Penta AQ151 Engine Conversion
 

Afternoon, as some of you will be aware I have been pondering at length about what to do with the engine situation in my 1988 740 Hearse. Unfortunately, it came with a B200E, which whilst low mileage and runs quite well, is just not up to the job of hauling the extended wheelbase brick around! So much so that we rarely get above 20 mpg, at least a portion of which is due to the fact you have to floor it to go anywhere!

The vehicle in question (excuse the leaners! None of them are me).
https://i.imgur.com/UT7ALXZh.png

We have been improving the hearse mechanically and cosmetically, and whilst it still has issues it is time to sort the engine department out. So, I went and bought an unknown, unseen Volvo Penta marine engine, an AQ151 with a B230 block and crankshaft with an 86mm stroke (96mm bore of the standard B230), giving a 2490 cubic capacity.

So, here is my plan to which I hope you will feel free to comment on and suggest improvements. I am still studying at home after work, so have very little time to do anything (like, anything...).

1. Block - I think it is wise to attend to the penta block first. It will obviously need removing from the penta engine and possibly dismantling. Then it can go off to be looked at by the local specialist. As it has been suggested, it will likely at least need a hone, and possibly new bearings and a rebore - hopefully not though as this will add a considerable cost to the project (with new pistons etc) and might delay things. Would it be worth checking the core plugs and any other block items whilst we’re at it?

2. Head – The next step perhaps is to look at the 530 head already in the Hearse. A decoke clean-up, valve clearance check/adjustment, skim and new oils seals are a minimum. Depending on where we are with cost so far, lapping the valves in could also be done.

3. Block Install - The superfluous distributor hole will need plugging and the flywheel, driveplate and backplate will need to be swapped over to the penta block, using new bolts for these parts. New engine and gearbox mounts too. All other ancillaries swapped over too.

4. Should the clutch be inspected? My knowledge of gearboxes is very very little, automatics even more so!

5. Head Install – New gaskets all around on a hopefully flat, nice and clean head. As it’s the original head (60,000 miles ish) only service stuff will need doing hopefully, new cambelt and tensioner, auxillary belts and perhaps water pump and thermostat. The current cam can stay for now.

6. The wiring of hall sensor on the distributor will need checking, I noticed something ages ago and can’t remember what the thing was.

7. Injection system – Now here is where my knowledge is a bit shaky. Instinct tells me to get the injectors cleaned (ultrasonic/chemical/both?) and replace the rubber bellows and any seals and filters present. Dave advised to hold off on this, perhaps when it is all back together and running, this would be prudent?

8. It is likely that the mixture will need adjusting, via the mixture screw which i'm led to believe will adjust the pressure of the fuel entering the K-Jet manifold. The emissions (HC and CO content?) of the finished product will guide the adjustment required.

That is all I can think of for now, I’d very much welcome any comments or thoughts from anyone that has taken engine bits apart, replaced engines etc. I can’t find any good info on the internet of a penta conversion in a car, apart from a few youtube videos.

https://i.imgur.com/AE3MJCIl.jpg
Bye bye B200E! Your gutless lower rev range and 120 odd bhp will not be missed.

https://i.imgur.com/8ij5Dg9l.jpg
Hello, B250E! Your hopfully increased torque and 150 odd BHP will be very welcome. This is the carburetted boat figure so it will be interesting to see the outcome of the 2.5 on k-Jet. I plan a before and after rolling road, there is one in the same garage that provided the exhaust quote in town.

Im sure you will find the K jetronic just fine , it is self calibrating really due to the nature of how it works , You will probably have to tweek the CO screw ( long 3mm alen key ) I used a K jetronic system off a 2.3 volvo engine on a 1 litre turbo engine I have and it ran beautifully , well matched too as it produced around 170 bhp ..

1) Some terminology hiccups here Tom. If you take the block from the Penta engine, you'll have a crankshaft, con-rods, pistons, oil pump and sump andthe head left. I'm guessing what you really mean is remove all the dedicated marine stuff, leaving the engie as it needs to be for installation in the hearse.

