TheSamba.com :: View topic - Impressive small displacement combo (chassis dyno eval)

Wed Dec 22, 2010 11:31 pm

A few years ago I built a 1679cc (with machine in 88mm cylinders) T1 engine for a friend of mine.. He put 60K miles on it, but decided to graduate up to a TIV engine for his 181 (and never look back!). He ended up donating me the tired RAT 1679 for R&D purposes a year or so ago.

I recently bought a 73 Super with no engine and had planned on throwing a TIV into it, but just haven't had the time to prepare one.. Well my Nephew has been in training with us for a year now, so I decided to have him tear down the 1679, reconfigure it and patch it up for some service in the Super. That worked well since I could stand another daily driver with heat while I finish my 912E revitalization, so I don't have to drive a damn 996 everyday!

So the 60K mile engine was torn down, the only thing that was worn were the camshaft thrust bearings. We honed the cylinders, replaced the bearings, replaced the rings and did a good valve job with new valves. The only changes I made to it was adding an Engle FK-41 Camshaft coupled to a 1.4 ratio rocker, a .035 deck and ended up at 9.6:1 CR.

My Nephew then balanced the assembly and assembled it. We topped it off with a Mallory Uni-Lite Dizzy and an ACE prepped single 40 Dellorto DRLA carburetor. I ran the single to keep the engine super simple and easy to work on. The Ace prepped carb ran perfect out of the box and needed zero tuning to dial in perfectly at both part and wide open throttle.. I only needed to touch the mixture controls.

All in all the cost to reconfigure the engine cost 237.00 to include the new cam and Engle lifters, bearings and rings. I spent more on the carb rebuild than the entire rest of the engine as it was 95% used parts, a true sweep the floor powerplant.

So today my Nephew installed the engine.. We then dumped a healthy dose of RAT Snake Oil Break In oil in the crankcase, fired it up and broke the cam in.. I then took it for a blast up the road and I was amazed! I returned from the blast up the road and rolled it straight onto our chassis dyno where it made the following power.

Now, its been a long time since an engine only made 70RWHP on my chassis dyno and we have never assembled an engine that made less than 100 RWHP on this dynojet. Its kinda of hard to get super excited about such little power, but this engine is REALLY IMPRESSIVE. To create 70 RWHP means this engine is producing 20% more power at the flywheel,(roughly 85HP) now I wish we would have taken the time to bolt it on the engine dyno too!

The torque curve is impressive and extremely flat with a huge concentration of torque below 3,000 RPM, perfect for the tall gearing the Super has as it was previously equipped with a 2270 TIV that loves tall gearing. 75MPH is achieved at only 3,400 RPM between the tall tires and tall gears, but this engine pulls the gear very well, unbelievably well.

I never expected this engine to produce this much power, or to have this level of throttle response with a stock weight flywheel and a single 40mm Dellorto with no port work and simply prepared 041 valved heads.

Even the exhaust system is used and its only a 1-3/8" Chinese system with a single quiet pack... It fits this combo perfectly and appears to have more potential in the top end as the engine is still leaning out up top, not richening up, which generally indicates inefficiency.

I highly recommend this combo for anyone wanting to build a small displacement, great driving, cheap torquer combo. The FK 41 camshaft is really impressive, we'll be watching oil samples from this engine to monitor the life of the new Engle lifters and to continue our oil development... The FK 41 was the cam that was closest to what my camshaft iterator chose for peak torque at such a low RPM when i set up the iteration parameters within the software. It is performing exactly as I expected, and that torque curve reminds me of a TIV!

Its been twenty years since I've driven a ACVW with less than 140HP, but this engine is so snappy and fun to drive, I don't miss the added power as much as I believed I would.. Its not "MassIVe and its not bad ass, but it is simple, does have great heat and didn't cost me anything to create while giving my Nephew more experience. I'll be doing my best to break it for the remainder of the winter!

