Controlling head lifting under boost.

[Ive]

DVandrews said:

You can prevent dig in from a triangular ring or wills ring using a shim. that will lower the CR a tad but that isn’t necessarily a bad thing. My experience with wills rings on Imp/FWM(A) Coventry climax engines showed them to be very tricky to get right.

Dave

I have used a 1mm annealed copper shim. The fire ring of the MLS gasket would dig into the copper, but this likely made it seal even better.
On the head side, you could not see anything of this Impression. I still have the used shims, so could measure the imprint Profile. it is maybe 100 or 200 micron deep. Need to take it to a Dektak profilometer (I have Access to)

Some good information and discussion here. Like it :-) Thanks for the insights we are given.

[stevieturbo]

The likes of an old B16 or B18 Honda engine/box would probably be on par with the Rover engine for weight ?

And probably stronger boxes too, and the engines have been well proven.

But a 700kg car with 500+...really should have no problem at all running 9's

I've seen cars around that weight, maybe a little less with n/a Pintos running low 10's, so you can bet nowhere near 500hp...and probably a lot less than 300hp.

But as for the current issue...it's just going to be lots of trial and error.

[anonymous-user]

it's too long ago now, and i can't remember, but are K series through bolts torqued to yield? (ie settling torque + angle)

If so, then any time you exceed the clamp load you have an issue (Because you are using the plastic region of the fastener. Terrific for ensuring repeatability of clamp loads in a production environment, hopeless for a performance engine that needs to be run much closer to it's limits)


If you want custom studs, try these people:

T&Kprecision


Highly recommended

[crossy67]

Yup stretch bolts. 20Nm +180+180.

[Boosted LS1]

turbotoaster said:

stevieturbo said:

You dont need to replace the head every time, but after a few builds it may require a skim. Eventually yes though, you run out of skims lol

But absolutely any type of ring system is hit or miss and can take a few goes to get right, as there is no generic ring, groove depth etc etc etc that works for every setup.
In fact, not much difference than your suggestion of running the liners a little proud...getting the height right will also be trial and error and you will probably get it wrong a few times.
Keep an eye on pressure in the cooling system and ensure you've failsafes in place to catch it before anything can cause harm. HG failures with MLS gaskets can tend to do a lot of damage.

And a car at that weight and if it has 500hp+ should be doing 9's nevermind mid 10's

Surely some of the Honda engines wouldnt be much heavier ? And undoubtedly more proven with good power boosted builds ?

the rover heads are pretty soft and get pretty porous so finding heads that arnt skimmed to death is already starting to become harder.

I currently run my liners at 8 thousand proud which seems to be working at the moment, but i have no idea if that will work if we want to turn it up further, suck it and see as you say, i also run a 0.3mm shim between the gasket and the head to try and protect it.

a honda k20 and gearbox is about 185kg, the rover k series and gearbox is about 120kg, so there is the weight penalty, the honda has potential for alot more power of course.

its never going to be a competitive drag car, the mid 11 was my 3rd ever pass with the car so i dont have the setup time to make an accurate assessment of the potential, but it couldnt race against the jap fwd cars as its not eligable and the rwd/4wd guys will have double the power so i wouldnt be competitive. running a 9 would be amazing but i dont think i could get it to run that fast, i think a mid 10 should be doable with practice.

The car is designed for track use so 600bhp+ isnt needed....but that go at drag racing was alot of fun and im to competitive for my own good!

I did wonder about the O ring option but if the head will want to lift from simply not having the bolt stiffness to hold it down i cant see it working

They're springy and will go to a round section if the head lifts. As other's have suggested studs will be of benefit to.

[turbotoaster]

stevieturbo said:

The likes of an old B16 or B18 Honda engine/box would probably be on par with the Rover engine for weight ?

And probably stronger boxes too, and the engines have been well proven.

But a 700kg car with 500+...really should have no problem at all running 9's

I've seen cars around that weight, maybe a little less with n/a Pintos running low 10's, so you can bet nowhere near 500hp...and probably a lot less than 300hp.

But as for the current issue...it's just going to be lots of trial and error.

according to online the b16/18 with transmission are also 185kg, so again heavier.

If i was going to change I would probably go duratec 2.0-2.5 as the weight compared to a k series and you can buy an adapter plate to use the rover pg1 gearbox which saves money on axles etc, i would imagine they would be capable to 600bhp+ with the correct modifications

Im not sure the limit of the box, i think when andy nichols with his 2.0 T series got to around 700bhp on drag slicks he had to have a custom set of 1-4 gears made as the k and T use the same gearbox.

Max_Torque said:

it's too long ago now, and i can't remember, but are K series through bolts torqued to yield? (ie settling torque + angle)

If so, then any time you exceed the clamp load you have an issue (Because you are using the plastic region of the fastener. Terrific for ensuring repeatability of clamp loads in a production environment, hopeless for a performance engine that needs to be run much closer to it's limits)


If you want custom studs, try these people:

T&Kprecision


Highly recommended

Yes they are torque to yield, the main issue being is they go all the way through the block into a separate ladder underneath the girdle, which then applys torque directly to the main journals, so when everything expands from cold to operating temperature the bolts can cope with that expansion and maintain the mains in round. the risk of the studs is that as the engine expands(ive been told circa 1mm) then the torque on the mains will change which will either be correct when cold and wrong when hot or vise versa.

ARP do a kit for his engine, but it has destroyed mains bearings in the past

[GreenV8S]

Do you have enough information to estimate the peak force from the chamber lifting the head, and the tensile force holding the head down? If so, it would be interesting to see how much of the OEM clamping force you have lost currently and how much is left, assuming you keep the original bolts.

[stevieturbo]

The PG1 is a pretty strong box yes, but Andy did break quite a few too, and from what I recall, after Elite touched the box...he had more failures than ever.

[anonymous-user]

turbotoaster said:

Yes they are torque to yield, the main issue being is they go all the way through the block into a separate ladder underneath the girdle, which then applys torque directly to the main journals, so when everything expands from cold to operating temperature the bolts can cope with that expansion and maintain the mains in round.

Through-bolting isn't really about expansion load control (as the liners carry the bulk of the clamp load, and they are made of steel) it's about being able to pare down the block to min weight because it ISN'T carrying much load!

[turbotoaster]

GreenV8S said:

Do you have enough information to estimate the peak force from the chamber lifting the head, and the tensile force holding the head down? If so, it would be interesting to see how much of the OEM clamping force you have lost currently and how much is left, assuming you keep the original bolts.

I have a graph for the bolts, which when fully torqued, the graph reads 39kN and 1600um, so since a kN is circa 100kg, that would be just short of 4 tons?

I dont have the sensors or ability to monitor cylinder pressure, i can only go off the torque output based on running at MBT with no knock

stevieturbo said:

The PG1 is a pretty strong box yes, but Andy did break quite a few too, and from what I recall, after Elite touched the box...he had more failures than ever.

last time i spoke to him he told me about making it a 4 speed with a cuff, but didnt mention whom made him the gears apart from he tried quaife but they were made of chocolate.

Being a light car will help a little, im taking spare driveshafts with me as I have no idea what torque they will take as they are pretty much the same as MGF ones