View Full Version : Electrics for first engine start

03-12-01, 02:00 PM
I will hopefully be in a position to install my engine at some time before Xmas. Once it's in, I'd like to start it to check it's OK (I've just rebuilt it) could anyone give me an idea of the minimum I need to start it electrics wise and any other bits I should do.
I guess I should connect an oil pressure gauge and a water temp gauge, anything else??



03-12-01, 05:10 PM
Whatever else you do, prime your engine (oil) first before you try to start it - usual way is to get a special shaft to drive the oil pump shaft (distributor0 out) with an electric drill. Make sure oil is peeing out of the rocker area before you stop. Have burnt out two drills doing this - watch for overheating of the drill!! It's amazing just how much power an oil pump absorbs.

Electrics - all you need is a feed to the ignition circuit and a much, much heavier feed to the starter. With an earth return from the block back to the battery. Leave all connections off the alternator - you don't need it for a (want to hear what it sounds like) run. You can just have a wire coming from your starter solenoid and "tickle" it across the battery terminal (love sparks - don't you??). The battery, if well charged up, would be good for 1 hour's running at least, assuming you don't flatten it trying to start the mother.
Have a switch to turn on the rad fan - dont rely on the thermostatic relay. (another circuit to wire up).
oil pressure and water temp gauges essential.

If your engine has non-roller cam followers, look up the recommended way to break them in - it usually involves running the engine at between 2000 and 2500 rpm for 20 minutes minimum, with no stop/starts involved, else you f**k up the cam and followers. Thus you need to be 110% sure of your water connections - most folk have a hose ready to play cold water on the rad if it overheats, and also a fire extinguisher is a very good idea. In fact be sure of all connections and oil etc.

have fun


03-12-01, 05:27 PM

do you have a loom installed ?
is the ignition coil & ballast resistor fitted ? (if needed)
Is it carb or inj ?

03-12-01, 07:05 PM
Have a large box of tissues ready to wipe of the big satisfied grin before you go to work
Paul :7 :7

Purple Ronnie
03-12-01, 07:29 PM
I'm not one to argue with you Wilf, but i'm going to pick up on one point. When the engine is run you must have the alternator connected up or it will s**g it, or you could disconnect the belt to it, but make sure it dosen't drive the water pump. Can someone confirm this for me it's a long time since I did my wiring.

03-12-01, 07:35 PM
I have a Chevy SBC pump primer - it strikes me we might run a club loan system for some of these items that you use once every blue moon but that most folk woulf like when their blue moon comes up.....:7

03-12-01, 07:37 PM
.........and take the air cleaner off or the first backfire through the carb and you'll be forking our for a new one!
How do I know?:-(

03-12-01, 09:35 PM
Sorry to flat contradict you Ronnie, but if the alternator has no exciting current, it won't generate any voltage at all, since they are not designed to have any residual magnetism in the rotor, unlike a dynamo which depended on that to get it charging. (that's why you had to "flash" a new one to make it work). So long as you leave all the connections off it should not come to any harm. If you wanted to be ultra cautious you could actually ground out the relevant connection (i.e. the exciting one, and I don't mean one that gets your juices flowing.)Good point you made tho' - you do need the fan belt in place to run the water pump!!

When I first ran my old lump I did not connect up the alternator at all, with no ill effects (other than deafness from the open headers).


03-12-01, 09:53 PM
Hi Wilf, Can one really f$*k the cam and followers up I am worried, I have a rattle problem on my SBCV8 New cam fitted and followers but on original start up there was a bad misfire due to float level problems with meant that the engine was started ran for a few seconds and shut down again, Eventually after a few goes and some adjustment the thing ran fine for 20-30 minutes.Cam should be ok shouldn't it there was loads of oil prevoiusly primed and cam lube. My rattle could be old domed racing pistons as they are wrong type and skirts could be rattling in bores as well as to higher compression. I looked at cam followers and lobes and they look ok to me.


03-12-01, 10:11 PM
Actually, my old electrical engineering knowledge is (slowly) returning - what I meant to say above is "residual magnetism in the field coils", not the rotor. Must be correct don't you know?


