type4 2.3ltr build

[DavidH]

Hi Rick,
I want one! Nice build  .
Cheers

[rstucke]

I was going to do a 2.3L type 4 but 66 crank and 103’s but decided it was way too hard and $$$$$

Barry that would have given you a weapon and would have more hp than what I'm doing at high rpm with the right camshaft
you could get away without opening the combustion chambers much but would need bigger valves, stronger springs etc.

I'm aiming at higher torque and hp in the normal driving rpm range. Sort of a lazy engine with grunt when you need it.

[rstucke]

whiles setting up a dial gauge to determin shim thickness for the deck hight i kept getting the feeling that the crank and bearings weren't right.
the crank had the correct clearance (determined with the green plastigauge earlier) and rotated smoothly but there as just the slightest hesitation to start the rotation, almost nothing.
It got the better of me after a couple of days and I pulled it all down. 

   

i'm glad i disassembled it
you can see where the bearing was touching the crank in a spot next to the oil hole.

           

[rstucke]

I papered the back of the bearing in that area and reassembled, no joy
I checked the surface of the tunnel in the case, papered it, cleaned it, reassembled and.....no joy
went home with the shits and thought these mahle bearings had a defect.
woke up in the middle of the night with the answer
Both sides of the centre bearing had the problem in the same area and it is the weakest part of the bearing
The bearings have been crushed by a tunnel that's to small and the bearing has distorted in that area.
I figured that the tunnel must just be slightly undersize and had a lot of trouble measuring the tunnel accurately with "T" gauges. So made go/no go gauges on the lathe. You can see the line of difference on the surface of the mandrel.
First part is under size (0.05mm), second part is exactly minimum specification for a first oversize bearing.
on the centre main the mandrel was pretty tight on the first part and no way would come close to accept the second part.
On the other 2 main tunnels the mandrel was neat fit all the way.
Anyway I used a parallel hone till the mandrel fit in the centre main tunnel, bought a set of Kolbenschmidt mains that are steel backed and problem solved.
Only took a fortnight
When line boring there are 3 cutters, centre one was obviously out slightly. 


               

[rstucke]

After that little hiccup it was time to check exact cam timing.
I don't have an adjustable came gear and I'm not sure of the accuracy of standard after market gear so wanted to know if I needed to get one.

Timing the cam gear is done by determining where the centre line of the inlet and exhaust sits compared to the crank shaft position and there are a couple of ways to get to the same result.

This was my way

I used a degree wheel attached to the crankshaft through the fan. Pointer on the lug where the crankcase splits you can see it on the right of the degree wheel.

I used dial gauges on no.1 piston (in the centre) and on no.1 inlet pushrod (dead in line with it).
Found exact top dead centre then loosened and rotated the degree wheel to line up zero deg with the pointer.
Rotated the engine by the fan till I had maximum lift on the pushrod.

The lobe centreline specifications that came with the camshaft were 106deg at 0.050". My dial gauge is metric so 1.25mm.

I rotated the engine backwards slightly past 1.25 down then back to exactly 1.25mm (gets rid of backlash) and noted the degrees wheel.
then rotated the engine forward to tdc and past till the dial gauge read 1.25mm and again noted the degrees.
Added the 2 degree numbers and divided by 2. 
I repeated the whole process a number of time and came up with 105.5deg each time.
I think this is close enough.


Time to get on and build the rest of the engine



   

[rstucke]

The rest of the construction was straight forward till we get to fit the pistons and barrels
Pressure blasted the heads, washed them with hot water and detergent and air pressure dried
I had old valves in the heads while using the burrs and Finnish smoothing and blasting the heads so didn't need to re-cut the seats. Lucky because the burr skated across the valves on a few occasions.

Re-machined the new valves (they didn't need it), binned the valves that came with the heads and lapped the new ones in.
I checked the new valve springs against Bentley spesifications and all were spot on. I don't need fancy springs with megga pressures cause I don't have larger valves and won't be revving the tits off the engine.

I lubricated the guides and reassembled the heads. There is a cast in boss near the spark plug hole that goes through the fins down to the combustion chamber at an angle. I machined the top of it and drilled down to near the chamber (more on that later)

           

[rstucke]

Time to fit the pistons and barrels.
I had them on the engine before to determine things like shims for deck height and cam timing but no rings and piston pin clips.

To fit normal pistons and barrels: rings on piston, piston pin clip on one side, piston half way into barrel, barrel onto studs, line up conrod, slide in piston pin, add clip, gasket glue around bottom of barrel and push home, repeat.

Because of the stroker crank I opted for pistons with a higher pin height, relieved skirts and standard length barrels. This keeps the width of the engine the same as a standard 2ltr and tinware will fit without stretching it over the heads, bending things around the fan housing or modifying it to make the foam seals fit.
The pin height goes into the oil ring area and on top of that there is a fortefied piece on the bottom of the 3 piece oil ring and the piston pin circlip is spiral wound.

So pistons without rings go on to conrods first, then the piston pin and spiral circlips before rings.
I had to make a tool to get the circlips in. I used a socket extension bar to stabilise fitting the clip, the other side is stabilised once the piston pin is in.

the pics show me trial fitting to a test piston from Wayne Penrose.

I fitted the clips to one side of my pistons being mindful of having room on the other side on the engine for installation of the piston pin and other clip.

The fortified piece and rings went on next and barrels were slowly fed over them with bleeding fingers (those wanky split compressors don't work).

This part of the build was stressful, so much that I forgot to take pictures till it was done.


       

       

   

[rstucke]

The heads went on and tensioned down next

The boss on each head that I machined and drilled are for pyrometers. 
   
   

I'm using lash caps on the ends of the valve stems which means checking rocker geometry
To do this I used a bubble balance attached to a flat magnet on the lash cap, and rotated the whole engine in the stand untill the bubble showed the valve was vertical.

   

I found half valve open height using a dial guage,cam follower and push rod (adjustable)

   


I used shims under the rocker posts (earlier tests saw the rocker arms connecting with valve caps due to the extra lash cap height when the valves were closed).
Then attached the shims and rocker gear on the push rod and head. You can just see the edge of the shim under the post.

 Put the bubble balancer on the end of the adjuster (which I machined flat and true on the valve grinding machine).

As the rocker gear was done up it pushed the valve down. Now all that was left was to adjust the push rod up or down untill the bubble ballance showed level on the end of the adjuster. This then is neutral side clearence at half valve opening (the best geometry for least amount of wear in the guide).

   

The adjusted pushrod is now the correct length (I did this for each cylinder and the length was the same for each) and I cut the semi finished molly pushrods in the lathe pressed in the ball ends and assembled the rest of the gear.

[rstucke]

           

[Oldman]

This is one tricky build Rick !!
In awe of the detail........