The Morbidmobile Blog

[Laird Scooby]

Originally Posted by classicswede

B200/B230 turbo swap is about as easy as you can get. The small turbo they have fitted means zero turbo lag. It does limit the power as does the cam.

IIRC you have the K jet engine in there now so you will need a wiring loom. If wiring is not your thing I do have drop in wiring looms that only need a handfull of connections.

If your engine is good then adding a turbo to that is a option. It is not a path I normally suggest as you need a lot of parts off the turbo engine but it is a option worth thinking about

LPG - if you are K jet you will need a full change of LPG front end system as you will be a simple mixer at the moment and the turbo needs injection


Another thought. How about building a 2.5 long strong NA engine. Lots of grunt, no turbo, keep your LPG and solves 99% of the problems of doing a engine conversion. (does not solve teh cost aspect)

Some good ideas there Dai, i thought about suggesting the "backstreet turbo upgrade" (adding a turbo to the existing or a B230E) as well, would probably be the most cost effective way of doing it but not without its problems.

I don't think it's on LPG at the moment, if memory serves that was the long-term aim. However reading Toms more recent posts, it seems to be that any engine that will offer an improvement in power/economy/efficency is the most pressing need at present.
Your idea of a long stroke 2.5 is probably going to be the ultimate solution and could remain on K-Jet with a mixer plate for LPG - even if it only does 18mpg on gas but pulls well, at the current average price of gas (about 60p/L from what i can see) that's still going to make running it regularly a much more viable proposition.

Just got to convince Tom now!

[TomSaintJames]

Lots of interesting suggestions folks, thankyou!

Luke - Volvo's aside I do love me a hydraulic Citroen, especially the BX, they are a little less mad than some of others but still very citroen! The comfort is just lovely. I would really love an SM or a CX GTI Turbo, but they are soo complex (and expensive) and rust even worse than the BX.

No LPG as of yet, that will happen when we start to actually convert the thing into a camper, we plan on using LPG to run the fridge and cooking device so may aswell get the engine converted too

Classicswede - a drop in wiring loom to upgrade the k-jet woiuld be a very welcome thing! Wiring is something I have little experience with and converting what is there to what is required would probably be over my capabilities!

What is this 2.5 long stroke? Is it a bored out redblock? Or is it the 2.5 straight six? I'm intrigued!

[Laird Scooby]

Originally Posted by TomSaintJames

What is this 2.5 long stroke? Is it a bored out redblock? Or is it the 2.5 straight six? I'm intrigued!

https://en.wikipedia.org/wiki/Volvo_Redblock_Engine

Have a read Tom - scroll down to the Volvo Penta section and you'll find the main difference which is the long stroke crankshaft. Mated to what looks like a B230 externally, it could be the easiest way of doing things. Finding one might be tricky but found this on fleabay, not too far from you either :

https://www.ebay.co.uk/itm/VOLVO-PEN...T/223576106382

Might need to do a bit of electrickery and/or blank off the distributor hole and use your existing head and igntion set up, could probably keep the existing K-Jet and alter the control pressure to suit the larger capacity, would need your existing flywheel/driveplate and bellhousing, possibly the engine backplate as well.

Would give you loads more torque which would help pull your behemoth along.

[TomSaintJames]

Oh dear... This is quite interesting, even has OH approval subject to cost and researching it properly!

So i've been reading up on this, and perhaps the simplest approach would be to install the penta 250 AQ151 crankshaft, rods and pistons into a B230 block then bolt this to the current set-up? That way there won't be an issue with a block-mounted distributor or any of the marine stuff. That is, if parts can be found!

[Laird Scooby]

Originally Posted by TomSaintJames

Oh dear... This is quite interesting, even has OH approval subject to cost and researching it properly!

So i've been reading up on this, and perhaps the simplest approach would be to install the penta 250 AQ151 crankshaft, rods and pistons into a B230 block then bolt this to the current set-up? That way there won't be an issue with a block-mounted distributor or any of the marine stuff. That is, if parts can be found!

Alternatively, buy that one linked to, swap your flywheel/driveplate and engine backplate if needed, fit your head, dizzy, inlet manifold, lose the marine bits amd block mounted dizzy and fit a blanking plate over the hole the dizzy came from.
The Penta crank etc is already in a B230 block if you look closely at the photos.

There are other ways of doing it, some will seem simpler but will need other bits changing that won't be as easy. While the head is off your engine, do a decoke and lap the valves in, clean everything up, check the valve clearances and have a new cam belt ready to fit.

Increasing the control pressure on the K-Jet is as simple as setting the idle mixture when hot, it should alter it across the rev range so would take into account the larger capacity.

