Rebuilt sprint engine won't start

[Novocastrian]

Can any engine builders please advise ?<br>
<br>
I have a spark, there is petrol at the carbs and the engine turns over fine but it won't run. I have noticed when the engine is turned over by hand there does not appear to be any suction when I put a hand over the carb mouths. When I put a hand over an exhaust port (where the manifold would sit) for part of the cycle as well as feeling exhaust (as I would expect) I also feel a strong suction. is this normal ?

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[MalcGE]

Can't comment about the suction as i've never tried your 'test'. Assuming that the cam timing is not out (and I don't know if it is poss to be out by 180 Deg on the cam cycle) then I would bet that your ignition timing is 180 deg out and you are firing on your induction stroke

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[tinweevil]

Sound like a thorough recheck of cam and ignition timing would be a good step. <br>
<br>
Where are you?<br>
Tinweevil

<p>1978 <!--EZCODE LINK START--><a href="http://www.triumphowners.com/704">Dolomite Sprint</a><!--EZCODE LINK END--><br>
1968 <!--EZCODE LINK START--><a href="http://www.triumphowners.com/705">GT6 II</a><!--EZCODE LINK END--><br>
1972 Spitfire IV<br>
39 anorak points on the Nicholas scale<br>
</p><i></i>

[alun n]

If you have the cam timing out on a Sprint engine you would be unable to turn the engine over by hand a full 360 degrees without the valves impacting on the piston crowns...unless the valves had already bent as you turned it over on the starter and then I think you'd feel the resistance of the bent valves in the guides. <br>
<br>
More likely your static ignition timing is 180 degrees out or you didn't allow for the rotation of the dizzy as it settles on the jackshaft skew gear.<br>
<br>
I don't understand the suction on the exhaust though. First call I'd check the static timing (scrutinise the inside of the dizzy cap as it is easily mistaken which terminal each lead lands on) and then do a compression test. Actual compressions are less relevant, though I'd be expecting at least 190 psi plus on a recently rebuilt engine; the important bit is they should all be within 5psi of a mean figure.

<p>1973 Dolomite Sprint<br>
1974 Dolomite Sprint<br>
1977 Dolomite Sprint (Pageant)<br>
1977 Dolomite Sprint (White)<br>
1979 Dolomite Sprint<br>
1979 Dolomite 1850HL<br>
1980 Dolomite 1500HL<br>
1998 Lotus Elise<br>
1999 Alfa Romeo 166 2.5 V6<br>
1999 Alfa Romeo 166 3.0 V6 (well...it was there wasn't it!)</p><i></i>

[ALG1K]

I hope you turned the engine over by hand first with no spark plugs in ?<br>
Its so easy to bend all the valves on the starter<br>
COMP TEST

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[bodgerben]

Dunno about the suction, provided the cam timing is ok and the so is the timing, does it attempt to start?<br>
<br>
I went to look at a lads car who had a lovely rebuilt Sprint lump that just would not start, he had fuel and a spark - just not a stong spark - he missed the engine earth strap, added that and away it went.<br>
<br>
Ben<br>
<br>
<!--EZCODE LINK START--><a href="http://www.dollysprint.com" target="top">www.dollysprint.com</a><!--EZCODE LINK END-->

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[Jon Tilson]

is all good. I find a can of easy start is an invaluable diagnostic tool. A quick squirt thru an SU will always lead to a kick and may even run a few seconds if you have good ignition. If you dont even get a glimmeer of life that way you have no spark, weak spark or out of time spark. Just because you have fuel at the float chambers doenst mean the jets arent blocked....See if you can see fuel in the jets by taking the dashpots off.<br>
<br>
How does it sound on the starter? You can usually here 4 even compressions...if one or more is off the starter will vary in speed as it goes past the easy ones<br>
Jonners<br>


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[Mark Larmour]

I will make an assumption here that every thing is correct. The cam timing is correct, igniton timing is correct, you have confirmed that there is spark at the plugs, and the the there is fuel in the cylinders (plugs are wet), and therefore the fuel pump is pumping, then how old is the petrol in the tank?<br>
<br>
From both experience and enquiries from petrol companies, if you are using high octance ULP (98 octane) it has a shelf life of only about 6 weeks before it starts to lose its properties.<br>
<br>
I have a De tomaso Longchamp which has a 5.8 litre Ford V8 which refuses to start if the petrol is a few months old. Also a TR4 that I owned which had a 10.5 to 1 motor and would often sit for a couple of months between starts would also suffered from the same problem.<br>
<br>
So if also else fails look at the simple things.<br>
<br>


<p><!--EZCODE LINK START--><a href="http://www.sprintparts.triumphowners.com">SPRINTPARTS</a><!--EZCODE LINK END--></p><i></i>

[Novocastrian]

Thanks to everyone for taking the time to reply - it's appreciated as there aren't any Dolomite specialists here in Newcastle.<br>
<br>
The engine was turned over by hand many times before trying it on the starter and the petrol is new. It looks like I will be starting by re-checking the engine earth followed by the timing.<br>
<br>
I'll post any news as and when I have any.

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[Novocastrian]

<br>
Had the engine trying to fire today. The H/T leads are probably due for replacement and are of the "silicone" type so I've ordered new H/t leads and a distributor cap.

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[Jon Tilson]

check the rotor arm. Ive had a couple go in recent weeks...but then you get no spark at the plugs, though you do get one if you try the king lead to block trick.<br>
Try turning it over with one lead on a spare plug hanging with the end touching a good earth, like the head. If you get a good spark at the right time then move to the carbs. Even if you have fule at the floats chambers jets can be blocked. Hence easy start is a good diagnostic tool. If it fires up after a good squirt as it will if the ignition is okay it must be fuel starvation.<br>
Jonners

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[Novocastrian]

Thanks for that Jon

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