Looking good! Exciting times.
Looking good! Exciting times.
You don't cockblock Mclovin
No-one cock blocks Mclovin!!!!Originally Posted by BRoadGhost
Quick engine update, no pics as I'm waiting on the progress photos from the boys.
Essentially it appears that someone (I can't even write the C units name) decided that +1mm inlet valves could just be fitted into standard valve seats and that +1mm exhaust valves should have seats cut so deep that they were recessed so deeply into the head we barely needed a shim on the bucket.
The bottom line is, we need to replace all 16 valve seats and re-cut all the valve seats and re-lap all the valves, then we need to blend the throats into the new valve seats. It's a lot of extra work but we have a solution and we're now working towards it, with any luck by the time I'm back from India 21st December we should have something that looks like an engine!!
I better get my ass in gear and get the rest of the car ready!!!
Edit to add I've just been told by Steveslim that the exhaust will work with +1 valves on standard seats, so I retract my previous statement regarding the exhaust seats.
Last edited by House; 03-12-15 at 10:10 PM.
Had a chat with a local motor rebuild specialist recently. He made an interesting statement regarding bedding in piston rings. Read on.
Harley-Davidson occasionally tests a freshly build motorbike (every one hundreth or so) by thrashing the nuts off it from the very first second. This in order to check performance figures and such. These particular bikes are sold on the the buying public, along with their non-thrashed bikes. Allegedly the bikes that have had their necks wringed, NEVER return for oil consumption or performance warranty claims. The theory behind this is that piston rings bed in (and subsequently seal) best when they are given a good kicking right after fitment. This essentially throws all running-in advice out the window.
Does anyone have thoughts on this?
One day I'll start a build thread. One day...
Bedding in rings is a massive debate and subject on it's own. I never found two bits of advice the same when I was looking into it. At least giving it to someone else gives you some more confidence.
I've been researching this very thing and having read Lee303's build thread on Mig as well as others who seem to have used the hard is best from the off method.
I've discussed it briefly with Modus as to their thoughts and also Jim at Track and Road, my worry would be making sure the fuelling is correct as the very worst thing would be to run it in hard on a map that isn't correct.
The thought process is that the "gentle" no loading method was used because the machining tolerances weren't as good as they are now.
The "hard" process is meant to force the rings against the cylinder walls and therefore create a better seal as the rings are forced to mate to the cylinder wall instead of gently polishing the walls as it may do when gently running in.
As above it's not that easy to run an engine hard when you don't have the correct fuelling, I guess we could richen the mixture up across the whole map, run it hard, then make some adjustments to get it closer fueling for the 10-15 hard runs needed to bed the rings.
Like I say Track and Road map new engines everyday of the week, I'm certain they'll know the very best way to do it.
Last edited by House; 07-12-15 at 01:59 PM.
Gutting on the Valves!
Running in is a 2sided camp i found.
All I wanted was a Pepsi, just one PepsiFar from suicidalStill I get them tendenciesBringing back them memories
That I really miss when I reminisce
The valve seats are in a long list of little things in this engine that just didn't make sense.
Despite no-one having heard of different Coscast castings, we have a Coscast head that has smaller throats than a GM head and another Coscast head that we measured it against. This is really strange, QED haven't heard of different Coscast castings but Jay said there is a suffix after the part number, very strange.
It seems that we should in-fact have +1 inlet valve seats that should then have had the throats opened up to match the bigger valve seats, then lapped in, this will lower the size of the shim needed on the inlet side, solving the question as to why the inlet valve clearance was so big.
What gets me is that the valves were all lapped in, meaning that "someone" thought the seats were ok and usable as they are, which they definitely are not, guess it's the same drill with the unpolished crank and no valve spring seats, more top quality engine building from you know who and I don't mean Lord Voldemort!!!
Last edited by House; 07-12-15 at 08:46 PM.
Just had a long conversation with Jay regarding running in, some very insightful things!!
This chat was on the phone whilst I was on the train, so I may have missed some of the very technical parts of the conversation but the general jist of it all is summarised below.
So, it's very important to remember that the running in period has absolutely nothing to do with wearing in main or big end bearing shells, as there should never be contact between those surfaces, so therefore there is nothing to "run in".
There is a small amount of running in for cams and cam "bearings" but the majority of the running in procedure is focused towards making sure the rings "seal" to the bores correctly and in such a way that they will give a long career of good piston ringyness.
Running in also depends on how the engine has been honed, Modus use a cork fine honer as the final stages of honing (Jay said come Jap manufacturers use a very fine stone, the end result is the same), my understanding of this is, when a block is fine honed, the bores are left with tiny "peaks and troughs" hence the criss cross you can see, the cork honer effectively blunts the peaks off the peaks, it is then easier for the piston rings to "wear" into those peaks during running in. If the peaks are not "blunted" then the peaks themselves will actually either cut into the piston rings or the peaks will literally "bend" over and in doing so fill the troughs. This has 2 effects, it reduces the amount of oil that the bores can retain for lubrication and also can cause excessive piston ring wear due the lack of lubrication and the sharpness of the peaks.
All running types of running in will "seal" the rings to the bore, it's simply a question of how long that "seal" will last.
Jay said that neither an overly gentle run in or an excessively hard run in are correct, it's essential the engine is run with a minimal amount of load as possible and a varying degree of revs and a lot of coasting to create negative pressure below the piston, constant revs for extended periods are also not advised accelerating on 3/4 throttle up through the revs with load isn't advised.
Jay said one of the most important things is oil, fully synthetic oil is a massive no no, it's simply too good at lubricating, it doesn't allow the rings to "grip" the bores and help with the blunting of the "peaks and troughs". The best oil to use is a mineral oil with added zinc to help the process he did explain this bit but I may have been in a tunnel at the time!!
If possible dyno running in is preferred as the load can be specifically controlled and changed to suit the revs that the engine is running at, Connaught a big player in the Ford engine world down this way run all their engines in on the engine dyno, they run in with light loads over the entire rev range for approximately an hour, then drop the mineral oil add new mineral oil and power map the engine, then drop the oil and onto the preferred engine oil job done.
Running in seems to be divided into two camps, one that wants to drive gently for 500 miles on the road with no revs and no real loading and one that want to give it a hard time the minute it's out the box. It seems that, assuming the honing has been carried out correctly, the answer is somewhere in the middle.
I'm happy that Track and Road will be able to map the car, hold any desired rev, with zero load (except transmission loads) if required or whatever load deemed appropriate and set the fuel safely to allow that running in to be safe.
No doubt this post will be rubbished by some pretty quickly and Modus branded idiots that don't know what they're doing and shouldn't be allowed to build performance engines but having seen some of the engines these guys have built that the owners have done exactly what Modus have advised I know where my money will be.
I also apologise if some of the terminology isn't 100% accurate.
Last edited by House; 07-12-15 at 08:55 PM.
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