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TA Performance Rover V8 Cylinder Heads

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Daniel C Jones

TA Performance Rover V8 Cylinder Heads
« on: January 14, 2016, 08:42:58 PM »
I just dropped off a set of assembled TA Performance Rover heads

(1.94" diameter intake valves, 1.6" exhaust) and Willpower single

plane intake at Stiegemeyer porting, a local cylinder head and

supercharger specialist near where I work.  I removed the valves from

one cylinder and Bob examined the ports, chamber shrouding, seat

margins and valve angles and asked me some questions about the engine

the heads will be going on (a higher compression 4.2L Rover), along

with how I plan to use the car (TR8, purely street).  He also asked if

I was going to run EFI or a carb, suggesting you can get away with

somewhat larger ports with EFI.  He thought the size of the as cast

ports were fine for my purposes, needing only detail work, and that

the best bang-for-the-buck would be to work around the existing valve

job.  He also threaded a spark plug in and indicated he would do a

little chamber work around the plugs.  Looking at the intake ports, he

thought they should go to 250 CFM fairly easily which would be plenty

for my application.  The plan is to flow bench the TA Rover head in as

delivered condition then let him have a go at bowl porting and port

matching the heads and intake.  He indicated that getting the port

floor of the intake manifold to work with cylinder head port floor was

especially critical.  I'm going to drop a block, gaskets (intake,

exhaust and head), a header flange with pipe stubs and some bolts off

this weekend so he can mock it up.  I think I'll also take an OEM 4.6L

Rover cylinder head along to flow bench as don't have any data on

unported Rover heads.  The TA heads are based upon the TA Performance

Buick V6 heads.  The guy who designed the TA heads also suggested:

"On the exhaust have him start by opening up the exhaust outlet, make

the port wider, The port will respond by doing this. Then have him

removing very little to none on the back side of the exhaust bowl.

Just blend the machined throat area into the back side. He should end

up with a slight bump even, on the back side. Blend the rest of the

bowl how he see fit."

The exhaust port shape is way better than the Rover/Buick but has been

raised 3/4" so it's not clear if off-the-shelf TR8 headers will work.

He also says the intake ports should flow 250+ CFM with only minor

work.  It'll be interesting to see what sort of power they make.  It

would also be interesting to test them on the 5.0L Rover V8 I have

sitting at the dyno but the valves have been relocated to the center

of the bore, have a different angle and are larger so chances are

there will be piston-to-valve clearance issues.

Given the bore size and chamber design, Stiegemeyer suggested no less

than 11:1 compression and we briefly discussed camshafts. I mentioned

the short block should handle a decent amount of RPM (cross-bolted

mains, 3.03" stroke Rover nodular cast iron crank, Carrillo rods,

forged flat top pistons) and I was considering running either a solid

flat tappet or a hydraulic roller camshaft. He put the valve springs

on a tester and said they were ideal for a hydraulic roller camshaft

but recommended titanium retainers for a bit more RPM.  He said they

would also work with a solid flat tappet cam if offset locks were used

to reduce the seat pressure.  If running a solid flat tappet, he

recommended using lifters with EDM holes supplying oil directly to the

cam lobe/lifter face.  On the tester, the springs were quite close to

the advertised specifications. Note these assembled heads were

delivered with TA's upgrade spring package for a hydraulic roller cam

(TA p/n 1160) and have the following specs:

Dual springs without damper

O.D. 1.385

160 lbs @ 1.900"

360 lbs @ 1.400"

400 lbs/in

Coil Bind 1.175"

Max Lift 0.650"

He also likes the blue Viton metal clad valve seals, mentioning the

white Teflon seals don't pass enough oil to the guides for most

applications (uses them in race applications where the springs are

flooded with oil over the top of the guides).


Dan Jones



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W Parris

Re: TA Performance Rover V8 Cylinder Heads
« Reply #1 on: January 14, 2016, 09:15:55 PM »
Sounds interesting and fun.



Greg Gall

Re: TA Performance Rover V8 Cylinder Heads
« Reply #2 on: January 14, 2016, 10:10:16 PM »
Thanks for all the info / technical details as always Dan!

