Mysterious SBC Oil leak
Discussion
Sounds like you have no time to sort this. So maybe Charles Dunn is the way forward. But I will still bet that it is the seal or lack of it between the back of inlet manifold and valley end plate. I ended up after 2 failed attempts using a high build silicone type sealer from 3bond to properly close the @1/4 inch gap there. However there was a tiny hole between the inlet manifold gasket and the head where oil could leak through as well. The comments about loads of oil ending up in the valley under high rpm are also correct because now I have a small leak from the distributor entry point. I am fitting a 4 stage oil pump to my new engine but wonder if adding another suction point at the back of the valley might be a good idea. I know that you checked for this leak but i was amazed at where oil ended up that was coming from there.
Mark - I have a horrible suspicion you're right! I hate to admit defeat but time, inspiration and patience have all run out on me. I don't normally take the 'give it to the man' route as I perceive it as a failure but 'needs must' it's currently leaking like a pig and driving me crackers 😭. Just hope that Mr Dunn (or similar) can fit me in.
Do read my earlier posts in this thread, particularly Page 2.
Sealing the Kinsler valley closing plate between magnesium manifold and aluminium engine block can be a b....r and even good engine builders can sometimes struggle to get a good seal seal owing to metal creep
Kinsler do make a pair of alloy fillers in different thicknesses which look a bit like stretched "s" shapes and are made to the shape of their own manifold. They are not shown in the Kinsler catalogue, so you will have to call Kinsler direct in USA (ask for Earl, their technical guy). Earl is very helpful, and will explain how to stop your leak, but essentially you will be removing the manifold, dummy fitting the whole assembly back together so you can accurately work out the thickness of the gap between the Kinsler valley closing plate and the top of your Rodeck block which you need to fill and seal. I would use good quality silicon RTV, black of course, to match your Kinsler manifold.
You do need to do the dummy fit exercise to get accurate measurements because the gap on every SBC is different depending on your combination. Fill the remaining gap with RTV, and DO NOT attempt any final "little adjustments" whilst the whole lot sets. Obviously measure up during your dummy fit with any gaskets you intend to use in final fit (compound angles between the two heads and the valley closing plates). Then once assembled get the runners bolted down and torqued and leave it till the next day.
Take great very care with your Kinsler linkages, and you'll have to check the synchronisation of throttle plates between each bank (another fiddly and time consuming job) when you re-assemble, and very likely have to make a minor adjustment here and there to get your engine idle back and somewhere sensible.
Whoever fixes your oil leak will have to go through this same process, and if you have built your own car very likely you can do all this yourself without the wait and associated cost of repair. Kinsler customer services are excellent and you'll generally get small items like these filler plates within 2-3 days. So you can be back out enjoying he car by next sunday if you get your skates on.
Of course this cures your oil leak (if done properly), but does not solve the problem of continuous higher engine revs leaving too much engine oil sitting in the valley plate waiting to drain back down. That particular problem can usually only be solved by using a third scavenge stage, which would mean taking the Kinsler closing plate off again (repeating the whole process) and machining the closing plate at the very front to get access for a third oil scavenge.
Probably decision time if you are looking for a one-time fix.
All small block chevy's leak a little - it's in their nature!
Sorry I didn't get back on to this thread sooner, but they don't generally let me out often.
Andrew
Sealing the Kinsler valley closing plate between magnesium manifold and aluminium engine block can be a b....r and even good engine builders can sometimes struggle to get a good seal seal owing to metal creep
Kinsler do make a pair of alloy fillers in different thicknesses which look a bit like stretched "s" shapes and are made to the shape of their own manifold. They are not shown in the Kinsler catalogue, so you will have to call Kinsler direct in USA (ask for Earl, their technical guy). Earl is very helpful, and will explain how to stop your leak, but essentially you will be removing the manifold, dummy fitting the whole assembly back together so you can accurately work out the thickness of the gap between the Kinsler valley closing plate and the top of your Rodeck block which you need to fill and seal. I would use good quality silicon RTV, black of course, to match your Kinsler manifold.
