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MG TD TF 1500 - Fanelli Cam & Valve Clearance

Anybody know if the high lift Fanelli cam can be used on a car with 147" off the head? Is there any possibility that the valves may not clear the pistons? No problems with the head & original cam. I could try it & see I suppose, but that's a bit like closing the gate after the $2,000 horse has bolted. If there was a problem I can only see three possible solutions. Dished pistons (pricey), replace the head (pricey) or a thicker head gasket which solves the potential problem but lowers the compression. Any thoughts? Cheers.
Peter TD 5801
P Hehir

Ok Peter I will relate a bit of my recent similar experience but mind you I am not expert in this area.
The head on my TD was .100 less than standard. I believe this increased my compression ratio to the point where I burnt a piston and shattered a ring due to the excessive heat. To lower my compression I used an oversized gasket. About .085-.090" thick.
If I recall correctly the standard head was 3.022" an mine was 2.922". The standard gasket is about .045" so I gained back about .040-.045" of compression chamber.

If I read your post above you say your head is undersized by.147"????? I am amazed that the pistons don't hit the spark plugs or am I missing something here?

I'm not sure about potential interference between the extra lift on the cam and the pistons. Check with Len on that.

I would definitely recommend the thicker gasket for both clearance and heat issues. If you want to go that way let me know and I will send you more info.

Mort

Mort 50 TD (Mobius)

BTW .... The car is running great with the new additions and work done. Friday we are off to the chassis dyno.
Mort 50 TD (Mobius)

Mort,

Are you running a blower on your engine?

Bill
TD24570
Bill Brown

Pete,

Len's cams are not outrageous in lift nor duration, but improve performance primarily by quicker opening and closing. If your previous cam worked good, Len's will most likely not have any problem either. For more accurate evaluation, measure the lift on your old cam with a micrometer or caliper, and then look up the roller lifter cam specs.

If you're really worried and don't mind an extra engine disassembly/reassembly, go through an evaluation with soft clay on the pistons and roll it over, to actually physically evaluate clearance.

If your engine was truly cut that much, the major concern is really how well the rocker geometry was dealt with. You cut your own pushrods, right?

Measure your existing head thickness and describe exactly which head you have (round hole or banana, TD TF 1250 1500???) we can argue over how much was trimmed down.

Yesterday, I welded a stainless thermocouple fitting onto the exhaust pipe right below the flange (and just above the O2 sensor bung) so I can document exhaust temps with the existing supercharged engine and cam before I replace them with a different engine with Len's cam. My expectation is lower temps with the new cam because it was specifically ground for a supercharged powerplant with less overlap and a bit longer exhaust, and should yield better power AND gas mileage.

JIM
JRN JIM

Jim - is the thermocouple bung something you buy separately, or does it come with a gauge?

Thanks. Tom
t lange

Hi Mort. When I had exhaust valve seats fitted for unleaded at Parry's here in Sydney a couple of years ago I had them measure the head. I just checked their figures. It is 2.875". I was advised the standard thickness was 3.0177" making it .143" undersize not the .147" that I had "remembered". I was aware at the time that the max recommended removal is 125" & when I queried this they didn't seem too concerned & they simply advised I should use 98 octane. This shaving was done by the owner before me. I drove the car for 18 months in the late 60's in that condition with no problem. She's been stored ever since. I've kept the original head gasket & will mike it however & check the thickness. If I find I have to get a thicker gasket Mort I'll get in touch. If you'll email me offline at pjbm@bigpond.com we can talk further about the installation of Len's cam. Yet to talk to anyone who's done it themselves. Be very interested in your dyno results!

Jim the PO had shortened the pushrods & used shims under the rocker posts. It's a banana, 22952. This setup will of course change with the Fanelli cam, roller lifters & his new pushrods. I intended to use putty or plastecine to do exactly what you suggested. Seems to be some confusion over the original thickness. I'm interested in your assessment. Have received some very encouraging reports about Len's cam. Can't wait! Cheers.
Peter TD 5801
P Hehir

Pete,
I'm anxious to run Len's cam, too, but our winter iced me out of the shop, so it is postponed for quite a while.
Do you have the smaller or larger valves? I'm working with a banana w/ small valves, going to the larger valves with exhaust inserts. You might explore getting the combustion chambers relieved around the valves- that'll lower compression ratio and improve breathing, especially for unsupercharged engines.

