Special 313 engines? - 407 and 408 MK1

[Connoisseur]

Hello - I'm writing an article for the magazine and I'm trying to find out whether the Chrysler A series engine used by the 407 and 408 MK1 was in some way modified from the standard Chrysler engine. I thought the best thing to do would be to ask an owner or anyone who has experience of the 313 cu inch engine used by Bristol. There are many myths about this and I'm trying to find what is the truth. Can you help?

[David C]

I think this depends upon what you mean by a standard engine.

The 313 in the Bristol was Canadian built and offered slightly different options from the USA plant. These engines would be supplied with what could be described as standard equipment of a 2 barrel carburettor but the option chosen by Bristol was for a Carter AFB 4 barrel.

I don't know if Bristol had any custom modifications done prior to delivery or whether they made any modifications prior to fitting the engines in the cars but there are accounts of modification to the Torqueflite gearboxes. From memory one of the modifications was to prevent overheating in the tailshaft.

I read recently that Chrysler sent over far more reps to Bristol than would be expected for a customer of that size. Supposedly this was due to the high quality of engineering feedback they received from the Bristol engineers.

I look forward to hearing what you discover on this subject. There is plenty of rumour and speculation but it's quite difficult to get hard facts.

[John Keighley]

I recall reading an interview with Tony Crook published somewhere and in this, he mentioned that although the Chrysler people had expectations of an engine life of around 100,000 miles, Bristol were expecting far more than this and enlarged oilways and among other things, a slightly warmer cam was added. The article said that the V8s were Bristolised for whatever that entails. What I don't know is if this was also applied to the 318 engines.

[Stefan]

Several different stories about this. Bristol only ever used tiny numbers of these engines so it's hard to expect Chrysler to " send engineers over".
Syd Lovesy told me " we just put the ancillaries on"- though there was a comment about extra sump baffling to prevent oil surge.
I understand a standard high output version was used by Bristol- "Police Chief Special" has been mentioned. Certainly there is lots of opportunities for performance tuning of these cleverly cast , tough and long lasting blocks.
One version circulated is that the Chrysler gearbox was ordered for testing- and arrived with a V8 attached- which Filton liked , at a time of sudden economic austerity.
Once the factory correspondence is sold off by the liquidators ( delayed by further legal action) and the Heritage Trust has a chance to obtain it all,
we will know a lot more and will have original documents as references.
. Meantime only shadowy rumours....

[David C]

I just found my reference. Page 260 of Christopher Balfour's "A very British Story"
This suggests Bristol engineers did some development of oil baffles that was later adopted by Chrysler. If so, no information on whether this was just Canadian built models.
It would be interesting to compare late 1950s Poly engines with those from the end of the 60s and even early LA models that shared bottom end components.

[David C]

A little further research - Page 118 of Setright's Bristol Cars and Engines - suggests more customisation but he refers to a Hemi head although it was polyspherical or semi-hemi. He also states that Bristol threw out the hydraulic lifters and substituted mechanical lifters but a bit of research on A series / Poly forums suggests that there was nothing unusual about solid lifters on stock US or Canadian 313 engines of the period.
So, as Stefan says, more shadowy rumours... If Setright could get it wrong only 15 years or so after it happened we will indeed have to wait for more factory correspondence to get a better idea of what really went on.

[Kevin H]

Originally Posted by David C

A little further research - Page 118 of Setright's Bristol Cars and Engines - suggests more customisation but he refers to a Hemi head although it was polyspherical or semi-hemi. He also states that Bristol threw out the hydraulic lifters and substituted mechanical lifters but a bit of research on A series / Poly forums suggests that there was nothing unusual about solid lifters on stock US or Canadian 313 engines of the period.
So, as Stefan says, more shadowy rumours... If Setright could get it wrong only 15 years or so after it happened we will indeed have to wait for more factory correspondence to get a better idea of what really went on.

David, if my memory serves me correctly, I believe Setright recanted some of his claims in Bristol Cars and Engines in his later book, "A Private Car - An Account of The Bristol". In particular the story about the hydraulic lifters.