I would love to build a nice Rover V8 some day so I really appreciate you

sharing what you learn!




Re: TA Performance Rover V8 Cylinder Heads
« Reply #3 on: January 15, 2016, 07:57:41 AM »
Cool, car nerd stuff.  And when you get done you can put it on his dyno.  Stegemeyer does a lot of race motors so the sky's the limit.



Dave Massey

Mark Elbers

Re: TA Performance Rover V8 Cylinder Heads
« Reply #4 on: January 15, 2016, 10:42:37 AM »

 I'm also interested in the flow numbers for those OEM 4.6  heads.

I have a set for my 3.5 EFI motor.  Be interesting to see if they are an

improvement over the standard TR8/SD1 heads.

Mark Elbers


Daniel C Jones

Re: TA Performance Rover V8 Cylinder Heads
« Reply #5 on: January 15, 2016, 02:30:02 PM »


Re: TA Performance Rover V8 Cylinder Heads
« Reply #6 on: January 15, 2016, 06:37:07 PM »
Cool.  True car nerd porn.



Dave Massey

Daniel C Jones

Re: TA Performance Rover V8 Cylinder Heads
« Reply #7 on: February 03, 2016, 06:43:52 PM »
Just a quick update on the TA Rover heads.  The head porter is

supposed to get started on the Rover heads late this week. I dropped

off the block, exhaust header flange, gaskets and head studs off last

week so we could do a preliminary fit check prior to porting the

heads. We positioned the TA heads and Willpower intake on the block

without intake or head gaskets and the intake manifold bolt holes

lined up with the holes in the heads and the intake ports were closely

aligned with the unported TA head intake ports. Given the fact that

the TA Rover heads are deeper, I expected the intake to sit up higher

in the V and the holes in the intake need to be slotted but that

wasn't the case. I assume TA must have adjusted those to match the

wider head so the intake lines up. I didn't run the studs all the way

down while I was there but the head bolt bosses are taller so its

possible they won't be long enough. I'll check that this weekend. The

blue Fel Pro Buick 300 intake gaskets (p/n 9944) are 0.042" thick and

should work with the 0.050" Rover composite headgaskets. The gaskets

are a decent fit but will likely need a bit of trimming and be shifted

up perhaps an 1/8". I'll glue those to the intake before installation.

I discussed Mike's information on porting the exhaust side and we put

machinist dye around the exhaust port and bolted a header gasket in

place. Widening the port per Mike's advice, he scribed an outline. The

resultant port is sized for a 1 1/2" ID primary tube header. That

means a 1 5/8" OD. The TR8 tri-y TR8 headers from the Wedge Shop are

available in two sizes:

Standard: 1 1/2" diameter primary, 1 3/4" secondary, 2" collector

Big Tube: 1 5/8" diameter primary, 1 7/8" secondary, 2 1/4" collector

I'll go with the big tube but the exhaust ports on the TA Rover heads

are raised 3/4" and Woody says his headers tuck up close to the

chassis so won't have the vertical clearance required. I'll have to

cut and lengthen them.

My block appears to be unmilled and specs for the Buick 215 and Rover

show a nominal deck height of 8.96". The forged pistons have a

compression height of 1.25". Crank stroke is 3.03" and connecting rods

are 6.2" center-to-center:

rod length + crank stroke/2 + piston pin height = 6.2 + 3.03/2 + 1.25 = 8.965"

If the block is 8.96", that would put the piston 0.005" out of the

hole at TDC. Close enough to zero deck. In the parts stash, I have a

couple of larger bore Rover headgaskets:

Rover ETC-7819 0.018" compressed thickness embossed head gasket

Rover ERR-7217 0.050" compressed thickness composite head gasket 3.77" bore

Unlike, the OEM Rover heads, the TA Performance Rover heads have a

quench chamber. The usual quench distance goal is 0.040" +/-0.003" and

the quench effect is supposedly negligible at 0.060". On the minimum

side, you need enough clearance to compensate for piston rock at TDC

and rod stretch at maximum RPM so the piston doesn't contact the head.

