Grady,
Well I started with the most worn 72T motor ever and after 6 months of wheeling and dealing for good parts I'm building my motor from a 72E case, 2.2E cylinders,heads and cams, 10.5:1 JE's (shimmed to 10.0-10.2) and a crank out of a 75 2.7. Canidate for gruppeB?

Tim,
What MFI are you going to use, 2.4E? How are the throttle bodies, pump, and injection nozzles? Why did you change the crank? How are the 2.4 rods?
I hope you have read Wayne’s stuff and Bruce Anderson’s book. Do you have copies of the ’72-3 parts and workshop manuals, the MFI CMA? Have you copied all relevant Pelican posts? You should have your own personal parts-workshop-specifics manual for your car/engine.

Some trivia: Pay close attention to all the latest mods for your 5R case. Pay close attention to the piston and head combination for proper clearance. Of course piston to valve might be an issue also. What cam and valve were the pistons cut for? If your pistons are designed for 10.5:1 use them that way or carefully more. At 10:1 you have to use high octane anyway, get all of the power out of it you can. A twin plug setup will slightly reduce your octane requirements and will greatly help with smoother running your MFI at idle and part throttle. Of course it will reduce detonation propensity at full throttle. There are some good all-electronic crank fired systems for reasonable price.

Best,
Grady
gradyclay@hotmail.com

Grady,
I"m planning on using a 2.4E MFI pump and stacks with 2.4T t-bodies (bored to 32mm). I've talked with my machinist several times about the single plug/twin plug and he wouldn't hesitate to run the 10.5:1 on pump gas and single plugs. I'm a little hesitent to run a full 10.5:1 on 93 octane gas so I plan on shimming the cylinders back to 10.2 or so. I've talked with rs911T who is running a 2.8L engine @ 10.2:1 with no detonation and my planned engine has smaller pistons.

I've read through every 2.4, twin plug/single plug, hi compression thread there is on Pelican and own/read through both wayne's book and bruce's book.

Really, Tim? I somehow remember Greg mentioning that he thought he had some detonation on pump gas, perhaps even on Sunoco Ultra (94 octane). I could be wrong, but I think he likes to run race gas as often as possible. Once again, I could be wrong so it would be good to hear from Greg. BTW, didn't Grady build Greg's engine?

PS: Can't wait til you get that engine build for the FT!

Jim,
I've PMed him and got the response that he hasn't noticed any pinging and it's been running fine since 1977. Daivd brown at speedwerks said he wouldn't hesitate to run 10.2-10.5:1 on street gas. I'd rather be just under 10:1 but it's either 9.0:1 with my 2.2E pistons or shim up dave's set of 10.5:1 JE's. I was seriously consitering twin plugging but after several talks with my machinist I'm being more convinced that I can run it with just 1 plug.

Sounds good, Tim. Can't wait to see the FT back on the road, terrorizing women and children. :)

Jim: Yes, you are right.

We built the 2.8S in Greg’s car in about 1975. Greg is the third owner and we don’t think the case has ever been split since ‘75. He can tell you how many events he ran last summer and how it still performs. That was one of many 2.8s (92x70.4) built on 2.4 bases. We also did some 3.5s (100x70.4) on 3.0 bases. Almost all were single plug Mahle Nicasil RSR set at 10.5:1 CR and with 0.028” deck and proper squish. Read Bruce Anderson’s book! He, I and JW collaborated on all this back in the late ‘70s. Between Rennenhaus Ltd. and Garretson Ent. lots was going on. It’s amazing what lots of cooperation across the Great Divide can accomplish. BA is THE writer from his days at HP.

Few engines were twin plug due to the high cost at the time. Now that there are choices in crank fire twin plug all electronic ignitions, the cost has come down to reasonable. Had the current systems been available back then, all would have been twin plug. I think that anyone who builds anything above 9.0 CR should seriously consider twin plug. There are so many technical benefits and the only downside is the additional cost of machining for the second plug, changing 12 plugs rather than 6, and the cost of the ignition system. I think it is well worth it and in some cases, absolutely necessary.

Greg (rs911T),
Please post some of my e-mails with you from prior to my system crash last fall. Detonation is an insidious thing as most is undetectable until too late.

I think Greg has been running on the street a mix of unleaded high octane pump fuel with a little leaded race fuel. A little TEL goes a long way. On the track 100+ octane. He can tell you.

Who else now has Rennenhaus 2.8s or 3.5s from that era (’73-’87)? I’m after all to do maintenance rebuilds and add twin plug.

Best,
Grady
gradyclay@hotmail.com


BTW, I retired in '87 and sold the ground to KFC. I'm still kicking.

Only in my dreams! But if anyone wants to send one my way...
http://forums.pelicanparts.com/uploa...1074825118.jpg

Paul,

Yeah, I'm interested in obtaining a set of the flex lines. I gotta' think that Classic tube is using techniques similar to those used for brake hydraulic tube manufacture. Like you, I think the flexible stuff looks very cool.

Stay in touch with availability and pricing.

Cheers, Chris

Jim,
You know those lines would look REALLY nice on Lu's car after you've completed the 2.7 upgrade. Add some nice dual airfilters to finnish off the look.

Yeah, I think you're right Tim. I'll keep an eye on this thread to see when these lines are available. The dual air filters sound good, too, just not sure what to do there. The watershield thread left me a bit confused, but hey, what's new?

Supertec fuel lines and a set of PMO air filters.
Operating pressure 520lb. and burst pressure of 1100 lb @ 500 degrees F.
http://forums.pelicanparts.com/uploa...1178512343.jpg http://forums.pelicanparts.com/uploa...1178512355.jpg http://forums.pelicanparts.com/uploa...1178512378.jpg