It started with a pop

[Kneeslider]

Have you ordered a JP Dansk oil cooler? I have just bought one, it looks to be OK, but can't fit it yet, because my case is still away awaiting an align bore.

[Ollie]

Your engine's coming together beautifully Andrew. Thanks for sharing the journey!

Ollie

[AndrewSlater]

I think the cooler is probably the Dansk one, but I've yet to receive it so will update once it arrives.

So here is my CR calculation

The big bore kit has a cylinder diameter of 86mm, so the swept volume is PI x (4.3)^2 * 7.4 = 429.85cc

My head volumes are all matched to 62.8cc ( took forever to match them all )
The piston domes are specified as 17cc ( I tried measuring them and they are possibly fractionally more but not by much )
My effective deck height is measure deck height + shim - head lip

The heads have a lip that is created from the previous big bore kits slowly wearing into the heads. With the big bore kit you have a thinner wall than standard and this creates more wear on the head.
The head volumes are measured from above this lip so best to take it in to account.
This lip has the effect of reducing the deck height as the heads sit fractionally closer to the cylinders.

The effective deck height is 1mm (measured deck height) + 0.25mm (standard shim supplied in top end gasket kit) - 0.1mm ( measured head lip ) = 1.15mm
The effective deck volume is therefore PI x (4.3)^2 * 0.115 = 6.68cc

My compressed volume is Head volume - Piston Dome Volume + effective deck volume = 52.48cc

This gives a CR of 429.85 + 52.48 / 52.48 = 9.19:1

This means that given tolerances I am still safely within the 9.3:1 ratio.

With the previous build the calculations give a range of CR of 8.56:1 to 8.75:1

The previous builder of my engine clearly hadn't tried very hard. Hopefully I will see an improvement in performance.

[AndrewSlater]

As I've been waiting for the delayed oil cooler I have been slowly getting on with some of the background jobs.

It's easy to concentrate on the engine and gearbox, but this is also an opportunity to check out the condition of the engine bay.



It's still all in pretty good order, but there was the start of a little surface rust around the engine seal lip.
A coat of rust converter, a repaint and a coat of some wax protection and that was sorted.

I've made a general tidy up including a new clutch cable outer and have replaced all the fuel lines with new and a new filter whilst there.

I also took the opportunity to fix some bitumen pads to the firewall and to install some additional sound proof foam, in addition to the original sound pad - hopefully it might reduce some of the engine noise intrusion to the cabin.


I have also been cleaning up the intake manifolds, removed the studs and spent a while flattening all the bases again using sand paper on a glass bed.


Always good when everything seats correctly and seals nicely.

During the process I noticed that my previous gaskets were incorrectly sized.
Here are the old blacks ones against the new correctly sized ones. That has got to improve air flow.

[AndrewSlater]

Another job was to trial fit the 'new' exhaust to check it fitted well.
Well it didn't - measuring the distance between the top flanges it was approximately 7mm too short to fit.
Now I have changed the cylinders and altered the shimming but that should only have moved things a couple of mm or so.

I got the old exhaust and it still fitted the engine fine, so clearly the 'new' exhaust was different.

After a bit of fruitless hammering an internet search suggested using my trolley jack to bend the exhaust inlets.


After a few attempts I got it to fit but the headers weren't quite perpendicular to the exhaust anymore.
I decided to file the headers back to match the heads, so that the exhaust gaskets didn't have too much sealing to do.

After a few hours it fits quite nicely.



As I did intend to fit the exhaust once the engine was back in the car, I'm glad I spotted this hiccup at this stage!

[AndrewSlater]

In other news - my new alloy oil cooler has finally arrived.



It looks like the same supplier that makes the one for Dansk but can't tell for sure.
I've checked it for leaks and all looks good.

The original one weighed 1374g so pretty much half a kilo lighter - slowly getting that power to weight ratio up

[Timo]

Andrew I’ve just fitted a new exhaust and heat exchangers to my car, I specifically sourced a liestritz one in the hope it would fit well. Although the flange distances were correct my first fit attempt revealed that the flanges were all out of square and needed filing, this was evident by lots of pops and bangs when I tried to run it.

I squared them all up nicely but to ensure a good seal I drew up my old gaskets on cad and had a small batch of graphite ones made. These fit really well and provide a perfect seal, no more pops and bangs.

3mm graphite on the left vs stock 1mm gasket on the right

A250CCA5-5237-4E25-9770-4FB645F9D3E2 by slammedsixty7, on Flickr

[AndrewSlater]

Yes I've spent quite a while squaring my flanges to the engine to make life easier for the gasket.
I suspect it will be OK but time will tell when I fit it for real.

I have seen others fit more than one gasket to solve the problem but not sure that's such a good idea.

Your graphite ones look like a great solution - got two spare?

[Timo]

A may have a couple spare. I had a batch of 15 done so I have some spares for future changes as they aren’t reusable.

Alternatively I could get another batch done if enough interest on here but supplier will only do a batch of 50 at a time for future runs. Being graphite they aren’t cheap but they work out about half the price you’ll pay elsewhere.

[AndrewSlater]

A may have a couple spare. I had a batch of 15 done so I have some spares for future changes as they aren’t reusable.

Alternatively I could get another batch done if enough interest on here but supplier will only do a batch of 50 at a time for future runs. Being graphite they aren’t cheap but they work out about half the price you’ll pay elsewhere.

I have to say I'm not familiar with graphite gaskets so I would be interested to know whether they compress easily, and do they have a metal core for stability?
You can buy sheets of graphite quite cheaply on eBay for gasket making, but I'm guessing that machining it well is quite difficult.
What would the price be if you had a batch of 50 made?

I'm not sure I have time to await a new batch as I'm getting close to fitting the engine back into the car stage.

I was going to fit the engine then exhaust, but I might fit the exhaust to the engine whilst it is more accessible, in which case that's pretty much the next job on my list.

[Timo]

I’ll pm you with some answers to your questions Andrew, I don’t want to flood your engine build thread.

[mycar]

Andrew, I've got a couple of Remflex graphite gaskets as supplied by PRS. I over ordered when I fitted my exhaust recently.

If you'd like them please Pm me you address and I'll stick them in the post.

[Timo]

Great offer Mike

[neilbardsley]

Ive heard good things about the reflex gaskets but put my exhaust on before PRS stocked them. I just doubled the gasket and added some paste. I figured PRS had built a few hundred engines with the older gaskets

Sent from my Redmi 7 using Tapatalk

[AndrewSlater]

Thanks to all for their kind offers and advice, I shall give the PRS ones a go - thanks to Mike.