Since aluminum blocks have a greater coefficient of linear thermal

expansion, can probably run a little tighter quench. If I got my units

correct, my back of the envelope calculation suggests maybe 0.006"

difference between a cast iron and aluminum block for a 100 deg F

temperature difference. Even factoring that in, the thinner headgasket

is too thin to be safe. The thicker gasket will be thicker than

desired but might be useable if the compression works out.

The combustion chambers are nominally 35 ccs but will get polished so

will likely end up around 40 ccs. I cc'd the piston dish and valve

notch at between 11 and 13 ccs, depending upon whether I cc'd them

with alcohol or white sand. Compression with these assumptions and the

thinner headgasket would be 10.85:1 and 9.89:1 for the thicker

headgasket. A 0.040" thick headgasket would give 10.17:1 compression

ratio and the goal quench. Given the aluminum heads, small 3.706" bore

and expected cam overlap, I'd like to be at 11:1 compression. That

would be no problem with quench heads and quench pistons but the

custom pistons I have were designed for Buick/Rover heads which have

no quench to speak of and are dished in the location of the quench pad

on the TA heads. The pistons were also designed for heads with the

valves in OEM locations but the TA heads have relocated them to the

center of the bore to permit larger valves. From the initial mock up,

I should be able to modify the existing valve pockets for clearance,

though the extra cc's will have to be figured into the final

compression ratio. Given that Woody runs 11:1 compression in some of

his engines that use Rover or Buick 300 heads, I should be able to run

11:1 without the quench effect. We'll see where it all ends up during

the final mock up assembly but I'll likely have to mill the heads to

get the desired compression ratio.

I could buy another set of custom pistons designed for the TA Rover

heads and swap the pistons over to the stock short block Rover 4.2L

that I have. It will get ported OEM Rover heads but I'd also need to

buy another set of 6.2" small (2.0") journal rods to make the

compression height work out. Come to think of it, the guy I bought the

parts of off tossed in a second set of 6.2" rods but I believe he said

they weren't narrowed properly. Worth a look anyway.

I also dropped of an OEM Rover 4.6L head for flow testing.

Dan Jones



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Daniel C Jones

Re: TA Performance Rover V8 Cylinder Heads
« Reply #8 on: February 12, 2016, 03:24:07 PM »
Just got word from the head porter that the TA Rover heads should be

ready for pickup next week.  He said they flow near 260 CFM intake and

200 CFM exhaust.  He noted that once you get past the intake port

entries, the center of the ports looks like they were designed for a

considerably larger displacement or higher RPM maximum effort

application.  If you raised the intake roof a 1/2" and epoxied the

floor, he thought it would flow well over 300 CFM with a larger intake

valve.  Given the intake port sizing, he thinks the engine would run

better with EFI than with a carb.  He is really excited about the

heads and the lightweight Rover/Buick engine and thought I should

ditch the hydraulic roller, go solid flat tappet and spin it to 8000

RPM.  He called a local engine builder over to look at the mock up of

the heads, intake and block just because he thought it was so neat.

More when I pick up the parts and flow sheets.

Dan Jones

Daniel C Jones

Re: TA Performance Rover V8 Cylinder Heads
« Reply #9 on: February 16, 2016, 06:10:57 PM »
Picked up the ported TA Rover heads today.  Heads were ported by Bob

Stiegemeier of Stiegemeier Porting Service (

in St. Charles, Missouri and were tested at a 28" pressure drop on a

SuperFlow 600 flow bench.  Intake ports were flowed with a clayed

radius around the intake port.  No pipe was used on the exhaust except

for one test with the stock 4.6L Rover head (noted below).  Flow is in

cubic feet per minute (CFM) and lift is in inches.  Intake valve

diameter is 1.94" and exhaust diameter is 1.6".  Note that the heads

were purchased assembled and Bob worked around the existing valve job.