I believe Bristol had a habit of using superceded Dodge/Chrysler engines when they first started using V8s. They were virtually unknown in the UK at the time and Bristol were very happy to allow them to be shrouded in mystery. They alluded to improving or Bristolising the Chrysler products
which contributed to this. To be fair, Bristol were not the only expensive car makers at that time who stretched the truth a bit!

I wrote this many years ago:
If anyone wants to read more about the origins of the 313/318 engines I can recommend Automobile Quarterly Vol 32 No.3 in a 16 page article titled "Maple Leaf Mutants - Chryslers North of The Border". It's an interesting article, but it's so difficult to extract the exact facts from it could have been written by Setright, although it wasn't.

The article makes it pretty clear that the Canadian Chrysler owned brands were never allowed to be as good a spec as the US cars. So the Canadian Plymouth/Dodge mutants - the "Plodges" - always got engines and other features which were in US Chryslers a year or two before. Although it doesn't specifically say this in the article, I'd say the US simply didn't want the Canadians to have an engine which appeared to be the same as a US engine. So in Canada they made the 313, which was effectively the same engine as the 318 in the US. In another example of this policy, they also made some high performance 303 V8s in 1955/56 in Canada which were exported exclusively for US cars and not available in the local Canadian market. So, while the Canadian Plodges got the Super Red Ram 313 in 1957, the equivalent cars in the US were being sold with the first B series engines. The Canadians got the 245 bhp Power Pack version of the 313 in 1958, which of course the V8 Bristol started using in the early 1960s.

[Kevin H]

Originally Posted by Connoisseur

Hello - I'm writing an article for the magazine ...

Which magazine?

[Connoisseur]

I've done quite a lot of research so far, so have come across nearly everything mentioned so far (and more) apart from Setright contradicting himself as I don't have his later book. However, getting other thoughts on the subject is really useful. Getting to the truth is very tricky, but I have drawn some conclusions... but they may change. Kevin H - I've not been able to track down "Maple Leaf Mutants - Chryslers North of The Border" online. It would be very useful if you could point me in the right direction. It's for the BODA magazine.

[Connoisseur]

Hello Kevin H - I've found a copy of Automobile Quarterly Vol 32 No 3 and ordered it. Thank you!

[Kevin H]

Originally Posted by Connoisseur

It's for the BODA magazine.

Will your article be published in a publicly accessible part of the BODA web site?

Or will you publish it here as well?

[Connoisseur]

Hello Kevin - It's in the paper edition of the magazine. It's not actually directly about the Bristol myths, but I will be covering that topic within the article.
It's in four parts. Part one is due to be printed, part two is at the research stage. Once it's published I try and make it publicly accessible one way or another.

[Geoff Kingston]

Guy Drummond wrote a very interesting article in the Boc bulletin number 37 headed "How special are our Chryslers? (or Plymouths?), the bracketed question related to the fact that in Canada and the US the smaller engines tended to be reserved for the Dodge and Plymouth lines rather than Chrysler despite the fact that the companies were all part of the same family. Guy was a Q.C. who if I remember correctly lived in Canada and at the time owned a 410 and before that a 408. The following extract may be of some help.



" The trouble is that the word 'special' admits of too many shades of meaning and allows too many misconceptions to be inferred. I say this because it's my contention that there is absolutely nothing special or unique to Bristol about the version of the 313/318 used by them -- nothing whatever !

The 'standard' engine had a 2 bbl carburettor and a 9:1 compression ratio giving 240 hp. SAE (note , not 250 ). Through the model years 1960-1962 (possibly before probably not afterwards) certain Plymouths and Dodges were available from the factory fitted with a 'Power Pack' engine.