I expect insane MPG due to the efficiency of this combo and the gearing.. We'll have to see!

Here is the recipe:
69X88
DPR 69mm CT/WT crank
Stock 311B rods
FK 41 cam, 112* LC
.035 deck, 9.6:1 CR static
Single Dellorto 40 with 34 vents
Genuine 041 heads, no port work, competition valve job, port fluffing only
1.4 ratio rocker
Manton pushrods

Thu Dec 23, 2010 12:22 am

Ive read the FK4x cams are hard on lifter bores, did you do anything to strengthen the case?

My 0 deck 1699 with 9:1 compression really surprised the hell out of me as well. pulls really hard and gives excellent mileage.

Do you plan on putting on some 36 or 40 duals and compare power/mileage?

Thu Dec 23, 2010 12:25 am

:D
I love me some 1679's.
Thats whats in my bus now and i love it, going on 15 years with this engine. It was out of my sight for 2 years and now back, refreshed and should be good for another 15 years. Same results, everything inside was great. Case all still std etc etc. Though i did have some lifter pits, so now i have a web cam and lifters. :)

Thu Dec 23, 2010 1:10 am

I don't care if its hard on lifter bores... The cams do have a fast ramp, which is why they make torque.. They make for loud valvetrain, but who cares! If a lifter bore wears so badly that it breaks, I'll laugh..

This engine is mostly all used parts, we even reused the 60K mile center main bearings because they were still good and were steel backed where the new ones weren't!

If the lifter bores start going away I'll see that in the aluminum and magnesium elements of the used oil analysis the engine will get every 1,000 miles like all our other cars.

I don't plan on using this engine for any other test work, no other comparatives, just drive it and carry out used oil samples.. Type 1 development isn't in my blood any longer and probably never will be again..

I wanted to see first hand what the Engle lifters were like. I never dreamed I'd even have another Type one, but it was cheap and got a car on the road that would otherwise be collecting dust.

One thing is for sure, I'd rather have this sweep the floor engine comprised of 95% 12 year old components than any new T1 with todays junk inside it

Thu Dec 23, 2010 1:22 am

jake can you anwer my question below?

Thu Dec 23, 2010 1:33 am

this small engine combo is cool for poor poeple like me, this small motor makes good power for the money and size, compared to poorly build larger motors that arent tuned as well, the motors we run into on the street, the 1776's and 1835's that run like dirt....unbalanced, and untuned...thats pretty cool

Thu Dec 23, 2010 1:43 am

yoshi123 wrote: jake can you anwer my question below?
Didn't see a question-

Thu Dec 23, 2010 1:49 am

not that one i had another question about another topic i wanted you to aswer before i lose what little money i have, look for the thread about running zero deck...plz answer

Thu Dec 23, 2010 4:18 am

wow those numbers @ the wheels is impressive..

i was about to comment on the a/f graph from 4-5k rpm

goin lean = good good effieciency

but then jake knew this before i realized it (as shown by his post hehe)

nice to see these T1 numbers from u jake..

although il bet mainly its cuz of the 12yr old parts (better quality)
attention to detail on the rebuild (by your nephew) + the valvejob

oh and ofcourse Art' touching the carbs , its been known that he does weird good things to carbs hahaha

Thu Dec 23, 2010 4:50 am

btw jake.. quick question

041 heads in stock form with just a good valvejob and fluffing..

does it mean its 39x32 valve size?

Thu Dec 23, 2010 6:33 am

Yes, the heads are stock 041 with 39X32 valves.. Its what I used on the engine 12 years ago when it went into a 181 application and was fed with CIS fuel injection.

This combo seems to be very efficient and it behaves well at all usable RPM. It runs smooth and has torque not generally found with a T1 combo anywhere near this displacement at lower RPM.