You do need to do the dummy fit exercise to get accurate measurements because the gap on every SBC is different depending on your combination. Fill the remaining gap with RTV, and DO NOT attempt any final "little adjustments" whilst the whole lot sets. Obviously measure up during your dummy fit with any gaskets you intend to use in final fit (compound angles between the two heads and the valley closing plates). Then once assembled get the runners bolted down and torqued and leave it till the next day.
Take great very care with your Kinsler linkages, and you'll have to check the synchronisation of throttle plates between each bank (another fiddly and time consuming job) when you re-assemble, and very likely have to make a minor adjustment here and there to get your engine idle back and somewhere sensible.
Whoever fixes your oil leak will have to go through this same process, and if you have built your own car very likely you can do all this yourself without the wait and associated cost of repair. Kinsler customer services are excellent and you'll generally get small items like these filler plates within 2-3 days. So you can be back out enjoying he car by next sunday if you get your skates on.
Of course this cures your oil leak (if done properly), but does not solve the problem of continuous higher engine revs leaving too much engine oil sitting in the valley plate waiting to drain back down. That particular problem can usually only be solved by using a third scavenge stage, which would mean taking the Kinsler closing plate off again (repeating the whole process) and machining the closing plate at the very front to get access for a third oil scavenge.
Probably decision time if you are looking for a one-time fix.
All small block chevy's leak a little - it's in their nature!
Sorry I didn't get back on to this thread sooner, but they don't generally let me out often.
Andrew
Andrew - thanks for your super detailed post! I've spoken with Earl previously and agree his knowledge and kinslers after sales care is EXCELLENT. I think the idea of buying their filler plates is a great idea (I'll order some on Monday). Whilst I'm perfectly capable of doing to work my patience (but more importantly my time) has run out. Having removed the kinsler assembly it was oil tight - but a couple of hours on the dyno was enough to undo my work 
.
Regards the additional oil scavenge I think this would be ideal BUT as the car will predominantly running on the road the opportunity for extended full throttle applications is limited (to say the least).....
The guy I'm sending the car too knows his way around a SBC so this coupled with the kinsler 'fillera' should maximise my chances of curing the big leak..... I can live with the engine sweating a bit of oil - part of their charm???!?
. Regards the additional oil scavenge I think this would be ideal BUT as the car will predominantly running on the road the opportunity for extended full throttle applications is limited (to say the least).....
The guy I'm sending the car too knows his way around a SBC so this coupled with the kinsler 'fillera' should maximise my chances of curing the big leak..... I can live with the engine sweating a bit of oil - part of their charm???!?
If your Ultima is predominantly a road car, then when you re-install your Kinsler runners and go on to synchronise your throttle linkages, you will need to close down the throttle plates right down to maybe about 2.5 to 3 thousandths of an inch gap, to reduce the air intake sufficiently to get a decent idle. Intuitively, you could not imagine such a tiny gap would allow a 6.7 litre engine to even run! But these are huge throttle plates, and you only need the tiniest gap. Also backing off the ignition advance on your map by 5-6 degrees at 500 and 1000 rpm cells will have this snarling beast of an engine just purring like a kitten at 900-1000 rpm or so. Magic!
Whilst you are on the phone to Earl, Kinsler also make a simple airflow meter called syncflow (or something very similar) which allows accurate measurement of the flow into the runners. Balancing the flow bank-to-bank perfectly definitely improves engine response, and this clever bit of kit makes balancing a doddle. Balancing can normally be a really fiddly job which can eat up your dyno time, but the Kinsler flow kit saves you or your builder loads of time.
Co-incidentally, I've been tuning a Kinsler EFI set up on the RR this afternoon and a 3 stage dry sump (i.e directly similar to your own set up) and I can still see a little weeping on the valley cover plate at the rear. Even with the Kinsler filler plates installed it seems you won't avoid a little "sweating" on the dyno because the engine is working very hard, and there is so much lightly-pressurised oil accumulating in the valley. But I know categorically that this same engine used in a normal day-to-day road environment doesn't normally leak here, so I'd be fairly confident that using your engine on the road you shouldn't really have a problem once you have your little tweeks installed.
