Quote:
Originally Posted by potential
I think this subject is worthy of a thread of its own. I don't have the experience you do with the cars but my understanding from what I'd read was that the engines were stripped down and 'blueprinted' - no parts changed from factory but rebuilt to aircraft engineering standards with all tolerances and torques at optimum and all the castings cleaned up. It's likely this is an optimistic view of what happened.
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Firstly I should point out that I have no personal experience with the 5.2 litre engine used by Bristol. However, I think it would be reasonable to assume that Bristol did not “blueprint” Chrysler engines as you describe above, because the cost would have been prohibitive, (it would also be hard to blueprint an engine without replacing some parts). Nor do I think Bristol ever claimed to do this. It's more likely down to some ignorant journalist with an overactive imagination.
As author Rick Voegelin says, "Blueprinting is without question the most used - and most abused - term in engine building."
Quote:
Originally Posted by potential
Has any mechanic or engineer who worked in Bristol ever talked?
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Yes.
Denis Sevier, Bristol’s chief engineer gave a lecture at a Bristol Owners Club meeting in 1976. Mr Sevier apparently explained that when Bristol started using the Chrysler 5.2 litre engine from Canada they (Bristol) installed stronger valve springs, a higher lift cam shaft and a 4 barrel Carter carburetor (commonly referred to as the Power Pack option offered by Chrysler).
He said Bristol also designed a mod for the early Torqueflight transmission extension housing to replace a plain thrust washer with ball bearing race. This reduced heat build up in the bearing on long trips and the mod was adopted by Chrysler.
Mr Sevier’s lecture also covered later cars such as the 411/412 which used the US Chrysler B block engines, but no mention was made of any changes to these engines by Bristol. It wouldn’t have made any sense for Bristol to modify them anyway, because higher spec production versions were available “off the shelf”
Even in basic spec these engines produced considerably more power than the 313/318 A series engines used by Bristol in the 407-410 and it begs the question why didn’t Bristol use the B block engines from the outset.
Quote:
Originally Posted by Claude
In 1995 I bought an engineless LHD 405 from Jim Rogers …. He cited one issue related to the early V8 engine where Chrysler had about 40 engineers on it, and when they visited Filton to check out what Bristol had done, they found two blokes with slide rules who were doing more than Chrysler's 40 man team.
It may be that some of the police specials and hot rod parts came compliments of British engineering.
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Ha ha, that's quite a leap Claude, from a quaint but improbable story suggesting Chrysler’s engineers were incompetent, to Bristol developing some of the higher performance engine mods used by Chrysler. I take it Jim wasn’t actually one of the Chrysler engineers he talked about!
Chrysler were producing "Police Specials" years before Bristol even contemplated using Chrysler engines. The term "Police Special" has also been widely used over decades and applied to all manner of car components.
As for the "hot rod parts", the old A series engine (used by Bristol in the 407-410) was dismissed by performance enthusiasts (because it wasn't very 'tunable') who either used Hemis, or the B block engines that were introduced in 1958, until the LA series engines came long in 1964. The LA smallblocks were used extensively by racers due to their high efficiency and relatively low cost.
As for Bristol’s contribution to Chrysler’s engineering, in his book A Private Car, Leonard Setright mentions the Torqueflight mod devised by Bristol. He also spends numerous pages praising Chrysler's "thorough engineering" and says they were "years ahead of the field". Given that Setright was one of Bristol's greatest fans, I think if Bristol had contributed significantly more to Chrysler’s engineering, then we would know about it.
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.