The hydrolic tappets are lightly dished on top but not all have worn evenly?

What is the general feeling: based on the fact it has probably done 126 thousand miles and sat with everything in the same position for 30 years?

Thank you for reading.
Dave
 
The fact that you have uneven wear on the camshaft tends to indicate a camshaft and follower replacement is due. A good engine clean is probably wise with the block being dipped and blown out to remove any build up in oilways.
Check the heads are not warped. and check the piston ring end gaps at the top of the bores and also the ring to piston groove gap. as you say the bearings may be a size up, not sure what Rover did for standard shells. It would also pay to check the oil pump gears and end float.

I always find with engine rebuilds thats its the old how long is a piece of string scenario and that you can get a way with a lot of sins and save a lot of coin and just let the engine run until you are forced to be a bit more spendy


Graeme
 
The camshaft and followers are likely to be junk anyway on an engine of that mileage. In fact it could be nearing the end of the 2nd set. 70,000 miles or so but it depends on how much power drop off you can tolerate. In the best US tradition these will just keep going, just slower as the valve open less. Any overhaul should replace these as you can do the cam and followers for less than £150. Also a new oil pump gears and waterpump.

Internal corrosion will happen if the car isn't stored at a constant temperature through condensation.

Sounds to me this was an everyday motor (just about reasonable in 1986) and the oil services were skimped a bit. Not unusual in cars which were beyond the owners pocket to run properly. Similar to upmarket off roaders that are a decade old today.
 
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Hi, I would agree with the above, it has probably had a rebuild at some point and had infrequent oil changes since. The bores do bear mileage very well and a re-ring will be enough with a glaze bust of the bores, ends and mains to replace subject to checking the journals for wear and possible regrind. Camshaft and followers replace also check the rocker shafts for wear on the underside, replace for what they cost. New oil pump, timing chain and gears. A good clean of the block.

Colin
 
Hi, I would agree with the above, it has probably had a rebuild at some point and had infrequent oil changes since. The bores do bear mileage very well and a re-ring will be enough with a glaze bust of the bores, ends and mains to replace subject to checking the journals for wear and possible regrind. Camshaft and followers replace also check the rocker shafts for wear on the underside, replace for what they cost. New oil pump, timing chain and gears. A good clean of the block.

Colin
That sounds like what I'd be considering at this point. Pull it out, strip it down, inspect everything and proceed to replace as required, based on finances and access. Being lazy, I'd spend more time and money on the basic core of the engine like pistons/rings, bearings before moving to accessible bits like rocker shafts and oil pump, providing they are all within acceptable tolerances for you. Those are all doable with the engine fitted, even if they are awkward, so could be persuaded to wait for funds.

Don't forget the Welsch Plugs in the block and the inlet manifold, also the carb tower bleed to the radiator that is so fond of clogging up.
 
HI Guys,
Thanks for your comments.
I have now stripped down the rocker shafts as suggested and they are very worn on the underside easily up to 1mm.
Some of the valve tops have a slight v worn in the top but the valve seats look good.
I will have to investigate the state of the pistons and bores further as the general appearance and bearing size of 010 is throwing me into thinking the bottom end has been rebuilt for some reason?
Another question: are the cylinder heads suitable for use with un-leaded fuel?
Dave
 
Another question: are the cylinder heads suitable for use with un-leaded fuel?

Technically only post-76 engines are. But in reality it is believed the earlier seats are no different. I don't use any supplements.
 
I have now stripped down the rocker shafts as suggested and they are very worn on the underside easily up to 1mm.
I have read that some of the aftermarket ones are worse than useless, turning to the same in short order, so rather spend the extra and get OEM.
 
Hi guys
My friends 72 3500s which i maintain for her has been using standard unleaded fuel for at least 10 years.
Its used every day although she does not do that many miles,runs a treat with no problems or pinking.
Runs electronic ignition with timing set at 4% BTDC .
If it was mine would use super unleaded only because i would drive it much harder!
cheers clive.
 
HI Guys,
Thanks for your comments regarding the heads and unleaded fuel, they are all very reassuring.
Sitting on the throne, looking through some back issues of the Driving Force magazine, i came across a very useful article on upgrading the V8 engine which made it pretty clear that the original cylinder heads should replaced, so decision made.
I have now stripped the pistons out and and given them a de-coak.
I have also read the workshop manual several times and cant relate what i have to the manual.
The Block is cast with what i assume is the grade letter "C"
The pistons are stamped on top with +020 L13 and marked internally 18069 G1
Does this mean the engine has been re-ground or is this original?
Thanks for your time.
Dave
 
Reboring and bearings are sounding more like 226k (or more!) than 126k... Unless the maintenance has been really poor..
 
Easily the most important part of your overhaul is the cleaning. Don't be tempted to do it yourself, get block, crank, heads and INLET MANIFOLD chemically dip cleaned. That way you can be sure that all oilways have had the tarr / scale removed and that YOU haven't dislodged scale into somewhere important. The inlet manifold because of the impotance of getting the internal water passages clear, particularly the one between the carbs. Don't do that and you will suffer from pinking and fuel vaporisation.....
 
HI Guys,
A quick update, following your wise words.
I took the cylinder block and crank shaft to my local machine shop who on closer inspection said that they were within tolerance and recommended the crankshaft be polished and the cylinders be re-honed. I always intended to fit new piston rings and bearings etc. I also had the engine block and inlet manifold acid bath cleaned as recommended.
Quite unexpectedly this was done on the same day for a total cost of £84.00 Inc VAT I'm very happy with the look of the finished product and more importantly with the advice i was given, after all they could have told me anything and i would have had to believe them.
For those that may be interested the company is called BANDA Engineering. Its a small family business, details can be found on line.
As recommended in the back issue of the Driving Force magazine mentioned earlier, i have managed to get some HRC2479 cylinder heads that are in good condition, i will replace the valves, guides and rockers etc regardless of condition. One thing the DF article didn't cover is what spark plugs should be used?
Many thanks
Dave
 
careful with replacement rockers - a lot of aftermarket ones are of poor manufacture and lose oil pressure very quickly... Your originals may be better if there is no sign of wear!
 
As recommended in the back issue of the Driving Force magazine mentioned earlier, i have managed to get some HRC2479 cylinder heads that are in good condition, i will replace the valves, guides and rockers etc regardless of condition. One thing the DF article didn't cover is what spark plugs should be used?

You can try Champion N9YC. I use these in my 4.6, now with 133, 000 miles (214,000km) covered since 2007, no problems with these plugs at all.

Ron.
 
Hi, I agree with rockdemon, just change the shafts because they definitely need doing, you can check the wear in the rockers if any. Soft will always wear hard,

Colin
 
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