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8 & 10 cyl Bristol cars Type 407 onwards - restoration, repair, maintenance etc

Advice opinions please

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  #41 (permalink)  
Old 26-05-21, 02:05 PM
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For eagle eyed readers / those that are interested..Kiley Clinton seem so far to have done an excellent job and I am now leak free on the steering front. Putting it all back together was a lot quicker and easier than taking it out - just under a couple of hours.
As noted earlier, the cills have been attended to but the aluminium covers were beyond saving so am having new ones made up by a chap who seems to be taking an age. He's doing them to the precise shape and so on of the original ones so hopefully not too much fettling will be required.
Have booked car in at end of June for the rumble at the rear to be investigated - hopefully nothing major but I won't know until it's apart.
That's all for now.
Andrew
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  #42 (permalink)  
Old 19-06-21, 11:17 PM
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Did the power steering improve noticeably with the newly fettled rack? I always thought your car was under assisted and wasn't sure if it was wear or adjustment.
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  #43 (permalink)  
Old 20-06-21, 05:02 AM
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Difficult to describe precisely - bit like Goldilocks and the 3 Bears it now seems "just right"!
Head gasket(s) now given up ghost(s) so expect questions/request for
suggestions as to improvements to heads and possibly cams in near future.
The rumble at the rear will have to wait...
Andrew
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  #44 (permalink)  
Old 20-06-21, 07:40 AM
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Regarding heads etc, I think there is a good chance that you already have a slightly hotter cam than standard as I think the parts for the rebuild would have come from the American Car Care Centre who were offering a mildly improved profile as standard at the time. Check cam bearings in the block and make sure the heads have suitable inserts for unleaded along with the right valves.

The heads themselves were pretty good. The breathing was let down by the inlet and exhaust manifolds. The single best improvement for my money would be a Weiand 7503 intake if you can find one. The original cast iron inlet forces the fuel / air mix to make a very tight turn immediately after it leaves the carb. The Weiand is about an inch taller and sweeps round. With the Edelbrock replacing the Carter carb the combined height is very similar to original.

I don't know what is currently available by way of exhaust manifolds but I thought I heard that SLJ had found someone to make an improved version although there is very little room for this without modifying the chassis rails. That was a bit of an extreme option for me.
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  #45 (permalink)  
Old 21-06-21, 03:08 PM
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Heads now off - not great to be honest a couple of valve guides non existent, two bent pushrods, the cam is pretty badly scored and the timing chain is US. On plus side no scoring in bores. Have ordered up cam and followers from States as poly cams not easy to find - the rest of the stuff I can get over here.
Still amazed how well it drove so am expecting great things when all back together again. For the time being am going to stay stock as it was quick before and once it's all working properly it should be even better!
The Weiand inlet manifold I'll keep an eye out for but as you say, they are rare and command big money - likewise SLJ's excellent exhaust manifold - it is a wonderful improvement but its an investment too far for this year (and I'd need to change the exhaust to get the best out of it).
Quick question - what colour was the intake manifold originally? Mines currently red which seems a bit garish. It needs tidying up and was thinking of toning it down a bit - has anyone done similar?
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  #46 (permalink)  
Old 21-06-21, 08:52 PM
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I'm pretty certain all the 318s in 409 and 410 originally had red inlet manifolds.

The Weiand manifold is aluminium and I thought that looked better. To stop it corroding I etch primed it and painted it silver. With any luck I have attached a picture.
Attached Images
File Type: jpg 410 engine.JPG (882.2 KB, 36 views)
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  #47 (permalink)  
Old 24-06-21, 10:53 AM
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Quote:
Originally Posted by David C View Post
I don't know what is currently available by way of exhaust manifolds but I thought I heard that SLJ had found someone to make an improved version although there is very little room for this without modifying the chassis rails. That was a bit of an extreme option for me.
No, SLJs swept exhausts do NOT involve any modification to the chassis rails, but they MIGHT require a small aperture into the wheel arch. They improve the breathing beyond all measure and also reduce the under bonnet temperature as the heat is no longer concentrated right under the cylinder head. They are a very impressive piece of knitting!

Roger M
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  #48 (permalink)  
Old 24-06-21, 10:58 AM
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Thanks for that Roger - they do look brilliant and work even better!
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  #49 (permalink)  
Old 24-06-21, 11:07 AM
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Quote:
Originally Posted by AndrewA View Post
Still amazed how well it drove so am expecting great things when all back together again. For the time being am going to stay stock as it was quick before and once it's all working properly it should be even better!
This seems a good point to repeat my earlier advice, for the sake of others

"The V8 Bristols, even if they are actually in quite a bad state, have so much torque that they cannot help but impress somebody who is used to lesser vehicles. So beware, even though one might seem great at first acquaintance, there may be a long way to go before it is actually up to the mark.

I speak from experience"



Roger M
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  #50 (permalink)  
Old 24-06-21, 06:07 PM
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Thanks...I think! To be fair - head gasket apart - nothing major has come up that wasn't noted in the pre-purchase inspection report as something to be dealt with. The head gasket I put down to very little use over the last 7 or 8 years and then 3500 miles in relatively few months.
No doubt there'll be more bugs to eradicate as the miles roll on but that's part and parcel of taking on new ownership of any classic car.
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  #51 (permalink)  
Old 25-06-21, 07:41 AM
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Andrew,
Have you considered having the cylinder heads compression tested before refitting them?
Brian
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  #52 (permalink)  
Old 25-06-21, 07:55 AM
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Morning - if you mean pressure testing to check the internal structure of the head for cracks and other leaks then yes. If you mean something else please enlighten me!
Thanks
Andrew
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  #53 (permalink)  
Old 25-06-21, 09:55 AM
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Andrew,

Yes, that is exactly what I meant.