My Nephew is well on his way to being another successful Raby.. He worked for me once 9 years ago, but back then he thought I was too much of a hard ass.. The second time around he is proving much more successful.. He has already successfully assembled a Porsche M96 test engine which is no small feat considering he did it with no assistance from any of us here and most Dealership Technicians can't do this correctly.. Still he has a long way to go with lots of challenges ahead of him.

Thu Dec 23, 2010 6:57 am

When I look at Jakes dyno sheets, compared to most T1s posted on the net, I
always seem to notice that his DOESN'T have the 2500-3000 RPM droop that ALL others have!

Look at ANY other T1 dyno sheet and you'll see what I mean! Must be in the heads?

What gives Jake? You holding on to *secrets*?

;)

Don

Thu Dec 23, 2010 8:25 am

Tell me more about the Carb...does the manifold have heat??
Would that carb work on a 1776? I do live in at 6500 and yea it snowed last night.

Thu Dec 23, 2010 8:31 am

Jake, would you mind if Glenn moves your opening post to the "Engines/Builds" section?

Thu Dec 23, 2010 8:38 am

Sweep the foor engines are so fun.... I built an 1835 for a guy in Idaho for a buggy.. Just like Jake it was all used parts, even the cam, and lifters were used bugpack 4061 kit.. it was a budget deal.. Made great power and the guy now has 4 years on it. with a single 40IDF made 85HP..

Some combos and kits just work out well.
It was alot like this one

Thu Dec 23, 2010 9:50 am

Could you please post the cam card for the FK-41?

Thu Dec 23, 2010 10:09 am

I knew as soon as you quoted the combo it was a nice engine Jake. This last Spring we did an engine like that for a local buggy kid on a tight budget and that thing impressed the Hell out of my Nephew and the kid was delighted with it. Lights up his Terra tires easily. I love the lower FK40 series cams in case anyone never noticed. That fk41 is a monster torquer and I don't believe the lifter wear on the lower series will prove bad even with the hot ramps.....better than any VZ series ramp. I won't even consider using an older 87 or 89 cam unless the customer is adamant about it, then the final product is on his head not mine. Nephews are pretty cool once they get a few years under their belts.....mine is for sure, great kid.

RC

Thu Dec 23, 2010 10:26 am

Yes the carb has heat.. I am going to modify the air filter top for even more added heat from the driver's side heaterbox so it'll perform even better in the cold because thats all I'll be using this engine for.. Come Spring it'll get a 2.7 liter TIV as I'll have the 912 revitalized and it has AWESOME heat.

Dstar,
I design combinations to make USABLE power within a concentrated RPM range based on more than just output and making impressive power on the dyno.

I generally start dyno pulls at 1,500 RPM, most T1 builds start pulling engines from 3K or even 3,500 RPM. I wanted down low power to pull the tall gearing the car already had from it's days as a TIV powered Daily Driver. I didn't want to change the trans and I really doubted that a 1679 would pull the gears, but it does well, it even spools up the 5,000 pound rollers on my dyno well in 4th gear..

Thu Dec 23, 2010 3:03 pm

hay rock crusher who the hells jake raby? is he some gear head or something lol lol i kind of like him because he likes single dellortos too lol spencerfvee................................................................................ RockCrusher wrote: I knew as soon as you quoted the combo it was a nice engine Jake. This last Spring we did an engine like that for a local buggy kid on a tight budget and that thing impressed the Hell out of my Nephew and the kid was delighted with it. Lights up his Terra tires easily. I love the lower FK40 series cams in case anyone never noticed. That fk41 is a monster torquer and I don't believe the lifter wear on the lower series will prove bad even with the hot ramps.....better than any VZ series ramp. I won't even consider using an older 87 or 89 cam unless the customer is adamant about it, then the final product is on his head not mine. Nephews are pretty cool once they get a few years under their belts.....mine is for sure, great kid.

RC

Thu Dec 23, 2010 3:11 pm

What is the trans gearing and rear tire?

3.87 with a .93 4th?