Best of luck.
Andrew
Whilst you are on the phone to Earl, Kinsler also make a simple airflow meter called syncflow (or something very similar) which allows accurate measurement of the flow into the runners. Balancing the flow bank-to-bank perfectly definitely improves engine response, and this clever bit of kit makes balancing a doddle. Balancing can normally be a really fiddly job which can eat up your dyno time, but the Kinsler flow kit saves you or your builder loads of time.
Co-incidentally, I've been tuning a Kinsler EFI set up on the RR this afternoon and a 3 stage dry sump (i.e directly similar to your own set up) and I can still see a little weeping on the valley cover plate at the rear. Even with the Kinsler filler plates installed it seems you won't avoid a little "sweating" on the dyno because the engine is working very hard, and there is so much lightly-pressurised oil accumulating in the valley. But I know categorically that this same engine used in a normal day-to-day road environment doesn't normally leak here, so I'd be fairly confident that using your engine on the road you shouldn't really have a problem once you have your little tweeks installed.
Best of luck.
Andrew
Have been taking my engine part today. I can say that the product that I used sealed the 6mm gap that I had perfectly with absolutely no trace of any weep at all from there. When taking off the inlet it was the last bit to come unstuck and took some unsticking! My problem now is that oil is weeping from around the distributor boss. I can find out what the stuff was if anybody is interested but basically a thicker version of gasket in a tube made specifically for sealing large engine gaps. It remained flexible but stuck to the metal very well!
I have used normal PU sealant with success (Wurth Bond N Seal as used by the factory).
I build a wall of it and cover it with clingfilm then put the inlet in place without gaskets.
When it is part cured I take off the inlet and clingfilm and see how good a job I have done and if needed trim or add additional sealant. Leave to cure then assemble in the normal way with the gaskets and another bead of sealant along the top of the new wall.
Steve
I build a wall of it and cover it with clingfilm then put the inlet in place without gaskets.
When it is part cured I take off the inlet and clingfilm and see how good a job I have done and if needed trim or add additional sealant. Leave to cure then assemble in the normal way with the gaskets and another bead of sealant along the top of the new wall.
Steve
Three bond 1217H
http://www.threebond.co.uk/Products/ThreeBondSeala...
http://www.threebond.co.uk/Products/ThreeBondSeala...
Edited by MarkWebb on Tuesday 2nd June 13:01
[quote=MarkWebb]Three bond 1217H
http://www.threebond.co.uk/Products/ThreeBondSeala...
Thanks Mark - looks like 1207B, may be an even better bet "and works effectively for the joint surfaces that have a larger clearance." I'll pass the recommendation onto Charles Dunn - who'll hopefully be able to take the car in next week.
http://www.threebond.co.uk/Products/ThreeBondSeala...
Thanks Mark - looks like 1207B, may be an even better bet "and works effectively for the joint surfaces that have a larger clearance." I'll pass the recommendation onto Charles Dunn - who'll hopefully be able to take the car in next week.
Update
So the car is now with Charles Dunn and the bad news arrived late yesterday
......With the engine removed and a list of remedial/preventative jobs listed (valve stem oil seals, valve spring check etc., etc.,) a leak down test was conducted and two cylinders on the left hand bank were much lower than all the rest (either a s a result of overheating or bore wash (or both!)). Nothing for it but to fully strip the engine to ascertain whether this is a rebore OR can be remedied with a light hone and a set of rings.
This has forced me into a decision - this is a very highly specced race engine and is not really suitable for the road. Essentially I think I need to sell the engine (either in component form OR rebuilt) and put the proceeds towards an American Speed 'crate engine' in a lower state of tune and thus more durable. 640 bhp is nice BUT not if it's going to bankrupt me.
The other option would be to sell the car as a rolling chassis (£28k?), "just add engine" + the engine (again either in components or rebuilt), lick my wounds and give up.