Do you have exhaust seat inserts already? If not, that's a good excuse to rework head.

Tom,
The K thermocouples on Ebay come with a stainless fitting- one compression fitting with ferrule and one male pipe thread. I picked up an O2 sensor plug and drilled/tapped 1/8" pipe thread for preliminary testing but finally pulled the pipe to weld the fitting to have both thermocouple and air/fuel ratio meter. I probably should've welded a female pipe thread on the pipe, but I cut the male pipe thread off thermocouple fitting and welded the hex to the pipe. There are also thermocouples with a hose clamp that don't need welding.
I bought a conventional 2" gauge for exhaust temp but also a cheapo digital display good to increments in 1 degree F. After salt washes off the roads, we'll be out on the road to test it.
JRN JIM

Jim I have the inserts (see post above) so don't wish to spend any more on the head. Valves are standard.
Peter TD5801
P Hehir

Bill Brown,
Yes I switched from my old Judson to the Moss blower.

Peter,
You have mail.
Mort 50 TD (Mobius)

To keep the proper rocker geometry I would think that just shortening the pushrods would suffice. I don't see the need to shim the rocker stands as well but perhaps I'm missing something.
JE Carroll

You're absolutely right JE. I intend to remove them. Cheers
Peter TD5801
P Hehir

Peter,
Len's push rod are longer than you need. He has an adjustable push rod to be used to determine the length you will need. I set my clearance to .018" to get a measurement. Then I took the rods to an automotive machine shop where he cut them all on a lathe with a grinding wheel attachment.
Mort
Mort 50 TD (Mobius)

Thanks Mort. Cutting them is not a problem for me but I wasn't sure how to go about determining the precise length. I do have spare original push rods & thought I may somehow use one of them, even though the ball end is a different size. Did you borrow the adjustable push rod you mentioned from Len? Be easier if there was a conversion factor to convert the existing length to the new, or if an adjustable rod was provided with the kit. Cheers.
Peter TD 5801
P Hehir

Pete,
It is said, the rocker stands should be the height where the rocker and valve are perpendicular at half the lift, to minimize sideways loading on stem...
...but then others may argue it should be closer to full stroke where spring force is greatest.

Len's roller rockers are an option, too.

I figure I'll set rockers perpendicular on the raised valves on the raised valves and then accurately measure the gap between the rocker stands and head to get started.

Tom & others,
One last point on the thermocouple, one can drill & tap an 1/8" thread into the exhaust manifold and thread the compression fitting in there.

JIM
JRN JIM

Peter,
Yes I used Len's adjustable rod. As per his instructions I set the tappet adjusting screw to about the mid point and tightened the nut. I used a .018" feeler gauge at the valve stem end and then adjusted the rod to just snug. Its good to check the adjustment on a few of the valves.
I then laid a new rod and cap in position and placed the adjustable next to it. I just scribed a line on the rod. Precision here is not critical since you will adjust the tappets anyway. This method gets you where you need to be.
Mort
Mort 50 TD (Mobius)

The Fanelli kit arrived earlier in the week & Len was kind enough to let me borrow his adjustable push rod which he'd included with my order. I've started another thread on the valve springs for the benefit on any other DIY type out there, so I wont repeat myself here.
I do have a query about the oil pump drive & its impact on the cam removal/reinstallation process. The car is up on stands with plenty of clearance below. Mention has been made of the necessity to raise the engine in other threads in the archive to allow the oil pump to be removed. Is this absolutely necessary bearing in mind that I have a horizontal pump fitted (not original I know) & the car is elevated about 2 feet?
As I don't have access to an engine hoist & am too mean to hire one, I will replace the cam with the block in the car. This of course means I can't jack up the engine as I will need to have the sump removed to gain access. Can I get away with just loosening the pump sufficiently to allow the drive to clear the cam or should I just remove it completely? Any & all thoughts from others who have replaced any sort of cam would be much appreciated!
(In anticipation of spending more time than I'd like on the concrete floor, I did take the precaution of carpeting the garage with free, used carpet before elevating the car, as winter is approaching here in Sydney) Cheers
Peter TD 5801
P Hehir

This thread was discussed between 19/03/2014 and 04/04/2014

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