Hi! All
Thinking of converting mt TR6 from carb to EFI.
I have 2 head cylinders and narrow intake port and a wide intake port
Narrow has numbers V3059, 051, 18812 397837, 516323
Wide has numbers V3267, 12L4, 313247,188 4, 219019 and under the rocker coverthere is an N in the back and a B in the front of the head
Engine block number is CC65955E
a few questions
1. Can I use the wide port head on the engine block?
2.I need to bring the compression up to 9.5.1 (not sure what the CR is now)
How much to shave off the head to be at 9.5.1 CR? and does the deck need to be zero?
what thickness head gasket is required?
3. 260 degrees Newman camshaft or similar
Do I need different pushrods and valve springs?
Any suggestions and directions would be appreciated
Thanks
Greg

You might be smart to go only to 9:1. Who knows what the octane of gasoline will be in the next 10 years. I believe there is enough range in the rocker arm adjuster screws to allow the use of stock valve springs and pushrods. Also the stock head gasket.


You MUST leave some deck height to allow for "rod stretch". Usually 0.020" is adequate for high output engines. Are you planning to strip the block for machining ?

Thanks Jeff,
I was going to do just the head.
should I go with the wide or the narrow head?
Greg

I think cam and CR should match, 260 is like stock.

Here is the one I would like. Single slide throttle.

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SR
73 TR6
86 930

Hey Steve who is the manufacturer of the fuel injection system?

I wish I knew.

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SR
73 TR6
86 930

Greg,

1) I'm fairly certain either head will bolt on and work ok although I do not recall ever doing that specifically. Someone else on here most likely has though.

I don't think the later head has any clear advantage either power-wise, or for longevity. Whatever improvements the later head has is fairly insignificant, I believe. I think your choice has to do more with what items are available that will bolt onto whatever head you use.

2) Probably best to do the math to get the exact amount to remove from the bottom of the head to achieve the compression ratio you choose. The counter bore in the block at the top of each cylinder is filled with the correct head gasket for the block. It does not allow for zero deck clearance. There will always be that amount of volume with that top thin slice of the bore volume, added to the volume of the combustion chamber.

I'll dig around and see if I can find the specification for the cylinder head combustion chamber volume and counter bore depth. I had one measured once. Maybe someone on here has this info more at the ready.

3) That Newman cam does not require different valve springs or pushrods unless you intend to run it up at the very top of the RPM range all the time. You may want to renew everything just as a matter of course though. These parts are old and who knows how many hours are on them. A close match to the stock double spring setup is good enough.

You don't need expensive heavy duty springs or pushrods though. Regardless the fuel system used. Not with that cam and compression ratio.

The valve adjuster screws have enough range to cover a small amount of reduction in cylinder head thickness and a small increase in valve lift. It's not uncommon to shim the rocker assembly pedestals 0.020" - 0.100" to put the geometry back how it was before shaving the head, if needed.

I'm curious about what fuel injection setup you are looking into.

Thanks everyone for all the inputs and suggestions.
I have a complete fuel system from a 1997 BMW 528i.
I have an original TR6PI plenum, but I am thinking of making one from scratch.

As a general rule, planing the head to achieve a measurement of 3.4" from the rocker cover gasket seat to the bottom of the head will result in a 9.5:1 CR. I do not know if that takes a 0 decked block or head gasket into consideration however. - Pete

Greg

Do a search on " how much to mill a TR6 head"

Also this from that topic gives the information on amount milled to CR.

http://goodparts.com/shop/index.php?ukey=auxpage_tr6-compression-ratio

Red

Found this online. Not cheap, but cool.

Fuel Injection

Perry

That is indeed some eye candy but very impractical for a driver car. Really much better to have an IR system connected to a plenum with a single throttle body. No synchronization issues and much simpler to add cold air and filtration onto the intake.

Further I expect that a long runner EFI intake would go a long way on these lower RPM engines towards further boosting torque across the effective operating range. If you study modern intake design you will find this to be very common now: longer sweeping curves of moderate cross section to provide better low RPM response (ie: torque).