Engine upgrade

stina

stina

New Member
Hi guys .
Been thinking for a while about a few modifications engine wise . While mine runs lovely , good oil pressure , smooth . I would like to get some bits up together and build it up when the time feels right ( next winter ) . Not a mad high revving monster just a few of the more common mods . Was thinking 3.9 cam , uprated timing gears/chain , sd1 heads , ceramic manifolds , electric fan . Would want to use my carbs as i rebuilt them few months ago , and i have electronic ignition . I,m in no hurry , the idea is to get the bits up together over the next 8/10 months as and when they turn up , and funds allow . ( plus i wanna burble around all summer ) .
I have seen sd1 heads on ebay , what serial no should they have ? What manifolds ( exhaust ) would i need to use with them ?
Where is the best place to source cam (3.9) and lifters , timing set etc . Obviously the heads will be second hand/rebuilt but i want all the rest new .
From what i've read on here this would make a nice engine , a little extra torque without ruining the character of the thing .
What do you thing of my specification , idea ?
All advice welcome , but not too technical at this early stage , i'm only at the planning/ thinking stage at the moment !
Stina
 
Stina

Have you checked out the V8 forum? Lots of good advice there and you might recognise a few people too :wink:

There area few people here who have done major engine work so have a look at their project threads. I know both vaultsman and testrider have done top end rebuilds so those would be a good place to start.

Dave
 
Hi Stina,

How many miles is on your existing engine and how many miles would you typically drive in a year?

If you wish to undertake a partial upgrade, then go for a steel timing set, new rocker assemblies, pushrods, lifters and camshaft along with a set of reconditioned SD1 or later 14 bolt cylinder heads. I would keep your existing exhaust manifolds as there is essentially no difference in exhaust port sizes between the P6 and SD1 heads. The 3.9 camshaft has a different profile compared to the 3.5 item, so power comes through sooner and also finishes sooner but that is not a problem unless you plan on racing the car. You will also need to fit different needles into the carburettors, BAK or similar will keep you out of trouble.

Real Steel can supply all the engine items that you would require, Burlen Fuel systems the needles.

Ron.
 
Cheers guys . Ron car has 63k miles which i believe genuine . I do about 2 to 3 k a year . I never really rev it past 4 k rpm so if the 3.9 cam lets the power out earlier then that would really suit the way i drive it . the other mods are for reliability and smoothness , a nice quiet engine with a little extra power is what i'm looking for . ERC 0216 , is that the right numbers for sd1 heads ?
Stina
 
Hi Stina

An intelligent spec as I'd expect from you!

A couple of comments. Are you going to disturb the crank, or is this purely a top end and timing chain job? Be aware that if you go to change main bearings there is a risk you will discover a main bearing cap fretting - that would be curtains for the block

Buy the best timing chain set you can - I'd go for one with a vernier adjustment for the cam.

Don't forget to convert the timing cover to a lip seal for the crank if you haven't already done that.

You've missed off a very important item - upgrade the oil pump to the later spec with the longer gears - they are sold for the P6 engine with an extension housing for the extra length. No effect on oil pressure, but ups the volume of oil going round.

If you're going to fit an electric fan, please start by making sure you are running a 3 row rad. If you don't already have one get the rad shop to mount a rad fan switch to the hot side tank whicle they are changing the core. Then you won't have to faff around with any of the various lash up systems for switching it.

There's a decision to make on what sort of compression ratio you want. Even using tin gaskets you will lower it somewhat, but using a composite gasket set will lower it a lot. Every time you lower the CR you get further from risk of pinking on poor fuel. But you also lower the power output and increase the fuel consumption. Personally I'd use the SD1 heads with tin gaskets.

You mention ceramic manifolds? I'm unclear what you mean by that. On the basis of improving engine efficiency it is worth fitting larger, fabricated manifolds (plus the system to go with them....) At the least, make sure you have "S" manifolds. and what about doing the "Lucky breathes easy" mod. For your use you don't need to open out the inlet trumpet to the extent I did.

After all this attention, you really do need to treat yourself to a rolling road set up to sort out what timing and what needles you will need. Add around £350 to the estimate to cover.

Hope that's constructive.

