Vee Engine Woes a.k.a. What I hate!

Pulled the engine out of the Vee the other day.
The suspension steering and brakes are sensational but the engine just lacks any ooomph! Plenty of revs, 6700@ valve float but just no grunt.

So pulled the engine with a view to taking it up to a M8 to do the cam timing.
Its carrying 3.5 degrees retard along with the big carb throat, short header pipe lengths and radical valve geometry and is set up with the likes of Phillip Is in mind where the engine performed well.

I pulled the oil pump and the rest of the paraphernalia off and had a look at the cam gear.
For whatever reason i rotated the crank a bit and the cam was not following as it should????? In fact winding the engine over with no plugs resulted in some ominous "clonks" at various intervals...................
Bugger it, there is about 0.50mm backlash in the gear!!!!!!!! yep, about .040".
Along with the 3.5 degrees of retard dialed in to the cam results in quite a bit of cam retard.
Interesting thing is that the tooth backlash varies around the circumference of the cam varying from almost nill to half a mm depending on the area of mesh????????

Anyway, needs a cam gear to start with so strip the fucker, first thing off is the ally sump extension and the remaining oil in the bottom is all nice and reflective........................(this is going to hurt).

Anyway, pulled the entire engine down and the cam gear and crank gear are badly worn, the cam bearings are lunched and the rear main bearing has eaten some rubbish and is worn and badly scored. Fortunately, the crank is undamaged.
Thought id better check the big ends and they are pretty sad as well altho the crank pis are spotless.

Some days its not woth getting up!

So, Im clobbering up a bastard of an engine with my old bottom end and my new top end.
I advanced the cam timing 1/2 degree from stock and Im using my longer 1&3/8" pipes along with my smaller carb. The radical rocker geometry has been calmed down with a set of shorter pushrods and different rocker shaft shims.

Motor will be assembled tonight and hung back in the chassis on the weekend.

L8tr
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L8tr
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Finished the motor this arvo but didnt have time to install it in the chassis.
No real surprises in the buildup apart from getting the correct crank float.
I ended up using the flywheel and clutch from the new engine as the clutch cover was located by rollpins.
After machining the fly to minimum weight, there is no positive method of locating the clutch cover accurately.
The flywheel that belongs to this engine had no dowele locating the clutch cover and there was over a millimeter clearance in the cluch cover bolts so the only way of actually centering the clutch was by eye! Damned iffen I know how the original engine builder aligned the clutch cover. mebbe he didnt!
Anyway, Id rather not mix and match fly's and clutches but shit happens.

Anyway, the point i was on about was that the "new" flywheel and the old flywheel had the same dimensions regarding the relationship to the thrust face and the clutch mounting face but when i tightened up the gland nut there was no crank endfloat at all. The crank turned smoothly but no float at all made me a bit nervous so i found a crankface shim about .004" and that brought things close enough.

Ill reinstall the engine tomorrow morning after the race starts and give it a kick in the guts.
L8tr
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Well, Baskervill has come and gone.

The "bastard" engine i clobbered up out of bits and bobs turned out to be a pretty tough race engine which gave little away to just about anything else!

I loaded her up with some el-cheapo multi-grade from the supermarket and didnt make the first race in time. That another story.....!
I ran it in in the second race and by crikey this thing stomped well from low down!
It needed the valves adjusted after the race but plug colours revealed quite a nice story going on in there.

Anyway, onto Sunday, fired it up again and i had some of the most cracking racing I have ever been in with muitple car dices, position swaps, late braking and other shenanigans. All completed with inches of room to spare with no stupidity.....danm it was fun. hats off to the guys i raced with all day.

What pleases me most was lowering my PB lap time by close to 2 seconds!!!

Its all the more sweeter whn you factor in my combined weight is 35 kilos over the class weight! Im also using the tallest (1.22) of the 3rd gears available to us and still the car gives little away to the rest up the very steep Baskerville hill!!
Im going to puill the box and fit a 1.26 third i have laying about which hopefully give it a little more up the hill!

Very happy supervee i can tell you. Im tempted to leave the "bastard" in the car now!

L8tr all
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You need a camera TSV

Ahhh yer ur right M8.🙄🤓🙄🤓
I always have the best intentions of clicking away and.........wellll........... I end up with the job done and the lights out and I think....hmmm pix!
My bad!
L8tr
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tassupervee wrote:What pleases me most was lowering my PB lap time by close to 2 seconds!!!

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Well done ! have you had a chance to run your vee on the dyno and get some output figures ?
I have just started helping Chris Bolton from Sydney with his vee and we had it on the dyno several weeks ago . We dont know at this stage what is inside the engine as Chris only purchased the vee 6 months ago , but the horsepower figures are down compared to other vee's up here . It showed a maximum of 42bhp @ the rear wheels in 4th gear . Other vee's have been known to have as much as 52bhp from a 1200cc engine .
We are not going to open Chris' engine up to check it , we will keep it as a spare engine as it is still sealed .
I am going to build him a new engine for next season and expect much better results .

Wayne
Thanks for the nice words M8!!

Dyno? Ummm nah M8
I had every intention of dynoing it before I ran it but just ran out of time.

I know my "new" engine (the rooted one) produced 49 HP.

An important thing to consider tho is eaxctly "where" the engine produced its torque peak.

if the engine is revving like mad to make power its functionally useless unless you are running at P.I.

The engines simply will not sustain the revs at the torque peak for long enough to actually exploit those power figures.

Another trap is the manner in which the dyno figures were arrived at.
Its a no brainer that just some subtle massaging of the dyno can result in some interesting output figures.
If you are getting 42 Hp on the same dyno with the same operator as those supposedly 50Hp plus engines then its worth investigating.

Lemme know what you guys find out.

L8tr
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