03-12-01, 10:22 PM
Graham - this is one of those areas where cam manuacturers will get all het up if you don't follow their instructions. The reason being that a "flat" (i.e. non roller) tappet has to bed into it's particular cam lobe, and they are designed to rotate in use. Rotation can only be guaranteed above certain engine revs, as can sufficient oiling, as the cam lobes are usually lubricated only be "splash" from oil dripping from the hydraulic cam followers (or tappets), or oil draining back into the valley from the heads.
Although you may have put lots of cam lube on, this will wipe away in the first few revolutions.

having said all that, I am utterly convinced that most newly - built engines don't roar into steady life first time out, a bit like your own. So it's probably one of those things you will get away with if you are lucky. If, like me, luck only arrives in the bad type, you won't!!

You say you have looked at the wear surface of your cam followers - if they all look the same, they are either all F****d, or all alright, the latter being the most probable. If one was not right, (trying to avoid that f word again here), it would, in all likeliness, make one hell of a knock, not a light rattle. I would look at the preload settings on your followers before thinking about the pistons - it's easier and cheaper!! I assume you have flat, hydraulic tappets, else all I said is bo**ocks!!
With roller rockers, no run in period is necessary, and they can also be swapped from lobe to lobe, unlike flat'uns. You did put them back in exactly the same places didn't you??


Purple Ronnie
04-12-01, 08:23 PM
Then, may I stand corrected.

04-12-01, 09:09 PM
Ronnie old pal, you may stand in whatever position suits you best!!
At least we can contradict each other in a logical and civilised fashion - very British don't y'know? And far more gentlemanly than some I could mention, but won't since that would be ungentlemanly.

BTW - sold your bike yet?


04-12-01, 09:19 PM

Cheers mate for your help, Yeah I thought I paid quite a bit of attention to preload and checking and adjusting a second time made things run quieter but still the medium deep rattle. Have had the heads of anyway. Let me run this by you then, I have 69cc big vale heads and according to the chart in Vizards book tis would equate to a CR of 9.9:1 with flat top pistons but I have discovered (iI bought this as an ex racing lump) that I have domed pistons probably racing type (not sure if cast or forged) so my CR would be sky high now wouldn't it, cam is 265 hydraulic (according to Rigman no valve overlap) so could I be detonating or amplifying a worn piston skirt problem? I think I need to changed them to something more sensible and check and replace bottom bearings and check conrods.

Going back to cam lobes How is it best to check for lobe failiure, can it be done visually?

Cheers for now


04-12-01, 09:48 PM
Graham - difficult to be exact about CR without knowing the exact spec of your pistons, if they are KB (or silvolite), try looking them up on their website - their listings give CR's with various CC heads etc. A lot depends on the measurement from gudgeon pin to piston top - you could actually have a lower CR than you think, depending on this measurement. If they are that different from the flat top items, what's happening to your valve/piston clearances? Did you check it out with the old "Plasticine dollop on top of the piston" trick?
Ultimately, if you don't know precisely what you are getting from your pistons, you can't really be sure whats happening. You could at least check out piston/bore clearances just by measuring to see if piston slap is a problem. I think something around 8 thou is the usual max clearance piston/bore, but find out what it should be for your engine specifically.
I would not think that detonation could occur at tickover or very light throttle openings unless something is really really wrong.

It is more likely that an ex-race engine could have much higher CR than would be suitable for the road, and also probably have far more piston/bore clearance than you might want. With ally heads, you can often get away with more CR than with Iron heads. Have heard of US friends who get away with 10:1 or more on pump petrol. If I were to respec my own engine, I think I would try for a little more CR - It's 9.5:1 right now, quite conservative.

If you have acute lobe failure on your cam it would be obvious - the tip of the lobe would be scored, and the entire width of the lobe would be marked. The base of each follower should be very slightly convex - if it's concave then its u/s. For a cam that's only run for a little while like yours you shouldn't see any significant marking on the lobes - a light wear pattern is there should be, and that not across the entire width of each lobe (remember convex followers?). From what you have said so far, I think it far more likely that any top end rattle is valve preload rather than cam failure. JMO, of course.


