Engine build advice please

[Spesh 31 1 Cars]

I'm making a start on my new engine as the bottom end is kinda tired in my car at the moment.

 

My proposed spec is as follows (pretty sure this is nigh on what welshpug runs?)

 

87mm XE pistons with pockets adjusted for xu10

92mm crank

Robson rods (to be ordered but looks like 158mm center to centre)

Stock head

Newmann PH4 cams, hydralic lifters and spring upgrade.

 

 

 

 

I've measured the combustion chamber to be 36.1cc (its had a light skim)

 

I'm assuming the piston value to be around 10cc although this is to be measured.

 

Given that I'm looking at a static of around 11.5 which if I'm reading the newmann sheet right with an inlet valve closing of 68degrees will give me a dynamic CR of 8.7. From what I can find the stock engine is around 9 dynamic.

 

 

So my questions are am i on the right track? and am i reading the newmann data correctly for the 68 closing angle?

 

http://www.newman-cams.com/wp-content/uploads/2022/01/PEUGEOT-CAMSHAFT-MANUFACTURING-PRICELIST-2022.pdf

 

 

Thanks

[petert 586]

Sort of. The 68º ABDC closing point assumes you'll use a 108º LCL. Newmans just publish a timing numbers for a typical LCL. They've probably never built and tuned an XU10. In reality, you'd install such a camshaft at 105-106º. This will move the inlet closing time to something like 65º ABDC, which will increase the DCR.

 

Is this a street or track car?

Edited September 2, 2022 by petert

[Spesh 31 1 Cars]

Thanks for the reply Peter.  Its mostly a track car although occasionally driven on the road (it will remain road legal).

 

If I go with 65 closing then it bumps the DCR to 8.9

 

 

Should have said in the original post buit it will be run on 98/99 Ron pump fuel.  

[petert 586]

If mostly track, you should convert to solid lifters.

[petert 586]

If mostly track, you should convert to solid lifters.

[Spesh 31 1 Cars]

Its still on my radar.  2 reasons for the hydraulic suggestions are that my rev limit isn't going to be that high considering the stroke/piston speeds and also ease of setup/maintenance 

 

 

Do my CR figures seem reasonable?

[Spesh 31 1 Cars]

Just noticed that the newman solid lifters are adjustable, that makes it much more appealing to me.  Anyone have any experience of these?

 

Also any suggestions for suitable valve springs to use?

Edited September 17, 2022 by Spesh

[Spesh 31 1 Cars]

On 9/3/2022 at 11:44 PM, petert said:

If mostly track, you should convert to solid lifters.

 

Emailed Newman and had a reply back saying that their hydro cams shouldn't be used with solids

 

"The PEUT/280/440H are designed to run against the hydraulic lifter. If you use the solid ones they will be quite tappety as the quietening ramps are 0.076mm instead of 0.25mm. "

 

Their solid cam, the phase 5, would be beyond my application I think

[Spesh 31 1 Cars]

Got a piston in and checked the volume at TDC and I get 11.9cc giving me a static of 10.9 and dynamic of 8.6 which I think might be a little low for those cams?

 

87mm Bore

92mm Stroke

158mm rod length

65abdc valve close

36.1cc head chamber

11.9cc piston volume at tdc

1.2mm gasjet thickness.

[petert 586]

11.9cc sounds like a dished piston. Are you sure you got this right?

[SweetBadger 94]

I was advised to use a PH4 inlet and a PH3 exhaust cam for my 1.9 MI build (advice and cams from Pug1off). Reason being that peak power with both cams PH4 would be at too high revs for the hydraulic lifters.

 

You might want to consider doing the same. It worked for me.

 

Newmans can also provide the cams nitrided. 
 

 

[petert 586]

1 hour ago, SweetBadger said:

I was advised to use a PH4 inlet and a PH3 exhaust cam for my 1.9 MI build (advice and cams from Pug1off). Reason being that peak power with both cams PH4 would be at too high revs for the hydraulic lifters.
 

 

This is good advice, as the exhaust port outflows the inlet port at lower lifts. Thus in order to maintain acceptable inlet/exhaust flow ratios, I always make the exhaust cam smaller, by 5-10º on 0.050" duration figures.