[TomSaintJames]

Further reading suggests that I may even be able to use the current engine block for the penta crank, as long as the bearing size and layout is matched up.

My B200E as an '88 should have the larger 13mm main bearings and the thrust bearing at the rear of the engine (compared to in the centre in earlier engines)? If this is so, I will need a crank/rods/pistons from an AQ151C or D.

I've found these forge numbers for the crankshafts;
early = 855482-6
late = 3514121-7

And this turbobricks thread appears to have a load of very useful information!
https://forums.turbobricks.com/showthread.php?t=24675

[Laird Scooby]

Originally Posted by TomSaintJames

Further reading suggests that I may even be able to use the current engine block for the penta crank, as long as the bearing size and layout is matched up.

Probably, but you'd only end up with something like a 2.2 if you were lucky, i haven't done the maths. A quick basic calculation (as you're only lengthening the stroke) is 86/80 x 1986 = 2135cc so only a 2.1 - chances are you'd be very disappointed! You'd gain about 7% in torque and it wouldn't be as eager to rev either.

[TomSaintJames]

Originally Posted by Laird Scooby

Probably, but you'd only end up with something like a 2.2 if you were lucky, i haven't done the maths. A quick basic calculation (as you're only lengthening the stroke) is 86/80 x 1986 = 2135cc so only a 2.1 - chances are you'd be very disappointed! You'd gain about 7% in torque and it wouldn't be as eager to rev either.

A very valid point Dave, I didn't think about the bore!

Would it be worth thinking about camshaft choice here whilst i'm at it? And how what would be involved in blocking off the distributor hole?

[Laird Scooby]

Cam choice i would think a V or VX would be the best, you can find out how to check your existing cam in the Haynes Book of Fantasy or i believe it's in the FAQ somewhere.

If you fit a different cam, you'lll have to check all the clearances and set them correctly by measuring the current clearance, removing and measuring the existing shim, calculate the difference between what the clearance actually is and what it should be then add that figure to the thickness of the existing shim to determine the new shim size.

Once the new shims are fitted, recheck the clearances as it's not unknown for a stray finger to press the wrong button on the calculator!

For example, using figures plucked from the air just to illustrate the procedure, the clearance (fictional) should be 0.25mm and you have measured 0.35mm so the difference is + 0.1mm
Now measure the shim, let's say it's 0.42mm, add the difference +0.1mm and the shim you need is 0.52mm.

Likewise, if the measured clearance is 0.12mm, that's -0.13mm under so the shim thickness needs to be -0.13mm so if the shim is 0.55mm to start then you need one that is 0.42mm - you've just removed a 0.42mm from the valve in the previous example, handy!

In this scenario i've picked numbers that are fairly close because often there is a tolerance on the clearances, for example the clearance might be 0.22-0.28mm with the optimum being 0.25mm - you can see you'd get away with simply swapping those two shims.

You will obviously need some decent feeler gauges and a micrometer and a bucket of patience - it's a fiddly but rewarding job.

[classicswede]

You know what they say about a little information in the wrong hands


Ok to discuss the 2.5 engine idea.

The penta engines tend to have corrosion issues and most are the early weaker crank. It is possible to convert a penta to road use but its not often done.

What I would suggest

Bag yourself a B230 to rebuild. (pref a K jet one)

Long stroke crank
https://www.classicswede.co.uk/B230_..._18369160.aspx

Pistons/ rods. You could use standard 13mm rods and the shorter pistons for the long stroke. You would be very lucky to find a engine with a good enough bore not to need a rebore so bank on needing new pistons.

Head wise, as a minimum give it a clean up with new seals. You could think about some porting and bigger valves to help it breath.

Cam wise the longer stoke will take a much more aggressive cam compared to the normal stoke engine. The V cam is the most common factory cam in a normal B230, the B23 had both H and K cams but I would suggest a modern grind like the T5 cam. Your CR would want to be 10-1 to 11-1

H cam if you want a Volvo profile https://www.classicswede.co.uk/B2323..._17750151.aspx

or T5 for a modern grind https://www.classicswede.co.uk/B2323..._18543132.aspx


Fueling wise the K jet unit is capable of working with the extra capacity, You could use the turbo injectors for some extra flow

Ignition you could keep what you have but better still would be a mappable ignition. If you fit a 240 cam drive shaft you can mount the side type dizzy
https://www.classicswede.co.uk/123tu..._18275269.aspx

this will allow you to get the most from the engine and best timing

To blank the hole use https://www.classicswede.co.uk/Cylin..._19233435.aspx

Exhaust you will want around a 2.5 inch bore system