I had what I thought was a blown head gasket on my 410 last year but
unfortunately I found a crack in one of the heads. I think the crack may have been caused by the butterfly mechanism which controls the choke in the offside exhaust manifold which was sticking. As I had fitted an Edelbrock carburettor with automatic choke, this device in the manifold was no longer required, hence its removal. With the additional heat build up it had also caused a small hairline crack to develop in the manifold, which fortunately I had caught in time and was able to have it repaired.
I ended up giving my engine a complete top end overhaul including a new timing chain, cogs and water pump.
If you havenít had the exhaust manifolds or the water pump off a Bristol V8 (318 engine particularly) before, please note, some of the threaded holes for the fixing studs and bolts that secure these parts to the heads and block are actually drilled through into the water jacket of the engine and head. These studs and bolts should have a sealing compound applied to the thread prior to fixing. I learnt the hard way!

Brian
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  #54 (permalink)  
Old 25-06-21, 10:40 AM
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Thank you Brian - that's really helpful info and advice.
I'm going to be doing a complete top end rebuild as well - looking through the history it was last apart 20+ years ago and while it's all apart seems a false economy not to.
Another question if I may - I'll be replacing the cam and followers and will be using plenty of cam lube - but a lot of engine builders particularly in the USA recommend using break in oil/running in oil (straight 30W with ZDDP) even with just a cam change.
I don't mind doing it if it really has some benefits - do you or others have a view?

Thanks

Andrew

Last edited by AndrewA; 25-06-21 at 10:47 AM.
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  #55 (permalink)  
Old 25-06-21, 11:46 AM
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Andrew,

I didnít need to replace my cams but after inspecting the cams and tappets, when assembling I poured a small quantity of oil into the cam/tappets prior to inserting the push rods.

You are probably aware that when fixing the timing chain cover the engine sump should be removed to do the job properly. The previous person who had my timing cover off didnít appear to do it and the result was a slight oil leak.

I didnít use any special oil after putting everything back together but I did treat the engine gently for a short time before checking the torque on the heads again and then all was back to normal.

When I was dismantling the various bits off my car, the job was made quite difficult, again by the previous mechanic who used steel nuts on the exhaust manifold (a number of studs sheared off in the head during their removal) and a combination of ďmake doĒ bolts and studs elsewhere, I decided to replace all the nuts, bolts, studs and washers (washers where necessary/required). Replacement brass nuts are readily available for the exhaust manifold with the correct thread.

I am not sure which part of the country you are in but please feel free to give me a call if you need a quick answer when putting things back together. My details are in the members section.

Brian
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  #56 (permalink)  
Old 25-06-21, 12:03 PM
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Thanks Brian
I'm at the southern end of the New Forest so too far to pop round (lucky for you!) but I won't hesitate to take you up on your kind offer if needs be.
Andrew
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  #57 (permalink)  
Old 25-06-21, 12:09 PM
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My understanding is that the flap in the offside exhaust is totally unrelated to the type of choke you have. The choke on the carburettor provides richer fuel to get the engine started. The flap in the exhaust shuts down the offside pipe which means exhaust gasses from that side of the engine have to pass through the inlet manifold and exit via the nearside exhaust, warming the inlet system as they go. As the engine heats up the bimetallic strip opens the offside exhaust and both pipes come into play.

The flap valve should regularly be lubricated with graphite. The easiest way to do this is to use an aerosol of penetrating oil with graphite. A little tricky to find but I have found it on Ebay.
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  #58 (permalink)  
Old 25-06-21, 01:17 PM
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Are you referring to the Edelbrock carburettor or to the original Carter carburettor fitted to the 410 which had the bimetallic strip in the inlet manifold which indeed operated the choke to enrich the mixture?

The choke on the Edelbrock is electrically operated and does not require the gases to circulate around the inlet manifold to trigger the bimetallic strip. I think these V8ís generate enough heat in a very short time to turn off the electric choke on the Edelbrock.
Yes, prior to the Edelbrock installation the butterfly in the exhaust manifold would be closed and the choke on the carburettor would also be closed for ease of starting; as the gases pass through the inlet manifold they warm up the bimetallic strip and open the choke. Hopefully at the same time the heat control valve on the exhaust manifold opens fully.

I appreciate that warming up a cold engine gently but quickly is more beneficial to the life of the engine but once the engine to up to temperature I wouldnít want a sticky heat control valve in the exhaust manifold or additional carbon build up behind the plate inside the inlet manifold giving me unnecessary heat issues. My motto is to keep it simple.
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  #59 (permalink)  
Old 25-06-21, 01:26 PM
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Neither. The bi-metallic strip wound round the end of the butterfly spindle in the valve that shuts off the exhaust.

The type of carburettor really isn't relevant.
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  #60 (permalink)  
Old 25-06-21, 01:33 PM
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I think you are referring to the bi metallic spring that sits in the inlet manifold and operates the choke on the Carter. This is indeed redundant if you go for the Edelbrock with electric choke or indeed a manual choke as was my choice.

The exhaust butterfly has no connection to this. It is a relatively subtle improvement during warm up so if you are anxious it may stick you are probably better to wire it open or remove it. However I never had any issues when using the car regularly. As long as the spindle is kept lubricated the weight is plenty to keep the valve open.
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