Do you have time to talk about volvo redblock?

[jute91]

New to this forum, I have read some write ups during years, but decided to start writing my stuff up. It's been years since I've been on some forums.


So I have own this budget engine studying project for over 6 years now. Started the project at hot summer day, cold beer causing brilliant ideas to come up

So anyway I started doing this brilliant swap that came to me.


Got it running and caged and then started the improvements.
My dad made mild porting and big valves to another head I was bolting on, also shaved and measured for improving compression ratio up.




46/38 valves were fitted into cylinder head and custom folk race cam was grinded for shimless buckets used from citröen. Valves were shortened for correct lenght. Also installed folk racing 4-2-1 exhaust header. Fueling was done by Dellorto dhla 45 twin carburetors.

So at the first dyno we made 158hp and did few other dyno sessions with different camshafts ending +/- 2hp. Few years later I decided to start building time attack car out of that bmw and decided to swap that engine into my peugeot 309 folk racing chassie. Swapped dueling system into fajs 50mm itbs and ignition went from distributor to wasted spark coil, that usual 2x2 bosch unit from fiat/alfa, that is sold for racing use.




Ended up into same 160hp but 400rpms lower. Torque curve recovered a lot, as fuel ratio was tuned better than with carbs.

So at least the throttles werent the restricting ones.

The engine has unopened bottom end and compression is rised up to 13:1. So next I am going to build much better exhaust manifold with anti reversion chambers, to see if the exhaust could improve the power a decent amount. Cam has 13,5mm of lift and plenty of duration so the overlap is hurting the low end torque without anti reversion chambers.

I'll post more content later on

[Nut124]

Your pictures do not show for me.

What is the engine? Volvo B21? Displacement?

How long are the header secondaries?

[jute91]

Bottom end is stock b230A

I haven't measured the manifold yet, it's the usual what people use here.

https://shop.klracing.se/sv/artiklar/ex ... 4-2-1.html

[BCjohnny]

I've built one or two B23s

I know it's all relative, but your output seems a little low

The B23 I put some thought into made 193 bhp @ 6300 with a 290 deg cam on 45s ..... it would have cracked two hundred if the customer hadn't listened to the rolling road tuner who advised on carb sizing with the reasoning 'Volvos don't rev'

Still, ended up being a bit of a torque monster and he won his class first season out

The head work I found to be key, don't go mad with the porting and re-shape the chamber

[Nut124]

...So next I am going to build much better exhaust manifold with anti reversion chambers, to see if the exhaust could improve the power a decent amount. Cam has 13,5mm of lift and plenty of duration so the overlap is hurting the low end torque without anti reversion chambers.

I'll post more content later on

How much seat to seat duration? What are the loce centerlines? In my 4cyl, if I keep IVC event at 80ABDC or less, mid/bottom torque is OK. Over 80 and reversion happens and can be heard in the intake sound. I went from a 4-1 to a 4-2-1 header with long secondaries and low/mid torque improved drastically.

[juuhanaa]

Hi Jute91,

Nice peogeot, love the colour. Just a quickie example about valve timing events and how i see it. Its like a example about how the data are results of the 4 cam timing events. Lift plays a big role how the port work. Do you have info about the cylinder head? I havent done any volvo, but i would like to check

IMG_20220508_195604__01.jpg

-juhana

[jute91]

The cylinder head is basic 530 with just 46/38 valves and combustion chamber opened up little bit. Haven't done a big porting to it so that might be reason also

[BCjohnny]

The cylinder head is basic 530 with just 46/38 valves and combustion chamber opened up little bit. Haven't done a big porting to it so that might be reason also

The example given used std seat inserts so the valves were only slightly oversize, by a mill, mill and half ish from memory (commonly available oversize 2.0 'Pinto' valves with lash caps)

Very little 'porting' was done, just tidying up what was there in the std head casting, which IIRC was a 530 ..... simply using established techniques and without a flow bench

The ports are all 'generously' sized as is, maybe too generous in reality

The combustion chamber was re-shaped, again using contemporary thinking (late 1990s), with simple three angle seats and blending

One hundred and forty thou (0.140") was whacked off the face to get the comp up

The 'small carb' dyno operator ended up with egg on his face, carburettors don't know what engine 'make' they're fitted to, only how much air they're expected to move

Just trying to show what can be achieved with moderate effort, from someone who didn't specialize in them ...... good luck with your build

Edit : Oh yes ...... all this through a std ish cast exhaust manifold & downpipes as the tubular mani didn't arrive for the dyno tune ..... just goes to show how good the OE pieces were

[Erland Cox]

What is done to your head except bigger valves? You should be around 200hp.

Erland

[jute91]

What is done to your head except bigger valves? You should be around 200hp.

Erland

valves are oversized meant for B20, springs are from vw beetle, citröen cups without adjustment, cam grinded for correct lash. minimal porting, just taking sharp edges off, small shaping of the combustion chamber. I need to dig into it later on