Replacement Engine project

[peteracs]

Had a call from Jon at Stanwood to say all done on the parts he still had which was a shock given how long it took to get the block sorted. I collected the parts today.

First up was the head which he has skimmed, apparently he took 10 thou off to clear the imperfections. He also checked the clearance on the valve guides and volumes one of the chambers which came out at 53cc which is close to what I had measured originally. I need to now go back and revisit the piston dome volume to get a more accurate CR value.

Next was skimming the VX flywheel I obtained from Alan C and then sending it off with the crank and clutch cover for balancing. Jon does not do this, but uses a company in Sheffield (see photo of report, only some of which I can understand…).

He gave a crank a final polish for me and now I can get on with a dry build to confirm if the pistons need any modification re crown and valve cutouts. Then it is put all away until I can see when I am likely to need the engine, most likely 2026 at the rate we going!

Peter

[peteracs]

A while ago I bought some new pistons and rings for the engine (+0.40). When I originally measured the oil ring set (2 flat outer and the middle rippled one), I measured it at approx 5mm where the slot I bone piston was 4mm. I had thought for a while that the set, although correct part nos from Hastings, had incorrect oil rings.

Thinking I had to buy a new set, I revisited the rings today, partly to look at the oil ones and partly to see what the gap would be when installed. The gap was 15 thou on the upper two rings which is pretty much where GC was looking for according to his book. I also had a good look at the oil rings and realised my mistake. The middle ring has raised locating pieces to align the two outer rings and when you correctly assemble the three the size comes to just under 4mm which is exactly the spec by the piston manufacturer, so purchase avoided!

Peter

[lancialulu]

Peter

Not sure if you use any assembly paste etc when you assemble bottom ends, camshafts etc.

I use Graphogen which creates a lubrication film on the bearing surfaces protecting them until the day oil is pumped round.....

[peteracs]

Hi

Yes I have assembly lube ready to go. I will however not be assembling the engine fully until nearer the time it is due to run rather than have it sit around for a year. I am aiming to get all the parts together and cleaned ready to do final assembly.

[peteracs]

One question I do want clarification on is regarding the thrust washers on the crank. The washer has two channels on one side and flat the other.  Can someone confirm the channel side faces the crank?

Thanks

Peter

[peteracs]

Hi I think I have answered my own question, the channels are for oil and must face the crank, not the bearing set into the block.

Peter

[lancialulu]

Hi I think I have answered my own question, the channels are for oil and must face the crank, not the bearing set into the block.

Peter

Correct

[peteracs]

Managed to get some time in the garage today and checked the end float of the crank using a pair of standard sized thrust washers. Result was 0.11 mm which is well within spec, so going to order a new pair of standard sized ones. I realise I should have done this BEFORE doing all the work on the crank, but I completely forgot about it until recently. Happily not a problem..

[peteracs]

Hi

It has been a long time since I did anything towards the engine as I aimed to mothball any further work until the car was ready to accept it which is some considerable time off.

However one job which I was reminded of in watching the build on YouTube that Nigel's Fiat 131 is doing on his engine, is the shaft that drives the oil pump which also has the offset end to drive the mech fuel pump.

As I am not going to use a mech pump, my first thought was to grind the excess lump off leaving a smaller lump on the end, however I thought that removing it altogether was probably a better solution. Just one problem, there is a drilling from that end through the centre of the shaft for oiling the bearings and a small bung inserted in the end. So I dug out a spare one which will never be used as a test, chopped off the end and knocked out the bung from it. The bung is larger than the drilling, so needs to have a 8mm relief put into the end of the shaft. This all went well and with sealant it should be possible to re-seal the end of the shaft with the lump cutoff. I may however go as per the crank and tap the end and use a grub screw which is a more secure way of doing it..

[WestonE]

Hi Peter have a look at Guy Croft's book on this. A tapped plug with Loctite is the right solution. However you want to be really sure you have all the swarf out of the drillings in this shaft to avoid big trouble later. Cutting the lobe off is normally a hacksaw in the vice job.

Eric

[peteracs]

Hi Eric

Yes I did the hacksaw job and have done the crank mod previously. I think it makes sense to tap and grub screw it. Cleaning out the swarf should be pretty straight forward as a simple channel to clear as opposed to the crank which was a bit of a challenge. 

Peter

[Ferrit]

This is really interesting.  Questions...

if you take a lot of material off the head in a skim (or two) do you need to fit thicker head gaskets, or in most cases is a std one fine?

Whats gasket set do you recommend, I quickly went through your posts but couldnt see if you bought a std one from AE Car?

Mark

[peteracs]

Hi Mark

Yet to buy the gasket as not required yet and want to revisit the volumes in the head etc to make sure I get the correct thickness as I will be running a fairly high CR.

My suggestion would be if a light skim needed, then same thickness as before, if significant removal, then adjusting the gasket thickness to suit.

Peter

[WestonE]

A light skim will make little relevant difference. With MLS gaskets (Multi Layer Steel) you can add and remove layers to adjust compression ratio. If you run high lift/ longer duration cams dry build tests should be used to ensure no valve to valve clash (dummy belt from VX and tensioner rigged). Also plasticine in the valve cut outs to check clearance with a sow turn over of your precisely timed engine. GCs books describe this in careful detail along with how to set up TDC precisely and time camshafts properly. For my engines I have a dry build tested range of cam swing I can use at the rolling road. For road engines a higher lift longer duration inlet cam (GC3A billet spec NOT reground) gives a great result with higher compression cast pistons of the kind you have. However this needs a VX or 130 TC head, 3 angle vale seats cuts etc. You would also use 45 DCOE or 44 DCNF with the right manifolds. 

Note I designed the Cometic MLS head gasket with their help after getting fed up with expense flawed gaskets. MLS technology runs on every modern production turbo diesel these days alongside every serious race series.
You will buy a resin gasket so buy the best quality you can and no NOS because the resin degrades over time. You should see obvious re-enforcing of fire rings compared to the ebay bargain junk that was fitted.       

[peteracs]

Hi

Nothing much doing on the engine as working on installing parts the main body for now, but had the cutting off the fuel pump lobe from the fuel pump/distributor drive shaft and resealing the resulting hole kicking around for what is months. I cut the lobe off last year and finally got around to ordering the grub screw (M8x1.0) and trying to tap the hole. Bit of a fail with the taps I have, so needed new tap pair. This done and the grub screw installed with Loctite thread sealant, another part put away for the hopefully not that far away day when I start building the engine...

Peter

[Nigel]

Nice work Peter.

Definitely a good thing to do, removing one Achilles heel.

Nigel