Chris
 
Just watching this thread with interest, because i suspect its something that will be on the agenda someday.
I do have some questions...maybe you would know Chris...and it mainly concerns the old 'bang for your buck" scenario.
After reading some posts on the "V8" forum, there was (a little) consensus that the 3.5 was quite limited, and that to get decent power (200+ HP), would cost a few $$.
Cut to the Rimmer Bros catalogue...and in here they speak quite glowingly of what a "stroker kit" will do for the ubiquitous 3.5.
Basically, it takes it out to around 4.3 litres with a "massive" increase in torque.
Whilst no prices are shown, the list of parts doesn't seem as long as those required for a topend rebuild.
On a $$ for $$ basis, is this a better scenario?
 
Mmmm. Things always get difficult when you try to weigh up value for money.

Lets start by looking at the 3.5, as per the P6, weak points. From a longevity point of view they can suffer from fretting between the main bearing caps and the block. If this happens you have a scrap block. Otherwise things on the 3.5 are generally mileage and abuse (= infrequent oil changes) related. The heads on the P6 definitely limit the engines potential through inability to shift volumes of air. So either it won't rev, or you can't effectively go up in capacity, or both.

So step 1 is that you need to take a leap of faith and assume the main bearing caps are OK.

Given that, then next step has to be liberating the power that Rover installed in the first place. Almost no cost for a Lucky Breathes Easy intake system mod, and moderate cost for decent fabricated exhaust manifolds and system. You'd have to do these whatever other changes you went on to make. That's got us around 20 bhp up - and that's really good value for money! Note that the exhaust is about the same cost as changing the carbs for a 4 barrel and liberates as much power - so definitely do the exhaust before you do carbs. In fact both Ron and I would contend that the SU's are perfectly satisfatory up into the low 200's of horsepower. So really a 4 barrel is a designer choice rather than a necessity, given that you already have the SU's!

After that the next step has to be heads from a later engine with the larger valves to open up the upper reaches of the rev range (say above 3,500 rpm - we're not talking screamers here!). I'd love to recommend some Merlins here, but they don't justify on cost. If you did something to the capacity it might be worth getting aftermarket big valve heads beyond the SD1 and later valve size, but the cost has just jumped a step change..

I'm going to leave cam chooice for a bit until we have a final spec for the engine fundamentals.

The only other thing I can think of to do to a 3.5 beyond this discussion is to use the crank from a 4.2 Range Rover Classic. That still works in the small journal block, and I see no reason why you couldn't use it with 3.5 rods and pistons. You can do the sums on what capacity that would give, but it'll be around 3.7 or 3.8 ltrs. 4.2 cranks can be had reasonably cheaply.

So back to the cam. With the 4.2 crank we now have quite a long stroke engine, so torque will look after itself to a large extent. We definitely don't want a 3.9 cam, as that will make things much worse - all torque and no go! A "fast road" cam would be my recommendation. Use that to open out the top end leaving the long stroke to look after torque.

So, we liberated 20 bhp from the intake system and exhaust. Perhaps another 20 to 30 from the capacity, heads and cam combined. That leaves you around the 200 bhp mark with at least as much torque as the original.

We haven't gone silly on cost, but the next discussion is what else we could have done. And that really boils down to finding a good large capacity engine in a Range Rover etc and doing a transplant. I'd be shifty about the likely internl condition of any small journal 3.9 engine, so that takes on to a 4.0 or 4.6. And along the way, that delivers having to change the timing case for the one from your existing engine. And if you do that you need a short nose cam. And could you resist having a look at the bottom end - in particular whether the liners have been moving, whilst you're changing the sump over (which is common on large journal engines). So this option isn't as cheap as at first appears. It's really only an option after you discover a dead block on your 3.5.

Now I'd want to talk that through with an engine professional before doing anything about it. I don't think I'm knowledgable enough to jump straight in without further consideration! And it won't have escaped you that a number of my suggestions diverge from conventional wisdom. But then most people who do this sort of thing have quite big budgets and also want shiny bits on the outside, or at least some pub posing points, which is not where I've come from for this spec.

What do others think?

