2.1L B20 build for Paul

jamesinc · 2024-04-20T02:02:14+00:00

@paul0075 has not been able to drive THE JAFFA for the past year or so due to a worn-out engine. Paul's a good friend, and I really like the Jaffa and I don'...

jamesinc

The head has had o/s hardened exhaust valve seats installed, and I've been opening up the exhaust ports. You can see in the first photo how large the step is from the valve seat.

Image description

And ported (need to work on the surface finish some more still).

Image description

I've gasket matched the exhaust side a bit but without touching the floor of the port.

Major Ledfoot

jamesinc I've gasket matched the exhaust side a bit but without touching the floor of the port.

Very, very wise. Working the floor of the port does very bad things for flow. If you've seen pics of Lindquist Racing's radical B20 head, they actually fill out the bottom of the exhaust ports and cut out the top of the head.

242GT

Is that head of the 1974 injected motor

Vee_Que

Major Ledfoot it's the same people who think going bigger than a D cam is going to ruin drivability. They want a tractor motor when Thier modern dd 16v doesn't make peak power until 4500rpm.

Vee_Que

Major Ledfoot I need to find someone to weld my head to shrink the exhaust port like Canuck does.

jamesinc

I've now got the head assembled barring a couple small items.

Image description
Back from the machine shop

Image description
I rinsed the casting off thoroughly with prepwash, to remove the WD40 coating from the machine shop, then painted it Volvo red. It's cold so I had the heat gun on it a fair bit.

Image description

Image description
Coolant distribution pipe installed (not pictured) and free plugs sealed and installed. After installing the freeze plugs, I scuffed them up and painted over them in red.

Image description
Sludgy rocker assembly

Image description
After spending some time in my solvent tin. I ran pipe cleaners through every oil hole and flushed out the inside of the pipe a few times with solvent.

Image description
Rocker assembly installed

Image description
New inlet port guides installed

One of the valve spring retainers disappeared at the machine shop, but fortunately I was able to source a spare from @Massey165 over the weekend.

Next up, I need to fit it to the block and check whether we need pushrods, and attach a couple smaller items like the coolant port at the back and some bungs and block off plates etc.

Vee_Que

So, what's the combustion chamber size now? Would be a shame if it is under 10.1:1 c.r

jamesinc

Good question - I will CC later this week and math it out

jamesinc

I figured out a setup that I am able to get accurate and repeatable readings from. I'm measuring the mass of 100% isopropyl alcohol (0.786g/mL) transferred to the chamber, weighing the syringe along with it to minimise error. As long as I don't spill any, it works well.

I'm using plexiglass and Vaseline to make the seal.

Image description

I know it is an unconventional setup. I am essentially measuring the mass of 100% isopropyl alcohol injected into the chamber, which has a density coefficient of 0.786.

I can't do the test yet as I need to swap the junk 240 plugs out for correct 140 plugs (shorter thread), stand by.

jamesinc

With the correct plugs installed, I calculated the CR at 9.98:1 with our current .045" head gasket choice, or we could go to 10.47:1 if I switch to a .027" gasket.

The chambers average 51.62cc

However, I think it is actually cheaper to just have the shop skim the surface a bit more.

I measured the area of the chamber (using rulers and Photoshop) and mathed it out that about 12 thou needs to come off to get to 49.62cc and a 10.3:1 CR.

I called my machinist and he said it's usually about 5 thou per CC, so looks like my measurements are pretty good.

242GT

When I modified ghe heads on my B20 motors , Hawker De Haviland had a large snow grinder and also a very nice surface grinder that they generously allowed me to use on my race car engine parts , must get around to thank I no them one day , they even donated the alloy and lathes so I could machine a new thermostat housing out of 7000 grade aluminium.
Great read watching your work James.
Are you going to put a remote oil filter holder on ghe inner mud guard & an oil cooler for our Australian summers

jamesinc

242GT nah I'm just building the engine, it's @paul0075's 144 that it's going in.

242GT

What year model Image description

People do silly things with 144's 😁

Major Ledfoot

242GT People do silly things with 144's 😁

Indeed. 🙂
I did many silly things with my black one... and the silliest was selling it.

jamesinc

242GT What year model

It's a '74 model, it has a thread on the forums here: https://ozvolvo.org/d/7029-the-jaffa-1974-144dl

paul0075

Major Ledfoot yep, wish I kept my 145 🙁

jamesinc

Okay so messed around with the head a bit more and got to 10.1:1 CR with the 0.045" gasket, which I think will work well for the intended application.

I greased up the lifters with molybdenum grease and installed them

Image description

I put the head on with new bolts and greased threads and torqued it down to 29ft lbs.

Image description

This is where it sits now, I haven't put the rocker assembly in or done the final torque, I think I am going to slacken the bolts off and spend a bit more time getting the head perfectly centred over the block.

paul0075

jamesinc Looks amazing! Can't wait to drive it!

Major Ledfoot

jamesinc I'll be most interested to read up about your First Start Procedure - from what I've read, solid lifter engines require a 'break in' period for their first start so the lifters don't eat the cam lobes, and I'd like to know how to do it properly.

242GT

Where are you getting the head gaskets from , years ago there was a bloke in Hornsby made custom B20 head gaskets when they converted to 2.1ltr

jamesinc

@242GT this one (and most of the new parts for this build) came from VP Autoparts

(92mm bore) https://vp-autoparts.com/en/artiklar/cylinder-head-gasket-b20-92-mm-cometic.html

« Previous Page Next Page »