[welshpug 1,657]

1 hour ago, SweetBadger said:

I was advised to use a PH4 inlet and a PH3 exhaust cam for my 1.9 MI build (advice and cams from Pug1off). Reason being that peak power with both cams PH4 would be at too high revs for the hydraulic lifters.

 

You might want to consider doing the same. It worked for me.

 

Newmans can also provide the cams nitrided. 
 

 

Might be true on 86x86 or close, but on a 92mm stroke?   Mine seems to peak at a safe rpm on ph4 on 92mm stroke

[Spesh 31 1 Cars]

11 hours ago, petert said:

11.9cc sounds like a dished piston. Are you sure you got this right?

I'll remeasure, I did it at TDC and am questioning whether I got it right.  Will drop the piston down a bit and subtract the volume above the piston as it was quite awkward at TDC.  (ignore the rods, they are going in the bin, robson ones ordered)

 

IMG_20210412_175718 by Mark Needs, on Flickr

Edited September 28, 2022 by Spesh

[Spesh 31 1 Cars]

also there isn't a ph3 cam for mine, it jumps from 2 to 4 with the j4rs.  The specs of the j4rs phase 4 look closer to the mi16 phase 3 also

 

@welshpug I'm pretty sure what I'm aiming for is almost a carbon copy of what you have

Edited September 28, 2022 by Spesh

[petert 586]

What is the deck clearance at TDC?

 

These are -9.1cc.

[Spesh 31 1 Cars]

I need to recheck the deck clearance as I've sent one of the crappy rods I've used for first dry build and its come up short, not by a massive amount but still.  Picked up a thicker bit of plexi to do cover it too so thats a revisit as I suspect I'm out on the piston measurement.

 

 

Robson came back with this today

 

Untitled attachment 00003 by Mark Needs, on Flickr

 

 

looks ok to me but I'm super nervous about dropping the cash and something being off lol.

[petert 586]

What is the compression height of your pistons?

 

I'd be giving Robsons a pin so they can get the small end clearance perfect.

[Spesh 31 1 Cars]

31mm.

 

235-46-158-31

[petert 586]

I couldn't find an XE piston with 31mm, thus why I asked.

 

[petert 586]

My calcs are 46 + 158 + 30.5 = 234.5

 

Thus they'd be 0.5mm of deck clearance, which is approx. 3cc. Meaning you'd need to deck the block to optimize squish and get the CR up.

[Spesh 31 1 Cars]

14 hours ago, petert said:

My calcs are 46 + 158 + 30.5 = 234.5

 

Thus they'd be 0.5mm of deck clearance, which is approx. 3cc. Meaning you'd need to deck the block to optimize squish and get the CR up.

You sir are a godsend.  I'm on shift at the moment but nipped out the shed when i got home last night and remeasured and you are 100% correct, the compression height is 30.5mm.

 

I put a piston and rod back in, found tdc with a dial, put a straight edge across and I can get a 0.5mm feeler in on the flat part of the crown which double confirms it.  I got given paperwork with the pistons that gave a 31mm height and cannot ever actually remember checking them, foolish of me.

 

I'll get hold of Robson on monday morning first thing and if they've not moved the rods on I'll go 158.5 on them else I'll deck as you say.

 

46+158.5+30.5=235

 

 

[petert 586]

I’d leave the rods at 158 and deck the block, as you need to do that anyway, so you have a fresh surface for the gasket.

[Spesh 31 1 Cars]

thanks for the help so far.  I have another question that I can't seem to answer.

 

Bearing choice.

 

What, if any, are the benifits of "race" or "upgraded" bearing shells?  I'm struggling to find actual reasons beyond hearsay.  I've no issue in spending more if its warranted but in my head (which may be misled for sure) the bearing is simply a surface for an oil film to be present on.  Regardless of how posh a shell is if there is metal to metal contact its game over anyway.

 

I've put glyco mains in and checked clearances etc but am now at a point where i need to order up big ends so any insights would be useful.  Thanks

[petert 586]

I only have experience with ACL Race rod bearings. They have a tighter/closer clearance. On the same crank, their race bearing would have a clearance of 0.002”, compared to 0.0025”-0.003” on a regular bearing.

Edited October 10, 2022 by petert