AJP 4.5 Red rose Specs
Discussion
Does anyone have a link or information regarding the difference between the 4.5 and the red rose.
Specifically measurements and such of the head, so I can work out how much to take off of the heads to bring it to a similar ratio.
While I have the engine apart it seems pointless not to really, I have the means and the time to do a port polish, triple cut valves is not a major issue.
If had a descent root around and I can find a generalised list but nothing concrete.
What is the compression ratio of the red rose, As I can probably work it out from that?
Cheers,
Jody
Specifically measurements and such of the head, so I can work out how much to take off of the heads to bring it to a similar ratio.
While I have the engine apart it seems pointless not to really, I have the means and the time to do a port polish, triple cut valves is not a major issue.
If had a descent root around and I can find a generalised list but nothing concrete.
What is the compression ratio of the red rose, As I can probably work it out from that?
Cheers,
Jody
spoken to a very knowledgeable chap at "kjrhlkjreshglksjg" no i can't tell you as it would reveal where the other place I took my heads to.
4.2 Std - 10.5
4.5 Std - 10.75
4.5 RR - 12.3
(also, the first 2 specs above are actually in the handbook filofax!)
In answer to my first question, the RR has 40 thou (1mm), taken off the standard 4.5 to raise the compression to the above.
Also, just for kicks, I asked what the input shaft play on the T5 is meant to be. To which he replied, "in 10 years, your the first person to every ask that question, as most people can't be bothered" - the answer in case your wondering, is zero! We both agreed, that sticky clutches are caused by this phenomenon due to micro seepage of oil on to the splines and then subsequently gooing up under heat!
Piston to bore should be 4 thou ideal but anything up to 12 is generally acceptable.
And also, the service limit for cam to guide is around 12 thou or 0.3 mm, which answers another of my threads.
And much more that I wont "bore" you with (see what I did there, yea it wasn't funny...)
all in all a 100% successful 40 minute conversation
J
4.2 Std - 10.5
4.5 Std - 10.75
4.5 RR - 12.3
(also, the first 2 specs above are actually in the handbook filofax!)
In answer to my first question, the RR has 40 thou (1mm), taken off the standard 4.5 to raise the compression to the above.
Also, just for kicks, I asked what the input shaft play on the T5 is meant to be. To which he replied, "in 10 years, your the first person to every ask that question, as most people can't be bothered" - the answer in case your wondering, is zero! We both agreed, that sticky clutches are caused by this phenomenon due to micro seepage of oil on to the splines and then subsequently gooing up under heat!
Piston to bore should be 4 thou ideal but anything up to 12 is generally acceptable.
And also, the service limit for cam to guide is around 12 thou or 0.3 mm, which answers another of my threads.
And much more that I wont "bore" you with (see what I did there, yea it wasn't funny...)
all in all a 100% successful 40 minute conversation
J
Edited by tofts on Thursday 30th April 23:38
Edited by tofts on Thursday 30th April 23:40
I had my heads ported and set up on a flow bench by a guy with years of experience. He got a proportional 7% increase in flow on the inlet and a 28% increase in the exhaust. Apparently the best mod on the inlet is to unshroud the inlet valve. He also commented that the combustion chamber size appeared to differ on each one due to poor quality castings and suggested that I sorted this out to get the best results.
It took me about 1 day to measure and remove the correct amount of material to get the chambers balanced. From memory they varied from 50.5cm2 to 52.5cm2. Before you skim the heads I would balance the chambers and then work out what needs skimming. Don't go to far as the front engine cover will not fit properly and the fuel rail becomes difficult to fit and seal correctly.
This is a bit off topic but if you are rebuilding the whole engine I would also consider the following:
I would also get the liners o ringed, use new head studs and bolts throughout. The 2 most important things on this engine to check are liner height protrusion (4thou is good) and liner ovality under compression. ie fit and torque down the heads with a gasket but no crank or pistons, invert the block and measure the ovality of the liners from the sump side. I gave up with the prefinished liners normally used, purchased undersize liners had a torque plate made and had the liners machined to size in situ under compression.
Good luck with the upgrade, there are plenty of clever guys on this forum so just ask if you are not sure.
It took me about 1 day to measure and remove the correct amount of material to get the chambers balanced. From memory they varied from 50.5cm2 to 52.5cm2. Before you skim the heads I would balance the chambers and then work out what needs skimming. Don't go to far as the front engine cover will not fit properly and the fuel rail becomes difficult to fit and seal correctly.
This is a bit off topic but if you are rebuilding the whole engine I would also consider the following:
I would also get the liners o ringed, use new head studs and bolts throughout. The 2 most important things on this engine to check are liner height protrusion (4thou is good) and liner ovality under compression. ie fit and torque down the heads with a gasket but no crank or pistons, invert the block and measure the ovality of the liners from the sump side. I gave up with the prefinished liners normally used, purchased undersize liners had a torque plate made and had the liners machined to size in situ under compression.
Good luck with the upgrade, there are plenty of clever guys on this forum so just ask if you are not sure.
I know some engine builders don't like skimming the heads too much as there's a finite supply of heads and a heavy skim reduces the meat available to correct anything in the future.
A much better way would be to weld up the chambers and cut the chamber shape you want for flow and CR. See the turbo AJP build at ICE Silverstone for ideas.
A much better way would be to weld up the chambers and cut the chamber shape you want for flow and CR. See the turbo AJP build at ICE Silverstone for ideas.
I am currently in the process of doing some port work ( pics will follow)
I wanted to get most of the rough edges off first, as the valve recess cuts are actually quite rough (again, pics will follow). My intentions after this was to balance the chambers within X, skim, then check the volume again after skim.
welding sounds great in principal, but I don't know the chamber volume of the RR so I would suspect it would be hard to match. And is there really enough room in the chamber to do this anyway, the valves must take up 70% of the total area!
I will be speaking to mr X later, knowledgeable on just about everything about these later. If I can establish a minimum thickness, then I will be able to work out how close the RR was to spec.
Will reply in more detail later with pics and such/
jody
I wanted to get most of the rough edges off first, as the valve recess cuts are actually quite rough (again, pics will follow). My intentions after this was to balance the chambers within X, skim, then check the volume again after skim.
welding sounds great in principal, but I don't know the chamber volume of the RR so I would suspect it would be hard to match. And is there really enough room in the chamber to do this anyway, the valves must take up 70% of the total area!
I will be speaking to mr X later, knowledgeable on just about everything about these later. If I can establish a minimum thickness, then I will be able to work out how close the RR was to spec.
Will reply in more detail later with pics and such/
jody
Just to confirm, the amount skimmed off the heads for a red rose engine from the factory is indeed 1mm and is stamped on the back of each head.
And the red rose button increases the ignition by 2 degrees at idle.
Have you considered building a perfectly balanced std engine instead?
The gearbox, diff, drive shafts and a couple of cv joints gave up on mine at different times. Perhaps the previous owner wasn't very careful or I'm too hard on it now, but I sometimes think the engine in my car is too powerful for the driveline.
They are fast in any guise.
Just thinking about it from a long term angle instead.
And the red rose button increases the ignition by 2 degrees at idle.
Have you considered building a perfectly balanced std engine instead?
The gearbox, diff, drive shafts and a couple of cv joints gave up on mine at different times. Perhaps the previous owner wasn't very careful or I'm too hard on it now, but I sometimes think the engine in my car is too powerful for the driveline.
They are fast in any guise.
Just thinking about it from a long term angle instead.
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