04-12-01, 10:27 PM
Who,hey,what,hello...what time is it?did someone mention my name?have i been asleep?:-)

05-12-01, 09:34 AM
...the reason you shouldn't let a new cam with conventional lifters idle is simply that the loading on the cam nose is greatest at low revs - that , combined with the minute point of contact , makes things a bit fussy initially !


05-12-01, 09:39 AM
If it is any consolation then when I broke my engine in (it's an unfortunate term isn't it!) I had a couple of stops as I first had a problem with the distributor cap and then fuel feed. I also didn't quite get twenty minutes in either as it started to over heat due to other problems. All a bit stressful if I remember rightly. Anyway, I've had no problems since so don't worry, you'll almost certainly be OK!


05-12-01, 09:41 AM
my bit....

You're proabaly OK with most alternators if you run-up the engine with the alternator disconnected. However, NEVER disconnect an alternator from the battery when the engine is running - this can definitely cause regulator damage but again will depend ultimately on regulator design.


05-12-01, 09:14 PM

cheers for info once again. I did have top end rattle which I largely cured with more preload adjustment (the roller rockers are 1.52:1 by the way) but still got a different medium rattle lower down and centrally which is why I kept on about piston wear or camshaft wear or even cam bearings. I am going to ispect everything as I have gone this far and see if I can see an obvious problem. If I find a problem then I am happier as I can address it as a probable reason.

Changing the subject a question for you on my cylinder heads, whilst all seem fine(checked guides, valve seating etc) though 'cause they are dated as 1962 early 327 heads (my block is later 1976) they look as though they dont have hardened valve seat inserts and I doubt chevy had hardened seats as standard at that time. What do you think? run with LRP or have heads done?

cheers again


Thanks for not laughing at my Chevy engine aswell!

05-12-01, 09:42 PM
Graham - when I first started using my engine I got all woried, like you, about its somewhat rattly, even "knocky" top end. I readjusted the preload (twice),using a very rigorous procedure that absolutely guaranteed I was on the base circle for adjustment and it quietened down some. Still has a hollow sounding light "knock" from the top/middle end somewhere, I have now realised that it's normal, and being amplified by the cast ally rocker covers which are, apparently, notorious for this. Roller cams can also add to the din, having very sharp initial ramps compared to a flat tappet cam (that's why they are "better" - they get the valve lifted more, earlier).

Without being able to see/hear your engine running, I can't go any further - if you feel it's bad enough to tear it down and investigate, then go right ahead. With those dodgy pistons it might make sense, and I can sense that you are not really happy with them. Have you had it really hot yet? By which I mean WOT for 5 miles and then listen to it?
If you do strip it down, when you check for piston slap, have a look at the small ends as well, I don't know if you reconditioned them. As a rule, race engines are built with far wider clearances than road engines (because they don't care about getting 100,000 miles out of them, but do care about reducing friction). Small end knock could sound like what you are describing. Many full race engines sound like a bag of spanners in a biscuit tin when they run.
I can't advise about the heads - I am most emphatically not a Chevy expert, just love engines. And I don't laugh at Chevy engines, I just spit at the thought of them in Cobra replicas!!!

Lots of Luck


06-12-01, 07:27 PM
Cheers Wilf and Rigman, I'll let you know. Wilf I understand where you are coming from I will try to not mention the word Chevy (oops) I'll just mention 'American V8 engine'. I just want to acheive an engine to work adequatly, go and sound ok and I am a happy man, who knows next time I may try a Ford (oooh lovely word that eh Wilf). Seriously thanks for you advice though, much appreciated. OOh Ford OOH.


Purple Ronnie
06-12-01, 08:05 PM
Wilf, no I haven't sold the bike yet. When I look at it I'm pleased I haven't, but when I look at the GD, so close to being finished, I wish I had. Still Rob might feel sorry for me and make a donation. :7

06-12-01, 09:35 PM
Graham - I think you might do well to speak to a few others using this site about their medication - even I don't get that excited about a Ford! (although Robert does seem to get rather hormonally involved with his chassis).

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