Chris
 
From what I understand rather than messing too much with the engine, stina might get more bang per Buck from a zf autobox?
 
chrisyork said:
The only other thing I can think of to do to a 3.5 beyond this discussion is to use the crank from a 4.2 Range Rover Classic. That still works in the small journal block, and I see no reason why you couldn't use it with 3.5 rods and pistons. You can do the sums on what capacity that would give, but it'll be around 3.7 or 3.8 ltrs. 4.2 cranks can be had reasonably cheaply.
Click to expand...

If the 4.2 crank uses a longer stroke to get the extra capacity, and you use the standard 3.5 rods and pistons then as the pistons come to the top of the bore on the 3.5, then with the extra stroke they're going to pop out of the top........(and the bottom.....)
 
Rockdemon - on the basis of "never mind what they say, watch what they do", look at my programme with Lucky. Having sorted out the intake system and the exhaust, my next major step is indeed the ZF. But then, I do long distance fast trips, so I'll be getting major value from that. Whereas I think Stina mainly does relatively local running, so the lack of an overdrive top on the BW is not so crucial.

Chris
 
Hi Stina,

The reason I asked you about the miles on your engine and what you typically covered per year was for good reason. My original engine saw 63,000 Miles in January 1988 so given worst case scenario of 3000 miles per year, you could happily drive for another 46 years and still be short of the miles I reached with mine. Unless your engine is jet black when you look inside the rocker cover I would add to what Richard had already suggested and leave well alone.

The standard P6 engine as it left the factory is perfectly satisfactory for all but flat out driving over 5000rpm for long periods of time. Provided regular oil and filter changes are undertaken, flame traps cleaned or replaced as necessary along with the other filters being equally treated the engine will just keep on going. Indeed I used to say that of all the parts on the Rover, the item that gave the least trouble was the engine.
My original engine still had the rope type oil seal and it never leaked. The only problems I encountered along the way was a failed head gasket, oh and some of my main bearing caps did work loose. I could hear heavy knocking while the engine was at idle but it wasn't obvious, you had to listen for it. That was around 78,000 Miles. I removed the sump and torqued the caps up, after that the knock was gone. Dare say as a result of them being loose there would have been fretting of the registers but it didn't stop my engine from working, and it ran for another 125,000 Miles.

Ron.
 
lack of an overdrive top on the BW is not so crucial.
Click to expand...

true enough but i was thinking of the fact that in 3rd the zf box locks up so that's a lot more power/mpg considering that's where my bw box seems to spend most of it's time? (dont they say about 20% is lost through an autobox?)

Rich
 
SydneyRoverP6B said:
The standard P6 engine as it left the factory is perfectly satisfactory for all but flat out driving over 5000rpm for long periods of time. Provided regular oil and filter changes are undertaken, flame traps cleaned or replaced as necessary along with the other filters being equally treated the engine will just keep on going. Indeed I used to say that of all the parts on the Rover, the item that gave the least trouble was the engine.
My original engine still had the rope type oil seal and it never leaked. The only problems I encountered along the way was a failed head gasket, oh and some of my main bearing caps did work loose. I could hear heavy knocking while the engine was at idle but it wasn't obvious, you had to listen for it. That was around 78,000 Miles. I removed the sump and torqued the caps up, after that the knock was gone. Dare say as a result of them being loose there would have been fretting of the registers but it didn't stop my engine from working, and it ran for another 125,000 Miles.
Click to expand...

I couldn't agree more.

I'd add the SD1 heads and timing cover, along with a 3.9 cam and a steel timing gear, if I was in there, but otherwise I wouldn't be busting a gut to do it.
 
HHMMM . I sort of knew it would go this way when i posted . Go back to my original question , what do you all think of the spec i sudgested ?
I have a limited budget of 5 to 7 hundred quid over the next 12 months , that doesn't allow for cross bolted mains , stroked big bore high revving motors etc .
When i did the top end this time last year there were a few things i wish i had the money to do at the time , New rocker gear rather than second hand , steel timing gears , uprated cam and new lifters etc .
I'm more looking for recomandations on suppliers , specs etc .
I don't need 6000 rpm and 300 bhp for the weekly shop and the odd blast to a show .
Appreciate al your comments but keep the original question and the budget in mind , lets not get too carried away and build me a 8 second weekend purse breaker ! :? :LOL:
 
You must log in or register to reply here.
Back
Top