So my question(s) to the group is a) does anyone know about the market for a SBC race engine (I'll try and contact Peter Knight to discuss with him today) and b) does anyone have a SBC kicking around they'd sell me - only interested in one that doesn't need any work?
Yours, dejected, frustrated, poor and in the dog house with the wife :smile:
Edited by Nabbott on Wednesday 1st July 08:17
Morning Nigel
If you are happy with the car less the engine then I would sell the engine when it comes back from Charles Dunn, rebuilt no miles with that mega spec would possibly suit a hill climb or drag racer. I would replace with a fuel injected LS3 or 7. As another option to AS you can buy from Partsworld and have the bits to make it connect to an Ultima from AB. Keep smiling mate, it's a journey to get the car to suit you and it doesn't have to be done straight away. I can feel a winter project coming on with yours.
Roj
If you are happy with the car less the engine then I would sell the engine when it comes back from Charles Dunn, rebuilt no miles with that mega spec would possibly suit a hill climb or drag racer. I would replace with a fuel injected LS3 or 7. As another option to AS you can buy from Partsworld and have the bits to make it connect to an Ultima from AB. Keep smiling mate, it's a journey to get the car to suit you and it doesn't have to be done straight away. I can feel a winter project coming on with yours.
Roj
If you have got pressurisation of the sump then this may well be the cause of your initial problem, but finding where the oil is leaking from due to the pressure would be nice too.
It doesn't sound like there is an easy and inexpensive fix.
If you can get a rebuild-cost-versus-sale-value from Charles on the existing engine would be a starting point. I suspect the former could be similar to the latter, so no win.
Cheapest fix would be another SBC. Everything would fit and it would be almost plug-and-play. Finding a good one is the problem.
Going LS is the long term solution but is a more costly and involved solution as many more changes will be needed other components.
Good luck.
Paul
It doesn't sound like there is an easy and inexpensive fix.
If you can get a rebuild-cost-versus-sale-value from Charles on the existing engine would be a starting point. I suspect the former could be similar to the latter, so no win.
Cheapest fix would be another SBC. Everything would fit and it would be almost plug-and-play. Finding a good one is the problem.
Going LS is the long term solution but is a more costly and involved solution as many more changes will be needed other components.
Good luck.
Paul
Nabbott said:
..................we're in the process of moving (next few weeks) and I have a house (and garage!) to build as first priorities! ...........
I guess you've answered your question there......unless you can get CD to down rate the engine on rebuild and sell off the Kinsler etc to off set costs or phone around a couple of tuners to see if anyone's got an engine they'd like to swap or maybe swap the Kinsler for a manifold and carb. The only thing I've got sitting around is an old 750 Holley that'll need a rebuild. The LS route I guess is out as it'll be way more than the rebuild cost with all the extra bits you'll need plus a lot of ear bashing you could probably do without!Good luck
Graham
I feel that the cheapest option if the block is not a write off would be to rebuild what you have and then "destress" it by fitting a new cam and springs to give less max power better torque spread & less max revs. Keep the kinsler unless you have massive probs with it. You will then have a less stressed more drivable motor whilst keeping all the top spec parts which will then run well within their capability. A new lower spec'd engine will be built to a price with lower spec parts.
Mark the issue is that the entire engine has been built for max BHP. Thus the heads, cam and fuel injection are all spec'ed together. Just 'downing' the cam would mean the engine was Massively over throttled and the heads would be 'wrong' - resulting in a poor tuning motor. I spoke with Peter Knight at length yesterday. His advice was to strip it, rectify the two bad cylinders and then sell the engine as a 'kit' to be assembled by someone wanting a trick SBC race engine.
He's of the opinion that the assemblies are worth £6k 'all day long' - which would provide me with sufficient funds to buy a turn key engine from American Speed.....
He's of the opinion that the assemblies are worth £6k 'all day long' - which would provide me with sufficient funds to buy a turn key engine from American Speed.....
Gassing Station | Ultima | Top of Page | What's New | My Stuff