For my application, only minor work was required on the intake side so

most of the effort was concentrated on the exhaust.  Heads were flowed

unported, ported and ported with a 30 degree back cut on the intake

valves.  Columns are as follow:

 1 = out of box intake ports

 2 = ported intake, no back cut on intake valves

 3 = ported intake, 30 degree back cut on intake valves

 4 = out-of-box exhaust ports, no pipe stub

 5 = ported exhaust, no back cut on exhaust valves, no pipe stub

I'll try inserting periods to keep the forum software from screwing up

the column spacing:




 0.100 067.7 076.8 078.3 047.9 063.8

 0.200 105.4 120.4 129.4 070.2 108.5

 0.300 143.0 173.1 185.1 102.1 146.7

 0.350 164.0 198.7 206.2 114.9 -------

 0.400 185.1 224.2 225.8 126.0 177.0

 0.500 220.9 255.9 251.3 137.2 189.8

 0.600 225.8 ------- 252.8 140.4 199.4

Bob noted the flow for the ported intake with back-cut valves was for

the first one he did.  He got closer to 260 CFM peak on subsequent

valves.  He believes he can do better if starting with heads without a

valve job.  The exhaust port was sized for a 1 5/8" OD header primary

(the larger of the two available tri-y headers for the Triumph TR8).

For reference, here's what my ported 1964 Buick 300 cylinder heads

flowed with 1.775" intake and 1.5" exhaust valves:

 Lift 1.775 1.5

 0.100 066 047

 0.200 129 104

 0.300 174 130

 0.350 187 139

 0.400 191 146

 0.500 196 152

 0.600 200 153

I had also previously flowed a stock Buick 300 head with 1.625" intake

and 1.312" exhaust valves at 154 CFM intake and 116 CFM exhaust.  The

unported Rover 4.6L head flowed:

 Lift  1.575 1.350

 0.100 060.2 057.4

 0.200 105.4 092.5

 0.300 132.4 103.7

 0.350 135.5 106.9

 0.400 135.5 106.9  (114.8 with pipe stub)

The ported TA Rover heads flow nearly double the stock Rover 4.6L

heads!  I dug up some small block Ford AFR 165 head flow numbers (CNC

ported but earlier version with the 11/32" diameter valves) from a

magazine article (Mustang 5.0 magazine, November, 2000, "Having our

Heads Examined"):

 AFR 165 1.9 1.6

 0.100 060 051

 0.200 123 108

 0.300 176 149

 0.400 210 174

 0.500 232 184

 0.600 232 188

Note the ported Rover TA heads outflow the highly regarded AFR 165

heads (best of the smaller valve size, stock port location, SBF


Bob clearanced the chambers to around 42cc then milled them 0.020" to

get them to 37cc.  He also installed thin wall bronze sleeves in the

pushrod holes.  The intake valves had sharp edges around the keepers

and damaged some of the valve stem seals during dis-assembly so he

smoothed the sharp edges and installed new seals.  The intake valves

(appear to be SI brand) were out of round so Bob cut them to get them

round.  The exhaust (Ferrea) were round and needed no adjustment.  The

intake manifold had a low spot on one of the flanges that he welded up

and milled back down.  The intake and heads were then port matched on

the block.  He tested the springs with and without the inner springs.

With the inners in place, they are 170 lbs on the seat and 400 lbs @

0.550" lift.  With the inners removed, they are 120 lbs on the seat

and 280 lbs @ 0.550".  Bob said he can adjust the seat pressure with

offset keepers once I decided on the cam.  He'd really like to see me

run a solid flat tappet cam with EDM lifters and beehive springs and

spin the engine to 8000 RPM.  Given the intake port size, he thought

I'd want to run a narrower lobe separation angle than the intake valve

diameter (to cubic inches ratio) might suggest with a bunch of initial

timing and a short advance curve.  He also suggested 11:1 compression

and thought EFI would work better than a carb with the large intake

ports.  Given the very strong exhaust port, he thought a single

pattern cam would be the way to go.  He mentioned that while the

exhaust would flow even more with a pipe stub, adding a full length

header usually gets it back to what the naked exhaust port flows so he

likes to flow them without a pipe stub.  Bob was really jazzed about

the TA heads and lightweight Rover V8.  He noted there was room on the

cylinder head to raise the roof a 1/2" and thought that raising the

roof, filling the floor and use a larger intake valve, he could get

well over 320 CFM out of the intake ports.

Photos to follow later this week or weekend.

Dan Jones