2) Are the injectors on your B200 in the head or in the inlet manifold? That will dictate the path with the heads but i suspect you'll have to fit the head from your B200. Part of a decoke is to lap the valves in and then check the clearances.

3) If the injector holes are on the inlet manifold, there's no reason you couldn't use the existing dizzy as it probably has the Hall Effect trigger in it already. Needs checking!

4) You don't have a clutch to inspect, might be a uni-directional clutch in the torque converter but you'll be swapping that anyway.

5) Depending which dizzy you use, you may be able to leave the head on the Penta engine, complete with the cam in it which if memory serves is either a V or VX cam. You might have a V cam in the B200 but i can't remember without checking.

6) See above comments on the dizzies.

7) I'd still say get it up and running first Tom before you go wild on "improvements" such as cleaning the innjectors. You know at the moment they function, not saying that cleaning them would cause a problem but the minimum disruption they have the better until you know the engine is a runner.

8) yes. :thumbs_up:

9) Get the Penta engine stood up and leaning over to port a little (that's the left) as it was alredy installed, to bring the plug holes near vertical.
Remove the plugs and dribble a small amount of synthetic ATF (preferably ATF-U if you have it) into the plug holes and refit the plugs. Leave it to soak for a few days.
Remove the plugs and try turning it over with a spanner on the crank pulley bolt, clockwise as you face the front of the engine.
If it turns happily, turn it until it's at TDC then 1/4 turn more. This will set all pistons about halfway down the bores.
Top up the bores with ATF and refit the plugs again. Leave for a few more days, remove the plugs again, turn another 1/4 turn.
Top up the two that didn't push any ATF out and refit the plugs again.

Leave a few more days, remove the plugs and turn the engine 1/2 turn. Again, top up the two that didn't push any ATF out, should be the other two that you didn't top up last time.

Leave a few more days and then remove the plugs, tilt the engine so the plug holes are more in their "normal" attitude from vertical, put a rag in place to catch the ATF and turn the engine by hand a few times to expel the ATF from all pots. This should hepl free up the rings, remove rust and make sure the engine is free to turn.

That's good to know, thanks Cian! 170bhp out of a 1.0 sounds mental, i'm intrigued.

Dave - Ah, in my mind the crankshaft, con-rods, pistons, oil pump and sump are all a part of the block.

I had to go back through my photo's but the injectors appear to be in the head rather than manifold, i'm happy to use the original head from the car, there has been some comment on facebook that I may even suffer from using the free-er flowing 531.

https://i.imgur.com/vfiV0dTh.jpg?1

The hall sensor is in the dizzy, I remember this from replacing the dizzy cap - I just jave a fuzzy memory of a slightly dodgy wire or something that I couldn't tackle at the time, so it'd be good to put that to rest.

No clutch to worry about is great. It all sounds like good advice Dave, thanks. :cool:

That pretty much dictates the use of your B200 head on the Penta block then Tom. Easier for the dizzy wiring and the sensors etc, not that there are many on a K-Jet engine! :tounge_smile:

I have a feeling the unused dizzy hole on your block whas a plate over it, held in place with one or two bolts - that could be transferred over if so, if not, easy enough to make one.

It's a shame you're not doing the work yourself, would be easier to point you in the right direction with things.

You've heard it from 3 of us now, the K-Jet is self-compensating. :thumbs_up:

Be interesting to see how this improves performance with a 2,5 bottom end,,,

^ not sufficient to pay for the costs and agro of conversion.

I dont think the extra 100 or so cc will make much difference except raise the compression ratio a bit which is always a good thing for efficiency :-)

Ultimately the answer lies with Tom on that one! :thumbs_up:


:eek: :nah:

2490cc (AQ151C) - 1986cc (B200F) = 504cc according to my calculator!

Should provide a useful power hike and an even more useful torque increase due to the longer stroke.

ahh , thought he had a B230 🙄