Porting a Triumph Spitfire engine head 

The good thing about spits is the head can come off easily without disturbing the valve timing,yes the rockers need re adjusting but that's no big deal,anyway,i'm going to be doing the same thing to my engine,one thing i noticed is the water ways to and from the block are gnarly and not well lined up,use the head gasket to get better coolant flow. There is also the drilling of the oil gallery feed in the rear of the distributor ,there's a vid on youtube giving details. Use a rocker feed kit,some say it lowers oil pressure but that's nonsense,it lowers pressure on a GT6 as the GT6 uses the same oil pump as a spit,which is at the max on a GT6,but a spit block can easily use the rocker oil feed kits and keep good oil pressure. I also have an oil cooler kit with a thermostat,the oil rad is from a van(bedford) or a ford,i'm in Scotland in the UK so the model really is not important the important bit is not to buy an oil rad from a triumph dealer$$$$$$$$££££££££$$$$$$$$$$$$$££££££££££££,the fittings are the same on most rads and they go by length and rows of cooler tubes for width. I'll clear up the flow issue,make the intake tract rough texture,that's where the little dimples would be,like a sharks skin the rough texture creates what's called a boundary layer that acts like an air bearing,secondly you need to match the intake port to the manifold gasket,just the first 1/8 to 1/4 inch or so to make a small funnel shape,removing too much material will lower air flow velocity and the fuel air mixture will fall out of suspension. Opening the intake tracts is for high reving racing cars that need max airflow but do so at max rev all the time with no low rev power at all. Polish to a mirror the combustion chamber to stop or minimise carbon fouling a shiny surface has little for the carbon to hold on to,also the shiny surface reflects infra-red energy(heat) into the cylinder and out of the exhaust port. polish the exhaust port and tracts,gasket matching the exhaust is not needed,and in fact a small step from port to exhaust pipe,from a small hole to a larger pipe creates a bit of turbulance that stops an effect called "REVERSION" where exhaust gases get sucked back into the cylinder,the step creates turbulence making the effective exhaust port look smaller to the exhaust gass trying to get back inside the combustion chamber,the polar opposite of the intake wher we use trumpets and gasket match to minimise turbulence to allow as much air flow as is possible but keeping the tract the same overall size to maximise air velocity. There is a guide to tract size based on the inlet valve size,but i would just smooth out the cast flashing and sharp edges ,make the transition from manifold to head smooth without opening up the tract,also make sure the gasket to manifold is clear,the gasket may need work too,ther may be a need to make a very short area to match manifold-gasket-head inlet that is a weird outward bulge,from a side view cut away it would be very short possibly a few mm long to allow the transition to be as smooth as possible. I have seen port to gasket match done that the funnel shape goes in way too far,the tract diameter is pretty much bang on,just a little rough,and in need of slightly better flow,which is easy,just as i went into length to describe just don't over do it. the corners inside the combustion chamber just need to be given a small radii to take of the angle,after that i would/will cc the chambers and raise three chambers to the largest chamber volume by using fine emery of around 800 to 100 grit on the flat area, a cc or so between chambers won't kill it,anal and fastidiousness is not needed,re-polish. then a light skim after working out the CR. kp-gasket.blogspot.com/2012/06/skimming-your-head-for-higher.html www.205gtidrivers.com/forums/topic/137630-working-out-my-compression-ratio-after-head-skim/ here's the second link text copied and pasted. ------------------------------------------------------------------------------------------------------------------------------------ If you have the combustion chamber volume then that's the hardest part done! What you need to do next is work out the rest of your volumes: Step 1a: (3.142 * Bore^2) / 4 = Piston Area Step 1b: Piston Area * Stroke = Swept Volume Step 2: Piston Volume = measured cc's of any piston dish or cut-outs Step 3: Gasket Thickness * Piston Area = Gasket Volume (approximate, but close enough) Then you work out the ratio of the total internal volume to the comressed volume i.e compression ratio. Step 4: Swept Volume + Piston Volume + Combusion Chamber Volume + Gasket Volume = Total Volume Step 5: Piston Volume + Combustion Chamber Volume + Gasket Volume = Compressed Volume Step 6: Total Volume / Compressed Volume = Compression Ratio So for example.. Stroke = 73mm, Bore = 83mm (divide by 10 for cm) Step 1a: Piston Area = (3.142 * 8.3^2) / 4 = 54.1cm^2 Step 1b: Swept Volume = 54.1 * 7.3 = 395cm^3 (On a side note, this is your cylinder displacement - multiply this by number of cylinders gives your engine displacement so 395 * 4 = 1580cc) Step 2: Piston Volume measured to be = 6cm^3 Step 3: Gasket Volume = 54.1 * 0.2 (say it's 2mm thick) = 10.8cm^3 Then say you measured your Combustion Chamber to be 28cm^3.. Step 4: Total Volume = 395 + 6 + 28 + 10.8 = 439.8cm^3 Step 5: Compressed Volume = 6 + 28 + 10.8 = 44.8cm^3 Step 6: Compression Ratio = 439.8 / 44.8 = 9.8 : 1 Obviously you need to substitute your values for my made up ones! ------------------------------------------------------------------------------------------------------------------------------------ I will add another text for finding CR skim, Going back to my engine building days I seem to remember the formula for calculating this is :- swept volume of cylinder / (required) CR - 1 for example :- on a 4 litre engine 3950cc / 8 = 493.75 493.75 / 10-1 = 54.861 so the total chamber volume must be 54.861 cc to get a 10:1 compression ratio From this subtract all the volumes that do not reside in the cylinder head, eg gasket wolume, dish in piston, volume above piston at TDC (due to piston not coming even with the block deck)you will then be left with the combustion chamber volume required to give you a 10:1 compression ratio. When you have this, put the spark plug in, set the cylinder head up on a level surface (must be level) then take a burette graduated in cc using paraffin put the ammount into the cylider head combustion chamber. Then measure with a vernier (or depth micrometer)from the head surface to the liquid and that is the ammount to skim off to get a 10:1 compression ratio. If your not into this, I would suggest calling one of the specialists like V8 Dev. (they will have a lot of experience in this type of stuff) ------------------------------------------------------------------------------------------------------------------------------------ I see you did what i did and get rid of the exposed seams,just a water trap in the rain directing water into the door aperture ,rot the doors and make a footwell swimming pool,i also changed out the door hing hanger plates to 10mm plate the original is like 5mm or so,not very good and the threads strip too easily,i also used stainless button head screws on the door hinges. All the best.

Rangers are great trucks. I've had 4, but my current daily is an 83 Dodge. You may be thinking of Elin Yakov, Rusty Beauties. He recently did a TR4 head.

Had you considered matching the ports to the manifolds using the gasket as a guide ?

Thank you for posting, and keep up the good work. I hope you are able to get it back on the road soon, Be well