The only changes were (1) a 4 bbl carburettor and appropriate inlet manifold (2) slight changes in the ignition advance curve (3) a camshaft giving a little longer opening period, a little more overlap and 20 thou more lift. Incidentally, I've compared the valve timing figures given by Chrysler for this Power Pack engine with those given by Bristol --- they are identical. This Power Pack engine is exactly what we have in the Types 407--410 with no alteration that in any way affects its output or adjustment.
Someone may point out that the Bristol version is really special --on my own admission-- because it wasn't offered by the factory after the 1962 model year. But all this only goes to illustrate how confusing that word can be!
One further notion seems to be that Bristol had the engine specially fitted with mechanical instead of hydraulic tappets. The fact is that the Canadian engine standard or Power Pack -- was never available with hydraulic tappets until about 1967, when the engine was completely re-designed and the polyspherical head scrapped"



Certainly some years ago when I had a major engine rebuild undertaken on the 313 in my 408 nearly all the parts for the rebuild were obtained off the shelf from Competition Cars of Hainault, only exception was a new crank and shells bought directly from Bristol Cars. There was no indication at all at that time that the engine had in any way been modified by Bristol's the only issue was that compared to the 318 the 313 was a rare engine over here but thankfully the parts were mainly interchangeable except for the crankshaft.



Geoff.

[Connoisseur]

Thank you Geoff, that's very helpful.

[Roger Morrall]

I haven’t researched this but it seems likely that at that time Commonwealth preferences meant that it was significantly cheaper to buy from Canada than from the US of A, hence the use of the Canadian engine which then got talked up by that consummate marketeer Tony Crook.

As far as I know nobody has yet come up with confirmation that Bristols modified the engines in any respect.

[Kevin H]

Originally Posted by Geoff Kingston

Guy Drummond wrote a very interesting article in the Boc bulletin number 37 ...

From memory Mr Crook wasn't very happy about that article.

Ironically it was this very subject (whether or not Bristol modified Chrysler's engines) that started a row between Mr Crook, BOC and your's truly and led to the formation of the BEEF mail list (Bristol Enthusiasts Email Forum), then this forum website.

[Nick Challacombe]

When I came to rebuild my 407 , 313 engine because, I think, very poor quality Irish petrol on a tour in Southern Ireland had caused one piston to loose its rings and scour the block.
When investigating the supply of 30th oversized liners in turned out to be far cheaper to use 40th pistons which were std on the 318. Every other dimension was the same.
I therefore think my engine is a 318 in effect. Not that relevant but I though interesting given the subject.

[Connoisseur]

Originally Posted by Kevin H

From memory Mr Crook wasn't very happy about that article.

Ironically it was this very subject (whether or not Bristol modified Chrysler's engines) that started a row between Mr Crook, BOC and your's truly and led to the formation of the BEEF mail list (Bristol Enthusiasts Email Forum), then this forum website.

I'd better be diplomatic in my article. Even if Bristol didn't do some of the things suggested there is probably more to this than first meets the eye.
Still quite hard to fathom out myth from fact here.

[Connoisseur]

Originally Posted by Nick Challacombe

When I came to rebuild my 407 , 313 engine because, I think, very poor quality Irish petrol on a tour in Southern Ireland had caused one piston to loose its rings and scour the block.
When investigating the supply of 30th oversized liners in turned out to be far cheaper to use 40th pistons which were std on the 318. Every other dimension was the same.
I therefore think my engine is a 318 in effect. Not that relevant but I though interesting given the subject.

That is interesting about the piston size...
Also that must be the worst petrol ever supplied if you need an engine rebuild when you use it. Do you mind if I hope you don't mind I use it in my article?

[Geoff Kingston]

This link on the Canadian engines I think throws up a lot of interesting information which supports the points Guy put forward, somewhere I have and at the moment can't find a lot of information on the parts and specifications of the 313 and 318 units which I came across when trying to help someone find parts for a 313. I found out some years after my 313 was rebuilt that the heads would have fitted a 318 block which would have been a cheaper option. The 313 after the rebuild ran beautifully and cemented my admiration for these V8's
especially after managing 17000 miles running mostly on seven cylinders because straight out of college I couldn't afford the engine rebuild. Like Nicks engine when mine had been re bored and fitted with a set of high quality pistons it too was probably approaching 318 cu ins.
Geoff.

https://www.allpar.com/threads/canadian-engines.229915/